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Clocked Morse Part 1
The fundamental concept is that every symbol is precisely the same length and is time aligned with all the other symbols sent during a QSO by the sender. The sender does not need better than TCXO stability. This requires : Implementing a dit frame clock which can be set to various durations. High accuracy not required. Just stability. Logic to align non-aligned input before output. User must hear side tone without latency. Receiving station can't detect latency. Logic to set the alignment of the receiver dit frame for the statistical processing Logic to compute the mean and standard deviation of the absolute amplitude of the receiver audio output during a dit frame. Computing the FFT of a Gold code sync signal over a 10 s window and then doing a linear fit to the phase delay to align the dit frame Periodically doing the FFT & linear regression to update the phase delay every Nth character I *think* everything else is just a combination of the above, but I could easily have missed some minor things. I think anyone with any embedded experience will see this is not difficult code to write. Have Fun! Reg
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Rick, Replying to the list as I want to capture this in the archive. First thought is build a coil winder. https://www.ebay.com/itm/382128211265 I just ordered a copy. It's one of the few Gingery books I don't recall buying. Dave explained concepts well, so it's worth the money even if you don't copy the machine. That should give you a sound grasp of the mechanical design. Add an MCU, rotation and translation to position the wire and you'll easily have perfect coils. However, if you're going to wind 40 AWG you'll need a very precise electromagnetic brake to properly tension the wire. Consider using a pair of hand tighten drill chucks mounted facing each other with common drive to both spindles to hold axial parts. The drill chucks are dumpster dive stuff. Turn it under MCU control while moving the wire feed back and forth to lay down an ideal winding. The MCU already knows how many turns it's made. To make such a machine, obtain a pair of junk drill motors, disassemble so you have the shaft and bearing supports inside the otherwise empty housing. Make sure you take them apart, clean them and put them back together with proper lubrication. Then clamp the chucks on a short piece of 1/4" drill rod. Make a wire mount that will hold the drills by the handles while you let concrete harden to permanently secure the drills. Then remove the temporary mount and the drill rod. Your winding spindle is ready. Cut holes in the drill housing for belt clearance and use a common shaft and two belts to drive the spindles under computer control. Then add steppers or DC motors and a Hall effect sensor, screw or belt drives and wire tensioning. A junk ink jet printer is perfect for the translation of the wire feed. I'd also like to suggest including an airbrush spraying polyurethane as the layers are put down. At the end of a layer, spray the layer for a single turn. This will bond the winding very firmly. This is all basic Arduino sketch stuff. Age 8 and up ;-) It's really quite cool. I'd sneered at it for a long time, but it's a very useful inexpensive tool for solving problems such as yours. Low mental overhead. There are so many sketches for the Arduino out there it's impossible to keep track. A custom winding machine requires taking bits from several of the most basic tutorials in an Elegoo Starter kit and combining them. I have some junk drill motors and was wondering what to do with them. I now know. Thanks! Have Fun! Reg On Sunday, February 18, 2024 at 02:52:53 PM CST, gren <hrgerson@...> wrote: hi Reg, Good job on your jig ! Wondering if you have some thoughts ? I need to make dozens ( say 60 ) of my own Rf chokes wound on 1meg 1/2W resistor forms. There need to be a consistent # of turns, Counted, about 1100 to 2000 turns of #20 to #40 copper enameled magnet wire. I don't want to buy a Coil winding / counting turning machine... My (likely stupid) Mk I idea is: Was thinking about using a drill or Dremel tool, a Varaic to control the speed and a double Chuck mandrill with an HP Rotary Encoder on one end. Having the rotary encoder connected to a Freq. Counter to count pulses should translate into revolutions & thus # of turns. Using a variac + a Speed controlled Dremel tool might make it slow enough to do the Rf choke windings in controlled manner by moving the freely spinning Cu bobbin from Left to right to Left until the correct # of turns has been reached. Do you have any better ideas ?? thanks, rick
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Questions via PM on list topics
