So what problem are we trying to solve here?
If we are solving for SNR, IMHO, good RX antennas provide the best bang for the
buck. Today's RX antennas are built on sound engineering principles, have
measurable performance, and offer operating flexibility a crystal front-end
can't.
If we are improving selectivity, I wonder if we are beyond the point of
diminishing returns. There are many modern radios that have performance beyond
what's needed during a contest. Further, during a contest, it is key clicks or
splatter that cause the greatest pain; how can the crystal front-end alleviate
the impact of such garbage?
Wishing everyone a happy holidays season.
73, Rudy N2WQ
Sent using a tiny keyboard. Please excuse brevity, typos, or inappropriate
autocorrect.
> On Dec 24, 2016, at 12:48 AM, K1FZ-Bruce <k1fz@myfairpoint.net> wrote:
>
>
> The one they are developing for marketing 'can' have 1 KHZ segment crystals
> channels..
> I would encourage anyone to insert a single crystal in their receiver antenna
> input to see the
> difference before considering a purchase. (Careful not to transmit into the
> experiement)
> 40 meters is a good test band as usually has many signals after dark..
> 73
> Bruce-k1fz
>
>
>
> On Fri, 23 Dec 2016 17:56:07 -0700, Dave wrote:
>
> About 15 years ago I built a switchable front end crystal filter, I was
> going to market it but it was too expensive for the Ham market. It covers
> 1800 to 1850 in 5kHz segments with a slight overlap so that there are no
> gaps, each section is a half lattice, the insertion loss is about 6dB but
> that isn't a problem because I always have about -15dB of attenuation in the
> receive path input. Nose bandwidth is 5kHz and about 8kHz at -20dB. Lack of
> noise blanker performance is not a problem because big signals make the
> blanker useless anyway. I used it during contests when my rig was an IC781,
> since changing to a more modern rig, an IC7851, the filter provides no
> significant improvement. For working DX on a crowded band it is useful if
> your rig does not have a good roofing filter.
> HNY /MX
>
> Dave AA0RS
>
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