[FoxHunt] The Joy of Rec mode.

[sdonnell]

"J. Craswell" wrote:

> wing.  "Ease of use" i.e. follow the pointer is all ok but I prefer the weak
> signal feature of Recv mode and I don't mind spinning around to get it.  We
> use the Flex-o Yagi and this helps with signals that are horizontal.  Plus
> we don't really do all that much spinning around since we just wave the flex
> around like a magic wand.
>

Hi Jay, I completely agree that using the ELPer in Rec mode is the way to go,
especialy for weak signals. By the time I get close enough to  get a strong
signal we usually swap over to some variety of sniffing. I dont know how correct
it is, but I feel that many of the performance(reliability/repeatabiltiy) can
often be traced to the antenna. Either how it is deployed or the condition of
the elements. This is why we invested in a padded shotgun case to carry our
ELPer and related gear. I also think that it would be advisable to tighten the
screws that hold the elements every so often, as loose/oxidized connections
could affect the readings, as could intermitant connections in the BNCs. A
couple of times Ive swapped my ELPer receiver to other ELPer antennas, and visa
versa, and the readings the recveivers produced were consistant, but varied,
depending on which antenna was used,,.

Ques: Is your Felx-o Yagi based on the design Ive seen by WB2HOL(yes I know the
dimensions are different). Your Web page is GREAT(I mentioned it on the NHWG
mailing list), but the yagi construction could use a bit more detail. Are the
flex tapes clamped to the boom using the PVC Tee's? Do you use any sort of
decoupling on the coax? I would like to see the specs for the 5 element version
sometime. This could be a fun project for the Cadets(and us old folks,).


>
> you also need to steer clear of power lines.  Maybe that should be #1 since
> following powerline "leaks" catches a lot of the fellows.    And beware
> reflections.  I think that trust your equipment is important also.  Had a
> weird conversation with a team that was sure a signal was East when all the
> indications from the equipment were West.  I asked "why" and they said they
> just had a feeling.  The L-Per in this case was right.  Feelings smeelings.
> BTW has anyone else noticed that real ELTs with good batteries travel a very
> long way?   A heck of a lot further than our training beacon. (I think)
>

Powerlines can also be your friend: While they can play havoc w/ DF bearings,
while mobile, I will ocassionaly check when I drive under them, as they can
sometimes provide the first "whiff" of a signal that you woudnt otherwise
catch...This helps when you dont have an Aircrew handy,,.

A lot can effect ELT signal range, terrain, elevation, antenna placemet to name
a few. Tyically, Id say 2-3 miles max for ground level reception, even w/ good
batteries. Sometimes only a mile or so. Although one a couple months ago that
was first heard using the Arrow yagi, was about 8 -10 miles. That one had good
batteries, and was in a house, on a small hill. Surprisingly, the SARSAT was
only getting intermitent hits on it. But it had also been reported by numerous
passing aircraft. Which brings up one question Ive had: How reliable do you find
SARSAT hit data. One positive asspect, Ive seen is that the lat/lon plots have
gotten MUCH better from where they were 10 yrs ago. But Ive also seen many
instances where the satellite did not pick up an active beacon signal at all, or
only produced interitent hits. Have they "tightened the squelch" on the receiver
so as to reduce false hits? I know that the angle of elevation for a given orbit
can greatly affect accuracy too. Although Im still amazed at times as to what
the SARSAT DOES pickup, like the old EPIRB that had its antenna removed; the
satellite was only seeing it's 243 signal.. Or the EPRIB we found floating in a
pond directly next to a garbage recycling center. One of the things that makes
ELT/EPIRB tracking easy(er) is that the tx power they produce is all roughly the
same, about 100 mw. This seems to produce a somewhat consistant range
"signature".

My (least)favorite ELT are those old EBC 102's; They have a hair-trigger switch,
and produce just enough tx power to produce intermitant SARSAT hits. Not to
mention, when they lay flat, w/ the antenna horizontal, they produce a very
weird signal pattern..

Steve Donnell
WA1YKL/Abenaki 102



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