Eric Lemmon wrote:
> Paul,
>
> When you push for a wide-spaced portable repeater pair on 2m, suggest a
> separation of at least 3 MHz. The reason is that you can buy "compact base
> station" duplexers that are specified for 3.0 MHz spacing, but the
> performance rapidly deteriorates as the spacing is reduced below that point.
> I bought a Celwave 5085-1 duplexer that was factory tuned to a 2.655 MHz
> split, and it works okay with a 10 watt R1225 repeater, but it took some
> tweaking. The entire repeater fits into a rugged fiberglass case that is
> less than a cubic foot in volume. I hope to complete the final version
> shortly.
>
> It will be a challenge to create a 3 MHz pair in only 4 MHz of spectrum, but
> it can be done. Let's not forget that the purpose is to support *temporary*
> communications of an emergency nature. While it would be nice to have a
> pair permanently set aside for this purpose, I'll bet that a true emergency
> will trump any other claim to existing frequencies. If the PL encode and
> decode tones are intelligently selected, any interference to established
> repeaters should be minimal to nonexistent. If the portable repeater is
> positioned in the area where radio comm is needed, low power works wonders!
>
> 73, Eric Lemmon WB6FLY
We can't even get real emergency groups around here to use STANDARD
OFFSET UHF repeaters most of the time.
Color me VERY skeptical that any more than a few people will ever truly
use a wide-split portable VHF repeater in a true emergency.
Overloaded, stressed out people, don't respond well to "dig out your
manual and figure out how to program in a 2.655 split repeater". And a
large number of people wouldn't or couldn't -- sad, but true.
Plopping a "simplex repeater" or even a "backup real repeater" on the
output of a dead repeater affected by the emergency... (no power or
whatever other damage it suffered)...
... right on the regular old coordinated pair... (once you know the real
repeater there is dead and down for the count)...
... is SO much more likely to be effective -- that anything else pales
by way of comparison.
We hams "over-engineer" this stuff, constantly.
Some of the silly stuff I've watched so-called "emergency" planners come
up with over the years is amazing. NONE of it can be reasonably done in
a REAL emergency, and isn't, usually.
(Ex: Yeah, everyone who hasn't used packet in 10 years is all of a
sudden going to fire up the Statewide backbone, put a couple more BBS's
on the air, and everyone's going to remember how to set up their user
stations perfectly and no one's going to hog the channel or interfere
with anyone else... Packet always comes up as one of the "big answers"
ES people seem to like, and NEVER EVER really USE. We had a 1200-baud
digital-regenerative repeater on the air from a site that had 5W outdoor
150+ mile coverage, and it was on the air for 5 or more years. Know how
many users it had? Maybe 5. Was it the perfect answer to the "hidden
node" syndrome of a busy packet channel? Yes. Want to know why ARES
didn't use it the two times in that 5 years they fired up packet for a
real emergency? PRIVACY CONCERNS! They could make the hops they needed
DIRECT so there the repeater sat, unused.)
The reality of emergencies is -- real emergencies -- people will
congregate on frequencies they're used to using -- even if just on the
output frequency -- and by putting something THERE in a REAL emergency,
it is 100% more likely to be effective and USED than anything else.
In fact, that's my experience... the gaggle of hams wanders around
kerchunking until they find the best coverage real repeater on the air
that covers the affected emergency area, and then that repeater
instantly becomes the busiest repeater around. No matter if it's the
worst-engineered, or the best... if it's on the air when the
big-bad-high-sites are down, and it covers the affected area -- whoever
built it better hope it has the ability to handle 100% duty-cycle.
Just common sense. People are going to use what they're used to, so
don't over-engineer an "emergency" solution -- build one that
capitalizes on people's repetitive and habitual nature. Build emergency
RF plans SIMPLER not more complex.
If I walked up to any member of ARES/RACES in Colorado and said,
"Without looking, can you tell me the Statewide Emergency & Special
Event VHF Frequency Pairs?"... they'd stare at me like I was insane.
Anyone here think a majority of the so-called "best trained" emergency
communicators in the State would know them, from memory?? Have them
programmed in all their radios??? Even know they exist????
"Anyone have the 220 MHz E&SE pair for Colorado memorized?" "440 MHz??"
Yeah, right. ;-)
It might be an interesting experiment to try on a few ARES nets this
week... heh heh. I could be wrong.
Try this one:
"What's the national simplex calling frequency?"
Yep, they'd ALL get that one... I guarantee it. Probably for multiple
bands. Maybe even for different modes!
Humbug, I say to E&SE pairs. For real big emergencies there's better
ways. For emergencies, I don't find them all that useful -- Just plan
to be on the repeater output until it comes back on the air. People
know where everyone else is, and they can pass around info about what
fixed location repeaters are still on the air.
For SPECIAL EVENTS -- E&SE Pairs are GREAT! Little portable repeaters
can be set up and torn down without any worry they're going to bother
another repeater nearby. That's good stuff.
If we have to call them "Emergency" AND Special Event to politically
keep the pairs open for events -- that's a different issue, and I'd say
DEFINITELY DO IT. But for real emergencies, people are not going to use
them -- really. They never do.
Nate WY0X
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