[Boatanchors] Link coupled output?

[Ron]

I should preface by saying that I know nothing
about RF circutry, but then, Electronics is
Electronics, so here goes...

Rather then search for lowest SWR, one could
search for highest power transfer to a resistive
load, which would occur when the load impdance 
matches the source impedance. So, to find the 
source impedance, get a high power non inductive
pot of, say, 250 ohms. Mark resistance at various
positions of, say, every 25 ohms. Drive the pot
from the transmitter and record voltage across
the pot at each of these positions. Calculate 
V Squared/R for each measurement. The pot
position yielding the highest result should
correspond to the output impedance.

Makes sense?

-- Ron




--- StephenTetorka at cs.com wrote:

> Hi all:
> 
> I am trying to determine what characteristic
> impedance transmission line to use with my
> homebrew 1948 transmitter.
> 
> The unit uses two 1625's in the RF deck with a B&W
> type JVL link coil for the output to the antenna
> terminals.
> 
> In this arrangement, the B+ goes into the center
> tap of the coil with one section of a two gang
> variable across each half of the coil from center
> tap.
> 
> The antenna terminal output comes from a separate
> 3 turn coil located in the middle of the coil
> between the two halves..thus obtaining the RF 
> coupling.
> 
> This arrangement is typlical of 1940's - 1950's
> rigs.
> 
> Would appreciate any assistance in this matter.
> Regards,
> Steve
> WA2TAK
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> 
> 


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