Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- Qrptech
- Messages
Search
Feel free to add information to the wiki or make edits as needed. Please respect the work of others by adding your own content rather than editing or removing someone else's content unless doing things like updating URL's etc.?
|
Re: 7 MHz Oscillator Ideas - good enough
JT,
toggle quoted message
Show quoted text
This is exactly how I used my old Ramsey kit back in the early '90s.? Had it next to my bed. It was the same NE602/LM386 design. An LC osc using the NE602 internal should work fine. A varicap (actually any diode should give your desired range) is nice and mechanically stable. The Ramsey kit made the mistake of not voltage regulating the varicap, using a 9V battery, there was a continuous small drift due to battery voltage drop. If you use a variable C or L instead of the varicap, the NE602 has internal voltage regulation, or use a stable supply, not a 9V battery. GL and 73, Gary WB6OGD On 12/7/2019 7:44 AM, JT Croteau wrote:
Hi Bill, |
|
Re: 7 MHz Oscillator Ideas
I like the receiver section of the SST xcvr for an application like this. It even has a simple AGC that works pretty well. You will probably need another stage of audio amplification if you want to use a speaker rather than headphones.
I deviated from the SST design a little and used the internal oscillator in the NE612 for the vfo. With two crystals in parallel (aka super VXO) and a whole lot of experimentation with various inductors I got a tuning range of better than 25KHz. The 40m design uses 4MHz crystals in the IF and 11.046MHz in the VFO. It has been many years but seems like I used 11.059MHz crystals in mine. Another good option would be the Universal Receiver Kit from Kits and Parts.? 73 - Jerry - W0PWE |
|
Re: K1SWL has done it again, the Phaser!
Dave has posted on the CWTD Group his thoughts on using a DC Receiver with the Phaser Transceiver:
"We considered interoperability between Phaser users to be an important design goal.?? That drove the design to single-sideband transmit, and we recently validated that goal with a Phaser-to-Phaser contact.? ? The use of DSB rather than SSB on receive was a simplification and a considerable one at that.? In view of the few instances where we felt this issue would arise, we elected to go forward with 'less complex' and still economical."
?73- Dave Benson, K1SWL |
|
Re: 7 MHz Oscillator Ideas - good enough
JT Croteau
Hi Bill,
toggle quoted message
Show quoted text
CW only. I just want something to monitor 7030 and 7040 while I am smoking a pipe and reading in my single room cabin or drifting off to sleep. 73 On Sat, Dec 7, 2019 at 9:42 AM Bill Cromwell <wrcromwell@...> wrote:
|
|
Re: 7 MHz Oscillator Ideas - good enough
Hi JT,
toggle quoted message
Show quoted text
What modes do you have in mind? CW and most of the digital modes are not particularly fussy about a little drift. A free running, L-C VFO should give you what you *need*. The ones I have that use vacuum tubes take a little longer - up to a half hour to settle down. A couple of the solid state oscillators settle in a few seconds. For some people, splitting hairs multiple times is a hobby. Hobbies have their own rewards. Most amateur modes do not require milliHertz precision. If you expect to work some of the super slow, deep noise modes like some of the JT stuff you better look at some of the digital VFO designs and even some of those are not "good enough". In my working life we made measurements with resolution and accuracy of a few millionths of one inch - in some cases two millionths. In my woodworking hobby that is just ridiculous:) I do hold "some" tolerances quite a bit closer than the guy who cuts pieces at Home Depot but nobody gets bragging rights for that:) At home depot the tolerances on those saws is "good enough". 'Good enough' does not mean "sloppy" or "inferior". Good luck with your fun project. Merry Christmas and... 73, Bill KU8H On 12/7/19 10:10 AM, JT Croteau wrote:
Hi folks, I'd like to build a simple NE612/LM386 receiver to cover --
bark less - wag more |
|
7 MHz Oscillator Ideas
JT Croteau
Hi folks, I'd like to build a simple NE612/LM386 receiver to cover
from roughly 7.028 to 7.042. I'm wondering what I should use for the oscillator. I've been poking around on google but it is making my head spin. Minimal drift would be ideal as I'd like to park it on 7040 or 7030 for a few hours just to monitor. Times like this I wish I still had some of my Doug Demaw books. Thanks |
|
Using Re-Purposing those Flat Mobile Phone Cells
From old mobile phones, I've saved several sizes of various AHr capacity cells.
