Possible solution to SSB QRM?

Skip to first unread message


Nov 6, 2021, 7:34:15 PM11/6/21
to digitalvoice
A question for any/all:

The first thing I noticed when I started listening with FreeDV (especially on Activity Day) was that hams on analog SSB are constantly QRMing the QSOs.

I think most of the QRM is only because the analog SSB ham doesn't hear a voice, and assumes the frequency is available. 

Has anyone suggested putting an analog SSB identifier at the end of each FreeDV transmit?

That way, analog SSBers could tell the FreeDV signal isn't "noise".

The identifier could be your call sign, seems reasonable because we're supposed to ID during QSOs.

WSJT-X still has a post-transmit CW identifier option, clearly those developers think it's useful.

Understood FreeDV is open source, and a good response would be "go do it yourself".. but that's not the issue. Is it advisable, desirable, useful, friendly, etc.?


Bruce Perens

Nov 6, 2021, 9:45:41 PM11/6/21
to digita...@googlegroups.com
I've long thought about adding PSK32 as an extra carrier just to identify us to all those people who have FlexRadio, etc. and see the PSK decoded in the waterfall. And of course you can stick a CWID on the end.

It may be that the SSB folks know what our modulation is and are just malicious.

You received this message because you are subscribed to the Google Groups "digitalvoice" group.
To unsubscribe from this group and stop receiving emails from it, send an email to digitalvoice...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/digitalvoice/5d802ce0-020f-4238-90bc-c1a24e182been%40googlegroups.com.


Nov 6, 2021, 11:08:04 PM11/6/21
to digitalvoice

>>It may be that the SSB folks know what our modulation is and are just malicious.

Unfortunately, during Activity Day, I saw evidence of that. 



Nov 7, 2021, 1:43:34 AM11/7/21
to digita...@googlegroups.com
As I mentioned to Andy privately, I see no difference here from when AM was king and SSB was the new kid on the block. Yes, there was intentional jamming just as there is today. The more things change - the more they remain the same.

{^_^}   Joanne/W6MKU

Keith Prosser

Nov 7, 2021, 9:20:29 AM11/7/21
to 'Bruce Perens' via digitalvoice
I hear a lot saying there is some funny noise and dot'n now what it is.
people  with they black box with a microphone !

Mooneer Salem

Nov 7, 2021, 4:45:39 PM11/7/21
to digita...@googlegroups.com
Speaking of QRM, there was a 1K wide signal on 14.236 MHz earlier today that seemed like it was originating somewhere in the NE USA. Anyone else happen to hear it? We haven't been able to identify what it was yet but it doesn't seem coincidental that it was being transmitted there.

-Mooneer K6AQ

n1ig anthony

Nov 8, 2021, 7:18:52 AM11/8/21
to digitalvoice

maybe I am just too optimistic, but I tend to think that most interference is accidental instead of being done on purpose.   

there is a good chance that a lot of people do not know what FDV would sound like, and just think it is someone sort of QRM.

it kind of sounds like the intermod I used to hear in NYC back in the mid-1980s.

Anthony - N1IG

Peter Reichelt

Nov 12, 2021, 12:33:22 AM11/12/21
to digitalvoice
Hi all

Does anyone have a feel for how badly affected the FreeDV was? I realise the effect is dependant on signal strength and differance in signal strength between the SSB and the digital signal. Genaral comments appreciated




Nov 12, 2021, 9:46:10 AM11/12/21
to digita...@googlegroups.com



We had a fantastic response to the FreeDV day event last weekend, with participation of stations from several places around the planet.


Just as with ANY place on the bands, even if your working ssb, there will always be the occasion where a station crowds you, or even transmits right over you.


As Anthony mentioned, the majority of the time is accidental with some areas just able to hear other areas as well, or no idea what the FreeDV noise actually is.


And of course, and sadly, sometimes it’s not so accidental, for unknown reasons.


But all in all, even with a little interference for what ever reason, FreeDV does pretty well against that, unless the interference is just too over powering.


A few of us have been using FreeDV through the linear ssb satellites with great success as well.


So there are plenty of opportuities to make great use of FreeDV, limited only by your creativity. 😊


Hope to catch you on the air!


Reply all
Reply to author
0 new messages