Just so we are all clear on this. If anyone sends me a technical query related to a list topic to which I reply, I will likely post the query and my reply to the list as received on the presumption that the PM was accidental rather than deliberate. This is common practice on several mailing lists to which I subscribe. Please post to the list, rather than email me personally unless it is actually a personal matter. Have Fun! Reg
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I took a break from organizing my shop to make this. I finally have a place to put things, so progress has been rapid. In 1/2 of the mess ;-( I made something similar out of a very light oak strip which bent like a bow when I was making and testing transformers for my electrically tuned xtal filter project. Here is the Mk II version with a stout enough piece of wood. The aluminum angle bridges serve to position the wires properly side by side. Once they have been stretched so the wires undergo plastic deformation, a thin coating of nail polish, lacquer or super glue will produce an easily handled multifilar winding. For this demonstration I made a 4 filament winding of #28. Before I wind this on a toroid, I'm going to spray one side with F77 spray adhesive so that it sticks to the core (I hope!). I strongly suspect that two screws and the angles are probably good enough, but I have had the tuner for ~50 years so I put it to use. Up until the advent of neodymium magnets, repairing a guitar side used a thin wire through the crack to pull gluing cauls together. This tuner came off my Yamaha FG-180 when I put Grovers on it. Have Fun! Reg
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A third hand system that actually works!
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FYI I thought this would be of sufficient interest to justify crossposting a link. https://www.eevblog.com/forum/reviews/a-3rd-hand-that-actually-works!/msg5248170/#msg5248170 Let's just say I bare the scars of the magnifying glass and alligator clip devices. These magnetic bases are really weak. Stronger ones will let you use a sheet of galvanized steel under the ESD mat which adds a lot of friction if you happen to push on one. But for ~$20 this such an improvement it's hard to describe. You can also just attach the arms to a flat steel plate with rubber feet and no magnets. Even stiffer and ~$6 cheaper. Have Fun! Reg
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My Class-E amplifier (Sokal, Jan/Feb 2001; https://people.physics.anu.edu.au/~dxt103/calculators/class-e.php; etc) investigation has struggled to find suitable devices for the final and its driver. The challenges include: Common BJT PAs cannot switch fast enough to minimize the time spent in the linear region (so much charge, so little time) MOSFET devices switch fast *if* the driver can supply the peak gate current (this can be measured in amps with some MOSFET finals!) No discrete driver of my design (including those with Schottky diodes and other accelerators) has rise/fall times for operation in the upper-HF region The only setup I've gotten to work is paralleled 74ACT00s driving the BS170 (widely used in many QRP projects) But the BS170 Vds(Max) is only 60 V, nor does Pd(Max) provide much headroom for operation at 13.8V Class-E Vds can easily exceed 60 V A similar QRPLabs thread suggested using paralleled 74act244 buffers, good for 600 mA dynamic current. Also suggested for the final was the FDT86256 MOSFET which has a 150 Vds(Max) rating. Does anyone here have a better suggestion for the driver or finals? Do you have Class-E design experiences to share? -- JimC (KQ7B)
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I gutted an ancient CB radio PSU yesterday which served as my main 12 V PSU along with a 5 V supply I built from scratch many years when I was in school. It's a 40 Vrms CT with 22 AWG leads. It used a bare LM317, so not a beefy transformer. I considered it 1 A max when I repaired it 50 years ago. I had been planning to use the existing chassis, but as I contemplate what I want to put in there I think a bigger chassis will save a lot of misery. So I think the transformer and fuse holder may be the only parts I use. Stage one will be a brute force full wave rectifier PS putting out about 28 Vdc with an IEC EMI filtered socket for the mains feed and large caps and chokes on the output. The LM317 datasheet shows -70 dB ripple rejection with a 15 V drop across the LM317. The LM399 needs 10 Vin so that makes the drop across the 2nd LM317 a bit marginal so I'll have to trim the pair of LM317s to see what produces the least ripple. For the 10 V feed to the LM399 I plan to use a 5-10 F super cap and similar on the 6.95 V output and also for the PS for the ultra low noise op amp that will