[ILQSO] Re: 40 meter horizontal mobile antenna ideas

[Hank Greeb]

Jim:

You have much more experience with the recent incarnation of OQP than I
have, but I'd like to lend a "newbie" perspective. During OQP 2006, W8B
worked 2 Ohio Counties on 20 metre CW, 4 on 40 Metre CW, and about 60 on
80 Metre CW. We had what might be called a "typical rover setup" though
we were portable at one site so we were classified as Multi/Multi. We
moved to 80 shortly after 2200Z (6 p.m. EDT) and had the best results
between then and about 0200z when the band started to get a bit "watery"
and it seemed that many folks decided to "hang it up." I tried tracking
some of the mobiles, but there appeared to be a skip zone even on 80,
because I never heard N8TFD after he got west of PIKE county, and didn't
hear anyone from within BROWn county.

In retrospect, we could have used a third receiving setup - to monitor
when and where the best possibilities were for maximizing rate. We
probably stayed on 20 metres too long, and we missed the short skip on
40. But, for a bunche of non contesters we did "okay, but nothing about
which to brag."

The CW antenna was a 200' long inverted vee, fed in the centre with 450
ohm ladder line, up 32 feet in the centre, and about 10' high on the
ends, pointing with the maximum radiation North and South on 80 Metres,
where it was an approximate extended double zepp in length. I didn't
bother to figure where the maxima and minima radiation would be on 40
and 20. I had planned to have a 80 metre half wave with the same kind of
feed, but I found a couple 100' hanks of antenna wire from some other
project, and was too lazy to measure 35 or so feet from each end.

My view is that one needs an antenna which radiates much of the power
between 30° and 90° from horizontal, but not so close to the ground that
the ground absorbs most of the power. I've never seen a vertical antenna
which radiates much power straight up, so that's a definite disadvantage
to most mobile installations. The "best" field antenna I had was at Lake
Hope State Park, VINTon County, during the 1978 (or so) OQP, where there
were strategically located natural antenna masts about 100 feet apart at
about 70 feet height (¼λ on 80 metres). With a trusty borrowed bow and
arrow, I got a 80' (or so) dipole up at about 70 feet. Conditions must
have been excellent, because it was almost like the DX end of a rare
DXpedtion, first on 20, then on 40, and last on 80 metres. The folks on
the 75 metre SSB net said I had as good or better signal as from home,
with comparable 75/80 metre antenna, but not quite as high.

Last point I'd like to make is that we folks from outside of Illinois
can add perspective, but our opinions will more than likely be taken as
a grain of salt. I'd say that if someone wishes to experiment with
horizontal polarization in a mobile setup, more power to him or her! I
would be surprised if it didn't do at least as well as vertical, and
more than likely better. The trick will be to get the thing fed and
minimize stray losses - problemmes which are not new to a mobile
environment.

73 de n8xx Hg

Jimk8mr at aol.com wrote:

>Whether you use a vertical or horizontal antenna, mobile or not, is not an issue.  The question is whether the ionosphere will support any short (i.e. in-state) propagation.  If not, what antenna you use does not matter.
> 
>In the Ohio QSO party this year, with solar flux in the upper 70s and a low A/K index, the first two hours (noon to 2 pm EDT, or 11 am to 1 pm EST) had good short skip on 40.  Then it went long for the rest of the day (bad for us in Ohio, good for the guys in Illinois!).
> 
>I interpreted this to mean that for an hour either side of solar noon,  there was enough direct radiation to support a low MUF.  Once the sun started to decline in the sky, there wasn't enough. Big stations with big antennas noted the problem as much as us HamStick kind of guys in the  field.
> 
>For a mobile, I don't think it is worth fooling with the mechanical issues of a horizontal antenna.
> 
>73  -  Jim  K8MR
>  
>