At 20:16 1/6/09 -0500, you wrote:

Does anyone know of a fairly reasonably priced CAT controllable (read doppler) 2m rig? Ham radio deluxe or other?

Also, maybe I am misunderstanding how it would work, thus the post to AMSAT-bb.

I want to auto correct the doppler on a rig connected to my CalAMP 130016 which puts 2401.016 at 123.000mhz.

Can I find an all-mode radio that will work with CAT control? The rotor is already controlled by Nova and a Unitrac unit.

Mike kb8zgl

****************************************************************** 6th January 2009 KB8ZGL de S.I., Mike,

Uni_Trac will "tune" your 2M radio making it look like a 2400 MHz radio.

There is provision in Uni_trac to allow for the "off-set" frequency, the down-converter's LO, which you have to manually enter in Uni_Trac's set up screen. Doppler tracking will be accurate.

Uni_Trac will also handle your UP-link Doppler (and steer your antennae) simultaneously thus giving you full Doppler control of a QSO.

You will need a radio that tunes to 123 MHz. Many 2M radios do not cover this frequency range. An alternative is to use a simple VHF down-converter from 123 Mhz to a HF radio. Converting the 2m spectrum to 10 Metres was a popular technique used many years ago before "Japan Inc" invaded the Amateur market with their 2m radios. Pick up an old 2m/10M converter and change the LO crystal, and retune the RF for 123 MHz input.

Then use your HF radio to receive 2400 MHz with Uni_Trac compensating for Doppler by tuning your HF radio!

The converter can have "minimal performance". Your system sensitivity will be set by the 130016. Keep the system gain low; just enough to avoid degrading the overall noise figure.

Contact me off-list if you need additional help.

73s, de John G3BVU/W1 amsat 439.

Yours truly,

C.J.Beanland, MSEE, C.Eng., MIEE, MRAeS. Sales Manager, Spectrum International,Inc. spectrum.ma.ultranet@rcn.com P.O. Box 1084, Tel: (978) 263-2145 Concord, Mass. 01742. Fax: (978) 263-7008