actually supply the OXCO Vctl divider. Not yet sure about the 5 V supply to the OXCO. At turn on they pull almost 1/2 A which is a lot to ask of an op amp. Once they are warm they drop to about 1/4 A. As there has been quite a bit of FUD about the CTIs "jumping" in frequency, I've attached a screen dump from a recent multi-day experiment using a tinyPFA, Bodnar GPSDO, new PCB OXCO, HP 5386A, Instek MSO2204EA and Instek GPE4323 PSU. The GPSDO and OXCO were feeding JFW 1:5 splitters so that the DSO, 5386A and tinyPFA all had the GPSDO for the reference signal. Over the course of 3 days I observed a constant 0.01 Hz (last digit) bobble on the 5386A and a 0.005 Hz bobble on the tinyPFA which was consistent with drift of the signals on the DSO. I attached the DSO to the PSU using a BNC to dual banana plug cable to capture the screen dump. I don't yet know what the source of the noise burst is. It is periodic and I know that the DSO has major SMPS noise problems and will be replaced with a low time Tek 2465B by the end of the day. The Instek PSU is a linear supply so it should be much quieter than the SMPS in the DSO. The CTI OSC5A2B02 datasheet specifies +/- 2 ppb for +/- 5% supply variation. That's 8 ppb/mV which translates to over 90 ppb peak shift during the 200 ns noise burst. The voltage regulation on the new PCB OXCO reduces that substantially, but measuring actual supply variation to the OXCO module at that voltage level without external EMI pickup will not be easy and will definitely require significant effort and a custom circuit. So I plod along in the midst of property management, trying to organize far too much stuff I have bought and sell the mountain of tube era electronics and other stuff Dad left me. Anyone interested in an NOS Montgomery Ward 3.5 cu ft cement mixer still on the original shipping pallet? FOB Heber Springs, AR. Have Fun! Reg
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I've discussed these in threads on several lists and concluded that it would be best to stick to a single thread here. These are available for $3 each on ebay. They are salvaged from old cell tower GPSDOs. The new specs are very good and they are well aged so long term stability should be excellent and an order of magnitude or more better than a new OXCO. 10 year aging rate is specified at 0.4 ppb/yr. The tuning rate is 1 ppb/mV or 0.001 ppb/uV. On the datasheet the short term stability is stated as 0.02 ppb/s. That happens to correspond to the 20 uVrms spec of an LM399 which are also available as salvage parts and which I plan to use for the Vref. That gives me some modest hope that if I clean up the noise and other factors I may be able to achieve 0.01 ppb. There are a couple of Chinese PCBs that have one of these on them. I have two of the version with the trimmer next to the OXCO module that are 0.1 ppb after adjustment using a GPSDO and DSO. Two others have drifted out of range of the tuning voltage divider and can't be set to 10 MHz without changing the fixed resistors in the divider. After some study, I've concluded that the main limitation on the stability of these is power supply noise and temperature stability. I'd like to get to 0.01 ppb/yr just to see if I can. The 10x rule of thumb dictates that I need noise and voltage drift in the single uV range which will not be easy or quick. Preliminary error budget analysis reveals that mains line voltage varies +/- 5% between 114 and 126 V. After reviewing the datasheet for the LM317 it appears that a mains supply which uses two LM317s in series with an AD 584JH to set the 10 V to feed the LM399 will prevent mains fluctuations from affecting the LM399 output. There are also temperature, device noise and EMI to contend with which I shall get to in due course. To save time and effort I am going to attempt to use Chinese LM317 and AD584 PCBs which I have on hand to supply the LM399 and an AD8429 ultra low noise instrumentation amp to buffer the LM399 from the OXCO Vctl line. The 20 uVrms noise of the LM399 will need to be filtered out and I'll have to find a truce among the various tempcos. In general I intend to follow Ken Thompson's aphorism, "When in doubt, use brute force." and rely on lots of filtering from the wall to the OXCO and several levels of thermal isolation and regulation. As I am certain that any knowledgeable reader will grasp that 0.01 ppb/yr for an OXCO is wildly ambitious, I should like to explain why I think it might be possible. The viscothermoelastoplastic continuum mechanics of crystals and voltage references produces an aging profile which asymptotically approaches a constant value. There can be several different aging rates which combine, but after enough time one will come to dominate the others. In general the form of the functions