[Elecraft] Rhombic antenna "gain"

[Vic Rosenthal]

Just bring 600 ohm open line feedlines down from each end to a common point, where you have a relay or two to switch the feed and the terminating resistor. Then you can reverse it with a flip of the switch. Although transmit gain is the same as bidirectional, you can cut the noise by 3 dB.

Victor 4X6GP 

> On 14 Sep 2019, at 2:21, Fred Jensen <k6dgw at foothill.net> wrote:
> 
> Mike:  Rhombics can be operated either terminated or unterminated.  If unterminated, they are bi-directional with half the power in each lobe.  If terminated, the resistor absorbs half the power in the reverse lobe.  Either way, half your power goes the "wrong" way, either behind your desired direction or heats a big resistor.  They have a very low radiation angle and a fairly narrow beamwidth which is why they're flame throwers and very common in military and commercial stations, particularly in the days of point-to-point radio circuits.  V-beams, sometimes called Half-Rhombics are sort of likewise only broader azimuth patterns more suitable for maritime ship-shore telegraphy circuits.  For ham applications, Google W6AM
> 
> 73,
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
> 
>> On 9/13/2019 3:24 PM, Mike Markowski wrote:
>> Can you expand on this, Ken, or if easier, a reference?  I'm curious what tradeoffs are made.  I used a rhombic at Ft. Monmouth, NJ before the Army base was closed in 2011, and used to boom into Europe and Russia.  It was amazing.  I also got copies of WWII manuals on rhombic construction while there.  You know, just in case I became wealthy with tens of acres of land.  :-)
>> 
>> 73,
>> Mike ab3ap
> 
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