[Elecraft] Antennas with resistor and OCFD.

[Fred Jensen]

On 12/10/2015 4:14 PM, Brian D. Comer wrote:
> I think stating any particular antenna configuration is unacceptable is
> ignoring what could be an ideal antenna for a given situation.

Absolutely!  Situations differ dramatically.  A low angle radiator on 80 
in the evening is likely to underwhelm you if your need is to 
communicate over 150 miles.

>  As I
> understand  it  a rhombic  uses a resistor, and sometimes works quite well.

Ummm ... rhombics *always* work well for their intended use. 
Unterminated, they are bi-directional.  With the terminating resistor, 
they are unidirectional in the direction from the feedline to the 
terminator.  Since terminated rhombics are usually 2 or more wavelengths 
on a side, they have very narrow beamwidths with a big F/B ratio, low 
radiation angle, and high gain.

They were used on point-to-point HF circuits in the 30's through maybe 
the 60's or so.  I worked coastal marine in 56-57.  We generally used 
V-beams with wider beamwidths since our targets were ships that moved 
around, but we had a couple of rhombics, one aimed at NMO in Hawaii. 
Tap the key at 5 KW and they told us we were QSA 11R5:-)

OCF's can serve well in the right situations and with the right 
precautions to mitigate the downsides.  The infamous B&W folded dipole 
was never billed as anything other than what it was ... an antenna with 
a non-inductive resistance that pretty much swamped any effects from the 
antenna, and could be used 3 - 30 MHz, in the right situations.

Tom Schiller, N6BT, likes to show his "illuminator", a 300 W light bulb 
fed through a common mode choke.  He even put three up as a "phased 
array.  Any RF in any conductor will radiate.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016
- www.cqp.org