[1000mp] Pream Off ?

[Robert Shohet]

Excellent explanation.  Thank you!

73

Bob KQ2M

> Well, now I am the expert on this cuz I just looked it up in my MP
Technical
> Reference booklet  (black book, pages 8,9).  Here's the way I would
> summarize what I think the black book says.
>
> IPO illuminated  = no preamp at all, in any band.  Period.
>
> If the IPO is not illuminated, then we go through one of three preamps.
The
> preamp to be used depends on whether menu 8-4 is set to TUNED or FLAT, and
> on the frequency to which you are tuned.
>
> If you select FLAT (no IPO), then,
>
> FLAT = Always uses RF Amp #2 (broadband preamp, covering 1.8 to 30 MHz.)
>
> If you select TUNED (no IPO), then you get a different preamp, depending
on
> your freq...
>
> TUNED, 1.8-7.299 MHz. = RF Amp #1 (low gain preamp, supposedly good large
> sig handling)
> TUNED, 24.5-30 MHz. = RF Amp #3 (higher gain, better noise figure)
>
> So between 7.3 and 24.5 MHz (e.g. 30, 20, 17, 15M bands) there is no
> difference between TUNED and FLAT, since they use the same preamp (#2).
But
> for frequencies below or above that, TUNED selects a different preamp.  I
> tend to just leave mine on FLAT most of the time.
>
> The step attenuator, if used, is at the very front of the RF stage, before
> any of this stuff.
>
> Look at the block diagram.  It's confusing in words, but it makes good
sense
> when you look at the diagram.
>
> 73,
> Tom / W7GT