Darryl
Not sketchy at all. Very well described and easy to envision without looking
at the citatations, which I will do after nets tonight.
What you describe fits well with what I had in mind for the build. It sounds
like you run two rotors, one front, one rear, I am anxious to look at the pics
and if you run dual rotors learn how they were, I assume, linked together for
parallel pointing for fast QSY, a later discussion.
It is fascinating to compare the set ups for the many replies I have had.
Each op area has slightly different configuration to take advantage of slightly
different strategies for the NE, Plains States, SoCal and PNW.
Reflector Users and PU Rovers:
So as not to clog the reflector with stupid newbie questions I will be putting
future replies direct to contributors and not cc'ing the reflector. If
contributors prefer I only reply directly to them so as not to make "secrets"
public let me know. We all work hard for the "unfair advantage" and I
appreciate that. If contributors dont mind the public discussion on the
reflector and no reflector members mind i will keep the discussion on the
reflector so others might benefit.
Darryl,
Thank you. Incredibly helpful.
73
John
KM4KMU
On Monday, January 27, 2020 Darryl J. Holman <djholman@uw.edu> wrote:
John,
Perhaps the best way to see photos is to go to my QRZ page and click on
the VHF contests and sprints from 2015 through 2019. There are many pictures
there of equipment, antennas, views, etc. You can find even more photos by
"directory browsing" (https://djholman.csde.washington.edu/ww7d/). Directories
have descriptive names and are a mix of VHF and HF mobile contests, SOTA
activation photos, and a few construction projects. Pick ones that seem like
they may be of use.
In Washington state, overhang limits are 4' off the rear bumper (without
flags/lights), 3' off the front bumper, 0" off the driver side fender and 6"
off the passenger side fender. Therefore, my rear 6m 3el Yagi, has a 6' long
mast and is stowed perpendicular to the direction of travel while in motion,
and is "barely legal." The rest of the rear antennas are pointing in the
direction of travel (or 180 degrees from that). When I extend the mast, the
antennas are all aligned to the same direction, of course.
For mounting the rotor frame, I build a bracket that attaches via the
tailgate hinge bolts. That bracket lives in the truck full-time (and sometimes
it is a nuisance). The rotor frame bolts up to that bracket. There is a
lightweight bracket at the front of the rotor frame, as well, that is connected
to the truck bed sidewalls with some home made clamps. But your pickup
probably has much better options for mounting things than my Toyota has.
The front antennas all fall within 3' of the front bumper when being
rotated. They are held in a rotor that is on a custom built frame that bolts
up to the front of the truck. It looks like I built that for the Jun 2013 ARRL
VHF Contest (https://djholman.csde.washington.edu/ww7d/JunVHFContest2013/). I
use short WA5VJB "cheap yagis" for all the front antennas except 6m. For 6m,
I use a classic hex beam. I don't use a Moxon for 6m because it would not be
legal unless pointed into or away from the direction of travel, as it would
exceed the 3' overhang off the front. The classic hex beam has a small enough
diameter to be legal. You can find pictures of the hex beam construction
here: https://djholman.csde.washington.edu/ww7d/6MeterHexBeam/. ; A full
construction article for the hex beam is part of the supplementary materials
for the newest (24th) edition of the ARRL Antenna Book. If you don't have it,
send me a email and I can share a preprint.
My masts (for both front and rear) are highly modified Harbor Freight 20'
aluminum flag poles. One must modify them by pulling out the internal segment
locks and building a simple external locking mechanism made out of two hose
clamps and a small aluminum connector between them. It is hard to describe,
but basically, I loosen one hose clamp per segment junction to raise or lower
the upper segment. I also add a short thick-wall aluminum pipe inside the
bottom so the rotor can be tightened without deforming the lowest tube.
Finally I add a fiberglass segment to the top to provide a bit extra height.
The fiberglass segment is a replacement section of a JackKite fiberglass pole.
It takes me about 5 minutes to unteather my antennas and extend the mast. I
use parachute chord with carabiners on the front and back of the rear antennas
to keep them from rotating while in motion. The other end of the cord goes to
small c-clamps placed along the pickup bed rail.
This all might sound sketchy and/or random, but it has worked pretty well for
me.
Best, Darryl ww7d
On 1/26/20 21:01, nosigma@aol.com wrote:
Darryl
That is very helpful. Having an aluminum bed and not being able to weld to it
for mounting the bed mast would need to be similar to what you describe.
Do you have any pictures of your rig that you can share?
You gave me the idea of adding a front hitch reciever to mount VV omni's and
loops for working on the move and reserving the bed mount (whatever that might
end up as) for beams and the rotor.
Please describe the mobile moxon install.
73
John
KM4KMU
On Sunday, January 26, 2020 Darryl J. Holman <djholman@uw.edu> wrote:
John,
I rove as a limited rover out of a 1988 Toyota pickup truck. My
installation is done without drilling ANY holes. I have an antenna
stack in the bed that extends up to 25', and another in the front that
has small antennas that can be used (legally) in motion. For me, the
trick has been to figure out ways to build a frame to hold rotors that
can bolt onto existing truck structures. Welding skills are very useful
here (for the rotor frame...I haven't welded anything into the truck :-).
You can see my approach in pictures and words here:
https://ww7d.wordpress.com/
Good luck, and I hope to catch you rover-to-rover via sporadic E
during a contest.
Best,
Darryl
ww7d
On 1/26/20 19:10, John Young via VHFcontesting wrote:
> John, KM4KMU here.
>
> I will be moving to Eastern Kansas this summer. The FM Only Jeep Cherokee
> will get retired from contesting duties. I plan on setting up my 2018 F-150
> shortbed crew cab as a Rover, 3456 and down.
>
> Looking to trade ideas with anyone out there who has configured a pick up as
> a Rover. Unlike the 92 Jeep that I could Butcher with a Saws-All and welder
> the XYL is not going allow that this time.
>
> I was in touch with a gentleman who Roves out of an F150 but lost the
> contact info. Hopefully you and others will reply.
>
> 73
> John
> KM4KMU
> Nosigma@aol.com
> Text: 703 678 6795
> _______________________________________________
> VHFcontesting mailing list
> VHFcontesting@contesting.com
> http://lists.contesting.com/mailman/listinfo/vhfcontesting
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