[TenTec] Omni-VI+ Phase Noise and INRAD roofing filter mod?

[Bill Tippett]

	Jerry, here are some measurements by
G3SJX (RSGB's test editor).  He has been doing
these tests consistently over an even longer period
than ARRL in RSGB's RadCom magazine.

Transceiver	10 kHz  RMN	5 kHz SFDR	50kHz SFDR
Orion			95		93		93
Corsair		98		90		90
Omni VI		96		88		88

where RMN = Reciprocal Mixing Noise (Phase Noise)
and SFDR = Spurious Free Dynamic Range (3rd order IMD)

This Orion was measured with a 2.4 kHz roofing filter (due to
apparent problems with the 1 kHz filter), but Sherwood measured
improvement using the 600 Hz Inrad 762 (same filter as in the
Omni VI mod) of 6-7 dB at 2 kHz spacings and ~10 dB at 1
kHz spacings.  I would expect a properly modified Omni VI
would give nearly identical results to Orion above.

	Bottom line is the rigs are fairly close, with
Corsair having slightly better Phase Noise and Omni
having slightly better IMD performance.  However the
differences are close enough that you might not notice
the difference.

				73,  Bill  W4ZV