[TowerTalk] Perplexing Antenna Problem

[Tim Duffy K3LR]

Hello Bernard!

Given the your information I would suggest that the PL259 on either end of the cable is bad (does not show up until you have more 1 watt or more going into the coax). The PL259 on the far end would be the best place to start. It may be intermittent, as when you have the 50 ohm load at the antenna end all looked OK.

You could have a problem with the SO-239 at the SteppIR as well.

Or, the coax could be crimped somewhere along the line (less likely).

Please let us know what you find!

73,
Tim K3LR

"Bernard(wtrone)" wrote:

>     I posted the following message on the Yahoo SteppIR board and thought that I might also get some ideas on this board.
>
>  I have an interesting problem for all of you antenna experts out there.  If you have been reading this thread (Yahoo SteppIR board), you know that I have been having problems with my new SteppIR 3 element beam.  I was able to borrow a MFJ-259B this morning and made a relatively extensive set of measurement, which taken as a whole, just do not make sense.
>
>         In summary (2 measurements on 20, 1 on 17, 2 on 15, 1 on 12 and 2 on 10M for each series of readings):
>
>             1. Set of measurements using the MFJ with a 20" length of coax to the SteppIR.  Measured from 20-10M SWRs of from 1.5:1 to 1:1 (also have the R and X measurements but won't go into those just yet).
>
>             2. Set of measurements using the MFJ in the shack using the full length of cable to the SteppIR.  Measured from 20-10M SWRs of from 1.4:1 to 1:1.
>
>             3. Using MFJ to measure Coax Loss from 20-10M showed 1.3 to 1.6 dB.  Probably about 135 ft of cable.
>
>             4. Put the cable in the shack directly on the antenna connector of a Daiwa NS-660PA SWR and Power Meter, and the SWR is 5:1 from 20-10M.  The reading on the TenTec Orion is high VSWR.  Take the PL-259 off the SteppIR and put it on a 50 ohm dummy load and the SWR is a flat 1:1 across 20-10M both on the Daiwa and Orion.
>
>             5. Tried varying the "tune" power of the Orion from about 1 watt to 50 watts.  No difference.
>
>             6. Tried taking the Daiwa out of the circuit.  No difference.  Orion still reads high VSWR.
>
>             7. Swapped out a complete set of coax cables to insure nothing was common.  No difference.
>
>     Anyone out there in radio land have any ideas?  I am going to talk to Jim on Monday, but this is really a STRANGE set of data.  I am a bit perplexed with what I am seeing!
>
>                 73,
>
>                 Bernard, WA4OEJ
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