PM
Subject: Antennas & digital modes
I want to bring attention to others what can happen with your DE with high
power
About five years ago, I downsized to a single 17B2 Cushcraft from four on 144
mhz. The stack was very hard to repair every year after ice storms here in the
Pocono's.
With the single antenna, I was doing some JT one evening on my moonset. My amp
will run a full 1,500 watts on CW but when doing digital modes, I always drop
the power to 1,000. I am not sure how long it took, but that evening I melted
the balun on the DE. Basically set it on fire. When I looked inside the
Cushcraft box, I could see how this happened. The balun of coax was very thin.
Just looking at this stuff, I knew there was no way it could take, especially
on two meters.
I probably had 750 watts at the driven element at the time..
This week I was running FSK with Bill ND0B in N.D. on 222 mhz. Bill decoded my
signal almost immediately. Good sign. BTW I was again running 1,000 watts and
about 750 at the antenna
We continued for about fifteen minutes until I saw my power had dropped. I
switched my watt meter to return and the meter was pegged.
With winter here, I have no idea exactly what happened but there can only be
two things. The DE on the M2 antenna, or my jumper cable from the 1 5/8
hardline.
It will be several months before I can find the problem. But I'm betting the
balun went bad.
Right now I can't complain about M2 but I do know that Cushcraft surely should
change their power numbers for the 17B2. In calling the company, they told me
it was PEP power. That's not what is marked on their advertisement.
That's the complaint of the year from the snowy Pocono's
73's and HNY
Herb at WA2FGK
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