[Elecraft] Salt Water Verticals

Mark Stennett mark at stennett.com
Mon Aug 2 12:14:04 EDT 2010


We packed 5 Force12 Switched Vertical Dipole Arrays and two 40XK 
antennas into a hard golf case for our recent C6AMS DXpedition. 20 and 
17 meters were set up on the beach while the others were set up on the 
lawn overlooking a cliff to the beach below. All antennas performed very 
well but the ones on the beach were exceptional.

We operated two K3 radios and with one on 20 while the other was on 17, 
antennas located within 20 feet of one another and a 3 pole bandpass 
filter on each radio, neither could tell the other was on the air. Even 
with the CW station running an amplifier.

http://www.c6ams.com/index.php?page=album&album=10



On 8/2/2010 10:01 AM, Tom Meier wrote:
> I've used vertically polarized antennas next to salt water for a number of
> trips with great results.  If you can't get the antenna right next to the
> salt water ground plane, get it high enough that the vertical can "see" the
> salt water.  Something that works extremely well is a *pair *of Sigma 5s.
> Feed one of them with 50 ohm coax and short the feed line on the second one
> so it becomes a parasitic reflector.  Spacing isn't especially critical, and
> about nine feet works well as a compromise for 20 - 10 meters.  Don't forget
> that the reflector needs to be switched also so that the reflector also
> stays resonant on the band selected.  Total weight: about 14 pounds.  No
> part is over two feet in length (i.e. it packs in a suitcase).  About 8.5
> dBi gain at that wonderful 10 degree take-off angle.
>
> 73 de Tom (K7ZZ)
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