Oh, no!?

A what ?
A PIC ?

Uhmm! This is?, like here in Germany , you have to choose an Opel or a Volkswagen, to be the better one,...
Or a Mercedes Benz instead? of an Audi , or a Porsche instead of a Toyata,...

Why not an 'Arduino'-type of controller? Maybe a lot of fellow HAM's will have this 6-pin 'up-load'-device from experimenting with the System Arduino-type - IC's, ... (Programmer)

No, it's only a joke!

But what I revere before, the choose of an Opel Astra instead of a Volkswagen Golf/Rabbit,... or a Comodore C64 instead a Sinclair ZX Spertrum (Timex 2000), ... or an 'YaeComWood' instead of a 'proud homebrew TRX',...

Just joking... It is Sunday! Go to your radios and 'transmit' , 'receive' and do amateur-radio.
Hope 2 meet u on the bands!

"... to the keys ..."? ?or:
"... to the keyboards ..." or:?
"... to the microphones ..."
What ever you prefere!

[instead: ... "to the stars" (ad astra) ,...]

73 es have a beautyfull sunday!

Markus ; db9pz

Thanks all of you for your suggestions of AGC. I appreciate them all. I have another few weeks (months) to do something reasonable and interesting..... I guess that the simplest design will have chance (I have my QCX in the original QRP-Lab enclosure)
TNX es 72! Jarda OK1MKX

Hi all,
I reported a couple of weeks ago about the gps noise and my qrp labs receiver, I have tried separate power supplies, shielded cable grounded one end only, metal enclosures.?
The gps is attached to my progrock and my solution is to simply disconnect the gps serial 1pps unless I check calibration of the progrock.?
I also have another, earlier, qlg1 attached to a u3s, in the same room and that one is quiet, both on the u3s and the receiver doesn't hear it. I haven't tried it on the progrock, receiver set up.
Andy

I’m using the same ear buds I use on my other QCX rigs. So I’m going to rule that out.
73;
Kurt W2MW?

Ok so a factory reset and still have the tone.?
Still digging
73;
Kurt W2MW?

Things I can rule out. I connected my WCX to a dummy load along with an RF meter in line. The tone I hear is not the side tone. The rig is not stuck in transmit.

So now to trace back the audio path to see which IC is in oscillation.?

Wish me luck
73;
Kurt

I'm curious if folks have identified a cure for this.

I'm running my QLG1 through a fairly long cable (QLG is upstairs in the kitchen) to my VFO/SigGen (it's in the
basement).? I am, like other posters here, hearing that pulse across a broad spectrum (don't have a precise
definition of that).

I tried wrapping the cable in ferrite cores, but that didn't help.

What I found was that if I disconnected the serial data line, the problem went away.? So, I can accurately
calibrate the VFO/SigGen, and I can show the 1pps heartbeat, but I can't show any of the data (date/time,
for example) that comes in the serial data stream.

Any hints would be appreciated.

- Bruce K1FFX

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Hi, Jarda

Here is a little circuit I added to my QCX. Not shown on the schematic is a 2.2k ohm resistor that I added between the middle leg of the volume control and the board. The 2N7000 transistor is installed between the ground end of the volume control and the board connection where the volume control middle connection goes.

To set it up, connect an antenna to the radio and set the volume to max, tuned to a clear channel (no signal). Starting with the 1K control set to the ground end, slowly rotate the control clockwise until you hear the band noise drop slightly. Back up slightly so the noise is not reduced.

Using the component values listed there is no "pumping", no loud blast and then reduce. It sounds like a "big radio", with signals against a quiet background, and background noise coming up when the signal fades to a bar or two on the signal indicator.

Jim W4JED

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Mr. Abeza

Menu item 8.5 sets the synthesizer reference frequency. Tweak the number a couple hundred hertz, SAVE and exit the menu. Try listening again. If the receive frequency has changed in the correct direction but not enough, tweak again in the same direction, judging how much to change it by the previous change. Etc. You should be able to get it within a few hertz of exact.

