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Hi,
I am LW1ECP, this is my 1st post. I love to design and build anything at home, my main limitation is lack of time to make solder smoke.
I'd like to build a sweeper for my home bench. I have an unused Si5351 board but it generates squarewaves. I could purchase one based on the AD9851 but its range is more limited. I know there are more advanced alternatives but importing in my country has important restrictions and taxes at present.
Where I worked in the late 70s, I used to play with a Wavetek 2000, a sweep/signal generator covering 0 to 1400MHs in 3 bands. It was based on heterodyning two oscillators. So I thought about building something like that. For now it could cover 0 to 200MHz, with DIY VCOs and mixer.
I got tired of searching the web for something like that.?Trying to duplicate the Wavetek circuit is quite involved. Can anyone point me to a more modest design?
Thank you.
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Hi, Daniel, My first post here also as I just found the list. I strongly recommend a tinySA or nanoVNA H4. Just make sure you don't get a clone. So check the [email protected] list for legit sellers. Erik designed both. They produce a square wave (Si5351), so you need a low pass filter for the band of interest. A 3 element Cauer will suppress all harmonics by -50 dBc or better. The photo shows a pair of tinySAs, one as a sweeper and the other as an SA using peak hold. The filter was designed for 40 m. You can get similar results for filters using a nanoVNA H or one of the quality variants. Erik's nanoVNA H4 has the advantage that you can also load FW to do phase and frequency analysis and a larger screen. The particular tests you want to make and your current T&M kit make a proper answer difficult. If you don't have a VNA, which I'd expect to be the case as you are seeking a sweeper without mentioning use case, you absolutely should buy a nanoVNA H or H4.
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Phooey. Hit the wrong button. Here are sweeps of the 40 m LPF using a pair of tinySAs and a nanoVNA H4.
I have 3x tinySAs and a nanoVNA H and nanoVNA H4. The reason for having so many tinySAs is as signal generators for a Field Day RF bench setup with Owon HDS272S DSO/DMM/AWG, DMM and various mixers, filters and a noise source.
These noise sources are quite good, though I see the price has gone up since I bought mine. They are quite flat out to about 1 GHz according to my HP 8560A.
The BG7TBL noise source is junk. Search on EEVblog using advanced search using "noise source" user rhb and titles only and you should find my test results.
I do quite a bit of testing of low cost RF stuff from China, much of which I have posted to EEVblog "rhb" is my user name. I also post a lot to the qrptech and qex lists.
Have Fun!
Reg
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Daniel,
A sweeper is of no use without a receiver of some type. An explanation of your intended use case would be very helpful.
My first suggestion for building one would be to use a pair of AD4351 square wave generators with switched low pass filters boards such as the QRP-Labs offering:
An alternative choice would be an AD4351 and a AD9834 or similar AD based DDS, Sweep the DDS and step the AD4351 after each DDS sweep.
I'm very interested in your quest and spent a lot of time pondering the subject before realizing I was now an old man and could buy anything I wanted for the simple reason I saved as much money as I could while I was working. I'm looking forward to your replies.
Have Fun!
Reg
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Reg, thank you for your interest on my topic! I am an old man too (66), I saved as much money as I could too, but the economic situation on my country is bad and I need to keep working after having retired (and I'm lucky I keep a job yet). I do know this is no place to talk politics, but so that you understand me, I am forced to mention the government tries to reduce debt by hindering imports, in a nutshell. If you are interested, I can elaborate more by private email.
And most electronics stores don't even know words such as "Amidon", "Minicircuits", "Analog Devices", etc. Their main interest is in sourcing components for digital systems and for repairs. For example, you can easily get Tx transistors just because they die and have to be replaced, BUT toroids never fail, so they aren't a common item.
Last but not least, I CAN afford to purchase those little wonders such as NanoVNA or TinySA, but I can't justify them in the face of my family, with a salary a fraction of those in USA or EU, I would use them only occasionally and an anticipated criticism would be why I spend in something that won't make any money. On the other hand, spending money on building or purchasing radios and making communications, a tangible usefulness, would make more sense for them.
That said, now you can understand better why I am resorting to old tech solutions. I would also enjoy building every stage. I do know I will face some inconveniences such as MHz versus time nonlinearity, and I will have to use birdy markers in order to find the frequency. One initial use will be to check HF response of DIY wideband transformers, a modest Ge diode detector plus 3/6/10dB attenuator will suffice. But if the opportunity to make more serious measurements ever comes, you can rest assured your advice will be taken very into account!
Daniel Perez
LW1ECP
P.D. Detector? Do you want to know an unusual detector? When I had the Wavetek 2000 at work, in order to get some decades in detection range I used an spectrum analyzer with its sweep frequency very different from that of the sweeper, in peak reading memory mode, and waited for the curve to fill valleys. Crude, a far cry from using a tracking generator, but I could get usable info even about an SSB filter.
El martes, 15 de agosto de 2023, 12:18:54 ART, Reginald Beardsley via groups.io <pulaskite@...> ±ð²õ³¦°ù¾±²ú¾±¨®:
Daniel,
A sweeper is of no use without a receiver of some type.? An explanation of your intended use case would be very helpful.
My first suggestion for building one would be to use? a pair of AD4351? square wave generators with? switched low pass filters boards? such as the QRP-Labs offering:
http://qrp-labs.com/ultimatelpf.html
An alternative choice would be an AD4351 and a AD9834 or similar AD based DDS, Sweep the DDS and step the AD4351 after each DDS sweep.
I'm very interested in your quest and spent a lot of time pondering the subject before realizing I was now an old man and could buy anything I wanted for the simple reason I saved as much money as I could while I was working.? I'm looking forward to your replies.
Have Fun!
