[amsat-bb] Re: 2m all-mode CAT controllable rig

[John Beanland]

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 at rcn.com
	P.O. Box 1084,			Tel: (978) 263-2145
	Concord, Mass. 01742.		Fax: (978) 263-7008