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Alan G4ZFQ
What is the recommended TCXO?Bruce, There is no recommended, as you say the one mentioned, the FOX, is a jumper. Some use it on HF with no apparent problems although my obsevations suggest that under poor propagation spots could be lost on the higher bands. I've kept notes on those reported here:- https://sites.google.com/site/g4zfqradio/incircuitprogramatmel168#Testing%20TCXOs Would it be better for me to order up a new synthesizer kit, rather than try to remove the crystal from my current board? I have about 5 I play with. They also fit the VFO and, depending how you build it, the Progrock. 73 Alan G4ZFQ
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Re: U3S Case front panel push buttons
Brian Summers
Mouser list a switch 629-GPB023B05BR which looks like it will fit the same diameter hole. Probably much better quality I would think. Brian VE7JKZ
On 12/6/2018 9:44 AM, Alan de G1FXB via
Groups.Io wrote:
To prevent excess heat reaching the switch body, clamp a haemostat* between the switch and the tag.
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Re: QCX CW transceiver
I used thin strips of masking tape to keep coil neat. One possible for those having issues getting the TI wires in the correct holes would be a thin piece of mica about 1" x 1" with the proper hole spacing so wires could be properly spaced making it easier to mount .
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Re: No GPS data with U3S - For Hans
geoff M0ORE
First send appeared here OK .
On 12/6/2018 10:39 PM, Brian Summers
wrote:
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Re: si5351a
#synth
Dave New, N8SBE
Hans, Had a crystal oscillator issue a few years ago that cause a lot of head scratching. We had been producing said module for several years with no problems, when suddenly we had a rash of dead modules (no oscillation) after they had been outside overnight in desert air that veered toward freezing, but not below. We found ultimately that the oscillator was failing to start under low temperature conditions, but our modules are meant to operate over -40C to 85C and had been tested to that repeatedly over the current production runs. Long story short (too late), we found that the original design had been marginal, in that the recommendation of the microprocessor manufacturer didn't line up with the recommendations of the crystal supplier. Production variation had exposed the margin, and thus, we started seeing failures at low temperature. So, after a lot of back and forth, we lowered the value of the ballast resistor in the tank circuit to increase the feedback, and voila! all the issues went away. Several more years (and a few million) modules later, we have never seen another oscillator failure in the field. Lesson: Every component has a data sheet, and often, they DON'T agree with those components' datasheets they need to interface to. Sometimes it takes a whole engineering team (and their OEM customer breathing down their back) to bash heads (and those of the component suppliers) until an optimal solution is found. 73, -- Dave, N8SBE
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Re: QCX CW transceiver
John VA7JBE
What I did on my T1 was to leave the tails end of all the wires at different lengths, going from longer to shorter in a clockwise direction. That way I was able to insert one or two wires at a time, pull them through, and then move on to the next pair without having to worry about running out of space or getting the wires mixed up. I got the idea from Hans' method of building the 50-ohm Dummy Load kit. If there's ever an update to the QCX manual, it might be worth including this method.