is very similar to the 1D heat equation with its infinite sum of exponentials. Some years ago I spent quite a bit of time studying sparse, underdetermined solutions of arbitrary sums of such functions. In my numerical experiments I found that I could predict future behavior to within 1-2% for a period in the future equal to the duration of the prior observations.That result is due to the work by Emannuel Candes and David Donoho in the 2004 -2008 period. In particular, Donoho proved in 2004 that if and only if a sparse L1 solution to an underdetermined system of linear equations existed it was the L0 optimal solution which is NP-Hard. I was already solving massively underdetermined systems with 50,000 unknowns and 100 or fewer equations following the discussion of bais pursuit in the 3rd edition of Mallat's "A Wavelet Tour of Signal Processing" when it sank it I had always been taught that was not possible because there were an infinite number of solutions. As a result I spent the next 3 years reading 3000 pages of the most difficult math I've ever seen. A single proof in one of Donoho's papers ran 14 pages. Ever since I have been searching for data with which to demonstrate the power of sparse L1 decompositions for
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[Question] CTI OSC5A2B02 OXCO module high precision frequency reference project
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As a consequence of a completely unrelated conversation I got the idea of comparing the OXCOs to a GPSDO or another OXCO by filtering out the harmonics, mixing with a GPSDO, filtering out everything above a few Hz and timing the interval between zero crossings of the difference frequency which should be in the milliHertz range. By using higher harmonics the measurement period can be reduced from 100 s as desired. Has anyone tried or heard of someone using such a technique? Given the long history of frequency comparisons I should expect it's been done by many others prior to the advances in the '70s and '80s in semiconductor technology. Have Fun! Reg
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FYI This is a repost from qrptech. I'm reposting this here so I can consolidate threads I start in one place. I've had people on one list bring up something I mentioned on another list and it's become confusing and difficult to avoid repeating myself. So threads I start will appear here. Threads other people start will remain where they started. I saw these for under $1 on temu.com and bought 10. I want to see if they can be used to maintain the input voltage for a portable QRP rig as the battery drains. With ~10 V @ 2.8 A input it produces 13.8 V @ 1.8 A output under load. It can just get to 2 A @ 13.8 V at which point I hit the 3.2 A limit of the lab supply current. However, under load the switching noise is quite bad. The screenshots are from my Instek MSO which has the MDO spectrum analyzer function enabled. As you can see there is both broadband noise and lots of strong harmonics of the switching frequency of 1.2 MHz. 160 is with the power off and 161 with it on. I'm going to need a lot of filtering to make it usable as power for a radio receiver. The DSO was connected directly to the Vout of the MT3608 via a 10x probe. I was using a wirewound rheostat for the load, so that likely has some influence. I'll run some experiments to see how well I can reduced the EMI output. It gets fairly warm, so a heatsink is also probably a good idea. Have Fun! Reg
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Re-engineering the uSDX+ project
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I'd like to consolidate this discussion in a single place as multiple lists are getting confusing. I'm quite impressed by the uSDX design concept, though less so about any of the implementations. This will proceed to modularize the radio in a series of steps. First up is a 50 ohm stripline relay switched suite of filter boards with 2-14 filters per board in even numbers. The filter footprint will accommodate 2 fixed SDM caps and a trimmer per leg with shunt inductor pads for each element of a 5th order LC filter. Connections will be SMA and IDC ribbon cables. I plan to design both LC Rx roofing filters and Tx LP filters for all the bands from 160 to to 70 cm. I am pressing a friend to do the PCB work for this board. A full fat version will have both Rx & Tx filters. The 2nd board will be the main RF board with provision for choice of crystal, internal TCXO and external clock or sine wave references via U.FL for the Si5351. There will be also be a precision PA drive attenuator and a diode noise source in addition to the current variable power out. All control functions will be performed by a front panel with a Nano compatible pinout