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Re: [Amps] Antenna traps

To: Amps <>
Subject: Re: [Amps] Antenna traps
From: Joe Isabella <>
Date: Tue, 13 Dec 2005 15:42:55 -0800 (PST)
List-post: <>
  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 <> 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

----- Original Message ----- 
From: "Gene Bigham" 
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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