You can find a better illustrated explanation here, starting at step 3.5 https://qrp-labs.com/images/dummyload/dummyload.pdf Cheers, John VA7JBE
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Re: No GPS data with U3S - For Hans
Brian Summers
Strange, I sent this several hours ago but it never appeared. Let me try again. Brian VE7JKZ -------- Forwarded Message --------
I've managed to come up with a procedure for repeating my problem. I've got the unit mode indices programmed so it operates as follows: 1. Power on U3S. Ultimate3S 3.12a appears. Then the display
switches to GPS data as it should. 2. Press the Menu button once and the display reads: 0]-0-000,473,000TX CW-------00-0 3. Press the menu button again and the displays reads: 1]-0-000,473,000TX CW-------00-0 4. All the above really shows is that I have the same message
in mode index 0 and 1. Not intentionally I might add. I'm new to
the U3S so this is all happenstance. 5. Now power off/on. Once again the Ultimate3S screen appears followed by GPS data. 6. Press the menu button once and see the display as para 2 above. 7. Now press the edit button twice to enable. The display will show: 0] 0 000,473,000TX CW 00 0 8. Power off/on. The Ultimate 3S screen appears, the GPS
data does not appear and instead the display shows as
follows. The beating heart appears where it should. TX CW 9. Press the menu button again and see: 0] 0 000,473,000TX CW 00 0 10. Press the menu button again and see: 1]-0-000,473,000TX CW-------00 0 11. You can see from 8 and 9 that I've created two messages identified with mode index 0]. Now you can repeat from para 8. The unit goes directly from the Ultimate 3S screen to the first mode setting every time, bypassing the GPS data screen. It all repeats. 12. To recover from this situation power off/on as para 8, go to the screen shown in para 9, then press the edit button twice to disable the mode setting. Now power off/on and GPS data will follow the Ultimate 3S screen. Doubtless there are other ways of demonstrating this but the above is repeatable for me. Here's hoping that when I post this the formatting does not change........ Brian VE7JKZ
On 11/30/2018 8:34 AM, Brian Summers
wrote:
GM Alan,
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Re: QCX CW transceiver
Ray Worrall
Hi David, Nail polish works just fine. Did this on two kits. On the primary winding try to keep it under a bit of tension, to prevent unraveling, while drying 72 Ray VE7AVG/VA7SK
From: David Wilcox via Groups.Io <Djwilcox01@...> To: QRPLabs@groups.io Sent: Thursday, December 6, 2018 2:03 AM Subject: Re: [QRPLabs] QCX CW transceiver Has anyone used any Q Dope or finger nail polish on the ends of the wires on the coil to hold the wires in place to make it easier to insert on the board? In other kits the wires started to loosen while fiddling with them trying to get them all in the correct holes. David J. Wilcox K8WPE’s iPad
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Bruce K1FFX
I think I've gotten the U3S/WSPR at, or close to, what I can achieve with a heat sink, foam, and rubber bands ... and it's pretty good. I'm interested in doing the TCXO experiment ... a bit more kit building, and more entertainment as the daylight gets shorter and shorter here (Dec. 14 is the first later sunset by 1 minute, but still losing sunrise daylight until the solstice).
What is the recommended TCXO? I've read that some parts have this frequency jump behavior which must be avoided for WSPR usage. I don't know if the part mentioned in the synthesizer assembly manual exhibits this behavior or not. For my ability, a part that can be mounted to the pads on the top of the synthesizer board would be preferable. Would it be better for me to order up a new synthesizer kit, rather than try to remove the crystal from my current board? Thanks for any suggestions! Bruce K1FFX
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Re: #wspr U3S for 2m WSPR: How to remove the frequency-swing at start of transmission
#wspr
Alan G4ZFQ
Changed to basic crystal reference.
I show my RX at ~27.005MHz of the crystal frequency with Park mode 3 at the end of one TX/beginning of another. And two using Park mode 0, one at the start after idle, one between two transmissions. "Start of TX from Parkmode3" shows a small section of the cyclic movement on 2m. The initial jump at the start of the transmission is quite fast, probably what Henning sees on 2m. Personally I do not think the initial rapid frequency shift is of any real consequence for WSPR. After another hour or so 1032 13 -0.5 144.490529 2 G4ZFQ IO90 0 a drift of 2Hz, not yet as good as Henning but not too bad. And 1042 13 -0.8 144.490540 0 G4ZFQ IO90 0 Zero drift. But after that it began to drift again, temperature? Not really, more a slow cyclic drift. Removed Synth module LM317, fitted low drop 3V3 regulator AMS1117, an Ebay module. No difference. I am thinking this is not entirely a heat-related problem, switching inside the Si5351 as the frequency is changed alters the capacitive loading on the 27MHz crystal? The cyclic drift could be associated with the pattern of WSPR tones. Now in another thread Hans reminds me that there are