[TowerTalk] Flagpole and Stealth Antenna

[Terry Conboy]

At 09:47 AM 2008-11-24, Joe WA6RKN wrote:
>I have a good friend that lives in a very ham radio repressive 
>area..  You know, the homeowner association that controls how many 
>plants you can have in your front yard and what kind they have to be?
>
>Well..his H.A. is that bad..however...they **DO** allow up to a 30 
>foot flagpole.
>So...Are there any recommendations as to a good brand of flagpole 
>that is 'all band vertical' friendly.

Joe,

I have used a Force12 flagpole vertical for several years now, which 
has HOA approval.  The stock F12 flagpole is 16 feet of 2" diameter 
aluminum, painted white, but I got it with 3 extra sections and it 
measures to be just over 26 feet.  I'm sure you could get a fourth 
section and have ~30 feet total.  It has a sturdy fiberglass 
reinforced base insulator.  Force12 now sells matching coils for 40 
and 80m, but a section of Airdux does the job for me.

I chose 26 feet because it is 3/4 wave on 10m, which isn't optimal, 
but there is still a pretty large lobe of the elevation pattern at 
low angles, so it works OK on 10m in practice.  It's ~5/8 wave on 15m, etc.

Either a 26 foot or 30 foot vertical will work great on 40m.  Mine 
only needs a small series loading coil to resonate on 40m and I get 
under 1.5:1 across the band and good signal reports with 40 radials, 
each 50 feet long.

I have matched it on 80m, but the bandwidth is narrow and the ground 
and loading coil losses exceed the radiation resistance, so the gain 
will likely be under -4 dBi.  Adding a drooping wire top hat will 
increase the efficiency and bandwidth on 80m significantly, but that 
may not be popular with the local CC&R "eagle-eyes".  (With a 
drooping hat with three nearly invisible #26 wires, each 50 feet 
long, it is easy to resonate on 160m, too, and it's good for having 
fun in 160m contests, but surely not competitive for DX.)

A 30 foot flagpole would work great for 40m and up (and maybe 80m) 
with one of the outdoor remote tuning units (SGC, Icom, etc.).  I'm 
frugal and just use tapped coils for matching.  The last time I 
checked, the F12 flagpole was much cheaper than the DX Engineering or 
Zero5 designs, but they are definitely battle ready!  Here at sea 
level in SoCal, there is NO ice and little wind, so the F12 does the 
job just fine.

The real challenge will probably be placing his flagpole far enough 
from the other homes to minimize RFI on TX and EMI on RX.  I lucked 
out and purchased a lot that backs up to a large open area owned by 
the HOA, so I get some relief with my flagpole right in the center of 
our back lot line.  Errr, those wires under the ground cover 
vegetation are for lightning suppression and are mandated by the 
National Electrical Code ... and say, doesn't that flag look great!

Good luck to your friend.

73, Terry N6RY