[aprssig] INVALID STREAM entry in aprsd logs

Stephen H. Smith wa8lmf2 at aol.com
Tue Dec 27 18:02:10 CST 2005

fred at wb4aej.com wrote:
>     I just pulled up that D700a.  Wow, that's cool.  
>     Does it simultaneously run APRS while you run HF or VHF or can it only do one at a time?  
>     73, 
It would be rather difficult to run HF since it only covers 2M and 
UHF.   Otherwise it is a "dual dual-bander" -- essentially TWO dual-band 
radios in one box.  This allows you to run APRS on the left side, and 
voice either on another 2M freq or UHF on the right side at the same time. 

The main limitation is that if you run both sides on the same band, you 
can't receive on one frequency while you are transmitting on the other 
since there is no in-band isolation between the two sides.  It is 
possible to configure the TNC carrier detect to monitor both receivers' 
squelches so that an automatic APRS beacon will wait until the second 
receiver closes squelch before  keying up.   If you don't do this, you 
get about a 1/2 second hole punched into your receive on the second freq 
each time the APRS beacon keys up.   This creates an effect similar to a 
priority channel scan where your operating channel receive gets 
interrupted periodically to check the priority channel.

If you run 2M on one side and UHF on the other, the two sides are 
totally independent and can operate simultaneously. 

Stephen H. Smith    wa8lmf (at) aol.com
EchoLink Node:      14400    [Think bottom of the 2M band]
Home Page:          http://wa8lmf.com

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