Rick,
Just curious - did you ever use any of the old analog TT rigs which had
a "Resonate" control (i.e. Triton, early Omni, etc.) there in DL land, and if
so, how did they hold up against the SW BC QRM? I'm wondering if the RF
amp/preselector subsystem from an old TT parts rig could be repurposed as an
RX preselector. (The "motive to my madness" is that the TT system appears to
be a variant of the 40M preselector schematic in the article you linked.)
73, Al
On Mon September 12 2016 10:55:59 pm rick@dj0ip.de wrote:
> Hi Sinisa,
>
> I'm sure you are right, you normally always are.
> However the Dunestar SPECS on their web site claim 40dB band-to-band
> rejection.
> I was just quoting the specs.
> http://www.dunestar.com/store/Single-Band-Bandpass-Filters-pid-4.html
>
> As I said, I use my own home-brew pre-selectors and the good one (40m only)
> has a 40db rejection bandwidth of 500 kHz.
> It is tunable using Topf-Kerns (I think the English name for that is
> pot-core or something like that).
> Description: download #8 on this page:
> http://www.dj0ip.de/downloads/
>
> 73 - Rick, DJ0IP
> (Nr. Frankfurt, Germany)
>
>
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of shristov
> Sent: Monday, September 12, 2016 11:51 PM
>
> > Of course one could also purchase extern BPFs like ICE or DUNESTAR at
> > $100 per band. They have 40dB or so of out of band attenuation.
>
> Filters like those have trouble in achieving 40 dB attenuation in the
> next/previous ham band.
>
> At +/- 750 kHz (or +/- 1.5 MHz) attenuation is practically non-existing.
>
>
> 73,
>
> Sinisa YT1NT, VE3EA
>
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