no loading capacitors on the crystal (apart from those inside the Si5351 which are lower than specified) Is the crystal therefore more sensitive to loading? So, in goes my Adafruit module with a 25MHz SM crystal. This is looking promising. Even though 25MHz means the WSPR frequency shift is compromised it is decoding reliably on 2m with drift 2 or 3Hz. Any fluctuation due to WSPR frequency changes was not obvious. Now back to the basic 27MHz crystal Synth, put in two 15pF loading capacitors, hoping that would overwhelm the cause of the "modulation" of the 27MHz. It started almost dead on 27MHz, drifting down, settling about 60Hz down. But this was far worse, the 27MHz was not stable even when the U3S was idle. That is about as far as I can go the Adafruit shows a simple crystal can work on 2m but my Synth board does not. It is better to use a TCXO and, presumably, the QRP Labs OCXO. (This is a U3S run with one BS170 and ~5V on the drain so not much heat generated. I have it in a custom box with the display on top, the synth module therefore at the bottom.) Maybe Park mode needs to be considered carefully? Mode 0 gives an output, my observations see less than 30dB below the WSPR signal level at 144MHz. A setting of 150MHz works OK but if my figure is correct a signal will go out. > You wonder about the source of 50 Hz sidebands. May I posit a cause?.... Glen, Thanks for your thoughts. It is OT if my observations are of locally created spurii but I thought I should mention it so others may check. I still observe spurii on HF with a different RX system all 50Hz apart, worst -44dB on 10m. 2m not noticed this time, in fact seems fairly clean. Strange, possibly just my test method. 73 Alan G4ZFQ
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Re: U3S Case front panel push buttons
To prevent excess heat reaching the switch body, clamp a haemostat*
between the switch and the tag.
toggle quoted messageShow quoted text
*A pair of needle nose or pointed pliers held shut with an elastic band is a good substitute. Alan
On 06/12/2018 17:02, Curt M. wrote:
I'm sure there's probably something else out there but it seems like the key with those switches is not put too much heat on the terminals when you solder the wires in place. They seem to act very similar to relay contacts when you put too much current across them. We used to always say that the contacts were "gulled", not sure if that is the correct spelling or even the correct term but that's what we used to say where I worked a number of years ago.
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Re: No GPS data with U3S - For Hans
Brian Summers
I've managed to come up with a procedure for repeating my problem. I've got the unit mode indices programmed so it operates as follows: 1. Power on U3S. Ultimate3S 3.12a appears. Then the display
switches to GPS data as it should. 2. Press the Menu button once and the display reads: 0]-0-000,473,000TX CW-------00-0 3. Press the menu button again and the displays reads: 1]-0-000,473,000TX CW-------00-0 4. All the above really shows is that I have the same message in
mode index 0 and 1. Not intentionally I might add. I'm new to the
U3S so this is all happenstance. 5. Now power off/on. Once again the Ultimate3S screen appears followed by GPS data. 6. Press the menu button once and see the display as para 2 above. 7. Now press the edit button twice to enable. The display will show: 0] 0 000,473,000TX CW 00 0 8. Power off/on. The Ultimate 3S screen appears, the GPS data
does not appear and instead the display shows as follows.
The beating heart appears where it should. TX CW 9. Press the menu button again and see: 0] 0 000,473,000TX CW 00 0 10. Press the menu button again and see: 1]-0-000,473,000TX CW-------00 0 11. You can see from 8 and 9 that I've created two messages identified with mode index 0]. Now you can repeat from para 8. The unit goes directly from the Ultimate 3S screen to the first mode setting every time, bypassing the GPS data screen. It all repeats. 12. To recover from this situation power off/on as para 8, go to the screen shown in para 9, then press the edit button twice to disable the mode setting. Now power off/on and GPS data will follow the Ultimate 3S screen. Doubtless there are other ways of demonstrating this but the above is repeatable for me. Here's hoping that when I post this the formatting does not change........ Brian VE7JKZ
On 11/30/2018 8:34 AM, Brian Summers
wrote:
GM Alan,
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Re: QCX CW transceiver
Roland Williams
I used clear nail varnish on the two I built and usually do that for anything that’s likely to move; it’s also good for stopping nuts from unscrewing to rattle around without making them impossible to remove. When I install transformers (the eight legged one is a great example) I just cut the wires to different lengths and use tweezers to put them in one at a time. Yes it’s fiddly but patience works fine.
toggle quoted messageShow quoted text
Roland AE6VL
On Dec 6, 2018, at 2:03 AM, David Wilcox via Groups.Io <Djwilcox01@...> wrote:
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Re: U3S Case front panel push buttons
Curt M.
