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Re: [TenTec] Orion Review By RSGB

To: tentec@contesting.com
Subject: Re: [TenTec] Orion Review By RSGB
From: "Ten-Tec Inc. Amateur Radio Sales" <sales@tentec.com>
Reply-to: tentec@contesting.com
Date: Wed, 19 May 2004 13:31:09 -0400
List-post: <mailto:tentec@contesting.com>
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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