Benjamin Naber wrote:
> thought the same you did, but nope didn't help
>
> Any one else?
I suspect the addition of the arrestor changes your match because the
antenna isn't properly matched to begin with. Try adding adapters to
the coax equal to the length of the arrestor to see if you get the same
results. When an antenna isn't properly matched at the feed point,
varying the length of the coax will artificially tune the antenna.
Jpoles are very seldom fed as a balanced antenna which they are.
Therefor the coax has RF on the shield and radiates as part of the
antenna. The match on a properly matched DC grounded antenna will not
change with the addition of a good lightning arrestor.
Dex
>>
>>On 7 Jan 2005 at 12:01, Benjamin Naber wrote:
>>
>>
>>>afternoon ya'll
>>>
>>> Done a little bit of reading and playing around,
>>>what is an advantage and disadvantage of using DC
>>>gounded antennas?
>>>
>>> One thing I am curious about is why when a
>>
>>lightning
>>
>>>arrestor is used with a DC grounded antenna, does
>>
>>the
>>
>>>SWR go up? A while back I installed a lightning
>>>arrestor in line with my j-pole and the SWR went
>>
>>WAY
>>
>>>up - something like a 3 or 4. Just recently I
>>>installed a 5/4 wave shorted stub and the same
>>
>>thing.
>>
>>>In either case, why would the SWR go up?
>>>
>>>~Ben, KB9LFZ
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