If you don't have a way to make compression contact to the terminals on the top, you can solder to them. The terminals are not connected directly to the cell, they use spot-welded metal strips** to make the connections. The tiny spot welds don't quickly transfer heat from the terminals on top to the cells underneath the plastic top piece. For charging without a cell phone, I use one of the universal chargers. Specifically the one with the charge indicator on one end. This one has spring-loaded pushpins that will make contact to rough uneven surfaces like solder connections.eBay has several versions, The least expensive works fine and they will handle a wide-range of cell widths. <https://www.ebay.com/itm/Mobile-Universal-Battery-Charger-LCD-Indicator-Screen-For-Cell-Phones-1-USB-Port/112928050208?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D20131231084308%26meid%3D91b72536d82e43799d94256405b46820%26pid%3D100010%26rk%3D3%26rkt%3D12%26mehot%3Dpp%26sd%3D121883657151%26itm%3D112928050208%26pmt%3D0%26noa%3D1%26pg%3D2047675&_trksid=p2047675.c100010.m2109> I'm using one of the re-purposed cells in my SMT keyer and after a couple of years now the voltage is still close to the charge nominal 4.2 V. ** I've taken them apart for a look-see. -- Chuck, W5USJ (ex K2OFN) Point, Rains Co, TX? EM22cv |
|
Re: K1SWL has done it again, the Phaser!
Eric KE6US
¿ªÔÆÌåÓýVery similar to the PSKs. When I first worked JT65, I considered converting my PSK-20 to JT65. In the end, I couldn't bear to cut up such neat little rig. I'm glad I didn't. JT modes remind me of stamp collecting only not as personal. They had one thing going for them, though. JT65 and JT9 are the only modes I've ever used where I actually worked the guy who invented them. I'm old, but Morse and Vail were long gone before I was born. Eric KE6US
On 12/6/2019 9:42 AM, JT Croteau wrote:
Just like the Warbler and PSK series of days long ago, K1SWL has done it again by teaming up with N2APB to produce a phasing SSB QRP transceiver for FT8 and other digital modes. With two frequencies available and a cost of only $50 per band, we can put our DSB toys out to pasture. Kits start shipping Dec. 16th: I've ordered two thus far. N1ESE |
|
Re: K1SWL has done it again, the Phaser!
JT Croteau
Thanks Ryan, I missed your write up. I'm hoping it will not be too
toggle quoted message
Show quoted text
difficult to modify one for 160M. On Fri, Dec 6, 2019 at 11:49 AM Ryan Flowers <geocrasher@...> wrote:
|
|
K1SWL has done it again, the Phaser!
JT Croteau
Just like the Warbler and PSK series of days long ago, K1SWL has done
it again by teaming up with N2APB to produce a phasing SSB QRP transceiver for FT8 and other digital modes. With two frequencies available and a cost of only $50 per band, we can put our DSB toys out to pasture. Kits start shipping Dec. 16th: I've ordered two thus far. N1ESE |
|
Re: NP0 Capacitors for QRP homebrew
Easy enough.
