[Premium-Rx] Ten-Tec RX-340 - Amateur Use

[Carcia, Francis A HS]

ARRL solid state handbook is a good place to look. Maybe the regular hand
book.
There are a couple different configurations some as simple as a 50 ohm
resistor
hanging off the mixer in series with a parallel tuned to ground resonated at
IF frequency. High series Z at IF with a 50 ohm plus Xc/XL load to ground
off that frequency. This way when a signal bounces off the filter back at
the mixer the network loads the signal. fc


-----Original Message-----
From: Henry Kolesnik [mailto:kolesnik at sbcglobal.net]
Sent: Tuesday, February 08, 2005 2:16 PM
To: Carcia, Francis A HS; premium-rx at ml.skirrow.org
Subject: Re: [Premium-Rx] Ten-Tec RX-340 - Amateur Use


Where is there a schematic for a good diplexer or do you have your own 
homebrew cct?  Does mini circuits make one?

73
Hank WD5JFR
----- Original Message ----- 
From: "Carcia, Francis A HS" <francis.carcia at hs.utc.com>
To: <premium-rx at ml.skirrow.org>
Sent: Tuesday, February 08, 2005 12:30 PM
Subject: RE: [Premium-Rx] Ten-Tec RX-340 - Amateur Use


> The tighter the filter the more you need a good diplexer. Easy to build
> though.
>
> -----Original Message-----
> From: John Miles [mailto:jmiles at pop.net]
> Sent: Tuesday, February 08, 2005 12:55 PM
> To: premium-rx at ml.skirrow.org
> Subject: RE: [Premium-Rx] Ten-Tec RX-340 - Amateur Use
>
>
> Keep in mind, too, that simply adding a 3-kHz filter after the first mixer
> does not guarantee improved real-world performance.  You may also need a
> diplexer after the first mixer to present a 50-ohm (or whatever) load 
> across
> the board.  A mixer that isn't terminated in a *broadband* load won't be 
> all
> it can be in the IMD department.
>
> -- john KE5FX
>
>>
>> First, as I mentioned, making a narrow filter at high frequencies is not
>> trivial.  You think paying $100 for a typical 9 MHz xtal filter is bad...
>> try and price a 40.455 3 KHz xtal filter!
>>
>> And I can think of many receivers costing much more than the TenTec that
>> don't have them either.
>>
>> > Tell me then, why don't all high end HF rigs have this capability?  The
>> > Ten Tec 340 roofing filter mod looked pretty straight forward and
>> > inexpensive (using a KIWA 4 kc filter).  Others have done this
>> mod and are
>> > happy, but I wasn't due to the loss of fidelity.  Guy Atkins and I had
>> > problems when we tried added a switch to the mod.  Somewhere along the
>> > line we lost a lot of signal strength, which was not the case if the
>> > filter was wired in permanently.  I've been wondering about
>> this problem
>> > for quite a while.  I don't understand why a $4k receiver (ie the 340)
>> > wouldn't have such a capability.  I re-iterate again that the
>> Ten Tec is a
>> > bit of a dog on MW in it's unaltered state.......Walt.
>> >
>>
>
>
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