Correct, my pre-selector is RX only, which the name implies.
That is why every transceiver I have had since the mid 70's was immediately
modified with two RCA phono jacks mounted on the back. I interrupt the RX
ANT line internally and run it thru the two jacks, jumpered of course when
no preselector is attached. Even my Eagle has this mod. The OM7 had it
available but very few people performed the mod. I did it on the OM7 I
tested here prior to its announcement and it made a WORLD of difference on
40m.
73 - Rick, DJ0IP
(Nr. Frankfurt, Germany)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of shristov
Sent: Tuesday, September 13, 2016 10:15 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Scads of used Icom IC-7300
"rick@dj0ip.de" <Rick@DJ0IP.de> wrote:
> 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
Hi Rick,
that's what I had in mind.
Taking the 7 MHz filter as an example,
there is 40 dB attenuation on ~3.5 MHz.
But on 6 MHz the attenuation is practically nil.
Your preselector is the right tool for the job.
But it's receive-only, given the 7.5 dB passband attenuation.
Dunestar etc filters must have a much wider passband in order to achieve low
enough passband attenuation, making them suitable for transmitting.
Best 73,
Sinisa YT1NT, VE3EA
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