Reg
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Hello, if I - a fellow old coot - can help by forwarding components from Hungary or Slovakia, let me know. 100g of Components, tracked, from SK is like 5USD shipped. Might beat customs Tam On August 16, 2023 6:01:10 AM GMT+02:00, "Daniel Ricardo Perez via groups.io" <danyperez1@...> wrote:
Reg, thank you for your interest on my topic! I am an old man too (66), I saved as much money as I could too, but the economic situation on my country is bad and I need to keep working after having retired (and I'm lucky I keep a job yet). I do know this is no place to talk politics, but so that you understand me, I am forced to mention the government tries to reduce debt by hindering imports, in a nutshell. If you are interested, I can elaborate more by private email. And most electronics stores don't even know words such as "Amidon", "Minicircuits", "Analog Devices", etc. Their main interest is in sourcing components for digital systems and for repairs. For example, you can easily get Tx transistors just because they die and have to be replaced, BUT toroids never fail, so they aren't a common item. Last but not least, I CAN afford to purchase those little wonders such as NanoVNA or TinySA, but I can't justify them in the face of my family, with a salary a fraction of those in USA or EU, I would use them only occasionally and an anticipated criticism would be why I spend in something that won't make any money. On the other hand, spending money on building or purchasing radios and making communications, a tangible usefulness, would make more sense for them. That said, now you can understand better why I am resorting to old tech solutions. I would also enjoy building every stage. I do know I will face some inconveniences such as MHz versus time nonlinearity, and I will have to use birdy markers in order to find the frequency. One initial use will be to check HF response of DIY wideband transformers, a modest Ge diode detector plus 3/6/10dB attenuator will suffice. But if the opportunity to make more serious measurements ever comes, you can rest assured your advice will be taken very into account! Daniel Perez LW1ECP P.D. Detector? Do you want to know an unusual detector? When I had the Wavetek 2000 at work, in order to get some decades in detection range I used an spectrum analyzer with its sweep frequency very different from that of the sweeper, in peak reading memory mode, and waited for the curve to fill valleys. Crude, a far cry from using a tracking generator, but I could get usable info even about an SSB filter. El martes, 15 de agosto de 2023, 12:18:54 ART, Reginald Beardsley via groups.io <pulaskite@...> ±ð²õ³¦°ù¾±²ú¾±¨®: Daniel, A sweeper is of no use without a receiver of some type.? An explanation of your intended use case would be very helpful. My first suggestion for building one would be to use? a pair of AD4351? square wave generators with? switched low pass filters boards? such as the QRP-Labs offering: http://qrp-labs.com/ultimatelpf.html An alternative choice would be an AD4351 and a AD9834 or similar AD based DDS, Sweep the DDS and step the AD4351 after each DDS sweep. I'm very interested in your quest and spent a lot of time pondering the subject before realizing I was now an old man and could buy anything I wanted for the simple reason I saved as much money as I could while I was working.? I'm looking forward to your replies. Have Fun! Reg With best regards Tam HANNA -- Enjoy electronics, 3D printing and cigars? Join more than 21000 followers on my Instagram at
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??
Hi Daniel,
Couple suggestions that may help your project
I second the QRPLabs Ultament U3 plus low pass filters for GPS local oscillator and or rf sweep generator
Along with a common diode es dc meter make a very nice 'calibrated' radio freq power meter
???? https://www.aa5tb.com/qrpmeter.html
Very nice PC soundcard scope es spectrum analyser es sweeper
????? https://www.zeitnitz.eu/scope_en
Of course sub radio frequency but very handy for tuning CW filters
72 73
John
N3AAZ
FM19 on DELMARVA Peninsula
ps...
I too just found this site
If being an 'ole-frt' qualifies to post...hi HI :>)
op 1941
ham 1956
retired 1997
Check my? qrz.com? page for current project
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Daniel,
My mother used to say my father carried a pair of Vise Grips in his pocket to squeeze the pennies and I was the same way until I was in my mid 60s. I literally spent years pondering how to make an SA on the cheap.. Just not as clever as edy555 and Erik. My sister and husband stayed with me for 8-9 months while I worked to make Mom & Dad's house wheelchair accessible. He went downhill so rapidly from Parkinson's associated dementia that I cut my purse strings and now enjoy more high end HPAK & Tek lab gear than I have a place to use it.
My single strongest electronics passion is low cost T&M kit. The tinySA and nanoVNA have fulfilled those needs
The method you describe is how I achieved the filter result shown using a pair of tinySAs.
Most of my electronics efforts were while I was in grad school 35 years ago. All I had was a 5 MHz recurrent sweep Heathkit scope, VOM, DMM and a 5 V supply I built and a 12 V supply I bought for $1 and fixed by replacing the regulator for a total cost of $1.20. I noted that on the bottom of the supply with a marker. I attemtped to build a DC 40 m receiver, but couldn't get a signal. I suspected that the input filter was wrong, but had no way to test it until years later when I picked up a proper scope and an 8601A 100 MHz sweeper.
You are pursuing the same goals as I am. As I have the luxury of a very well equipped RF lab I am focused on testing stuff from China and the performance of my own projects.
Time permitting, I'll attempt to replicate and measure performance as you work on your sweeper design. The easy way would be a pair of AD4351s, mixer and some filters. However, those would cost as much as a nanoVNA. However, they would be more capable.
I have been assembling a large collection of RF modules both from top line US makers and Chinese ebay stuff. The goal is to be able to build any sort of test kit such as a VNA, SA, etc by connecting the right pieces.
Have Fun!
Reg
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Daniel,'
As you have an Si5351 I'd like to suggest examining using a fast (e.g. Potato Chip) TTL part with sub 1 ns rise time to increase the harmonic content to over 1 GHz, filtering the unwanted harmonics and. mixing the two Si5351 outputs. This would require some MCU programming, but my initial examination suggests that with proper choice of frequencies and mixer you could sweep the Si5351 from 10 kHz to 1 GHz with relatively little effort.
I plan to work on the frequency plan some more tomorrow to eliminate some gaps in my attempts. today. A tinySWEEPER looks to me to be a viable Si5351 project from 10-100 khHz TO 1 GHz. That would be a huge boon to the RF community..
Have Fun!
Reg
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Reg,
Interesting idea. It would require a tracking passband filter as frequency is sweeped, to select the desired harmonic. But I fear you should need to have selected the 15th harmonic in the range of, say, 1500 to 2500MHz and mix it with 1500 fixed, in order to cover 0...1000.
I had thought of something like that but with a single PLL. As varactor tuned filters can't span much more than 1:3 frequency, two or more should have to be switched in and out if 1 or more decades range are needed. There would be an unavoidable amplitude and phase transient during the handoff, sweep should have to be stopped until stabilization, and the detector should have to be instructed to ignore during the transition.
If the transients can be tolerated, e.g. ignoring them by software after the detection, there is another possibility: instead of multiple tracking filters, have multiple VCOs, phase locked to the Si5351 thru programmable dividers
I am thinking while writing... Why not combining both ideas? Get 1500...2500 from a single VCO, phase-lock it to 94...156MHz thru a /16 fixed divider, mix it with 1500 locked from another 5351 output.
Lots of ideas, little free time...
Daniel LW1ECP
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Show quoted text
El jueves, 17 de agosto de 2023, 23:17:08 ART, Reginald Beardsley via groups.io <pulaskite@...> ±ð²õ³¦°ù¾±²ú¾±¨®:
Daniel,'
As you have an Si5351 I'd like to suggest examining using a fast (e.g. Potato Chip) TTL part with sub 1 ns rise time to increase the harmonic content to over 1 GHz, filtering the unwanted harmonics and. mixing the two Si5351 outputs.? This would require some MCU programming, but my initial examination suggests that with proper choice of frequencies and mixer you could sweep the Si5351 from 10 kHz to 1 GHz with relatively little effort.