toggle quoted message
Show quoted text
Let's expand that range to all values from 0.0000001 F to 100000 pF. What more could you want?? ?;-) Jerry, KE7ER ?? On Mon, Dec 2, 2019 at 10:43 AM, Nick Kennedy wrote:
|
|
Re: NP0 Capacitors for QRP homebrew
Heh yeah, they are just listing then numerically rather than by capacitance. Kind of silly, but there's a good variance in the capacitors themselves.? Ryan Flowers On Mon, Dec 2, 2019 at 10:43 AM Nick Kennedy <kennnick@...> wrote:
--
Ryan Flowers W7RLF
https://miscdotgeek.com |
|
Re: NP0 Capacitors for QRP homebrew
I got an email from Amazon a couple days ago offering a capacitor assortment from 0.1 uF to 100 nF. Could we expand that range a little? 73- Nick, WA5BDU On Mon, Dec 2, 2019 at 11:54 AM John KJ4IFO via Groups.Io <svsunbow=[email protected]> wrote: |
|
Re: NP0 Capacitors for QRP homebrew
Thanks everyone for the awesome replies. I decided to go halfway with this. I ordered the cheap kit, knowing that NP0 isn't needed for anything that RF circuits. I usually use QRP Labs kits for those anyway. The rest will work okay as long as I match them in pairs when using them for phase?filtering etc. I can buy NP0's as needed in that case.? Again, thank you!? Ryan Flowers On Mon, Dec 2, 2019 at 9:54 AM John KJ4IFO via Groups.Io <svsunbow=[email protected]> wrote: --
Ryan Flowers W7RLF
https://miscdotgeek.com |
|
Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
The Si5344 apparently does not support programmable phase shifts.
toggle quoted message
Show quoted text
Jerry On Thu, Nov 28, 2019 at 08:17 AM, Jerry Gaffke wrote: something like the Si5344 |
|
Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
Hans,
toggle quoted message
Show quoted text
So the VCO in the Si5351 seems to work from roughly 200 mhz to 1200 mhz. The max is 6 times the min, absolutely amazing! I had assumed the VCO was a straight up analog oscillator using a varactor diode, can't imagine how it can have that much range. It's like building a stable VFO that sweeps from 80m up to 15m in one go. The phase shifting is in the Si5351 to allow digital clocks to be lined up, compensating for different trace lengths and different clock setup times within IC's. We are indeed lucky that this works so well for quadrature clocks. Curious that the third overtone 27mhz crystal gave a 9mhz reference. I had been thinking that the shaky results when driving 10mhz into the crystal oscillator pin were due to an internal 25-27mhz bandpass filter, allowing overtone crystals to be used. I was wrong. Excellent write up on measuring phase noise, not something I know much about. And to prove it, I will wonder aloud if a DC receiver (with a very stable LO) could measure phase noise, just analyze the resultant audio. The ham community has zeroed in on the Si570 (the first one that was easy to use) and the Si5351 (really really cheap).?? There are several score of such parts that SiLabs has now,? and a few from other manufacturers as well.? Hard to keep track, especially since their selection guide is organized so poorly: ? ?? They try to bust the product line into groups by application, which I find absurd, Smells like a decision made by some middle manager rather than an engineer. Or perhaps whoever it was that wrote AN619. I just want to know if it's i2c/spi programmable, cheap, range, jitter, etc.? Spend 10x the price of an Si5351 and jitter can be vanishingly low, an spi interface would make it fast enough to synthesize eer type SSB transmissions. Would be nice to at least have one on the bench as a signal generator. If a PCB and some C code were available for something like the Si5344, it might take off within the ham community. Jerry, KE7ER On Wed, Nov 27, 2019 at 11:19 PM, Hans Summers wrote:
|
|
Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
Hi Jerry > Somebody in one of the other forums (bitx20?) was playing with driving an external clock into a crystal oscillator pin? > on our cheap Si5351-A in the MSOP8, it worked (I believe down to 10 MHz) but phase noise got quite bad. > Apparently the amp behind the crystal pins really does want to be somewhere up around 25-27 MHz. That was on the QRP Labs forum. Or at least, we DID have that on the QRP Labs forum, but maybe others have done it too on other forums. I think the initial idea came about because I had a batch?of 500 of my Si5351A Synth kit back in 2015 or so, where the supplier had messed up and given me 3rd overtone 27MHz crystals, not the 27MHz fundamental I was supposed to get. It's a continuous battle with suppliers and you never can imagine the new ways that they will find, to screw?up... anyway so this thing of course oscillated at 9MHz fundamental, in the Si5351A circuit... and the surprise was that it DOES work, just gives 1/3 the output frequency. That could be