via a mezzanine board. The panel will have an as yet unknown number of switches, a 240 x 135 or 320 x 240 OLED display, one or more encoders, etc. Provision will be made for using an OXCO to autocal the TCXO and then turn off the OXCO. . By using the Nano as the base, the existing FW can be used followed by a port to the Mega256. Goal is to internally implement all the digital modes on the MCU with Bluetooth and WiFi control interfaces by using something like a Heltec ESP32 module with a radio chipset Internal power will be supplied from a 3-5 Ah LiPo with built in charger operating off the single 13.8 V power input. The aim is to produce a set of OSHW modules which can be connected to form an enhanced uSDX+ with proper RF shielding on all boards. Or alternatively some other architecture such as a superhet by adding crystal IF filters ahead of the quadrature. I have enough experience comparing the sensitivity of the uSDX+ to my Icom 705 to I think that a sub $300 retail radio with lower current consumption and comparable performance to the 705 is viable with a bit of community engineering effort. As it stands, the uSDX+ has better FW than the $600 Xiegu X6100. So I'm returning one of those and will exclusively focus on the uSDX concept until such time as the X6100 becomes a viable radio. the current FW is pretty useless. I have the design and programming skills, but no PCB layout skills and not enough time to complete other projects and learn KiCAD. I also have a very well equipped RF lab and would prefer to spend time on extensive testing. I'm hoping that someone else will take an interest in this and help with the design and layout. JLCPCB has cheap multilayer boards so real microstrip is inexpensive. Have Fun! Reg
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AM modulated class E amplifier
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Pascal's question about SSB distortion in the uSDX+ served to focus my attention on the widely reported problems with severe SSB distortion in the uSDX+. The distortion problem was part of my decision to buy a 339A. I have a Keysight 33622A 120 MHz AWG. The sine wave output measured 0.028% THD vs the datasheet 0.03% and the 2nd channel can provide pulse trains to drive a class E amplifier. As a consequence I should not need much to make a proof of concept test. Can anyone supply a design or links to additional information about a suitable circuit design? Thanks, Reg
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OT: Looking for Surge Protector module Construction DIY projects for Whole Lab, or Whole Ham Shack from QEX or QST , etc. ??
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Apologies if this off-topic question is too far out for this group. If so, please delete and ignore. Looking for DIY construction project References or .pdf's in QEX or QST or other , for Surge Protectors capable of protecting a Whole Amateur Radio Shack or/& Electronics Lab at the Breaker Panel or Sub-Panel level. The articles would typically list the component, have a schematic, and the "best-practice" PCB layouts already worked out. Of course, a number of Commercial products are available, such as the Siemens FS-140, which has good specs. These are listed as "Whole House Surge Protectors" (WHSP's). An example article of listing of such can be found here: https://www.bobvila.com/articles/best-whole-house-surge-protector/ However, the cost for the Siemens FS-140 or other modules is steep, in the $300 to $400 range, while the actual components costs are in the $20 range. - not a bad cost bad for a single home, -- but with multiple buildings on a farm, and separate antenna shacks , the cost for 8 of these adds up. So, looking to build some myself. It is not that difficult a thing to do, and I have added MOV's to specific individual equipment myself across the L1 L2 & ground lines, (both internally & externally) to protect them, and that has worked out fine. Thus the request for some DIY .pdf's articles or Web Reference from say QEX or QST or other, for my own self-edification, would be appreciated. thank you, rick
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An IF in search of a radio
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I recently bought an Icom 705 and have been stunned by the performance of twin tunable pass band filters. I want to duplicate that using analog filters. As it happens, 5 MHz HC-49/S crystals are less than a dime with other frequencies available at similar prices. But 5 MHz provides some interesting options in radio design. Particularly in the self diagnose and repair department. Key concepts: a 5 MHz IF allows using WWV for very precise calibration and alignment in conjunction with a noise source the required frequency shifts are very small relative to Fp & Fs varactors should easily perform the shifts a nanoVNA will measure the xtal to provide the values needed to match that xtal a program will calculate the optimal choice of xtals and capacitors & varactors from small pools (10-20) of parts to meet design goals with manual trimming as needed. A pair of 4 pole varactor tuned filters shouldn't be that hard. Why go to all the problem of matching filters only to have a fixed frequency filter? Worst case use a latching DAC and MSP430 to set the varactors. All a question of current drain. Have Fun! Reg