I'm sure there's probably something else out there but it seems like the key with those switches is not put too much heat on the terminals when you solder the wires in place. They seem to act very similar to relay contacts when you put too much current across them. We used to always say that the contacts were "gulled", not sure if that is the correct spelling or even the correct term but that's what we used to say where I worked a number of years ago.
When I solder those terminals I quickly push and release the button multiple times as soon and I pull the soldering iron tip away. There were times a while back that the button would stick on the in position and it was from too much heat. Now they seem to hold up better with a lighter touch with iron but those switches are not good quality right out of the gate so I know what you are saying.
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Re: Active Aerials
ajparent1/KB1GMX
John, VA7JBE
No, That's designed for VHF and UP. it would be terrible for a whip. The amrad whip was a project maybe 10 years ago and use the CP600 series JFET. The article is posted with this message. FYI the fest are still available from teh source listed as of last year when I ordered some. For loops I included a copy of Chris Trask's paper, its a very good design. FYI most MMIC amp including the PGA103 suck at less than VHF. The coupling caps are too small, The output choke used is too small a value for HF and the Phemt based devices used are not very good at HF. Allison
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Re: Active Aerials
Perhaps it's the AMRAD active antenna featured QST Sept 2001 ? Alan
On 06/12/2018 13:51, Karl Heinz Kremer
- K5KHK wrote:
Allison,
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Re: Active Aerials
Karl Heinz Kremer - K5KHK
Allison,
toggle quoted messageShow quoted text
do you have a title or an author for the QST article?
On Wed, Dec 5, 2018 at 01:10 PM, ajparent1/KB1GMX wrote: AMSAT active antenna --
Karl Heinz - K5KHK
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Re: Active Aerials
Graham, VE3GTC
Try the PGA-103 MMIC (Mini-Circuits brand).
toggle quoted messageShow quoted text
while not targeted for MF/HF use it does work remarkably well at that frequency range. VHF and up oriented but a good all round intro to the device: http://www.w1ghz.org/small_proj/Simple_Cheap_MMIC_Preamps.pdf https://www.sv1afn.com/pga103m.html Active antenna preamp for HF use: http://www.g8jnj.net/activeantennas.htm cheers, Graham ve3gtc
On 12/6/2018, "erik@kaashoek.com" <erik@kaashoek.com> wrote:
I did try a MICC as amplifier for an broadband loop but I found they either have insufficient gain (as their 50 ohm input impedance is badly matched with the loop) or when cascaded tend to get overloaded due to the huge dynamic range of the received signals.
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U3S Case front panel push buttons
Vernon Matheson
Hi all,
Has anyone found a better quality push button . I replaced the original with ones from Ebay…same type and they have not lasted that long. Get loose inside and start skipping and double clicking etc.
Vernon
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KB3USG
Hey everyone,
I appreciate everyone's feedback and suggestions. On 2018-12-03 18:09-0700, Ronald Taylor wrote: First, No it is not right for this kit to have huge hum by touching the potThanks for this, Ron. I did check out the pot as you suggested, and I couldn't determine anything really physically amiss. However ... I did this, and nothing was really very different from the readings inMy current plan is to: the manual (or from my first check-out of the voltages across the board). However... when I was holding the board on one edge and my fingers touched the case of the 7805 regulator, the hum went away. Really sounding like a grounding issue. I'm thinking that I've done some irreversible damage to the pot that was not recoverable when I backed off the tension on the pot (I wouldn't think this possible, so I'm grateful for some of the remarks in the manual). I'll hunt down a pot to put in place for now and see whether that makes everything better. And then get to this: I'll keep updating the thread as I make progress.* (As part of my work peaking the BPF), take a couple of winds off Again, thanks to everyone who's reading these messages and musing to themselves, and to those who have spoken up with some advice for me. Thanks, Paul KB3USG
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