[Heathkit] SBA-104-1 and another Question

[Donald Spoon]

Just how "conductive" is the plastic PVC conduit?  My son-in-law, who is 
an Electrician, says they use it all the time for underground power runs 
where it provides a good water seal and never rusts or weathers like the 
metal conduit.   This feature attracted my interest.   I have seen 
articles using it for winding baluns and also for use as antenna 
insulators.  It seems to me to be a pretty good insulator at HF 
freqs...  Dunno for sure though.  Back in the 1970s when I knew much 
more than I do now (I knew it all then), there were several warnings 
about using PVC around RF, and I seem to recall a test or two showing it 
would absorb RF at VHF and/or UHF, i.e. it was "lossey" as demonstrated 
by putting it into a microwave to heat it up for forming.

-Don Spoon-
K0APK

On 12/22/2010 2:53 PM, Ron Youvan wrote:
> Donald Spoon wrote:
>
> /*snip*/
>>  I
>> have found that the LL that I have fits nicely into the Gray, 1" PVC
>> conduit found at Lowes / Home Depot.  I am using some of the shorter,
>> curved sections to provide a support function at turning and end points
>> presently without any adverse affects that I can determine.  I was
>> wondering if I could use the conduit to "pipe" my ladder line where I
>> wanted it to go (underground, up an outside wall, under a deck, etc).
>> Does anyone have experience with this, or even concerns based on
>> theory?  I am looking for both positive and negative aspects of doing
>> this... (Weather Protection = Good, Increased line loss = Bad, etc).
>
>   Not a good idea where anything conductive comes withing an inch of 
> the two conductors.
> If you can center the line within a 2.5 or 3" conduit you will 
> probably be OK.