SDR# CPD loss of signal

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Jphila20

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I put up a temporary 800mhz antenna and was pulling Cleveland in using an SDR. I'm about 30 miles from downtown Cleveland. Signal was 20 to 45, voice was choppy but it was working. Then all of a sudden no signal. A drop to zero. Switched over to MARCS with no issue.
If they switch to a different control channels would that create the issue.
 

Jphila20

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How would a different control frequency change the signal strength? Wouldn't it still be the same transmitter and tower? I can understand an increase if the new control channel frequency has less similar frequencies between me and the tower.
 

a417

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How would a different control frequency change the signal strength? Wouldn't it still be the same transmitter and tower? I can understand an increase if the new control channel frequency has less similar frequencies between me and the tower.
It shouldn't necessarily be the same transmitter, it's called redundancy. Programming multiple frequencies into a single transmitter gives you none. Having extra hardware onsite w/ failover capability does.

If transmitter x on frequency x s**ts the bed, then every frequency programmed into transmitter x is unavailable.
If transmitter x dies, and transmitter y on frequency y is colocated and set as a backup, it takes over w/o significant effort.
Subscriber units just look for another c/c, and life goes on.

Maybe transmitter y is backup unit set for a slightly lower power, or its got a different signal path / EIRP...different hardware, different output.
 

WA0CBW

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Could be there are two transmit antennas at different locations on the tower. Transmit combiner 1 might be for channels 1 thru 5 and transmit combiner 2 might be for channels 6 thru 10. Each combiner has its own antenna. Depending on each repeaters physical location each repeater is a different distance from the combiner and each frequency can have a different loss through the combiner. So there are many reasons each frequency can have a different radiated power output.
 

Jphila20

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Thanks! Been playing with these SDR's with DSP+ and CPD is a challenge because of the distance. Signal is always changing 55, 80, 60, etc. This makes audio adjustments a nightmare. I have an old GRE Super Amplifier 3001 on the feed and it helps stabilize it some.
Is there a list of definitions for the error codes on DSD+? Or a lists of what I am seeing? I get the Sync:p25p1 NAC:491 which I understand. It's the TDULC, LDU1, LDU2, no sync, invalid DUID, unrecoverable NID.

If I knew what they meant I may be able to better adjust.

Thanks again.
 

a417

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is it a TXCO dongle?

and no, there is no master list of error codes. If you want to post a snippet of what you think is an error code, some of the hive mind on here can tell you what's normal and not to worry and what is a legitimate error.
 

slicerwizard

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Is there a list of definitions for the error codes on DSD+? Or a lists of what I am seeing? I get the Sync:p25p1 NAC:491 which I understand. It's the TDULC, LDU1, LDU2, no sync, invalid DUID, unrecoverable NID.

If I knew what they meant I may be able to better adjust.
Invalid DUID and unrecoverable NID are decoding errors, simple as that. You're overthinking this.
 
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