Reducing Bandwidth for better RADE performance

[Alan Beard]

I can change the bandwidth for the SSB decoder in the WebSDR here.

What settings are recommended?

Currently 200 to 2800 Hz, Can I reduce this and improve the small signal

l

performance?

Alan VK2ZIW

[Rick, W4XA]

Hi Alan, 

I use 1.5kHz (BW) for receive and 500-2000 Hz tx with my IC705

73/Rick

[Rick, W4XA]

Correction:  500-2500Hz with SSB-D for the IC705 tx bandwidth (2000Hz) 

[Stefan N.]

750-2250 Hz would give you the intended 1.5KHz of the RX Signal. Often a problem to (easy) setup this on non SDR Radio's, if you use SSB for FreeDV, like i do on the 991a. 

It’s easy to adjust that on WebSDR‘s (and SDR Radios) and helps, if you want to cut of QRM below, or above the 1.5Khz FreeDV „mainstream“.

73, Stefan

[Alan Beard]

I've reduced the bandwidth to 700 to 2300Hz and decode seems as good as before.

Nepean Mens Shed SDR

Alan VK2ZIW 

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[Rick, W4XA]

Yeah.  It would.  500-2500 is the SSB-D selectable limit on the IC705.   Don't know about the IC7300 or other radios.

[Alan Beard]

Stations heard with this new setting, 700 to 2300 Hz, over an hour of QSOs.

VK3FAR VK3AOB VK2VCO VK3AOB VK2VCO VK3AOB VK3AOB VK2VCO VK3FAR
VK3FAR VK3AOB VK3FAR VK3FAR VK3SRC VK3FAR VK3SRC VK3FAR VK3SRC
VK3FAR VK3SRC VK3FAR VK3SRC VK3FAR VK3SRC VK3FAR VK3SRC VK3FAR
VK3SRC VK3AOB VK3AOB VK3AOB VK3AOB VK2VCO VK3AOB VK2VCO VK3AOB
VK2VCO VK3AOB VK3AOB VK3AOB VK2AWJ

This is from the freedv-ka9q log.

Alan VK2ZIW

[Stefan N.]

Rick,

Non-SDR radios usually only have 'presets'. I use the settings mentioned (750–2250) for the TX/RX bandwidth on my Flex6400M. 

I can set any bandwidth with 1 Hz accuracy, which is very helpfull in this case of course ;-)

It might be helpful to discuss this topic via Internetreporter Chat? I feel that accessibility via this forum is quite limited?

BTW, unfortunately, it is also difficult to communicate to the majority that the "calling frequencies" should not be used for long QSOs or networks, which has already been discussed here. 

Bummer, without success.

73, Stefan

[Rick, W4XA]

REF: "Calling Frequencies" I wholly agree.

For example,   7177kHz is absolutely NO GOOD on the US West Coast and possibly MidWest because of the Mabuhay Net that is on the 7178KhZ just about every afternoon and evening.  

I would LOVE to get these guys to try FreeDV.....But,   If they hear DV on 7177 jamming their net every evening from US stations on the east coast and MidWest (and even some on the west coast) it's going to put a damper on getting them interested in trying DV

The above is a screenshot.  It's not "clickable" but there are several links for the Mabuhay net including on Facebook etc.

When 40m "goes-long" in the evening on the east coast, we start hearing east coast stations on west coast.

Kudos to Fred,  N3FL and the 40m Activity Net for choosing a frequency that well avoids 7178 !! He's REALLY strong on the West Coast at about net time and later.

For the rest of us, we can EASILY find clear frequencies using the Reporter, and or briefly selecting "Analog" and either listening for SSB stations or just asking if the frequency is in use before blasting out a DV signal!

I recently answered a message on eHam from a PNW amateur that asked "what is that digital signal I hear on 7186kHz" 

https://www.eham.net/community/smf/index.php/topic,144094.0.html

I did reply explaining what was going on,  but he didn't reply nor did anyone else reply to my answer.

I know I should not have to say this, and I know not everyone is doing this..... but we absolutely need to encourage amateurs to try FreeDV instead of enraging them by (intentionally or accidentally)  transmitting over established analog SSB QSO's in progress!

Just saying!

73/Rick

W4XA 

Buckley, WA