[TenTec] Argonaut filter question

[Ken Brown]

Regarding 9 MHz Filters, Ten-Tec 9 MHz IF filters are mostly (maybe not
all) NOT centered on 9 MHz. They have bandpasses of various widths covering
a frequency range centered a kilohertz or so above 9 MHz. They are intended
to be used with BFO frequencies of 9.000 MHz, 9.003 MHz for the two
sidebands (and some others in between those for other modes). A 9 MHz IF
filter that is actually CENTERED on 9 MHz is not going to work properly in
most Ten-Tec radios unless non-standard (for Ten-Tec) BFO frequency
crystals are used. Even if you did that there may be other problems caused
by other filters also in the 9 MHz IF that have bandpasses not coincident
with a non-standard (for Ten-Tec) 9 MHz IF filter.
DE N6KB

On Wed, Aug 31, 2022 at 2:49 AM Shawn Upton via TenTec <
tentec at contesting.com> wrote:

> You you to both of you, W5FH and DJ0IP.
> Radio is a 505.
> Looking up the HyGain, I found this manual:Bama Manual Archive
>
>
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> Bama Manual Archive
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>
> which lists the 2.1kHz filter as 2.1kHz at 1.8 shape factor.  Not sure if
> 50dB or 60dB, but it should be better than the stock 2.4kHz filter
> (although the copy of the manual I have indicates 2.5! at 1.7:1 shape
> factor).  Better.
> I'm not sure it would be easy to change this: this is not a plug in filter
> like used on Omni, Corsair, etc.  It looks like the soldered each crystal
> to the board, I think.  Someone removed the crystals and flew in the Galaxy
> filter--it doesn't look too bad, but it's not plug and play, it is soldered
> down.  For now it looks best to not mess with that, and instead to focus on
> the BFO crystal, and see what can be done there--I don't see indication it
> was changed, but it also doesn't say what it is, just is stamped 48002 on
> the top.
> Shawn kb1ckt
>
>     On Wednesday, August 31, 2022 at 02:38:10 AM EDT, <rick at dj0ip.de>
> wrote:
>
>  Hi Shawn,
>
>
>
> That is the 9 MHz SSB filter out of a Galaxy/HyGain R-1530 receiver.
>
> The Argonaut's 4-pole SSB filter was not centered exactly on 9.000 MHz.
>
> I think it is about 9001.5 kHz.
>
>
>
> The same filter was later used in the Argosey’s.  There was an option to
> replace it with a 9 MHz filter and many people did that, so I’m sure
> several people still have the original 4-pole filter in their junk box.  I
> have one, but shipping from Germany is expensive.    If you query the group
> and also the Tentec.com group, you might be able to find one and restore it
> to its original condition.
>
>
>
> 73 - Rick, DJ0IP
>
> (Nr. Frankfurt, Germany)
>
> May the Sunspots be with Us!
>
>
>
> -----Original Message-----
> From: TenTec <tentec-bounces+rick=dj0ip.de at contesting.com> On Behalf Of
> Shawn Upton via TenTec
> Sent: 31 August 2022 04:24
> To: Discussion of Ten-Tec Equipment <tentec at contesting.com>
> Cc: Shawn Upton <kb1ckt at yahoo.com>
> Subject: [TenTec] Argonaut filter question
>
>
>
> So at a hamfest last spring I picked up a TenTec Argonaut.  It said it was
> broken and so of course I took pity on it.  I finally opened it up tonight
> and on the SSB board someone took the liberty of replacing the discrete
> crystal 2.4KHz filter section with a Galaxy 117-21 filter module.  Says (in
> magic marker) that it's a 9MHz SSB filter.  A google search shows nothing.
>
> Now I bought this rig broken and if this is a repair too far I won't feel
> too bad, I can do other things with this (it's not in pristine condition)
> but I'm curious: does anyone know what a Galaxy 117-21 is?  Any good?  or
> maybe that's why it was sold as a problem child? (someone did a bad mod,
> bad impedance match and killed the radio while trying to "make it better",
> who knows what else is wrong inside this radio, I haven't even powered it
> up yet).
>
>
>
> Shawn kb1ckt
>
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