I should correct that, the copper coils on the rx side are
separated, the tx exciter is the double assy.. Same problem however
was on each, getting them in to range with sufficient tuning and
energy to still pass the correct multiplier through...
I ended up checking the factory rx injection with a spec
analyzer, at its normal 800, to get a level injection reference and
found that my 900 equivalent was low until I traced where... In some
of my early iterations of the mod ( before it re-engineered and
published by Gene W7UVH) I used outboard injection amplifiers to
Boost the injection to the rx to overcome the losses until correct
values were discovered by others to do it right...
Doug
KD8B
At 08:29 AM 12/7/2007, you wrote:
>While I have never seen or heard of a case, it may be possible..
>However, it is most likely not the case. I suspect insufficient drive
>from the oscillator chain through to the mixer.. The copper helical
>bandpass filter at the end of the L.O. chain will not tune without
>mods, getting them into the correct range was a lot of trial and
>error for me, and is suspect in my opinion. Insufficient injection
>level after a L.O. mod on any Mastr II conversion is normally the
>culprit of low sensitivity, OR you have something tuned to a wrong
>lobe.....in one of the helicals right now... There are more than one
>"peak" in some cases...
>
>Doug
>KD8B
>
>At 01:56 AM 12/7/2007, you wrote:
>
> >Do the Mastr II 800 MHz receivers have the "tin whisker" problems
> >that some of the other bands do? I have one I converted to 900 MHz
> >and the sensitivity will not go below 2.2 microvolt's for 12 db of
> >SINAD. I have tuned it right by the book and it never gets any
> >better. I have not opened up the helical resonators, but that will
> >be the next step.
> >
> >Thanks
> >Jack
> >K6YC
> >
>
>
