[HCARC] Invertyed L Antenna

[SARA SANDSTROM]

Gary, 

The latest (March 2014) issue of QST has as its first article "Designing a Shortened Vertical for 75 and 160 M eters.  You might want to take a look at it as it is basically an inverted L or a top-loaded shortened vertical, take your choice on its name!.  The author's claim is that the horizontal wire on 160 makes the antenna an isotropic radiator rather than an omnidirectional one.  The difference being the omnidirectional antenna doesn't have any radiation straight up which the isotropic does.  He didn't see much directionality. 

Butternut made a 160 m accesory for their verticals.  T he acces ory was a top-loading scheme for what was essentially a 30 foot vertical radiator.  The top- loading was a series of wires, I think 4, that went from the top of the antenna diagonally down towards the ground.  The wires didn't go all the way down.  The angle of the wires was pretty steep, at least 45 degrees.  

So based on the above, I don't think the hill and the down sloping wire will give you very much directivity.  My guess is the hill is small compared to the 160 m wavelength and will be barely noticed.  You probably won't be able to measure the n on-uniformity of the pattern. 

As far as your question on the "spy radio", I never have heard one on the air.  There were a lot of guys using old surplus rigs when I first got on in the 60's.  All the surplus I heard/saw was US made, typically members of the ARC -5 series on HF and SCR-522's on 2 meters.  Interestingly, the ARC-5 radios were aircraft radios as was the ART-13.   This particular radio was made in the UK by Marconi so I suspect few ever got to the US.  With 5 Watts, the chance of them being heard accross the Atlantic was not very good given the likely experience of the operat ors  and the state of equipment then.  I bet if the life expectancy of the operators was a month, the radios were destroyed at the same time the operators were.  Probably not many survived.  By the way, people are still looking for HF radios being used clandestine ly    and it is not easy to locate them unless you are lucky and can get close to the transmitter.   I am amazed that anyone would use one for 30 minutes at a time.  If it was me, the messages would be infrequent and more like 30 seconds long! 

Kerry