"k1drw" wrote in message
oups.com...
Hello:
I am looking words of advice on conducting an informal exercise to
evaluate performance of 75m mobile systems. I have done much reading
of rec.radio.amateur.antenna threads and have learned much from Cecil,
Reg, Keith, Roy, et al. The msg threads addressing how measurements
were taken during past shootouts have been very helpful but equipment
used in those events seem to be beyond my capabilities.

I am part of an ARES/RACES HF Mobile team. We are in the early stages
of assembling our team and have conducted a couple of field
exercises. I believe I adequately understand many of the issues
related to operating 75m mobile and have concluded (from assessing our
mobile configurations) that our systems are VERY compromised. As we
conduct our EmComm field exercises we take the opportunity to
experiment and make system adjustments that clearly improve
performance. Primarily we are using 100w mobile hf rigs with 75m
Hamsticks or Hustler resonators. We understand that the vehicle, the
antenna, the ground, etc comprise the "System". One important note
is that we are not focused on achieving DX communications. Our field
of operations is primarily Groundwave within a tri-county area in
Eastern Pa (many 600-700 ft ridges and valleys, heavily forrested),
perhaps 100 miles max. We do use and experiment with NVIS (using
restricted space configurations: tilted whip, Hamstick dipoles, etc)
however, this query is relative to Groundwave.

I would like to add an occassional field exercise expressly for the
purpose of measuring the performance of our systems (for improvement
and detecting problems). We currently have no equipment for this
purpose. One device I see advertised and would like some feedback on,
is the MFJ-802 Field Strength Meter.

- Would the MFJ-802 be an adequate measuring device for our use ? Any
caveats ?
- What test FIELD environment should we try to arrange (e.g. large
empty parking lot, or a rural open field) ?
- When testing each vehicle, what space should separate it from other
vehicles waiting to be tested ?
- Should the vehicle sit stationery, or be moving in a circle ?

Any suggestions offerred to assist with this effort will be sincerely
appreciated.

regards,
Dennis, K1DRW

If you are actually looking for EmComm antennas (as well as the test
equipment, I would strongly urge you to look at the screwdriver. In
addition to blowing the socks off the hamstick/Hustler, it has a flexibility
that is amazing. For example, if you are looking at fixed and
fixed-portable operation, the screwdriver can be used as BOTH a mobile
system OR a FIXED antenna. Simply make a "half-dipole" arrangement with a
random length of wire, a rope and the usual insulator. Remove the whip,
and, using a 3/8" X 24 TPI bolt, attach one end of this one-pole(?) antenna
to the top of the screwdriver and sling the other end (rope) into a nearby
tree. You can then tinker with NVIS, high-angle slopers, height of the
wire, or the mobile whip to get whatever configuration that works at the
time PLUS quickly QSY to ALL frequencies of interest. Of course, the longer
the wire, the better it works on the lower frequencies and you will lose the
higher ones. But you can make more 'poles to put in your kit to account for
this and/or place the whip in a variety of positions. LOTS of ways to play
with this. The screwdriver is definitely the way to go!

73

Jerry
K4KWH