Garry wrote:
> Years ago, Bill Orr wrote a book titled Wire Antennas. On page 104 in this
> book, he described an inverted-L type of antenna called a Twin Lead Marconi
> built using TV win lead in the L section with a length of single conductor
> wire making up the last 17 feet of the L with a few radials. It was suppose
> to give a reasonable match to 50 ohm coax. Has anyone on this forum ever
> built this antenna and what were the results?
>
>
> Gary, For portable use this is a fine antenna IMHO. This is precisely the
> antenna I used for numerous DX-Peditions from South America and rare
> Caribbean Islands in the 60's. I was compact to pack along with the gear and
> was easy to get to work with a nearby palm tree on the beach. The twin lead
> Marconi (mine was 1/4 wave of 300 ohm twin lead over the entire length) was
> an easy match for my Drake's T-4XC Pi network which fed the antenna directly
> sloping out of the cottage window to the highest palm tree on the beach. For
> portable or vacation use antenna worked well and I was able to give many new
> countries to those chasing DXCC on 160.
>
> I do recall however that the theory that the ground losses were reduced by a
> 4 to 1 base impedance multiplication factor has been disputed. I always
> carried along some small 1/4 wave bell wire radials which terminated at the
> rig ground. The twin lead Marconi may improve on the rigs ability to match
> the antenna with a built in tuner but you can raise the impedance by making a
> single wire the antenna longer like 180 feet. This antenna can be generally
> brought to resonence by a series variable capacitor to remove the inductive
> reactance it imposes.
>
> The twin lead is two close spaced for much bandwidth improvement and the
> ground loses are a factor of the radial system. But for certain applications
> it is a good antenna to consider.
73
Herb, KV4FZ
>
>
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