[TenTec] Orion Review By RSGB

[Ten-Tec Inc. Amateur Radio Sales]

No - I looked again at the RSGB test report.  The numbers are stated as I 
said in
the below.  Of course, we don't have an error of measurement data point
to correlate them against - but assumption of +/- 3 dB is generally valid.

The point he was making about the 1 kHz filter was simply that you can keep 
very loud,
very close signals from having a negative impact.  A 90 dB greater signal 
than S1 at 500
Hz away from the target frequency might have a larger negative impact on 
receiver
performance at 2.4 kHz roofing bandwidth than at 1 kHz - that's 
understandable. I don't
think he was meaning to imply that one was better than the other.

5 kHz spacing dynamic range, 1 kHz roofing filter, 7 MHz band, 500 Hz DSP
CW filter
(they measured 20, 6, 2.4, and 1 kHz stock filters only):
91 dB

5 kHz spacing dynamic range, 2.4 kHz roofing filter, 7 MHz band, 500 Hz DSP
CW filter
94 dB

Scott Robbins W4PA

At 11:18 AM 5/19/04 -0400, you wrote:
>W4PA wrote:
>
>*************************************************************************
> >From the RadCom review:
>
> >5 kHz spacing dynamic range, 1 kHz roofing filter, 7 MHz band, 500 Hz DSP
>CW filter
>(they measured 20, 6, 2.4, and 1 kHz stock filters only):
>91 dB
>
> >5 kHz spacing dynamic range, 2.4 kHz roofing filter, 7 MHz band, 500 Hz DSP
>CW filter
>94 dB
>
><SNIP>
>
> >"With the 1 kHz [roofing] filter, measurements showed it was possible to 
> copy
>an S1 signal with an interfering signal 90 dB greater only 500 Hz away.  This
>is truly awesome performance."
>*********************************************************************
>
>         More contradictory information!  The above says 5 kHz IMD is 
> better using
>the 2400 Hz filter (94 dB) than the 1000 Hz filter (91 dB), yet the second
>comment above implies the 1000 Hz is best (as ARRL, YT1NT and Sherwood have
>all reported).  Scott, did you possibly transpose RadCom's data?  If not,
>these measurements contradict Sherwood's which were first reported in March
>by W0YG (terrible format but I attempted to redo it):
>
>http://dayton.akorn.net/pipermail/orion/2004-March/000309.html
>
>Dynamic Range Test
>
>@5 KHz     @2 KHz       @1 KHz  Filter
>
>96dB      95dB         89dB             2.4 KHz
>96dB      94dB         93dB             1.0 KHz
>
>         Will the REAL data please speak up now?
>
>                                         73,  Bill  W4ZV


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