[Premium-Rx] Question re WJ 8718A/MFP RF GAIN

[Dan Robinson]

Yeah thanks, this is I am embarrassed to say beyond
my understanding at this point.  Seems to me, when you
go to MGC the RF control should engage and you can vary,
or you overload, which indeed is what happens on very strong
signals, even on this fine 8718A.  Have to think that someone
along the way modified the radio to disable manual RF gain.

On Sat, Apr 30, 2016 at 6:56 PM, George Georgevits <georgg at bigpond.net.au>
wrote:

> Hi Dan,
>
> I have an 8716, not the 8718 MFP. However, on the 8716, as on many other
> comms receivers I have used as well, I am pretty sure that AGC (Automatic
> Gain Control) and MGC (Manual Gain Control) are considered conflicting
> functions, which is why such receivers are designed to have the RF gain
> only
> work when the AGC is turned off.
>
> My guess is that with the AGC ON, the AGC controls gain of the RF stage.
> However, the manual RF gain control also controls the gain of this stage,
> so
> the two conflict. The AGC also usually controls the gain of one or more of
> the IF stages.
>
> Perhaps someone with more in-depth knowledge may care to confirm this???
>
> Cheers,
> George Georgevits
> VK2KGG
>
>
> -----Original Message-----
> From: Premium-Rx [mailto:premium-rx-bounces at mailman.qth.net]On Behalf Of
> Peter Gottlieb
> Sent: Sunday, 1 May 2016 5:44 AM
> To: Dan Robinson
> Cc: PREMIUM-RX
> Subject: Re: [Premium-Rx] Question re WJ 8718A/MFP RF GAIN
>
>
> I didn't see any response from you on the WJ list. Does AGC function
> properly?
>
>
> Peter
>
> > On Apr 30, 2016, at 3:29 PM, Dan Robinson <dxace1 at gmail.com> wrote:
> >
> > Hello to all in the group.   I would like to
> > repeat her a question I posted earlier in
> > the WJ Yahoo group, of which many here
> > may be a member, in hopes of finding an
> > answer.
> >
> > The receiver works perfectly except for
> > one aspect I have always wondered about,
> > which is that the front panel RF gain does not
> > seem to function at all.   This is the case when
> > the receiver is set to MGC.
> >
> > I have received several replies asking if I have
> > turned automatic gain control OFF, which I
> > assume means MGC.
> >
> > Does anyone who may be a 8718A owner have
> > a similar issue or able to provide any information
> > on this?
> >
> > Something tells me that RF was disabled at some
> > point years ago with this particular receiver and wonder
> > if it's possible to re-enable it.
> >
> > Thanks
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