I plan to work on the frequency plan some more tomorrow to eliminate some gaps in? my attempts. today.? A tinySWEEPER looks to me to be? a viable Si5351 project from 10-100 khHz TO 1 GHz.? That would be a huge boon to the RF community..
Have Fun!
Reg
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Daniel,
I need your mailing address! I'm not licensed so I can't look up your address on the call lists. I hope to correct that soon, but am too busy playing with other toys.
I intend to send a pair of tinySAs and a nanoVNA as they are so versatile. There is also the possibility of designing useful accessories such as filters for using the tinySA as a signal generator. A 5th order Cauer is very effective if designed carefully. Please send me your lab inventory so I have a better idea of what should be most useful to you. I've sent nanoVNAs to other people in the UK and EU as a "Thank You" for having designed useful OSHW/OSSW kit that I use. So I should be able to order from China for delivery to Argentina without too much trouble.
A bit of personal history. I "retired" at 54 in 2007 to move to Arkansas from Houston. The move took 7 months and 3 28' tractor trailer loads. I disposed of one trailer load of stuff in Houston.
Dad's health was failing and as the eldest child as well as the closest it was my duty. I also wanted very much to get away from Houston because of the crime and hurricanes.
I sold my house for $500 below asking price on 23 June 2008 a few weeks before the credit markets froze and Ike hit Houston. The area in which I lived was without power for 3 weeks. Houston summer without AC is very grim.
I had worked as a contract research scientist/programmer since 1992 and was well known in the oil industry having missed 3 annual Society of Exploration Geophysicists meetings in 28 years. I was absolutely confident I'd get work once I was unpacked. I have a 5000+ volume technical library, computers, etc. Plan was to spend 1 week a month in Houston and do the rest of the work from Arkansas. But alas it was not to be. I deeply miss the the social aspect of working and have suffered from severe depression from the technical social isolation in a village of 7000 where the ham radio club doesn't even discuss radio at their meetings.
There is also a personal visceral component. Dad's big passion was radio, but he also had a lathe, mill and woodshop all fully stocked with parts organized in labeled bins. At age 42 his employer moved us from NYC to Bluefield, West Virginia (Dad was selling coal processing equipment) and then 2 years later decided to move us again. Dad quit and we moved to Arkansas to speculate on real estate and operate a restaurant. Dad lived another 49 years, but never had anything better than a bit of space with a very disorganized portion of his shop equipment available. Before the moves he was building 5-6 radios and T&M projects a year or more judging from the detritus he left. So between my frustrations with lack of proper T&M kit and realizing what happened to Dad, designing low cost electronic T&M kit is an all consuming passion for me. However, Dad left me almost 1000 sq meters of stuff in several commercial buildings a meter or so deep with which I have been grappling for 15 years. I'm finally getting close to the end. I've boxed up an initial shipment of vacuum tubes to a dealer. After the 1200-1500 tubes are gone I will start on the passive components, sorting and inventorying them to sell to a dealer.
When Tom Oldbury (tom66) contacted me via EEVblog asking for DSP assistance with his DSO project I was delighted and we had a lot of fun working together. He did all the work. I simply provided advice and assisted with expenses. I bought a 2nd hand iPad for Tom and we used Facetime audio and MS Whiteboard to conduct technical conversations. Not quite as good as a whiteboard in the same office, but very close. Do you have access to an iPad and iPencil? If not. I shall investigate getting one for you so we can carry on proper technical discussions more easily. The goal is to have fun playing with a shared project.
Back to the sweeper project. As an example, a pair of ADF4351s, one fixed at 2 GHz and the other sweeping from 2 - 4 GHz would require 2 fixed filters, a 2 GHz low pass and a 4 GHz low pass to cover the kHz to 2 GHz range. There are lots of ADF4351 VFOs with the ability to sweep, but none produce sine wave output. It's under $40 for a pair of ADF4351 boards from China which leaves only the filters, mixer and a suitable MCU (e.g. Arduino, STM32, MSP430, etc). All of that is cheap from China.
This is your project. I am merely here to assist as I can and you request. Though I reserve the right to supply items I deem important to your working efficiently.
Aside from the $4000 I expect to get for the bulk of the tubes, I have 24 VT-4C/211s and 42 VT-52/45 specials. The former sell for $1000 to audiophools and the latter are running $300-400. I have ordered a uTracer 6 and plan to curve trace all the tubes and sell them on ebay with the measured curves for each tube in a set plotted on the same graph.
The graph will be publication quality so they can put them in a matted frame to show off. That's just entertainment for me. The real value is having the commercial space cleared so my sisters and I can sell the property. It's just play money for me. I already have a suite of HP, Tek and other top tier stuff that had a $750k list in the mid '90s. All acquired for well under $30k. Having only bought a single new vehicle, a base model 1993 Toyota pickup for $7800 in my entire life, the lab is the new car I didn't buy.
I'd like to note that so far as I know there is no low cost means of curve tracing transistors except the Peak DCA75 which is painfully slow. There's not a lot to one and a well designed unit sold exclusively through R&L and a few other ham radio dealers might be commercially viable.
Another potential product is an in-circuit capacitoror tester. I have several LCR and ESR meters, but the EDS-88A is the only one that actually works in circuit.. However, it's rather pricey.
In closing I want to emphasize that you are not under any obligation whatsoever. If you develp the next major piece of low cost test kit that's fantastic. If nothing happens that's OK. Life is unpredictable and often turns out very differently than we expect.
I am not a gambler and have never bought a lottery ticket or placed a bet. Simply not interested as I can calculate the odds. In this instance I can't calculate the odds of success. I'm really just bribing my way into someone to talk to.
Have Fun!
Reg On Thursday, August 17, 2023 at 10:50:25 PM CDT, Daniel Ricardo Perez via groups.io <danyperez1@...> wrote:
Reg,
Interesting idea. It would require a tracking passband filter as frequency is sweeped, to select the desired harmonic. But I fear you should need to have selected the 15th harmonic in the range of, say, 1500 to 2500MHz and mix it with 1500 fixed, in order to cover 0...1000.
I had thought of something like that but with a single PLL. As varactor tuned filters can't span much more than 1:3 frequency, two or more should have to be switched in and out if 1 or more decades range are needed. There would be an unavoidable amplitude and phase transient during the handoff, sweep should have to be stopped until stabilization, and the detector should have to be instructed to ignore during the transition.
If the transients can be tolerated, e.g. ignoring them by software after the detection, there is another possibility: instead of multiple tracking filters, have multiple VCOs, phase locked to the Si5351 thru programmable dividers
I am thinking while writing... Why not combining both ideas? Get 1500...2500 from a single VCO, phase-lock it to 94...156MHz thru a /16 fixed divider, mix it with 1500 locked from another 5351 output.