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Message blocking
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I'm the owner and I have no idea who is doing this or how to contact them. None of it makes any sense. Reg
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Fw: [qex] Your message was not approved
I have no clue who DaveD is am NOT happy. Reg ----- Forwarded Message ----- From: Group Notification <[email protected]> To: Reginald Beardsley <pulaskite@...> Sent: Monday, June 19, 2023 at 01:37:49 PM CDT Subject: [qex] Your message was not approved Hello, A message you sent to the group [email protected] was not approved by the moderators for the following reason: YouTube content is usually copyrighted (by the perso who uploaded the content). Since we don't allow the posting of copyrighted materials, I am goingvtk reject this post and ask that you re-post without the image. DaveD The message is attached. hi, Apologies if this off-topic question is too far out for this group. If so, please delete and ignore. Looking for DIY construction project References or .pdf's in QEX or QST or other , for Surge Protectors capable of protecting a Whole Amateur Radio Shack or/& Electronics Lab at the Breaker Panel or Sub-Panel level. The articles would typically list the component, have a schematic, and the "best-practice" layouts already worked out. Of course, a number of Commercial products are available, such as the Siemens FS-140, which has good specs. These are listed as "Whole House Surge Protectors" (WHSP's). An example article of listing of such can be found here: https://www.bobvila.com/articles/best-whole-house-surge-protector/ However, the cost for the Siemens FS-140 or other modules is steep, in the $300 to $400 range, while the actual components costs are in the $20 range. - Perhaps the cost of one (1) Commercial unit is not so bad for a single home, -- but with multiple buildings on a farm, and separate antenna shacks , the cost for 8 of these adds up. So, I would like to build some myself. It is not that difficult a thing to do, and I have added MOV's to specific individual equipment myself across the L1 L2 & ground lines, (both internally & externally) to protect them, and that has worked out fine. But, I'd like to add a Whole Lab & Whole ham shack modules, as well as for the Antenna shacks at each breaker box. Our grounding rods & plates are all adequate, up to date and to code, so none of that is an issue. We are in a high lightning strike area, and the soil type is well drained, stony and conductivity is poor when conditions are dry. -- So having multiple and redundant (Whole House type ) Surge Protector modules installed at every location is what we are looking to build. Thus the request for some .pdf's of articles or their Web Reference from say QEX or QST or other, for my own self-edification, would be appreciated. thank you, rick An example of the insides of the Siemens FS-14 , found in some random YouTube video: (MOV's are the blue discs, etc. )
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Circuit for monitoring RF compression with a VU meter
Been reading QEX almost from the beginning and have enjoyed all my issues. I also have a fairly nice technical library. I have a question which I've never seen an article on and I wonder if some of you that are way above my pay grade, might have seen a reference somewhere else, or might know how to design it. I have a nice Kenwood TS-590-SG plus 500 watt SS amplifier, which I like to engage the Kenwood's digital audio compression from time to time, for SSB operations. I have the compression set per the manual recommendations, but I'm never quite sure it's set so as to give good compression, but not introduce objectionable distortion. I also forget from time to time to turn the compression back on after I've been on FT8, etc. An outboard visual indicator would be helpful. My query: I have a very good quality VU meter. I would love to find and build a circuit and a way to calibrate it for the desired compression after demodulating an RF sample, of my signals. Has there been such an animal in our world? I realize a good scope is the best monitor like my Tek 465 or 2246, but I don't want that in my set up because of the physical size. The Kenwood panel meter gives some indication but the resolution falls a little short. I would prefer to calibrate a larger panel meter for day to day operating. Thank you for your attention. Any assistance or comments will be appreciated. Ray, W4BYG -- "If you want to build a strong house, I'll give you my engineer's number. If you want to build a strong life, I'll introduce you to my carpenter." Lebron and Heather Lackey Virus-free.www.avg.com
