[Microwave] Rigs that have all mixer injectionfrequencies derived from a master oscillator

[Dave Brown]

----- Original Message ----- 
From: "Dr. Gerald N. Johnson" <geraldj at storm.weather.net>
To: <microwave at mailman.qth.net>
Sent: Tuesday, April 14, 2009 3:32 AM
Subject: Re: [Microwave] Rigs that have all mixer injectionfrequencies 
derived from a master oscillator


> On Mon, 2009-04-13 at 22:57 +1200, Dave Brown wrote:
>>  I've been looking hard at the Icom 706 recently as it has 1 Hz 
>> dial
>> resolution and all mixing frequencies are locked/derived from a 30 
>> MHz
>> master oscillator that can be externally sourced and GPS referenced
>> etc very easily.
>>  See this-
>>
>> http://g4hup.com/FC/DFS30/DFS30.htm
>>
>> The 706 also has the advantage it is getting cheaper all the time 
>> as
>> its now no longer current at Icom-although I expect there's still a
>> few new ones available.
>
> I like the FT-857(D). The DSP isn't great though. The optional
> mechanical filter for CW enhances weak signals, the DSP doesn't. It 
> also
> derives most all frequencies from a single module that is available 
> as a
> TCXO to give about 0.1 ppm, enough to meet US federal regulations 
> for
> CAP, MARS and other such services. I don't recall that the frequency 
> is
> one convenient to lock to a 10 MHz standard, but a synthesizer can 
> take
> care of that. Its not all that great a benefit to have the IF 
> controlled
> to 1 Hz when the transverter is wandering about kiloHertz or more.
>
> I really like the way I can run CW with it in SSB mode, no stupid
> frequency shifts, no mode shifts, just start sending (hard on 
> sequencers
> though), and the way that its noise blanker works. I've heard the 
> 706
> noise blanker is deficient.
>
> And for two bands, it will compute the frequency offset and hold the
> power down to under 4 watts, in transverter mode. Unfortunately 
> reached
> by a menu, not a front panel switch.
>
> 73, Jerry, K0CQ

Tks for the input Jerry, the intention is to  have BOTH the 
transverter AND the transceiver referenced to a common frequency std- 
as you said, there's not a lot of point having one without the other. 
It's just that knowing what rigs are capable of being totally 
referenced to a master frequency is the tricky part as the makers 
don't consider this a selling point worth including in the usual data 
sheets. And there seems to be a common tendency to use really oddball 
frequencies for those rigs that DO have a master osc for all mixers. 
Binary v. decimal, I guess.

Will check out the FT-857-I may have a copy of the service manual 
here.

73
Dave, ZL3FJ