Lots of ideas, little free time...
Daniel LW1ECP
El jueves, 17 de agosto de 2023, 23:17:08 ART, Reginald Beardsley via groups.io <pulaskite@...> ±ð²õ³¦°ù¾±²ú¾±¨®:
Daniel,'
As you have an Si5351 I'd like to suggest examining using a fast (e.g. Potato Chip) TTL part with sub 1 ns rise time to increase the harmonic content to over 1 GHz, filtering the unwanted harmonics and. mixing the two Si5351 outputs.? This would require some MCU programming, but my initial examination suggests that with proper choice of frequencies and mixer you could sweep the Si5351 from 10 kHz to 1 GHz with relatively little effort.
I plan to work on the frequency plan some more tomorrow to eliminate some gaps in? my attempts. today.? A tinySWEEPER looks to me to be? a viable Si5351 project from 10-100 khHz TO 1 GHz.? That would be a huge boon to the RF community..
Have Fun!
Reg
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Quick reply: please wait a little, I am consulting a couple groups on how to send it, otherwise there is the risk of Customs charging in the order of its cost. What is your idea, e.g. FedEx, USPS, etc.?
El viernes, 18 de agosto de 2023, 11:27:43 ART, Reginald Beardsley via groups.io <pulaskite@...> ±ð²õ³¦°ù¾±²ú¾±¨®: Daniel, I need your mailing address! I'm not licensed so I can't look up your address on the call lists. I hope to correct that soon, but am too busy playing with other toys. I intend to send a pair of tinySAs and a nanoVNA as they are so versatile. There is also the possibility of designing useful accessories such as filters for using the tinySA as a signal generator. A 5th order Cauer is very effective if designed carefully. Please send me your lab inventory so I have a better idea of what should be most useful to you. I've sent nanoVNAs to other people in the UK and EU as a "Thank You" for having designed useful OSHW/OSSW kit that I use. So I should be able to order from China for delivery to Argentina without too much trouble. A bit of personal history. I "retired" at 54 in 2007 to move to Arkansas from Houston. The move took 7 months and 3 28' tractor trailer loads. I disposed of one trailer load of stuff in Houston. Dad's health was failing and as the eldest child as well as the closest it was my duty. I also wanted very much to get away from Houston because of the crime and hurricanes. I sold my house for $500 below asking price on 23 June 2008 a few weeks before the credit markets froze and Ike hit Houston. The area in which I lived was without power for 3 weeks. Houston summer without AC is very grim. I had worked as a contract research scientist/programmer since 1992 and was well known in the oil industry having missed 3 annual Society of Exploration Geophysicists meetings in 28 years. I was absolutely confident I'd get work once I was unpacked. I have a 5000+ volume technical library, computers, etc. Plan was to spend 1 week a month in Houston and do the rest of the work from Arkansas. But alas it was not to be. I deeply miss the the social aspect of working and have suffered from severe depression from the technical social isolation in a village of 7000 where the ham radio club doesn't even discuss radio at their meetings. There is also a personal visceral component. Dad's big passion was radio, but he also had a lathe, mill and woodshop all fully stocked with parts organized in labeled bins. At age 42 his employer moved us from NYC to Bluefield, West Virginia (Dad was selling coal processing equipment) and then 2 years later decided to move us again. Dad quit and we moved to Arkansas to speculate on real estate and operate a restaurant. Dad lived another 49 years, but never had anything better than a bit of space with a very disorganized portion of his shop equipment available. Before the moves he was building 5-6 radios and T&M projects a year or more judging from the detritus he left. So between my frustrations with lack of proper T&M kit and realizing what happened to Dad, designing low cost electronic T&M kit is an all consuming passion for me. However, Dad left me almost 1000 sq meters of stuff in several commercial buildings a meter or so deep with which I have been grappling for 15 years. I'm finally getting close to the end. I've boxed up an initial shipment of vacuum tubes to a dealer. After the 1200-1500 tubes are gone I will start on the passive components, sorting and inventorying them to sell to a dealer. When Tom Oldbury (tom66) contacted me via EEVblog asking for DSP assistance with his DSO project I was delighted and we had a lot of fun working together. He did all the work. I simply provided advice and assisted with expenses. I bought a 2nd hand iPad for Tom and we used Facetime audio and MS Whiteboard to conduct technical conversations. Not quite as good as a whiteboard in the same office, but very close. Do you have access to an iPad and iPencil? If not. I shall investigate getting one for you so we can carry on proper technical discussions more easily. The goal is to have fun playing with a shared project. Back to the sweeper project. As an example, a pair of ADF4351s, one fixed at 2 GHz and the other sweeping from 2 - 4 GHz would require 2 fixed filters, a 2 GHz low pass and a 4 GHz low pass to cover the kHz to 2 GHz range. There are lots of ADF4351 VFOs with the ability to sweep, but none produce sine wave output. It's under $40 for a pair of ADF4351 boards from China which leaves only the filters, mixer and a suitable MCU (e.g. Arduino, STM32, MSP430, etc). All of that is cheap from China. This is your project. I am merely here to assist as I can and you request. Though I reserve the right to supply items I deem important to your working efficiently. Aside from the $4000 I expect to get for the bulk of the tubes, I have 24 VT-4C/211s and 42 VT-52/45 specials. The former sell for $1000 to audiophools and the latter are running $300-400. I have ordered a uTracer 6 and plan to curve trace all the tubes and sell them on ebay with the measured curves for each tube in a set plotted on the same graph. The graph will be publication quality so they can put them in a matted frame to show off. That's just entertainment for me. The real value is having the commercial space cleared so my sisters and I can sell the property. It's just play money for me. I already have a suite of HP, Tek and other top tier stuff that had a $750k list in the mid '90s. All acquired for well under $30k. Having only bought a single new vehicle, a base model 1993 Toyota pickup for $7800 in my entire life, the lab is the new car I didn't buy. I'd like to note that so far as I know there is no low cost means of curve tracing transistors except the Peak DCA75 which is painfully slow. There's not a lot to one and a well designed unit sold exclusively through R&L and a few other ham radio dealers might be commercially viable. Another potential product is an in-circuit capacitoror tester. I have several LCR and ESR meters, but the EDS-88A is the only one that actually works in circuit.. However, it's rather pricey. In closing I want to emphasize that you are not under any obligation whatsoever. If you develp the next major piece of low cost test kit that's fantastic. If nothing happens that's OK. Life is unpredictable and often turns out very differently than we expect. I am not a gambler and have never bought a lottery ticket or placed a bet. Simply not interested as I can calculate the odds. In this instance I can't calculate the odds of success. I'm really just bribing my way into someone to talk to. Have Fun! Reg On Thursday, August 17, 2023 at 10:50:25 PM CDT, Daniel Ricardo Perez via groups.io <danyperez1@...