DSDPlus How Do You Make The Bandwidth Stay Put?

[CanesFan95]

I use -b12.5 but it still keeps changing it. Same thing if I type b/B. I want it to stay put.

 

[BM82557]

From the Notes.txt file --

-b-<bw> bandwidth locking command line option added

Example: -b-12.5

When this option is used, FMP24 ignores bandwidth hints from DSD+;
use this option to manually control bandwidth in -rc and -rv modes

 

[CanesFan95]

Well, I tried that one and get an error:

 

[RaleighGuy]

Well, I tried that one and get an error:

View attachment 99033

Could it be, as you were told in the OTHER thread, you are using older software. You need to be using the most current and should download and update the base files

 

[CanesFan95]

I actually did just get the base files before that error.

 

[BM82557]

From the Notes.txt file --

-b-<bw> bandwidth locking command line option added

Example: -b-12.5

When this option is used, FMP24 ignores bandwidth hints from DSD+;
use this option to manually control bandwidth in -rc and -rv modes

Not valid to use with FMPA

 

[wgbecks]

Not valid to use with FMPA

Yes! But it need to work for Airspy and SDRPlay as well. Without out it DSD+ keeps setting to a narrower bandwidth that causes bit errors and loss of frame sync upon modest multipath. This has been observed primarily on P25 Phase-1 whereby DSD+ switches to LSM causing loss of frame sync then realizes that it's not simulcast and switches back to C4FM. Not good and I have emailed the development group twice in this regard and have been ignored!!!

I am far from a DSP expert, but forcing the signal through the narrower filter causes group delay that aggravates/triggers the above state condition that otherwise is not a problem on the same system and same identical conditions if you give up your Airspy or SDRPlay and just use an RTL SDR.

 

[Forts]

Example: -b-12.5

You have an extra - in there. It should just be -b12.5 (or 4, 7, 9.5, 12.5, 22)
This command is the same for FMP24, FMPA and FMPP.

 

[CanesFan95]

That's a bummer that it doesn't work on an AirSpy. I wonder why on Earth they would do that? I've already been using -b12.5, but every new transmission, the bandwidth changes and I want it to stay put.

 

[Forts]

I haven't noticed that with my Airspy.. I'll have to try it later. What if you drop the -b from the command line and just set the bandwidth manually from within DSD+?

 

[CanesFan95]

If I type b or B, it'll change the bandwidth, but it'll just keep going back to something else. It won't stay put.

 

[kd5dga]

The -b12.5 option works very well.

 

[CanesFan95]

Not for AirSpys.

 

[moonbounce]

I use -b12.5 but it still keeps changing it. Same thing if I type b/B. I want it to stay put.
[/QUOTE

Try putting a putting a - in front of the 12.5 as well as the b like -b-12.5

 

[CanesFan95]

^ Is that whole post a quote?

-b-12.5 doesn't work (see above).

 

[moonbounce]

^ Is that whole post a quote?

-b-12.5 doesn't work (see above).

I don't know how the post ended up as a quote, it was supposed to be a reply, just like this one.
So if I take out the minus in front of the 12.5 my BW will switch between 9.5 and 12.5, I use an RTL2838u v3.

 

[moonbounce]

One other thing I forgot to mention is that after you make the change you have to exit out of the program and restart it for the change to take effect.

 

[GTR8000]

RTL2838 ≠ Airspy

FMP24 ≠ FMPA

 

[rmosier]

The OP is absolutely correct. I have the SDRplay RSP1A with up to date DSD+ Fastlane files and I have the same issue. I applied the "-b12.5" command to FMPP-CC and later to FMPP-VC. And as the OP stated, after a short time, it changes to 9.5 I too used the b/B function from both the wave form display as well as the FMPP DOS command window. The program responds with " 12.50 Khz RF bandpass filter selected" but it still changes back to 9.5 . The problem is real.