[TenTec] RE: [Orion] Orion subreceiver

[Barry N1EU]

I looked at this briefly and believe there are off-the-shelf 4khz wide 450Khz i.f. ceramic filters that could just be dropped in where the 15khz filter is.  Perhaps some experimenter might try this on their Peg/Jup or in the Orion subrx.

73,
Barry N1EU

Duane - N9DG <n9dg at yahoo.com> wrote:

>Although I think such a roofing would help some the Orion's
>sub RX, and the Pegasus/Jupiter too. I think that you'll find
>that these "ghost" signals are at +/-12 or 14 kHz away
>(depending on radio model) as you move away from the strong
>signal that is causing them. What is happening is that they
>are images that fall inside the the first IF roofing filters
>bandwidth.
>
>Adding a narrower filter in the first (45 Mhz) IF should
>alleviate this problem. That 1st IF roofing filter needs to
>be narrower than the 3rd IF's (12 or 14 kHz) offset from its
>injection frequency for it to help though. So wide modes like
>FM will have to go or be bypassed when such a roofing filter
>is in use.
>
>I thought about trying such a mod for the Pegasus in the past
>but haven't actually tried it. 
>
>Duane
>N9DG
>
>--- Barry N1EU <n1eu at netscape.net> wrote:
>
>> "n4lq" <n4lq at iglou.com> wrote:
>> 
>> >This may be another opportunity for INRAD. I think their
>> roofing filter 
>> >for the MP is 75mhz. 
>> 
>> Yes, and the 4Khz wide filter showed no improvement in the
>> MP's close-in cw performance.  The Omni VI and Orion fitted
>> with the 600hz (9Mhz) roofing filter performs so far above
>> the nearest competition in tight 160M condx that it makes
>> me want to avoid vhf i.f.'s.  (Omni VI performance based on
>> assumption and initial glowing reports from W2VJN).
>> 
>> 73,
>> Barry N1EU
>> 
>
>
>
>        
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