> wrote: Reg, Interesting idea. It would require a tracking passband filter as frequency is sweeped, to select the desired harmonic. But I fear you should need to have selected the 15th harmonic in the range of, say, 1500 to 2500MHz and mix it with 1500 fixed, in order to cover 0...1000. I had thought of something like that but with a single PLL. As varactor tuned filters can't span much more than 1:3 frequency, two or more should have to be switched in and out if 1 or more decades range are needed. There would be an unavoidable amplitude and phase transient during the handoff, sweep should have to be stopped until stabilization, and the detector should have to be instructed to ignore during the transition. If the transients can be tolerated, e.g. ignoring them by software after the detection, there is another possibility: instead of multiple tracking filters, have multiple VCOs, phase locked to the Si5351 thru programmable dividers I am thinking while writing... Why not combining both ideas? Get 1500...2500 from a single VCO, phase-lock it to 94...156MHz thru a /16 fixed divider, mix it with 1500 locked from another 5351 output. Lots of ideas, little free time... Daniel LW1ECP El jueves, 17 de agosto de 2023, 23:17:08 ART, Reginald Beardsley via groups.io <pulaskite@...> ±ð²õ³¦°ù¾±²ú¾±¨®: Daniel,' As you have an Si5351 I'd like to suggest examining using a fast (e.g. Potato Chip) TTL part with sub 1 ns rise time to increase the harmonic content to over 1 GHz, filtering the unwanted harmonics and. mixing the two Si5351 outputs.? This would require some MCU programming, but my initial examination suggests that with proper choice of frequencies and mixer you could sweep the Si5351 from 10 kHz to 1 GHz with relatively little effort. I plan to work on the frequency plan some more tomorrow to eliminate some gaps in? my attempts. today.? A tinySWEEPER looks to me to be? a viable Si5351 project from 10-100 khHz TO 1 GHz.? That would be a huge boon to the RF community.. Have Fun! Reg
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This is what I did before building the tinySA
Build two single transistor oscillators, one on fixed 100MHz and other variable 100MHz to 200 MHz using a varicap
Triangle steering of the varicap done using two opamps and three potmeters for speed, span and center
Send both to a mixer made from two torroids and 4 diodes
Output of the mixer through a dyi low pass filter at 75MHz
Frequency verification and scale calibration done using an FM receiver and a cheap all band shortwave receiver
Verification of the low pass filter can be done using the sweeper and any form of power detection at 100MHz (FM receiver?)
Voila, a simple but clean sweeper from 0-75MHz
|
No worries. Figure things out and let me know what to do at my end. When is your birthday?
My tinyPFA came today. Time to test my Chinese OXCOs :-)
On Friday, August 18, 2023 at 11:10:34 AM CDT, Daniel Ricardo Perez via groups.io <danyperez1@...> wrote:
Quick reply: please wait a little, I am consulting a couple groups on how to send it, otherwise there is the risk of Customs charging in the order of its cost. What is your idea, e.g. FedEx, USPS, etc.?
El viernes, 18 de agosto de 2023, 11:27:43 ART, Reginald Beardsley via groups.io <pulaskite@...> ±ð²õ³¦°ù¾±²ú¾±¨®: Daniel, I need your mailing address! I'm not licensed so I can't look up your address on the call lists. I hope to correct that soon, but am too busy playing with other toys. I intend to send a pair of tinySAs and a nanoVNA as they are so versatile. There is also the possibility of designing useful accessories such as filters for using the tinySA as a signal generator. A 5th order Cauer is very effective if designed carefully. Please send me your lab inventory so I have a better idea of what should be most useful to you. I've sent nanoVNAs to other people in the UK and EU as a "Thank You" for having designed useful OSHW/OSSW kit that I use. So I should be able to order from China for delivery to Argentina without too much trouble. A bit of personal history. I "retired" at 54 in 2007 to move to Arkansas from Houston. The move took 7 months and 3 28' tractor trailer loads. I disposed of one trailer load of stuff in Houston. Dad's health was failing and as the eldest child as well as the closest it was my duty. I also wanted very much to get away from Houston because of the crime and hurricanes. I sold my house for $500 below asking price on 23 June 2008 a few weeks before the credit markets froze and Ike hit Houston. The area in which I lived was without power for 3 weeks. Houston summer without AC is very grim. I had worked as a contract research scientist/programmer since 1992 and was well known in the oil industry having missed 3 annual Society of Exploration Geophysicists meetings in 28 years. I was absolutely confident I'd get work once I was unpacked. I have a 5000+ volume technical library, computers, etc. Plan was to spend 1 week a month in Houston and do the rest of the work from Arkansas. But alas it was not to be. I deeply miss the the social aspect of working and have suffered from severe depression from the technical social isolation in a village of 7000 where the ham radio club doesn't even discuss radio at their meetings. There is also a personal visceral component. Dad's big passion was radio, but he also had a lathe, mill and woodshop all fully stocked with parts organized in labeled bins. At age 42 his employer moved us from NYC to Bluefield, West Virginia (Dad was selling coal processing equipment) and then 2 years later decided to move us again. Dad quit and we moved to Arkansas to speculate on real estate and operate a restaurant. Dad lived another 49 years, but never had anything better than a bit of space with a very disorganized portion of his shop equipment available. Before the moves he was building 5-6 radios and T&M projects a year or more judging from the detritus he left. So between my frustrations with lack of proper T&M kit and realizing what happened to Dad, designing low cost electronic T&M kit is an all consuming passion for me. However, Dad left me almost 1000 sq meters of stuff in several commercial buildings a meter or so deep with which I have been grappling for 15 years. I'm finally getting close to the end. I've boxed up an initial shipment of vacuum tubes to a dealer. After the 1200-1500 tubes are gone I will start on the passive components, sorting and inventorying them to sell to a dealer. When Tom Oldbury (tom66) contacted me via EEVblog asking for DSP assistance with his DSO project I was delighted and we had a lot of fun working together. He did all the work. I simply provided advice and assisted with expenses. I bought a 2nd hand iPad for Tom and we used Facetime audio and MS Whiteboard to conduct technical conversations. Not quite as good as a whiteboard in the same office, but very close. Do you have access to an iPad and iPencil? If not. I shall investigate getting one for you so we can carry on proper technical discussions more easily. The goal is to have fun playing with a shared project. Back to the sweeper project. As an example, a pair of ADF4351s, one fixed at 2 GHz and the other sweeping from 2 - 4 GHz would require 2 fixed filters, a 2 GHz low pass and a 4 GHz low pass to cover the kHz to 2 GHz range. There are lots of ADF4351 VFOs with the ability to sweep, but none produce sine wave output. It's under $40 for a pair of ADF4351 boards from China which leaves only the