dipole rfi/tvi reduction
 

Hi

was wondering if their was anything that could be done (antenna/feedline
wise) to reduce chances of giving off interference from any type of
wire antennas

such as for ex a center fed coax fed dipole i'll use a 1:1balun at
the end, try to make dipole resonant

i believe the coax run should also be within 1/2wave or so

(everying at radio end is ok , good grounds ,tuner etc)

any tips??

Depends on what you mean by "giving off interference". In my experience,
most interference situations today involving HF are the result of a
perfectly clean fundamental HF signal being detected by an appliance or
other electronic device which should be rejecting such signals. There's
nothing you can do to your HF station to minimize that other than to
increase the separation between the HF antenna and the device experiencing
the interference (or reduce the transmitted power). Depending upon the
device in question, use of bypass caps on the AC line and/or ferrite chokes
on the line cord and other external leads MAY provide relief. It's
certainly possible that feedline radiation is contributing to the problem
and in that case judicious use of a balun and proper grounding may provide
some relief.

K8AC


"ml" wrote in message
...
Hi

was wondering if their was anything that could be done (antenna/feedline
wise) to reduce chances of giving off interference from any type of
wire antennas

such as for ex a center fed coax fed dipole i'll use a 1:1balun at
the end, try to make dipole resonant

i believe the coax run should also be within 1/2wave or so

(everying at radio end is ok , good grounds ,tuner etc)

any tips??

In article ,
"Floyd Sense" wrote:

Depends on what you mean by "giving off interference". In my experience,
most interference situations today involving HF are the result of a
perfectly clean fundamental HF signal being detected by an appliance or
other electronic device which should be rejecting such signals. There's
nothing you can do to your HF station to minimize that other than to
increase the separation between the HF antenna and the device experiencing
the interference (or reduce the transmitted power). Depending upon the
device in question, use of bypass caps on the AC line and/or ferrite chokes
on the line cord and other external leads MAY provide relief. It's
certainly possible that feedline radiation is contributing to the problem
and in that case judicious use of a balun and proper grounding may provide
some relief.

K8AC


"ml" wrote in message
...
Hi

was wondering if their was anything that could be done (antenna/feedline
wise) to reduce chances of giving off interference from any type of
wire antennas

such as for ex a center fed coax fed dipole i'll use a 1:1balun at
the end, try to make dipole resonant

i believe the coax run should also be within 1/2wave or so

(everying at radio end is ok , good grounds ,tuner etc)

any tips??

ok i follow all this , didn't think about putting ferrite onto pwr
line but good idea

anyone know a place to get some clamp on ? or other ac chokes/ferrites
at good price , ? radio shack isnt the best

"ml" wrote in message
...
Hi

was wondering if their was anything that could be done (antenna/feedline
wise) to reduce chances of giving off interference from any type of
wire antennas

such as for ex a center fed coax fed dipole i'll use a 1:1balun at
the end, try to make dipole resonant

i believe the coax run should also be within 1/2wave or so

(everying at radio end is ok , good grounds ,tuner etc)

As for telephone interference - its the phone's fault usually.
When you shop for a phone - pick it up and hit it on the side with the heel
of your hand - and if you hear a 'ding' (a bell) then it usually will be
ok - (will not receive your radio signals)
as for tv - it should be designed to take interference. sometimes high-pass
filter will help on the tv


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ML wrote:
"Was wondering if there was anything that could be done (antenna
feedline wise) to reduce chances of giving off interference from amy
type of wire antennas."

Almost all medium wave broadcast stations reduce harmonic radiation by
allowing only magnetic coupling to their radio towers. Capacitive
coupling favors harmonics. The tower feedline is interrupted by a
cpupling transformer which has a Faraday screen between its primary and
secondary. Capacitive coupling is grounded out on the scree, Magnetic
coupling is unaffected. Multiples of the fundamental frequency don`t get
any boost from lower capacitive reactance at higher frequencies.

Best regards, Richard Harrison, KB5WZI