[aprssig] Ham Radio MOBILE Traveler PL-FIND device?

Wed Nov 29 12:34:52 CST 2017

Most analog FM repeaters that are worth anything usually have a voice announcement as to what the tone is. This helps a lot. 


FWIW. I travel now with APRS on Band A and VHF simplex on Band B on my Kenwood D710. So it transmits my B band freq. I have gotten a few calls on simplex from this setup.


On my ICOM 5100 I have my hotspot simplex freq loaded, and the hotspot on REF030C for the trip. Never have to change repeaters. And 30C is normally linked to my home repeater. 





From: aprssig [mailto:aprssig-bounces at tapr.org] On Behalf Of Robert Bruninga
Sent: Wednesday, November 29, 2017 11:09 AM
To: aprssig at tapr.org
Subject: [aprssig] Ham Radio MOBILE Traveler PL-FIND device?


APRSSIG thoughts about Mobile TRAVEL operations.


In the USA, at least everywhere that I travel, almost all voice repeaters are PL.  This PL, removes the fun of traveling and joining new conversations.  Fortunately, some brands (Kenwood does) have PL SCAN which helps to find the PL of an existing QSO, but it takes a few button pushes on each frequency to operate.  The wife does not like me touching buttons while I am driving.


But when there is no existing QSO and traveling in a new area, would it be practical to make an Emergency FIND-PL dongle to plug into the ACC jack on the back of a mobile that when activated on a given frequency, would automatically KERCHUNK while trying every PL until there is a response…


In the old days “KERCHUNKING” was a bad thing, because people did not like to hear a dead kerchunk without someone IDing.  But now, most repeaters are NOT USED much.  And PL keeps them quiet from noise. QSO’s are rare, its hard to find a contact…  And so maybe to increase activity, people wouldn’t mind an occasional PL-FIND search?


Plugging the dongle into the ACC jack gives all the access that is needed.  The PTT and SQL detect as well as the modulator input (with passband to pass PL tones generated by the dongle).


This idea of course violates some conventional thinking about kerchunking (up to 38 times till found).  But for the listener to a repeater that is being FIND-PL-searched, the other users will not hear anything until the correct PL is found and they will only hear the found repeater come up once, and then the person activating the FIND-PL search will of course voice ID.  SO to the casual observer, nothing unusual happened other than a Traveler just found a way in to call CQ..


The only second thought is that for up to maybe a minute the input to the repeater was being kerchunked causing some possible other user blockage.  But again, the timing could be such that if a real user with correct PL keyed up, then the auto-FIND-PL would stop anyway, so I don’t think there is any jamming issue either.


To do this, we would need to understand the typical ANTI-CHUNK delays in most repeaters.  If it was a full second, then it might take over a minute worst case to try all 38 tones while waiting to hear a response and while allowing some time every try for another user to bring up the repeater without any collision.


Just thinking…


Traveling without being able to play on repeaters due to inaccessible PL’s is no fun anymore.




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