filters, mixer and a suitable MCU (e.g. Arduino, STM32, MSP430, etc). All of that is cheap from China. This is your project. I am merely here to assist as I can and you request. Though I reserve the right to supply items I deem important to your working efficiently. Aside from the $4000 I expect to get for the bulk of the tubes, I have 24 VT-4C/211s and 42 VT-52/45 specials. The former sell for $1000 to audiophools and the latter are running $300-400. I have ordered a uTracer 6 and plan to curve trace all the tubes and sell them on ebay with the measured curves for each tube in a set plotted on the same graph. The graph will be publication quality so they can put them in a matted frame to show off. That's just entertainment for me. The real value is having the commercial space cleared so my sisters and I can sell the property. It's just play money for me. I already have a suite of HP, Tek and other top tier stuff that had a $750k list in the mid '90s. All acquired for well under $30k. Having only bought a single new vehicle, a base model 1993 Toyota pickup for $7800 in my entire life, the lab is the new car I didn't buy. I'd like to note that so far as I know there is no low cost means of curve tracing transistors except the Peak DCA75 which is painfully slow. There's not a lot to one and a well designed unit sold exclusively through R&L and a few other ham radio dealers might be commercially viable. Another potential product is an in-circuit capacitoror tester. I have several LCR and ESR meters, but the EDS-88A is the only one that actually works in circuit.. However, it's rather pricey. In closing I want to emphasize that you are not under any obligation whatsoever. If you develp the next major piece of low cost test kit that's fantastic. If nothing happens that's OK. Life is unpredictable and often turns out very differently than we expect. I am not a gambler and have never bought a lottery ticket or placed a bet. Simply not interested as I can calculate the odds. In this instance I can't calculate the odds of success. I'm really just bribing my way into someone to talk to. Have Fun! Reg On Thursday, August 17, 2023 at 10:50:25 PM CDT, Daniel Ricardo Perez via groups.io <danyperez1@...> wrote: Reg, Interesting idea. It would require a tracking passband filter as frequency is sweeped, to select the desired harmonic. But I fear you should need to have selected the 15th harmonic in the range of, say, 1500 to 2500MHz and mix it with 1500 fixed, in order to cover 0...1000. I had thought of something like that but with a single PLL. As varactor tuned filters can't span much more than 1:3 frequency, two or more should have to be switched in and out if 1 or more decades range are needed. There would be an unavoidable amplitude and phase transient during the handoff, sweep should have to be stopped until stabilization, and the detector should have to be instructed to ignore during the transition. If the transients can be tolerated, e.g. ignoring them by software after the detection, there is another possibility: instead of multiple tracking filters, have multiple VCOs, phase locked to the Si5351 thru programmable dividers I am thinking while writing... Why not combining both ideas? Get 1500...2500 from a single VCO, phase-lock it to 94...156MHz thru a /16 fixed divider, mix it with 1500 locked from another 5351 output. Lots of ideas, little free time... Daniel LW1ECP El jueves, 17 de agosto de 2023, 23:17:08 ART, Reginald Beardsley via groups.io <pulaskite@...> ±ð²õ³¦°ù¾±²ú¾±¨®: Daniel,' As you have an Si5351 I'd like to suggest examining using a fast (e.g. Potato Chip) TTL part with sub 1 ns rise time to increase the harmonic content to over 1 GHz, filtering the unwanted harmonics and. mixing the two Si5351 outputs.? This would require some MCU programming, but my initial examination suggests that with proper choice of frequencies and mixer you could sweep the Si5351 from 10 kHz to 1 GHz with relatively little effort. I plan to work on the frequency plan some more tomorrow to eliminate some gaps in? my attempts. today.? A tinySWEEPER looks to me to be? a viable Si5351 project from 10-100 khHz TO 1 GHz.? That would be a huge boon to the RF community.. Have Fun! Reg
|
If your project needs 3D printing, my old butt is ready to help.
My equipment is not top notch, but I will try.
For untracked shipping as a padded letter (they usually slip
through customs as everyone thinks all Hungarians are poor and
cant ship anything of value), turnaround to the USA is 5 to 7
working days.
Tam
With best regards
Tam HANNA
Enjoy electronics? Join 21k4 other followers by visiting the Crazy Electronics Lab at
On 2023. 08. 18. 16:27, Reginald
Beardsley via groups.io wrote:
toggle quoted message
Show quoted text
Daniel,
I need your mailing address! I'm not licensed so I can't look up
your address on the call lists. I hope to correct that soon, but
am too busy playing with other toys.
I intend to send a pair of tinySAs and a nanoVNA as they are so
versatile. There is also the possibility of designing useful
accessories such as filters for using the tinySA as a signal
generator. A 5th order Cauer is very effective if designed
carefully. Please send me your lab inventory so I have a better
idea of what should be most useful to you. I've sent nanoVNAs to
other people in the UK and EU as a "Thank You" for having
designed useful OSHW/OSSW kit that I use. So I should be able to
order from China for delivery to Argentina without too much
trouble.
A bit of personal history. I "retired" at 54 in 2007 to move to
Arkansas from Houston. The move took 7 months and 3 28' tractor
trailer loads. I disposed of one trailer load of stuff in
Houston.
Dad's health was failing and as the eldest child as well as the
closest it was my duty. I also wanted very much to get away from
Houston because of the crime and hurricanes.
I sold my house for $500 below asking price on 23 June 2008 a
few weeks before the credit markets froze and Ike hit Houston.
The area in which I lived was without power for 3 weeks. Houston
summer without AC is very grim.
I had worked as a contract research scientist/programmer since
1992 and was well known in the oil industry having missed 3
annual Society of Exploration Geophysicists meetings in 28
years. I was absolutely confident I'd get work once I was
unpacked. I have a 5000+ volume technical library, computers,
etc. Plan was to spend 1 week a month in Houston and do the rest
of the work from Arkansas. But alas it was not to be. I deeply
miss the the social aspect of working and have suffered from
severe depression from the technical social isolation in a
village of 7000 where the ham radio club doesn't even discuss
radio at their meetings.
There is also a personal visceral component. Dad's big passion
was radio, but he also had a lathe, mill and woodshop all fully
stocked with parts organized in labeled bins. At age 42 his
employer moved us from NYC to Bluefield, West Virginia (Dad was
selling coal processing equipment) and then 2 years later
decided to move us again. Dad quit and we moved to Arkansas to
speculate on real estate and operate a restaurant. Dad lived
another 49 years, but never had anything better than a bit of
space with a very disorganized portion of his shop equipment
available. Before the moves he was building 5-6 radios and
T&M projects a year or more judging from the detritus he
left. So between my frustrations with lack of proper T&M kit
and realizing what happened to Dad, designing low cost
electronic T&M kit is an all consuming passion for me.
