[TenTec] Paragon II Failure to Transmit

[Rick - DJ0IP / NJ0IP]

Pete,

The Omni VII is a different design than the Paragon.
Ten-Tec put a bit more intelligence into the front end of the OM7.

What they did was pay careful attention to the amount of stage gain in the
early stages, through to the first mixer, keeping the gain as low as
possible, and then insert the mechanical filter to protect the downstream
stages, ie. 2nd mixer and DSP circuitry.  The result is a significantly
better BDR3 in the OM7.  

The results measured and reported by Rob Sherwood prove that they did their
homework.

73
Rick, DJ0IP

-----Original Message-----
From: Peter Bertini
Sent: Saturday, January 19, 2013 6:37 PM
To: TenTec at contesting.com
Subject: Re: [TenTec] Paragon II Failure to Transmit

I may be missing something, but I don't see how the 455kHz mechanical
filters can do much to improve the 2nd mixer in band IMD performance for the
Omni VII. The limiting factor is the 70 MHz 1st IF filter which has a wide
20 kHz BW. It looks to me the same problem when comparing in close CW
performance between my Omni VI and Paragon II. The Paragon has the same 70
MHz 1st IF problem and lack of early protection for the second mixer.
(Besides the phase noise issues).

Pete k1zjh
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