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TX Problem
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"john349624"
Received my QRSS kit2 today.
Built it and started testing on wspr. everything runs ok, except that after the 2 minute tx period in wspr the display switchs back to the clock and displays the next tx cycle time, but the RF Output don't stop, it just keeps on txing , only way to stop it is to cycle the power, then start from scratch again. Any ideas??? G4PIR. |
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John Randall
Ovious question is if there is any RF floating around? and then if all grounds are grounded to common ground. I have frame =10 and start = 0 for WSPR mode. You could try this and if that fails, then try cw mode or another mode to see if you have the same problem there. Make sure all boards are fully plugged into each other. Also make sure you have 5v on the supply line. Mine is reading 4.95v John ? Digitally signed mail - M0ELS From: john349624 To: QRPLabs@... Sent: Tuesday, 30 July 2013, 19:21 Subject: [QRPLabs] TX Problem
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Received my QRSS kit2 today.
Built it and started testing on wspr. everything runs ok, except that after the 2 minute tx period in wspr the display switchs back to the clock and displays the next tx cycle time, but the RF Output don't stop, it just keeps on txing , only way to stop it is to cycle the power, then start from scratch again. Any ideas??? G4PIR. |
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"john349624"
Frame = 10 start = 0
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All gnd's are common PSU Set at 4.9v TX 14.097100 Output 9VPP After tx cycle output drops to 2vpp. If I go into menu between tx cycle then output drops to 0. Same on all modes. so is it firmware ? or I'll try again tomorrow with it boxed up. John. --- In QRPLabs@..., John Randall <m0els@...> wrote:
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John Randall
It could be that the chip is not seated properly. Push it firmly into its socket and then try again. John ? Digitally signed mail - M0ELS From: john349624 To: QRPLabs@... Sent: Tuesday, 30 July 2013, 20:15 Subject: [QRPLabs] Re: TX Problem
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Frame = 10 start = 0
All gnd's are common PSU Set at 4.9v TX 14.097100 Output 9VPP After tx cycle output drops to 2vpp. If I go into menu between tx cycle then output drops to 0. Same on all modes. so is it firmware ? or I'll try again tomorrow with it boxed up. John. --- In QRPLabs@..., John Randall wrote: > > Ovious question is if there is any RF floating around? and then if all grounds are grounded to common ground. > I have frame =10 and start = 0 for WSPR mode. > You could try this and if that fails, then try cw mode or another mode to see if you have the same problem there. Make sure all boards are fully plugged into each other. > Also make sure you have 5v on the supply line. Mine is reading 4.95v > John > > > ?? > Digitally signed mail - M0ELS > > > > ________________________________ > From: john349624 > To: QRPLabs@... > Sent: Tuesday, 30 July 2013, 19:21 > Subject: [QRPLabs] TX Problem > > > > ?? > Received my QRSS kit2 today. > > Built it and started testing on wspr. > > everything runs ok, except that after the 2 minute tx period in wspr the display switchs back to the clock and displays the next tx cycle time, but the RF Output don't stop, it just keeps on txing , only way to stop it is to cycle the power, then start from scratch again. > > Any ideas??? > > G4PIR. > |
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"andyfoad@..."
Hi John,
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When you say does not stop tx'ing I presume you are lstening on a nearby RX. If so then what you are probably hearing is the bare DDS output breaking through at a low level which I think is quite normal. Upon the next TX cylce you should see it restart at full power again. 73 de Andy --- In QRPLabs@..., "john349624" <g4pir.john@...> wrote:
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"andyfoad@..."
Sounds like the PSU is the problem.
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Are you using something simple like a 5v regulator to power it ? If so attached a voltmeter scross it under no load and then observe the voltage whilst putting your finger on the regulators metal case / tab. If you see even a minor variation like 10mv then you've got a decoupling problem and the regulator won't perform properly. What exactly is the PSU ? 73 de Andy --- In QRPLabs@..., "john349624" <g4pir.john@...> wrote:
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"john349624"
Hi andy thanks for the reply.
