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FLAmp on VHF through linked repeaters

Bart N5BLP
 

I participate in a digi net that works VHF on a linked repeater system with four repeaters.  They mostly do FLMsg traffic, but I've tried to send FLAmp traffic on it.

It just doesn't seem to work as well as it does on HF (which, of course, is simplex). For a nice, clean signal environment it drops a lot of blocks.  Some operators eventually get it completed when I retransmit the missing blocks, and others don't. 

We've done everything we can to cope with the repeater environment.  We've enable TX/RX interval so the repeaters don't time out, use a 2.5 second pre-signal tone on the RSID, and have the SignaLink delay set to about 60%. 

FLMsg works pretty well (although sometimes parts of it get scrambled), but FLAmp just doesn't seem to.  Is there something about the way FLAmp does it's error checking that isn't compatible with a linked repeater environment?  Has anyone else ever tried it over linked repeaters?

Bart N5BLP

Dave
 

You did not say what modes are being tested on the linked repeaters.  My guess is that one or more of the repeaters are distorting the signal with the pre and deemphasis associated with voice repeaters.  You also might check to be sure that the repeaters do not have tone notching enabled.  Lastly, the signal levels should never drive the repeater audio sections into clipping.

David

On 4/8/19 9:33 AM, bartpearl via Groups.Io wrote:
I participate in a digi net that works VHF on a linked repeater system with four repeaters.  They mostly do FLMsg traffic, but I've tried to send FLAmp traffic on it.

It just doesn't seem to work as well as it does on HF (which, of course, is simplex). For a nice, clean signal environment it drops a lot of blocks.  Some operators eventually get it completed when I retransmit the missing blocks, and others don't. 

We've done everything we can to cope with the repeater environment.  We've enable TX/RX interval so the repeaters don't time out, use a 2.5 second pre-signal tone on the RSID, and have the SignaLink delay set to about 60%. 

FLMsg works pretty well (although sometimes parts of it get scrambled), but FLAmp just doesn't seem to.  Is there something about the way FLAmp does it's error checking that isn't compatible with a linked repeater environment?  Has anyone else ever tried it over linked repeaters?

Bart N5BLP

Bart N5BLP
 

Dave:

I tried MT63-2000L and MFSK-128. 

I'm sure the signal levels are OK.  Next time I get a chance to talk to the repeater custodian I'll ask about tone notching.  Given that we routinely use FLMsg and FLDigi over these repeaters, would that indicate it's NOT using tone notching, or would that be more of a problem for FLAmp?

I agree with your guess.  I'll ask the custodian about pre and de-emphasis also.

Bart N5BLP

Marvin Penepent
 

We have used FLDIGI on a repeater and worked well. Have no filters on no notch and if using a Signalink the delay all the way to the left. 


Larry
KF5MLP

From: "bartpearl via Groups.Io" <bartpearl@...>
Sent: 4/9/2019 8:15:34 AM
Subject: Re: [nbems] FLAmp on VHF through linked repeaters

Dave:

I tried MT63-2000L and MFSK-128. 

I'm sure the signal levels are OK.  Next time I get a chance to talk to the repeater custodian I'll ask about tone notching.  Given that we routinely use FLMsg and FLDigi over these repeaters, would that indicate it's NOT using tone notching, or would that be more of a problem for FLAmp?

I agree with your guess.  I'll ask the custodian about pre and de-emphasis also.

Bart N5BLP