Marty,
I don't a loose filter, but I built one for my 540 from a schematic
for an external filter that MFJ had years ago using some 741 (or the
dual version) op amps. It works really well. You just have to go
into the empty place where the filter goes inside the rig, remove
the jumper, connect to input, output, power and the switch that controls
the # of poles in place.
I can probably find the schematic, since MFJ had them with products then.
On the other hand, I just got a kit of the filter kit sold by the NEQRP
group, and I'm thinking of putting it in another 540 to see how it will
do. Should be much more capable and should fit in the same place.
see http://newenglandqrp.org/nescaf
You would probably need to mount it externally to use controls...
Let me know if I can send you the diagram...
John, K4AVX
k4avx1@windstream.net
> Message: 1
> Date: Tue, 29 Jun 2010 15:03:18 -0500
> From: Marty Hartwell <mhartwe@gmail.com>
> Subject: [TenTec] 540 Triton model 245 cw filter
> To: Ten Tec <tentec@contesting.com>
> Message-ID:
> <AANLkTimgJe2Wof0zR2wIu0meD6KX8UqJbHqw-sDL9IHL@mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Hi
> In a trade recently I acquired a TT540 with out the model 245 CW
> filter. I think
> those are maybe somewhat hard to find these days but thought I might ask
> here if
> anyone has one for sale.
> Another thought crossed my mind also, I believe the Argonaut 509
> used the same
> filter in an external plug in accessory and was wondering if someone may
> have a circuit
> drawing for that available that I might have a copy of, any costs
> reimbursted. It would be
> real convenient if it could be sent via email too.
> Along that same line anyone know if Ten Tec may have a copy of that
> model 245
> CW filter I could down load. I looked last night for a little while and had
> no luck I may
> try calling them yet today and ask.
>
> Marty kd8bj
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