Jim W4JED

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??? ??? Dr OM Jarda ,

Indeed, Digital AGC will solve you problem .

This is a project based on a digital POT and a PIC12F683 Pic ?P .

Pass me your E-mail address and I will send you the full doc .

Note this project is open for hardware and software .

WD9HNU reproduced this 3weeks ago with success . Maybe you can ask him for a duplicate of the PCB , however this is also proposed in the doc , basedd on Kicad .

It's your choice .

in attachement the response curves of this project .

on5kn@...

73 Willy ON5KN

Hi Kurt. Looks like you got the first issue solved. I had a similar issue as you are now seeing with one of mine. PLEASE connect a dummy load before turning it on again ... and then check to see if it's transmitting. Listen for it on a receiver or look with your scope, or feel if the 3 power transistors are getting hot. It could be stuck in transmit mode and you are hearing the side tone. That's what happened to me. The issue on mine turned out to be a bad microswitch (the built in key) which was causing it. If it is stuck in transmit you need to trace out the keying circuit and see what's causing that. Good luck

73,

Ron WA7GIL

I have built and tested the digital AGC designed by Willy, described at this link.
Works quite well.
72 Fred WD9HNU

Thanks Alan,? I resolved my LCD display problem per your valuable assistance.
I went to the web site you indicated, and learned how to fixed my problem by changing
the 8.5 Ref Freq from 27,004,000 to 27,006,000. You made my day.
August WA2HTF

Generally there are three ways...

*Audio compressor in the audio stream.? The problem here is while the audio is?
kept from getting too loud if the station is strong the audio system will overload
and the use hears distortion.? There is a limit to dynamic rage of such a system.
Getting the levels and time constants correct for best possible dynamic range
is tedious.

*Use the audio to control a diode or fet based variable attenuator at the RX input.
This is before the receiver and both protects from overload and distortion
as well as keep loud signals from causing ear pain.? Biggest thing is connecting
to the receiver after the TR switching and before the receiver input.? Second is
getting the agc time constants correct.?

Manual switched RF attenuator (or variable) to lower the RF in for strong signals.
Its manual, just like volume control.

All work and both have the specific issues to implement.

I've implemented the RF AGC in a similar receiver using diodes with good result.
The system samples audio from the volume control rectifies it to DC that varies
with audio level and after amplification applies that to the electronic attenuator
(in my case using diodes).? ?Obviously I had to design it.? ?However it was easier
to do as I controlled the board layout and allowed room.? ?

The insertion point for such a circuit would be between Q5 and T1.

Allison

I wonder if anyone has an idea how to implement the AGC into QCX.....Tnx for hints !

Jarda

/g/QRPLabs/message/26070?p=,,,20,0,0,0::Created,,agc,20,2,0,24613271

73 Alan G4ZFQ

You're using the wrong ohmmeter. The black foam that semiconductors are packaged with can be used to make strain gauges. As you compress, twist, or stretch the foam the resistance changes.

Jim,
Or, maybe I had a piece of fake foam:-)
It certainly does work as you say.

73 Alan G4ZFQ

receiver to a specific frequency, the LCD display is indicating 500 hz lower then it should be.
As an example, W1AW is display as 07.0470 instead of 07.0475, this occurs on all selected frequencies.

The calibration is mentioned in the manual. Menu 8.5
And answered recently read /g/QRPLabs/message/26706 but look at the following post, I got it a little wrong.
Also you could see all of that topic.

73 Alan G4ZFQ

Assembled the QCX 40M kits, performed all the alignments, receiver
and transmitter functions properly. Transmitter output with 12.3 VDC applied,
indicates 2.65 Watts. The only problem I am experiencing, is when I adjust the
receiver to a specific frequency, the LCD display is indicating 500 hz lower then it should be.
As an example, W1AW is display as 07.0470 instead of 07.0475, this occurs on all selected frequencies.
Any help to resolved this problem will be greatly appreciated.

Hi Gents,
I wonder if anyone has an idea how to implement the AGC into QCX.....Tnx for hints !
Jarda OK1MKX