Re: NEC-LIST: Bazooka balun verification.

Consider the possibility of connecting your *inner* coax to an antenna
of some sort, perhaps a quarterwave vertical with finite groundplane. The
vertical plane pattern depends on whether or not one is exciting the outer
conductor of the usual coax feed, up near the feedpoint. If your choke is
*not* working you will likely be able to affect the vertical plane radiation
pattern with "hand" or other (metal preferred) ("tinfoil") object experiments
near the base of the groundplane.

Not at all quantitative, though.

There is a ham radio antenna company in the Northwest that uses two rather
long metal cones to choke off V-pol VHF transmission line currents thus getting max
V-pol radiation where you want it -- at the horizon. No wasteful "cloud warming" with that approach. Seems to me they or their consultant have published a useful paper
on V-pol vertical plane patterns as affected by unwanted transmission line currents.

dab

 At 06:22 PM 3/12/2003 +1100, you wrote:
>>
>> Hi All,
>> I need the Transmission line experts to pitch in with thier expertise
>> to my query..........
>>
>>
>> I want to fabricate a transmission line choke with the Belden 9222 triax
>> .The inner conductor and the inner shield layer of the 9222 will be used
>> for TEM wave propagation of the signal picked up by a transducer while the
>> outer most shield and the inner shield form a bazooka balun ( a quarter
>> wave length of line which is shorted at one end and open at the other).
>> When these are assembled with coax connectors and convoluted tubing, the
>> problem that I am facing is that, I dont have physical access to the outer
>> most shield layer as its not connected to any connector , and hence I am
>> not able to verify the operation of the bazooka balun as there are no
>> physical connections available to me where I can test after proper
>> assembly.
>> Do have any non destructive methodology by which I can verify the
>> performance of this unique balun without any physical access to the layers
>> forming the quarter wave choke?
>>
>> regards,
>> George.
>>
>>
>>
>>
>>
>
>
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