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[aprssig] APRS and UHF voice

Dave Baxter dave at uk-ar.co.uk
Wed Jul 29 09:51:03 UTC 2009


Indeed, it's suprising how far UHF goes, even under "flat" conditions.
 
Notwthstanding the contest operation I've been involved with in the
past, there is a customer I visit on a regular basis here in the UK,
where in the past (before they started to use modern "digial" radios)
the security guards had a regular unofficial sked most mornings with
"other people" in Germany!

That started when they asked me one day, if hearing "German voices" from
their handies when patroling one part of the site early in the mornings
was "normal".  (They knew I was into Ham Radio, as I always had to
surender my rig to them on entry to the site, getting it back OK, when I
left later.)  I explained a bit about a posible propagation method, and
jokingly suggested they call back and see if the Germans can hear
them...

The next thing I hear some weeks later, was that it was indeed a two way
thing, and so reliable that it resulted in later years with face to face
social visits being made both ways!  They were using 5W UHF handhelds,
what the radio was in Germany, I (and they) dont know, maybe a private
site repeater?

That in turn I've been told, threw up some interesting coincidental
stories regarding the past uses of the sites at both ends of the RF
link!

The security radios at that UK site are now the new fangled digital
types, that dont work reliably from one side to the other of the site,
let alone anywhere outside it.  The phone has taken over for the German
link...

Cheers All..

Dave G0WBX.


________________________________

	From: lloyd at mitchell-web.net [mailto:lloyd at mitchell-web.net] 
	Sent: 28 July 2009 16:22
	To: bruninga at usna.edu; TAPR APRS Mailing List
	Subject: Re: [aprssig] APRS and UHF voice
	
	
		Bob, UHF is a real jewel for Amateur Use.  I changed my
Echolink link from VHF simplex to a local UHF repeater for the very same
reason you indicated....no blocking of signals...

	I was just as you were (all VHF) until a few months ago...

	KO4Lloyd

		-------- Original Message --------
		Subject: [aprssig] APRS and UHF voice
		From: "Robert Bruninga" <bruninga at usna.edu>
		Date: Tue, July 28, 2009 10:18 am
		To: "'TAPR APRS Mailing List'" <aprssig at tapr.org>
		
		Old Dog - New Tricks... 
		VHF =>> UHF
		
		For some reason, for my 40 years of VHF mobile
operation, I seem
		to only use 2m repeaters, just I guess out of habit..
And as an
		APRS mobile operator with a D700, I put up with the
occasional
		blocked voice and blocked packets while I drive around
only
		using the 2m band. But this weekend Appalachian Trail
event was
		an obvious eye opener for me.
		
		With all the coordination we were doing on 445, it was
just an
		all new experience to be TALKING on the radio, and
seeing
		packets coming in at the same time. And never be blocked
when
		packets went out. And with Murphy and his entire family
hanging
		around all the mountaintops, we were using the voice
		coordination channel orders of magnitude more than
expected.
		
		In my mobile, I have 117 VHF channels in memory and only
ONE
		(446.0 national simplex) in a UHF channel. Yet, in my
area, we
		have scores of UHF repeaters... And really good ones too
		(though silent 99.9% of the time)... That I have never
bothered
		to use... Thanks... This gives me a new bunch of people
to talk
		to...(and better reliability on APRS at the same
time)...
		
		In fact, for the Golden Packet attempt next year I hope
we can
		eliminate all 2m contact freqs, the reason being that
every
		second we might be talking on 2m, is totally blocking
our reason
		for being there, weak-long-haul packets. Also, every
time a
		packet goes out, we lose a second of audio on the voice
channel
		and have to ask for repeats..
		
		I agree, that the UHF is several dB worse than the 2m
links for
		omni-omni links, but I hope that is just something we
plan for,
		because once we are operational and lots of packets are
flowing,
		we cannot afford to lose even one packet (that may have
taken 13
		hops to get to us and only have one hop to go to its
		destination) because we were talking on 2m.
		
		So thanks for raising this issue. In fact, I'm going to
		re-program my mobile and see who is out there on UHF!
		
		Bob, WB4APR
		
		
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