The Alpha-Deltas seem to be pretty stout, but they are somewhat
unconventional in that they don't use discreet capacitors. The coil's internal
capacitance does it for them. I used their 80/40 shorty dipole for several
years without hurting the traps. However, I added a 1:1 current balun at the
feedpoint and replaced the end insulators several times. The reason the ends
went is that I used my tuner to use the antenna out of resonance -- probably
okay at 100W, but not at legal limit. I now use a full-length dipole fed with
450 ohm twin lead. So far, no problems.
Joe, N3JI
Osten B Magnusson <sm5dqc@areteadsl.se> wrote:
I have also bought Unadilla 80 CW traps for a wire vertical,
have burnt two at 700 watts - I thought there was something
wrong with the first one, but the same thing happened also
with the second one... I have not yet made an autopsy, but
will do and see what's inside that blue melting plastic.
73 de Osten SM5DQC sm5dqc@areteadsl.se
----- Original Message -----
From: "Gene Bigham"
To:
Sent: Tuesday, December 13, 2005 11:16 PM
Subject: [Amps] Antenna traps
>I know this is not about amplifiers, except for being able to use one on a
> trapped antenna, but has anyone found a set of traps for 40 and 80 that can
> handle a legal amplifier output?
> I have now fried two sets of 40 traps by Unadilla and one set of 80's which
> the new replacements have not been tried at power yet.
> The old traps shorted through the cap insulating material, they were old but
> never used, so I thought the epoxy was just old. The new ones have melted
> the blue insulator on which the coil is wound on these 40 meter traps with
> 500 watts power level.
> I tuned the antenna to resonance of 1:2 to 1 SWR, worked several stations,
> increased power level and after two hours and 500 watts started seeing swr
> creep up slow then rapid. Examination showed the blue material melted and
> oozed between coil turns and the coils are now also intermittent.
> I need some bullet proof traps.
> Any ideas?
> Thanks in advance
> Gene Bigham
> KB0GU
>
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> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
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