Yuri, You might want to remove the sheet metal screws that connect the
trap body to the actual driven element. (You might want to check the
reflector and director as well) Occasionally some aluminum oxide builds
up there. Also, and it may not be that easy, slide the tape apart and
make sure that coil wires are not bridged by insects or a carbon arc.
If everything else looks OK put a GDO on MFJ-259 coupled to the traps in
free air and see where the each resonate. They should turn out to
resonate at the same place on 15 and 10 meters. If not then you might
have found the problem. I have a box of A4 traps and was going to put
them on eBay but let me know what you need.
Herb Schoenbohm, KV4FZ
On 11/10/2014 6:12 PM, Yuri wrote:
I have Cushcraft A4S which I haven't been using for a while. It worked
perfectly and was tuned to CW portion of the 20,15 and 10 m bands.
Few days ago I noticed that SWR on 10 meters went up (to approximately 4:1) and
antenna started to resonate well above 29.0 MHz. At the same time the resonant
frequency moved higher on 15 m, but is still tolerable in the CW portion
(1.6:1).
20 m remains unchanged.
I took it down today and examined the traps. They all look O.K. except I found
few small spider nests inside. Also checked them for dc which appears to be
fine.
It's on the step ladders about 7 feet above ground level now.
Is there anything I can do? Anybody experienced same problem before?
Any tip would be appreciated.
Thanks.
Yuri VE3DZ
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