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I was able to pick up a CW filter for my TS-520 and ran a series of tests using my 8593A SA w/ TG. The photos show the "matching" network and the spectrum for cases I've tested so far. Next up are the addition of caps to the resistive match, reactive matching and transformers. Shunts are 51 ohms and series are 2k. I'll test the filter on my 8753B before I install it with a different fixture which has had a custom SOLT cal. Several other people on the Kenwood hybrids list have posted their transfer function measurements and all have a >6 dB ripple in the pass band. At present I'm not sure if it's good or bad. I'll decide when I hear it. Have Fun! Reg
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NaN The "Not a NorCal 40" project
FWIW I am currently working on measuring and sorting 500x 5 MHz HC-49S crystals into 10 bins based on Fs at 0 C and then sub-sort into 10 bins based on Fs at 50 C drawing the crystals from a water bath. This is a prelude to building the 4th order 5 MHz example in EMRFD and then figuring out if I can tune it electrically +/- 200 Hz. If that works I'll build a 2nd one which would provide an 8th order response. A Bessel is the maximally flat delay filter. As the orders get higher it converges to a Gaussian. With the low height of the HC-49S a pair of 4 crystal filters will fit in the same space as the NorCal 40A filter. The NaN concept main features are: Fully analog operation 5 MHz IF with dual tunable BP filters direct connection of IF to antenna for WWV reception noise diode at antenna input for self test quadrature baseband mixer with IQ output an analog audio section to convert IQ into binaural audio to highlight pitch and relative relationships interface to separate module with waterfall, digital readout and recording to uSD using its own power <250 mA receive drain analog section The logic is that when you are setting up to keep a sked in portable mode, you need to look for a frequency that's open and start calling. But once the QSO starts you no longer need the waterfall or the frequency display. The Icom 705 does this, but the FPGA still eats a lot of power. The premise underlying the effort is that I can make an analog version of a digital filter. I've done digital filters for 40 years. Have Fun! Reg
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I bought an Icopm 705 a few weeks ago and it has me very eager to get re-licensed. I was looking for a Vibroplex Code Warrior Jr. but couldn't find one in stock, so I waded through the ebay listings and found these. https://www.ebay.com/itm/115688429540 I bought one to use with my Icom 705 and liked it enough to buy a 2nd one to tinker with. I'm going to replace the ground contact hex spacer with a piece of .999 silver bar, make silver caps for the contact screws and replace the hex insulators with rectangular bars with a hole to access the magnet mounting hole so I can adjust the position a la CWJ and switch to using a spring if I don't like the magnets. The second paddle arrive along with 4 of the 5 magnets I ordered. I measured them with a Gauss meter and installed the strongest one. The 5th one should be stronger, but this is quite usable. With some minor changes I can switch to using a spring. The vertical members are simple hex spacers and insulators tapped M3-0.5, so easy to make nicer supports. Happily, the key fits in the box long with the cable. This is my first iambic paddle, but so far I have no complaints. After a few days practice I can produce run 15 wpm with few errors in timing. I'm wathcing the do-dash space using the 706 audio scope feature while I wait for my Morserino to show up. I'll make a paddle from scratch is this comes up short. For a portable paddle I can't see how you can beat it. It has ball bearings. The photos are in reverse order from finished result to start. There is a metal slot in the base that the zip ties fasten the cable to.The blue plate in 2834 is a self stick steel plate you can use to mount the key to a non-ferrous object. The only keys I found under $110 were all mostly plastic, some 3D printed and at prices that were not attractive. Have Fun! Reg
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Sat 8:39am
Sat 8:39am