[TowerTalk] Cushcraft XM-240 problem

[E. Glenn Wolf, Jr.]

I posted this for Vitaly ... please reply to him direct... email is at the
bottom.

I working to figure out why it isn't working.

glenn


Hi All,
Just finished assembly and test of my XM-240.
On the roof of the house it was resonating @ about 6.9 MHz with low SWR
and impedance close to  50 ohms (measured with digital frequency
counter).
Now it is up on the tower at 66'. Measurement at this hight shows
resonance at 7.07 MHz and lowest SWR of 2.5:1!!! SWR goes to 3:1 at 7.0
and 7.25 MHz. Reading is very unstable (SWR metre is moving up and down
a little).
The only difference between the first and second measurement is the coax
cable (100' of RG-8U).
I've connected it to my FT-1000D and with 200 Watts made a few contacts
with good reports (one with Ukraine & 599 from the side of the beam as
antenna is not rotating yet and is pointing Florida.). The SWR (tuned
with internal tuner) is 1.1:1 @ 7.0 MHz to 1.4:1 @ 7.3 MHz and stable!
This antenna can not be so flat across the band?!
Now the question:
Matching Network (MNXM) that comes with the antenna, is it a balun? What
is the DC resistance it measures? My shows open circuit.
Owners of the antenna, please measure the DC resistance across your
cable and let me know the results.
Am I transmitting on a tuned feed line?
Please reply direct.
Thank you.
73! Vitaly (VE6JO)


Please reply direct to .....MARKV@SNC-LAVALIN.COM



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