[Antennas] Re: DBJ-1 J-pole from Feb QST mag

2003年10月21日 10:37:46 -0400

Thanks for the response, Tim. I see you don't make use of his
unusual "Schedule 200" PVC pipe, which was one problem I encountered. :)
 But let me ask about your statement: "As the author said, SWR isn't
great on 440, but it's resonant, ... ". Without obtaining a low SWR
reading, how do you know your antenna is resonant on the 440 band? Is
it just a matter of getting improved performance over a stock rubber
duck?
 I understand that the SWR reading is just part of the big picture,
but I felt that without any other adverse conditions to hinder the
antenna, if I could not get the SWR down below 2.0:1 it would indicate
to me that the antenna was NOT resonant on the 440 band. That is what I
experienced both when building my DBJ-1 and testing the author-built
version. My tests were conducted outdoors, 20 feet high, with no metal
in the vicinity. I had a coax coil, as you mentioned.
 --- Judy KG4QHC
Tim Conway, n9hmg wrote:
>> I ... built 2. ...
> As the author said, SWR isn't great on 440, 
> but it's resonant, and works
> well. I've considered soldering a 17.5cm 
> stub to it to try for better
> match on 440, but that's just too much trouble.
>