Reminds me of one morning back around 1980 when Mike VK6HD and I were in QSO
on 80m. Mike had given me a 579 report but suddenly on one over he said my
signal had dropped to S5 but he still copied everything OK. It was then I
noticed that my last transmission had been on the 200-foot West beverage, 8
feet high instead of the vertical! In those days I had to manually switch
the beverage each transmission. Some day I'll have to try working Mike with
a smaller antenna, hi...73/Jon AA1K
At 08:26 PM 10/8/96 +0100, you wrote:
>
>
>Reading a story in a german amateur radio magazine about a "big" 80m magnetic
>loop from Karl DL1VU gave me an idea of a small topband antenna with the
>possibility of working DX. Well, Karl reported to have worked VK6HD with this
>antenna and 100W on 80 Meters.. so it can't be too bad.
>
>The antenna with dimensions for 160m would be:
>
>
> l = 15.3m ( 50.2ft)
> ****************************************
> * *
> * *
> * *
> * *
> * *
> * *
> * *
> * *
> * *
> l * * l
> * *
> * *
> * C1 C2 *
> *-||-*--||-*
> | |
> | |
> Coax Shield Coax Center
>
>
>C1: about 130pF C2: about 3000pF Cs are variable
>Polarisation: vertical
>Well, it is sure that this is not a optimum as using a circleinstead of the
>triangular configuration.
>Also you have to use a good conducting and thick wire. I think of coax shield
>from RG 213 or so. Karl reportet a bandwidth of 60kHz on 80 (SWR less 1:1.5)
>that would mean about 30kHz on 160. Maybe the losses in the circuit pay its
>price, but on the other hand it should be less than a small loop. Bigger
>dimensions for the loop are not usefull, cause C1 runs to 0.
>
>Well, I'm thinking of an antenna for DXPedition and making DX from a place,
>where you are not able to put up a higher one. 15m high trees are everywhere
>and the wight of this construction is much less than a vertical.Sure a tall
>vertical or Inv. L over a really good radial-net workes better.
>DL1VU gives a good mathematic fundamental ground for this antenna. I decide
>not to repeat it here cause it is in many antennabooks.
>
>
>Did anyone try such a configuration?... any command ?
>
>73s Dieter
>## CrossPoint v3.1 ##
>
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