Re: Unusual PSK31 in Waterfall


Jerry N9AVY
 

In my 16 years tenure as an Official Observer with ARRL,  I used to find a lot of wide signals.  My first move was to turn off AGC and insert attenuation. This usually proved whether the signal was at fault or not.  In most cases the signal was fine.

 

Many times the fault may lay in the computer’s sound card as no 2 soundcards are alike and may introduce distortion into signal.  There are also other factors such as strong adjacent signal interference or mixing of products of modulation or even local noise in shack.

 

Upshot of this is if it happens with regularity it should be a concern, but if it’s only a one time thing , don’t be too concerned.

 

Jerry  n9avy

 

 

Sent from Mail for Windows 10

 

From: Bill Garwood
Sent: Monday, July 22, 2019 9:55 AM
To: 070Club@groups.io
Subject: Re: [070Club] Unusual PSK31 in Waterfall

 

Probably overdriven as Jerry mentioned.  But a clean signal can become distorted at the receiving end.  If you receive a wide or distorted signal, maybe try turning down the RF gain on your receiver or turn on an RF attenuator to see if this improves the reception of that station.  There is also some debate as to whether to turn on or off the AGC in your receiver.  Just be aware that it is not always the transmitting station at fault as the distortion which causes the PSK software to have problems decoding can be caused by propagation and /or by the technical capabilities and adjustments or maladjustments of the equipment at the receiving end.

Enjoy PSK31.  Hope to see you soon on the waterfall.

 

Happy Radio and 73!

Bill N4GBK in FM16

 

Sent from Mail for Windows 10

 

From: 070Club@groups.io <070Club@groups.io> on behalf of Jerry N9AVY <n9avy@...>
Sent: Sunday, July 21, 2019 5:37:53 PM
To: 070Club@groups.io <070Club@groups.io>
Subject: Re: [070Club] Unusual PSK31 in Waterfall

 

Looks like overdriven or overpowered signal is my guess.  Also seems to be mis-tuned. Signal should be between the red lines.  Hope you had mode set to BPSK31.

 

What software are you using ??

Jerry  n9avy

 

Sent from Mail for Windows 10

 

From: Tom
Sent: Sunday, July 21, 2019 4:01 PM
To: 070Club@groups.io
Subject: [070Club] Unusual PSK31 in Waterfall

 

Hello,

 

            Bill, # 1191, just told me there is no such thing as a stupid question in this group so here goes.

 

            I spotted the below on my waterfall the other day during a QSO with the transmitting station. It’s a PSK31 signal but looks very different from what I am used to seeing:

 

 

           

 

            What is unusual are the side bands that appear on both sides of the main signal. At first I thought it was another protocol interfering with the station but the side bands only appeared when the station was transmitting. The QSO did not go so well. He was getting good copy on me but I was only getting about 20 to 30 percent of what he was sending. 

 

            I am curious if anyone has seen this before and if it’s indicative of some type of interference or operating problem.

 

Thanks.

 

 

                                                --Tom, KC3DNG

 

 

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