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PSU at the moment is a bench supply. When the kit is boxed up it will have its own 5v supply. As you said on your last reply it is the DDS carrier that i'm seeing after TX. So this is what happens. 1. Turn on the Kit. 2. Set Clock. 3. Set mode. 4. Start up. 5. No output On Watt meter. 6. First TX cycle I see 25dbm output (300mw or so) 7. Stop TX, Display returns to Clock and counting to next cycle. 8. I still see 7.6dbm output (5mw) 9. Next cycle starts output 25dbm. 10. stop tx , still 7.6 dbm output. So is this normal operation ? Regards. john g4pir. --- In QRPLabs@..., "andyfoad@..." <andyfoad@...> wrote:
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"andyfoad@..."
--- In QRPLabs@..., "john349624" <g4pir.john@...> wrote:
Hmmm, I'd normally expect a decent bench PSU not to create the problem you've described. But at unless there's a problem with the PA stage then it does usually point to the PSU. You'll need about 120ma for the DDS+LCD and about the same for 3 x BS170's at 9v. Thought so ;-)
It's the same as I observe here. I thought that Hans had changed the firmware to switch the DDS to another frequency when the TX goes off, in order to make monitoring the tx frequency easier. I wonder if a bit of code got lost from the beta version - Hans ? Kind regards, Andy |
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"andyfoad@..."
I thought that Hans had changed the firmware to switch the DDS to I wonder if a bit of code got lost from the beta version - Hans ? Aha - did that feature get dropped in order to meet the GPS calibration procedures ? 73 de Andy |
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Hans Summers
Hi Andy, John There was a request to keep the output on frequency and the TX going, in FSK/CW mode in between frames, except during the 13 seconds calibration, so that the temperature would be more constant and reduce the drift. This was put into v2.03. An unintended consequence was that on WSPR, the kit stays on frequency, though it is in key-up mode. However even in the key-up mode, some signal leakage does occur and I believe this is responsible for the effect you see.?
In v2.04 I do plan to eliminate this effect: I'll move the DDS off frequency or put it to zero frequency during key-up so that you don't see this effect. As soon as I get a chance to do this, I will. But there are only so many hours in the day, and they never seem really enough :-(
So in conclusion: just don't worry about it. It won't trouble WSPR decodes and I'll take care of it in the next firmware version, for anybody who still is worried about it.? 73 Hans G0UPL On Wed, Jul 31, 2013 at 8:47 AM, andyfoad@... <andyfoad@...> wrote:
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"john349624"
Thanks Hans.
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Mystery solved. --- In QRPLabs@..., Hans Summers <hans.summers@...> wrote:
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"andyfoad@..."
Hi Hans,
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Yes I had a sneaky suspicion something might have changed in 2.03. In the back of my mind seemed to suggest that in 2.02 it got shifted, but I blew my 2.02 chip up with a little accident I had (cough) so I couldn't confirm it ;-) I've got a good stock of 2.03 chips now just in case I have any more "senior moments". Doesn't bother me either way, I'm entirely content here with the versions I have, for me they are perfect. 73 de Andy --- In QRPLabs@..., Hans Summers <hans.summers@...> wrote:
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Hans Summers
Hi Andy Yes, it does appear from all reports that v2.03 is perfect. ALMOST perfect. A very few wishes include shifting that residual 25-30dB down on-frequency signal between frames. I'll get to it... v2.04 will come some time soon
73 Hans G0UPL On Wed, Jul 31, 2013 at 6:00 PM, andyfoad@... <andyfoad@...> wrote:
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"Don"
John,
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Check Frame option. It should be greater than 2. I use 4, thus giving me 2 minutes on, 2 minutes off. Don --- In QRPLabs@..., "andyfoad@..." <andyfoad@...> wrote:
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