However, Dad left me almost 1000 sq meters of stuff in several
commercial buildings a meter or so deep with which I have been
grappling for 15 years. I'm finally getting close to the end.
I've boxed up an initial shipment of vacuum tubes to a dealer.
After the 1200-1500 tubes are gone I will start on the passive
components, sorting and inventorying them to sell to a dealer.
When Tom Oldbury (tom66) contacted me via EEVblog asking for DSP
assistance with his DSO project I was delighted and we had a lot
of fun working together. He did all the work. I simply provided
advice and assisted with expenses. I bought a 2nd hand iPad for
Tom and we used Facetime audio and MS Whiteboard to conduct
technical conversations. Not quite as good as a whiteboard in
the same office, but very close. Do you have access to an iPad
and iPencil? If not. I shall investigate getting one for you so
we can carry on proper technical discussions more easily. The
goal is to have fun playing with a shared project.
Back to the sweeper project. As an example, a pair of ADF4351s,
one fixed at 2 GHz and the other sweeping from 2 - 4 GHz would
require 2 fixed filters, a 2 GHz low pass and a 4 GHz low pass
to cover the kHz to 2 GHz range. There are lots of ADF4351 VFOs
with the ability to sweep, but none produce sine wave output.
It's under $40 for a pair of ADF4351 boards from China which
leaves only the filters, mixer and a suitable MCU (e.g. Arduino,
STM32, MSP430, etc). All of that is cheap from China.
This is your project. I am merely here to assist as I can and
you request. Though I reserve the right to supply items I deem
important to your working efficiently.
Aside from the $4000 I expect to get for the bulk of the tubes,
I have 24 VT-4C/211s and 42 VT-52/45 specials. The former sell
for $1000 to audiophools and the latter are running $300-400. I
have ordered a uTracer 6 and plan to curve trace all the tubes
and sell them on ebay with the measured curves for each tube in
a set plotted on the same graph.
The graph will be publication quality so they can put them in a
matted frame to show off. That's just entertainment for me. The
real value is having the commercial space cleared so my sisters
and I can sell the property. It's just play money for me. I
already have a suite of HP, Tek and other top tier stuff that
had a $750k list in the mid '90s. All acquired for well under
$30k. Having only bought a single new vehicle, a base model 1993
Toyota pickup for $7800 in my entire life, the lab is the new
car I didn't buy.
I'd like to note that so far as I know there is no low cost
means of curve tracing transistors except the Peak DCA75 which
is painfully slow. There's not a lot to one and a well designed
unit sold exclusively through R&L and a few other ham radio
dealers might be commercially viable.
Another potential product is an in-circuit capacitoror tester. I
have several LCR and ESR meters, but the EDS-88A is the only one
that actually works in circuit.. However, it's rather pricey.
In closing I want to emphasize that you are not under any
obligation whatsoever. If you develp the next major piece of low
cost test kit that's fantastic. If nothing happens that's OK.
Life is unpredictable and often turns out very differently than
we expect.
I am not a gambler and have never bought a lottery ticket or
placed a bet. Simply not interested as I can calculate the odds.
In this instance I can't calculate the odds of success. I'm
really just bribing my way into someone to talk to.
Have Fun!
Reg
On Thursday, August 17, 2023 at 10:50:25 PM CDT, Daniel
Ricardo Perez via groups.io
<danyperez1@...> wrote:
Reg,
Interesting idea. It would require a tracking passband
filter as frequency is sweeped, to select the desired
harmonic. But I fear you should need to have selected the
15th harmonic in the range of, say, 1500 to 2500MHz and
mix it with 1500 fixed, in order to cover 0...1000.
I had thought of something like that but with a single
PLL. As varactor tuned filters can't span much more than
1:3 frequency, two or more should have to be switched in
and out if 1 or more decades range are needed. There would
be an unavoidable amplitude and phase transient during the
handoff, sweep should have to be stopped until
stabilization, and the detector should have to be
instructed to ignore during the transition.
If the transients can be tolerated, e.g. ignoring them by
software after the detection, there is another
possibility: instead of multiple tracking filters, have
multiple VCOs, phase locked to the Si5351 thru
programmable dividers
I am thinking while writing... Why not combining both
ideas? Get 1500...2500 from a single VCO, phase-lock it to
94...156MHz thru a /16 fixed divider, mix it with 1500
locked from another 5351 output.
Lots of ideas, little free time...
Daniel LW1ECP
El jueves, 17 de agosto de 2023, 23:17:08 ART, Reginald
Beardsley via groups.io
<pulaskite@...> ±ð²õ³¦°ù¾±²ú¾±¨®:
Daniel,'
As you have an Si5351 I'd like to suggest examining using
a fast (e.g. Potato Chip) TTL part with sub 1 ns rise time
to increase the harmonic content to over 1 GHz, filtering
the unwanted harmonics and. mixing the two Si5351
outputs.? This would require some MCU programming, but my
initial examination suggests that with proper choice of
frequencies and mixer you could sweep the Si5351 from 10
kHz to 1 GHz with relatively little effort.
I plan to work on the frequency plan some more tomorrow to
eliminate some gaps in? my attempts. today.? A tinySWEEPER
looks to me to be? a viable Si5351 project from 10-100
khHz TO 1 GHz.? That would be a huge boon to the RF
community..
Have Fun!
Reg
|
Erik,
Thank?you?for?your?comment!?That's?exactly?what?I?intended?to?do,?except?I?was?aiming?at?higher?frequencies.?Even?though?this?is?a?very?basic?approach,?after?many?web?searches?I?found?only?these?three implementations:
-
This?is?the?one?I?am?attaching,?from?a?Romanian?magazine,?found?thanks?to?being?republished?by?Iulian?Rosu?YO3DAC/VA3IUL.?Anyway?I?distrust?it?a?little?because?of?no?buffering?between?VCOs?and?mixer,?I?fear?about?injection?locking?of?the?VCOs?at?certain?harmonics?combinations.
-
Ukranian design up to 250MHz, little info. Also no buffering.
-
This seemed interesting because the author began talking about experiments with VCOs with maximum possible frequency, but ended up using Minicircuits units (forget about purchasing Minicircuits here), and the project is incomplete.
I have the UHF section of an old Zenith TV tuner, covering about 500...900MHz, the special thing about it is it uses a discrete transistor, the idea would be to downconvert to 0...400MHz.
Also a Jerrold 400 cable box, also a piece of museum. I guess it covers about 50...400MHz upconverting to ~500MHz using a discrete DBM. A possibility is to inject a 500MHz signal at the output, and extract 0...350MHz at the input.
