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<div class="moz-cite-prefix">On 10/5/2025 8:37 AM, Arte Booten
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:c8713108-ab77-4825-bc06-265ba9461ccc@gmail.com">Hi all,
<br>
<br>
I'm retiring next year and will be living in a Class A Motorhome -
roughly the size of a bus. I already have a Yaesu FT-991A
160M-70CM principally for HF & C4FM and two 2M/70CM FM
antennas.
<br>
<br>
Ideally, I'd like an all-HF-bands antenna rather than have to
climb the ladder to change hamsticks though I don't intend to
operate HF SSB while driving - too many potential distractions.
<br>
<br>
What's worked for you. Equally pertinent - what didn't? 73
<br>
<br>
</blockquote>
<p>[On the road in Grand Junction, Colorado, returning to Michigan
after a week in Los Angeles.]</p>
<p> <br>
</p>
<p>Assuming you are going to use the FT-991, I think the
"no-brainer" choice (assuming you don't need 60 and 80 meters) is
the Yaesu ATAS-100 or ATAS-120 mini-screwdriver mobile antenna.
The FT-991, like the FT-857 and FT-891, can completely
automatically control the ATAS. Just select the band/frequency
40M-through-70cm and hit the TUNE button on the radio. No
separate control cable for the screwdriver motor is required --
the motor control voltage is sent up the coax to the antenna.</p>
<p>When the ATAS is hard-mounted on a substantial sheet metal mass
like the roof of a vehicle (not on a crappy gutter clip or
trunk-lip mount) it works amazingly well, even on 40 meters. It
tunes onto 30 meters very well for HF APRS operation too. (I have
mine in the center of my Jetta TDI's trunk lid.) It's no taller
than a common 2M 5/8ths wave - about 56-60 inches depending on
what band it is tuned to. (Gets longest on 40 meters; shorter on
the higher bands.) You might need one of the motorized tilt-over
mounts to lay it flat while enroute if mounted on the roof of a
Class A. <br>
</p>
<p>The ATAS base is a PL-259 connector; you will need a mount with
an SO-239 socket; not an NMO. I have multiple heavy-duty Larsen
NMO mounts (that are made of stainless steel-not the usual brass)
on my car. I then use the Tram NMO-to-SO239 adapter. Note that
the Tram is the only such adapter that is cylindrical (not
tapered) and fully supports the entire base of the ATAS which is
almost 2" diameter around the recessed PL-259 connector. (There
are a lot of other NMO-to-SO239 adapters out there but they all
taper to a smaller size at the SO239 end only suitable for
supporting lightweight VHF/UHF whips with PL-259 bases.)</p>
<p>As for the other post about using the SGC-230 Smartuner:</p>
<p>Normally the Smartuner is used with at least a quarter-wave of
wire at the lowest frequency of interest, like the back-stay of a
boat. It WILL tune into a 9' solid CB whip even on 75M, but will
be hideously inefficient on the lower bands (40-60-80 meters).
The tuner's internal L-network has to configure to such an extreme
matching ratio with such a short radiator that most of the TX
power is dissipated in the tuner - not delivered to the whip.
SGC used to offer a 9' fiberglass whip with two concentric
copper-tape helical windings that was far more "tuner-friendly"
than a simple 9' solid stainless whip. It was dramatically more
efficient on the lower HF bands. Alas, SGC no longer exists. <br>
</p>
<p>For any kind of a end-fed whip to work efficiently, you MUST have
an effective ground. This means connecting the ground terminal of
the SGC or similar tuner to a substantial metallic mass. At least
the vehicle body. If you are only operating in camp (not
mobile), consider the LOG (loop-on-ground) ground. Instead of
just stretching a straight wire outward from the ground terminal
of the tuner, you stretch 40-50-70 feet of wire outward from the
tuner ground terminal, form a roughly circular or elliptical loop
on the ground and bring the far end of the wire back to the tuner
ground terminal. This DRASTICALLY increases the coupling to earth
ground compared to a straight wire without having to drive ground
stakes into the ground. <br>
</p>
<p><br>
</p>
<p>One final comment: I considered the FT-991 for my "Studio B"
radio trailer setup. It looked appealing due to it's
"DC-to-light" band coverage, it's built-in sound card, the
continuously-variable DSP IF filters (nice for digi-modes
including my HF APRS-over-VARA operation), and it's ability to
directly control the ATAS screwdriver antenna. My radio trailer
is intended to be powered by batteries and solar power. </p>
<p>I rejected the '991 because of it's rather high power consumption
on receive: nearly 3 amps while most HF rigs (FT-857, FT-891,
IC-706, etc) consume only about 1 amp on receive. If you are
boondocking on battery-power-only, this is a major issue. The
ultimate power conservation setup would be an FT-818
"porta-luggie", with an external 5-watt-to-100-watt amplifier. If
you can tolerate the tiny front panel of the FT-818, it draws less
than 300mA on receive. It's actually essentially an FT-857 minus
the 100-watt-output PA. It has the same 160-thru-UHF coverage as
the FT-857 and looks essentially like an FT-857 to CAT control
software. However the '818 lacks the auto control for the ATAS
screwdriver -- the FT-857/897 and the FT-891 do have the ATAS
control capability. <br>
</p>
<p><br>
</p>
<hr width="100%" size="2">
<p>Stephen H. Smith wa8lmf (at) aol.com <br>
MS Teams:: WA8LMF<br>
EchoLink: Node # 14400 [Think bottom of the 2-meter band]<br>
Home Page: <a class="moz-txt-link-freetext" href="http://wa8lmf.net">http://wa8lmf.net</a><br>
<br>
Live APRS Mapping on HF & VHF<br>
<a class="moz-txt-link-rfc2396E" href="http://WA8LMF.net/map"><http://WA8LMF.net/map></a><br>
<br>
"Studio B" Ham Shack on Wheels<br>
<a class="moz-txt-link-rfc2396E" href="http://WA8LMF.net/Aliner"><http://WA8LMF.net/Aliner></a><br>
<br>
-- APRS over VARA --<br>
<a class="moz-txt-link-rfc2396E" href="http://wa8lmf.net/VARA/APRSoverVARA"><http://wa8lmf.net/VARA/APRSoverVARA></a><br>
<br>
---- Sent from my Panasonic Toughbook mobile laptop<br>
<br>
<br>
-<br>
<br>
</p>
<p><br>
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