compensated in the software calculations. Not an ideal situation. I remember complaining loudly and the supplier sent me a bag of 27MHz (fundamental mode) crystals, and I had to mail 80 little envelopes out, to people who had bought the synth kit before the problem became apparent!? Anyway someone did more study on it, looking also at 30MHz reference. It did indeed degrade various aspects, including the phase noise and spectral purity. But as I recall, these studies were at VHF output frequencies. I believe when it is operated at the other extreme (LF) there is no significant degradation. Spectral purity is excellent.? > Page 3 of AN619 does say the PLL feedback MultiSynth divider can have a range of 15.0 to 90.0.. > The why of 90.0 makes sense, if the RFCLK is 10 MHz then we need 90.0 to put the VCO at 900 MHz. > The 15.0 minimum strikes me as just wrong, as is much of the other stuff in that section. > If the datasheet is correct and REFCLK can be 100 MHz, than that PLL divider > would have to go down to 6.0 in order to bring the VCO down to 600 MHz. > Perhaps the original plan at SiLabs was targeting a REFCLK max of 40MHz: ?40*15=600 > but they later found it worked fine up to 100MHz? > I'd guess it is the same MultiSynth as the output divider, and that both the 90.0 and 15.0 > are not hard limits.? Have you ever tried going below a ratio of 15.0? Yeah, a lot of the Si5351A datasheet makes no sense at all. It has plenty of plain errors, typos, and other more subtle inconsistencies such as the one you mention. They keep changing the documentation too, but the errors and inconsistencies don't get fixed. The lower frequency limit has always been a bit mysterious. It used to say 8kHz to 160MHz but the latest datasheet says 2.5kHz to 200MHz. How do they get 2.5kHz and stay within their spec? With 600MHz output the lowest available frequency should be 600 / 900, and use the 128 final divide-by-2 stage, so that gives 5.2kHz. Even if you disrespect the 600MHz lower limit, that still only gives you 375 / 900 / 128 which gets to 3.26kHz not 2.5kHz.? A lot of mysteries remain... I have not tried going below 15, part of the issue is that the configuration registers aren't a plain straightforward configuration where you put the divider in one register. There's also the numerator and the denominator of the fractional part. The way the configuration is spread between the 8 8-bit registers of each fractional divider is not simple.? > When pressing the lower limits of the VCO frequency, we may be getting more phase noise >?due to the PLL loop filter having been designed for 600 to 900 MHz. >?But since we have the rather large 126.0 output divide ratio, >?the phase noise of our output signal is still quite small. Recently I got into doing phase noise measurements for the first time, and documented that here??. I definitely will use this setup to check what happens with phase noise when the SiLabs spec is broken, at LOW frequency outputs (not trying to get VHF).? > Once you go to integer mode on the output divider (not fractional mode as in the si5351bx routines), > the phase register of CLK1 pretty much has to be locked to that output divide ratio > to generate quadrature clocks.? I wonder if that VCO/4 step size is by design or just > a happy coincidence. I'm sure it is a consequence of the chip architecture. But the fact that we can use it for generating quadrature clocks, is I think a happy coincidence. I think if SiLabs had realized this when designing the chip and its documentation, they probably would have made some song and dance over it in the documentation. It's a very nice capability to have, and would be useful for marketing. The documentation speaks very little of the phase offset register and does NOT describe properly, how to use it. Neither does the documentation properly describe the PLL Reset register and when that should be used (which is NOT every frequency change!). This is why many early Si5351A firmware implementations gave nasty tuning clicks.? > > ?a 14MHz crystal available, then this would also work - giving a minimum output frequency in quadrature mode,? > > of 14 * 15 / 126 = 1.67MHz. >? > Wow, that puts the VCO at 14*15=210 MHz, far far below the 600 MHz spec. > Have you tried this? Yes, I have. It works fine. The specific case I have tried, is for 160m operation. I used a 25MHz Si5351A reference for 80m and up; and divided that by 2 to 12.5MHz, for 160m operation. Since I required quadrature output, I used the VCO at around 250MHz (since 250MHz / 126 = 2MHz, perfect for 160m band). In this case the PLL multiplier used is around 18 to 20 (since 12.5 * 20 = 250MHz). It worked perfectly and I did not observe any unpleasant effects.? 73 Hans G0UPL |
Chuck Carpenter
Nick Kennedy
Bob N1RC
to navigate to use esc to dismiss