> A local has recently had to repair his CushCraft A-3WS yagi and I
> gave him two of my CushCraft TM traps. To replace my TM traps, he
> ordered replacement 17m traps from CushCraft/MFJ. What he received
> was TB-1 traps. The invoice from CushCraft/MFJ said these were 17m
> traps. So are TM and TB-1 traps the same?
The TB-1 and TM traps are almost certainly not the same. If you
look at the manuals for the A3WS and A103 (10 meter add-on), the TB-1
is the inner (12 Meter) trap on the A3WS; it would be resonant about
24.5 MHz (isolates the 12 and 17 meter sections of the elements). TM
is trap from the A-103 add-on (the 17 meter trap) and is resonant about
17.5 MHz (isolates the 17 and 10 meter sections of the driven element).
As a confirming point, look at the D3W (10/17/12 meter dipole) manual;
it shows that TL (TB-1 with a different "outboard end") is the inner
24 MHz (12 meter) trap and TM is outer, the 18 MHz (17 Meter) trap.
The A3WS manual is here:
http://www.cushcraftamateur.com/pdffiles/951370.pdf
The A103 manual is here:
http://www.cushcraftamateur.com/pdffiles/A103.pdf
The D3W manual is here:
http://www.cushcraftamateur.com/pdffiles/D3W.pdf
73,
... Joe, W4TV
On 11/24/2010 6:15 PM, K9AJ wrote:
> Dear all,
>
> I have a CushCraft A-3WS WARC yagi w/ the 30m add on kit. Some years
> ago, I had to replace the 17m traps on this antenna and when I
> ordered the TM replacement traps from CushCraft, I ordered extras, in
> case I would have to replace these traps in the future.
>
> A local has recently had to repair his CushCraft A-3WS yagi and I
> gave him two of my CushCraft TM traps. To replace my TM traps, he
> ordered replacement 17m traps from CushCraft/MFJ. What he received
> was TB-1 traps. The invoice from CushCraft/MFJ said these were 17m
> traps. So are TM and TB-1 traps the same? Are they
> interchangeable? Can I have a TM trap on one side of the DE and a
> TB-1 on the other side?
>
> I sent this query to cushcraft@mfjenterprises.com over a week ago and
> have not received a reply.
>
> Thanks.
>
> 73's.....Mike, K9AJ
>
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