Well stated... I have and use a "custom" extended BWD-90 (now at 200') for
Ham/MARS. The BWD-90 falls off fast below 4 MHz. and becomes more and more
a true dummy load. The BWD-180 is good to 2 MHz. before it starts falling
off and the extra 20' in my custom version will keep it going through 160
meters. I have the antenna mounted in NVIS mode with the apex at about 40'
and the ends at 15' so the pattern is basically omni-directional. It is NOT
my main Ham antenna and is used more for MARS and MARS-ALE where you are
scanning 5 channels per second from 2 to 30 MHz. It works, as Joe states,
well for a frequency agile antenna with regional coverage. I doubt it would
work worth a flip as a DX antenna though I have had the occasional DX
contact on it. I use it with a TS-480HX for ALE (at 100 watts) and with my
TS-2000 and TL-922A for voice.
These antennas have their place but they aren't for "barn burning" by any
73 de Perry - K4PWo
[mailto:email@example.com] On Behalf Of Rik van Riel
Sent: Friday, April 22, 2011 4:00 PM
Subject: Re: [TowerTalk] Multi-band dipoles
On 04/21/2011 11:38 PM, Joe Subich, W4TV wrote:
> Most reputable (commercial) manufacturers of the terminated folded
> dipole for military/government service give "gain" specifications
> ranging from -1 to -4 dBi in free space and efficiency ratings of
> 15% to 50% (30% average). Such performance is equivalent to turning
> 1 Kw to 250 watts ... or a barefoot 100 W rig into a 25W pea whistle
> on most bands (and even worse on 160 or 80 meters depending on the
> antenna size).
> While such performance may be fine for military/government use with
> frequency agile, high power ALE circuits, or in short range NVIS
> applications, the terminated folded dipole belongs in the same
> category as the Isotron, cross-field, and fractal antennas for
> amateur purposes.
It works great with ALE, because the radio automatically
picks the path with the best propagation. Losing 6dB in
the antenna is no big deal, when the radio reduces the
propagation losses by 20dB over whatever random frequency
a radio-untrained soldier might otherwise pick.
For amateur use there really is no need to choose such
an antenna, since the ham frequencies are largely
We do not need frequency agility over all of HF.
All rights reversed.
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