[TowerTalk] Perplexing Antenna Problem

[Bernard(wtrone)]

    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