Re: End Fed antennas w/ uBITX #ubitx

Bill Cromwell
 

Hi,

I have not done any engineering work and I don't have lab grade instruments to accomplish. I lean toward end fed wires and my own experiences fall right in line with Warren's statements. I favor L network matching at the antenna feedpoint. I always use counterpoise wires. My best experiences used counterpoise wires a quarter wave long on each band. That means a different counterpoise wire for each band. One antenna had a multiple counterpoise wires connected in parallel and 'seemed' to work well. Sometimes I have altered that configuration and performance obviously suffered. In short, my empirical results match his more careful measurement results.

Maybe this will help somebody.

73,

Bill KU8H

On 07/26/2018 12:10 AM, Warren Allgyer wrote:
Haha. Bless you for even trying read this entire mess. Much of it from me.

Let me try to boil it down to three bullet points:

1) The rubbish transformer loses 90% of your power on most frequencies.
When used on a frequency for which the attached wire is a true half wave
it only loses 20% of your power. The SWR however will be acceptable on
almost all bands.

2) A binocular core transformer can only be used on one band for which
the antenna is a resonant half wave. On that band however it will lose
less than 5% of your power. SWR will only be acceptable on this one band.

3) A tuner can make any wire have acceptable SWR so long as the wire is
at least a half wavelength long. This combination will lose 1 - 5% of
power depending upon the quality of the tuner itself.

For multiband operations only option 3 has performance that I would
accept. For single band operations any of the 3 is OK with 2 and 3
preferred.
--
bark less - wag more

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