But if someone else has a tried-and-true design, that will save me effort.
Daniel LW1ECP
toggle quoted message
Show quoted text
El?viernes,?18?de?agosto?de?2023,?13:51:35?ART,?Erik?Kaashoek?<erik@...>?±ð²õ³¦°ù¾±²ú¾±¨®:
This?is?what?I?did?before?building?the?tinySA
Build?two?single?transistor?oscillators,?one?on?fixed?100MHz?and?other?variable?100MHz?to?200?MHz?using?a?varicap
Triangle?steering?of?the?varicap?done?using?two?opamps?and?three?potmeters?for?speed,?span?and?center
Send?both?to?a?mixer?made?from?two?torroids?and?4?diodes
Output?of?the?mixer?through?a?dyi?low?pass?filter?at?75MHz
Frequency?verification?and?scale?calibration?done?using?an?FM?receiver?and?a?cheap?all?band?shortwave?receiver
Verification?of?the?low?pass?filter?can?be?done?using?the?sweeper?and?any?form?of?power?detection?at?100MHz?(FM?receiver?)
Voila,?a?simple?but?clean?sweeper?from?0-75MHz
|
I haven¡¯t followed this thread closely, so I apologize if the NE/SA602 has already been discussed. Depending on your ambitions for performance, basing a heterodyne sig gen on that venerable part might be worth considering. The 602¡¯s integral buffer helps with unwanted injection locking (you¡¯ll still need good shielding and bypassing, of course).
It was a popular little bug in its day, so lots of app notes and projects based on it have been published. You might want to search for some of them for ideas.
Cheers
Tom
Sent from an iThing; please forgive the typos and brevity
toggle quoted message
Show quoted text
On Aug 19, 2023, at 06:53, Daniel Ricardo Perez via groups.io <danyperez1@...> wrote:
?Erik,
Thank you for your comment! That's exactly what I intended to do, except I was aiming at higher frequencies. Even though this is a very basic approach, after many web searches I found only these three implementations:
-
This is the one I am attaching, from a Romanian magazine, found thanks to being republished by Iulian Rosu YO3DAC/VA3IUL. Anyway I distrust it a little because of no buffering between VCOs and mixer, I fear about injection locking of the VCOs at certain harmonics combinations.
|
On Fri, Aug 18, 2023 at 09:52 PM, Daniel Ricardo Perez wrote:
?Anyway?I?distrust?it?a?little?because?of?no?buffering?between?VCOs?and?mixer,?I?fear?about?injection?locking?of?the?VCOs?at?certain?harmonics?combinations.
As the variable frequency range will probably be less than from the fundamental to close to the second harmonic I'm not sure injection locking will be a problem. It may required some "pulling" to move away from zero Hz output. Instead of the second winding to generate the low impedance current for the mixer you may opt for one transistor emitter followers using 51 ohm emitter resistors to match the mixer and provide very good decoupling.
|
On Fri, Aug 18, 2023 at 09:52 PM, Daniel Ricardo Perez wrote:
I have the UHF section of an old Zenith TV tuner, covering about 500...900MHz, the special thing about it is it uses a discrete transistor, the idea would be to downconvert to 0...400MHz.
Also a Jerrold 400 cable box, also a piece of museum. I guess it covers about 50...400MHz upconverting to ~500MHz using a discrete DBM. A possibility is to inject a 500MHz signal at the output, and extract 0...350MHz at the input.
But if someone else has a tried-and-true design, that will save me effort.
If you can get bidirectional access to both the RF and IF ports of the mixers the Jerrold cable box may be your best option
|
I've been reading the ADF4351 datasheet and app notes and cannot figure out if one can sweep one output while holding the other constant. Does anyone know from experience? My impression from the diagram is that the two outputs must be fractionally related.
Sweeping from 2 - 4.4 GHz with one output and 2 GHz on the other plus a couple of LPF filters to eliminate the harmonics ahead of the mixer seems as if it would serve nicely. A 2nd ADF4351 is about $15 USD, so not a major increase in cost if A & B can't be set separately.
Running the output of a 100 MHz clock through a < 1ns logic chip and filtering out a single harmonic may or may not be cheaper in the long run.
Reg
On Friday, August 18, 2023 at 11:53:00 PM CDT, Daniel Ricardo Perez via groups.io <danyperez1@...> wrote:
Erik,
Thank?you?for?your?comment!?That's?exactly?what?I?intended?to?do,?except?I?was?aiming?at?higher?frequencies.?Even?though?this?is?a?very?basic?approach,?after?many?web?searches?I?found?only?these?three implementations:
-
This?is?the?one?I?am?attaching,?from?a?Romanian?magazine,?found?thanks?to?being?republished?by?Iulian?Rosu?YO3DAC/VA3IUL.?Anyway?I?distrust?it?a?little?because?of?no?buffering?between?VCOs?and?mixer,?I?fear?about?injection?locking?of?the?VCOs?at?certain?harmonics?combinations.
-
Ukranian design up to 250MHz, little info. Also no buffering.
-
This seemed interesting because the author began talking about experiments with VCOs with maximum possible frequency, but ended up using Minicircuits units (forget about purchasing Minicircuits here), and the project is incomplete.
I have the UHF section of an old Zenith TV tuner, covering about 500...900MHz, the special thing about it is it uses a discrete transistor, the idea would be to downconvert to 0...400MHz.
Also a Jerrold 400 cable box, also a piece of museum. I guess it covers about 50...400MHz upconverting to ~500MHz using a discrete DBM. A possibility is to inject a 500MHz signal at the output, and extract 0...350MHz at the input.
But if someone else has a tried-and-true design, that will save me effort.
Daniel LW1ECP
El?viernes,?18?de?agosto?de?2023,?13:51:35?ART,?Erik?Kaashoek?< erik@...>?±ð²õ³¦°ù¾±²ú¾±¨®: This?is?what?I?did?before?building?the?tinySA Build?two?single?transistor?oscillators,?one?on?fixed?100MHz?and?other?variable?100MHz?to?200?MHz?using?a?varicap Triangle?steering?of?the?varicap?done?using?two?opamps?and?three?potmeters?for?speed,?span?and?center Send?both?to?a?mixer?made?from?two?torroids?and?4?diodes Output?of?the?mixer?through?a?dyi?low?pass?filter?at?75MHz Frequency?verification?and?scale?calibration?done?using?an?FM?receiver?and?a?cheap?all?band?shortwave?receiver Verification?of?the?low?pass?filter?can?be?done?using?the?sweeper?and?any?form?of?power?detection?at?100MHz?(FM?receiver?) Voila,?a?simple?but?clean?sweeper?from?0-75MHz
|
Daniel Ricardo Perez
