[1000mp] Re: filter strategy

[George & Marijke Guerin]

Dear 1000MP readers,
    I agree with Jim Smith.  Fill the 8.2 Mhz IF slot(s) first.
The idea is to minimize the unwanted signals as soon as possible, and not
let it get to the 3rd IF.
    George        K8GG


----- Original Message -----
From: "Jim Smith" <jimsmith@shaw.ca>
To: <1000mp@mailman.qth.net>
Sent: Tuesday, August 06, 2002 4:21 AM
Subject: Re: [1000mp] Re: filter strategy


> IMHO the 2nd IF slots, i.e. the 8 MHz ones, should be filled first .
>  It is very disconcerting (other, stronger, terms come to mind) when
> trying to work a weak station on cw to see your S meter jumping up to S9
> + on cw as the AGC is being controlled by a signal outside the filter
> passband.  Same of course on SSB.  In other words, with no filter in the
> 8 MHz slot and a narrow filter in the 455 kHz slot, a strong signal just
> outside the passband of the 455 filter will "pump" the AGC rendering the
> weak signal somewhere between hard to copy and inaudible as the AGC
> reduces the gain to accomodate the strong (but pretty well inaudible)
> signal.  If, instead, there were a filter in the 8 MHz slot, the strong
> signal would be filtered out before it got to the AGC system.
.... snip....
>
> Hope this helps and 73
>
> de Jim Smith    VE7FO
>
>
> Gorsline wrote:
>
> >In several postings about how to filter the MP family, there's been
contradictory advice for how to start if you're not able to add matching
filters in both IFs.  Should you start with filling the 2nd or 3rd IF slots
first?  .... snip...
> >
> >tnx  73,  George  VE3YV / K8HI
> >
>