[ICOM] 751A Main RF Board

[Mike Andrews W5EGO]

On Thu, Oct 23, 2008 at 12:43:35PM -0400, EP Swynar wrote:
> Hi Gary,
> 
> Bingo...! Yes...!
> 
> There is, indeed, a "J17" marked on the pc board, right next to the pin
> terminal...
> 
> What does it all mean, then...? Can I safely install the board into my
> existing rig --- minus the black wire / J17 connection --- and expect it to
> work OK...?
> 
> I assume PBT refers to "push button tuning"...? If I hook-up the board LESS
> the wire, will some button on the face of the rig allow me this option, vs.
> my simply spinning the dial...?

Nope. "PBT" refers to PassBand tuning -- moving the IF passband up or 
down a bit, to move ARM/ARN outside the filter bandwidth -- if I recall 
correctly. Someone brought suit against ICOM for infringing a patent 
which included PBT, and as part of the settlement ICOM changed the 751A
(and possibly 751; I don't remember) to do IF shift: moving the IF up 
or down against the filters. Others may recall more of this particular 
tempest-in-teapot and will be able to tell me where I've gone w0rng. 

> ...And how'd you get so smart about these things, anyway, Gary...?! Hi Hi.
> Seriously, it's great to have the knowledge & experience of guys like you
> available to aid & abet dunderheads like me...I sincerely do appreciate it.

Amen. I couldn't agree more. 

73, de

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin