Unable to receive anything on my 20m #chat


gabri22_@...
 

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Hi all, 

Months after I purchased the kit, I found some spare time to build it. I think everything went fine during the alignment process. I am able to find a maximum in the peak BPF menu and the plates of the trimmer capacitor are somewhere in their range.

However, I was unable to hear any station after several days and I am starting to think that there might be a problem.
Regarding this issue I wanted to ask whether it is possible to receive anything using this portable loop antenna: https://www.radioworld.co.uk/wonder-wand-wonder-loop-750-portable-loop-antenna

Do you think that could be the "problem"?  Or should I look for a hardware failure?

I do not know what can be wrong, the only thing I can think of is that during the alignment process, in the I-Q balance, Phase LO and Phase Hi menus, the amplitude bars jump around maybe too much (However, I can find a minimum value even though it does not remain "static")
I'll record a video of this so that you can actually see it if you think it is helpful.

This is my first transceiver ever, so I am a newbie in this topic and I feel a little bit overwhelmed about all the things that could be wrong. Maybe you can help me a little bit with your expertise on how should I proceed.

Regards,
Gabriel

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Rich
 

Did you get the loud tone in the headphones when aligning?  Have you checked that you have continuity (with an ohm meter) across L1, L2, and L3?


Rich
 

And - just in case you aren't aware, loop antennas have an extremely small tuning range.  You need to turn the antenna tuning knob slowly until you hear an increase in background noise.


jjpurdum
 

I think it's misleading to say they have a small tuning range. The range is fairly large, but the bandwidth without retuning is small. Indeed, many mag loops are multiband, but with less performance on some bands than others.

Jack, W8TEE

On Monday, September 17, 2018, 6:26:27 PM EDT, Rich <rich@...> wrote:


And - just in case you aren't aware, loop antennas have an extremely small tuning range.  You need to turn the antenna tuning knob slowly until you hear an increase in background noise.


Rich
 

Good point - my post was poorly worded - they have a very narrow in-tune range for a given frequency.


gabri22_@...
 

Yes, I get the loud tone in the headphones and I've also checked the continuity across L1, L2, L3. However I did it only with the audible signal of continuity. Should I specifically check the resistance?
Thanks for your response.


gabri22_@...
 

And yes, I tune my loop antenna and I am able to hear the increase in the background noise.

Thanks again, I am really lost with this because everything seems to be fine (at least in the receiving part). I will upload the video of the tuning process so that you can see how the amplitude bars jump around (which I assume it can be a problem for the receiving part)


gabri22_@...
 

Ok, so here you have the video example of the alignment process I performed. (Not too precise for having to hold the camer with the other hand, but you get the idea of the amplitude jump around and the values I get): https://www.youtube.com/watch?v=5lD0yGqcWmw

Thanks for the time you take to help me, I really appreciate it.


N3MNT
 

Make sure you are making contact on the solder pads and not the wire ends when checking the connectivity of the T1 windings.  Readings that "jump around" when doing alignment is an symptom of poor solder connections on T1.  Use a ohm meter not audible tone.


gabri22_@...
 

Hi again,

I've just checked the resistance between wire ends of L1, L2, L3, L4  and T1 on the soldered pads below the PCB and I get 0 ohm readings :s . 

Thanks for your response Chopper.


Richard G4TGJ
 

If you hear an increase in noise as you tune the loop then the receiver must be working. Listen on 14.074MHz. This should be full of FT8 signals during the day. The band will close in the evening.
--
73
Richard
G4TGJ


gabri22_@...
 

Thanks for your answer Richard, I'll give that a try. :)


gabri22_@...
 

Hi all, I've tried to listen on 14.074 MHz and I was unable to hear anything. So as a first approach to solve a possible hardware issue, I checked the voltages on the critical points pointed out in the manual. All of them seem to be correct except for the ones I attach:

I used 12.98V as the input voltage:
- IC6: Pins 1 to 8 should read: 2.44, 2.44, 1.63, 0, 1.55, 2.44, 2.44, 11.67 and I get: 2.88, 2.88, 2.87, 0, 2.87, 2.88, 2.88, 12.51. Should I assume pins 3 and 5 are wrong??
- IC7: Pins 1 to 8 should read: 2.64, 2.64, 1.99, 0, 1.89, 2.64, 2.64, 1.67 and I get: 2.91, 2.91, 2.90, 0, 2.90, 2.90, 2.91, 12.47. Again pins 3 and 5 are wrong?
- IC8: Pins 1 to 8 should read: 2.46, 2.46, 0.65, 0, 0.67, 2.48, 2.48, 11.67 and I get: 2.86, 2.86, 2.82, 0, 2.86, 2.88, 2.88, 12.50. Same situation?
- IC9: Pins 1 to 8 should read: 4.84, 4.84, 0.65, 0, 0.67, 2.44, 2.44, 11.67 and I get: 4.87, 4.87, 4.40, 0, 2.82, 2.82, 2.85, 12.50. Same weird thing for pins 3 and 5...
-IC10: Pins 1 to 8 should read: 5.83, 5.83, 5.83, 0, 4.21, 3.94, 5.83, 11.67 and I get: 6.26, 6.26, 6.26, 0, 6.20, 6.21, 6.22, 12.50. In this case pins 5 and 6 do not meet at the appropriate values.

Finally, some of the LCD voltages are strange too, but the LCD is working properly so I do not know whether this is related. Namely, LCD pin 4 is 0V when it should be 4.92, 7 to 10 are 4.96V when they should be ~1V and Pin 14 is 4.6V but it should be 0V. However, it is working fine...

I am sorry to ask so many times, but I am really lost with this.  I really appreciate any help or tip for continuing the troubleshooting.
Also, I've uploaded a new video where you can see that only "Phase Lo" alignment parameter seems to oscillate too much, just in case this is of any help.
https://www.youtube.com/watch?v=8IYG2aQI3CI
Thank you very much :)