[AMRadio] Old Ham, New AM Enthusiast

[Larry Szendrei]

On 12/28/2010 2:27 PM, rbethman at comcast.net wrote:
> Larry and crew,
>
> That is a far more drastic method than I was thinking about.

Drastic, how?

It's not very much work at all to do (or undo), and I guarantee that 
much more "invasive" and time-consuming mods would be needed if one were 
to attempt to use more of the original Apache audio/modulator section, 
in order to achieve the equivalent audio quality.

Not trying to push "my way" on anyone, of course, it's totally up to the 
owner/operator of the station according to the results he wants, and the 
approach to take to get there.

73 and Happy New Year,
-Larry/NE1S

> From: "Larry Szendrei" <ne1s at securespeed.us>
> To: "Discussion of AM Radio in the Amateur Service" 
> <amradio at mailman.qth.net>
> Sent: Monday, December 27, 2010 5:59:39 PM
> Subject: Re: [AMRadio] Old Ham, New AM Enthusiast
>
> On 12/27/2010 1:24 PM, rbethman wrote:
> > Jerry,
> >
> > You are getting good advice - so far!
> >
> > One other made comment regarding the Apache.  It has a "well earned"
> > nickname. * Scratchy Apache *
> >
> > It take a bunch of work reworking the audio circuitry to make it sound
> > like "you" REALLY sound.
> >
> > It also REALLY needs negative feedback added in.
> >
>
> I used to have an Apache. When I bought it, the modulators had been
> converted to triode-connected 6146s driven by outboard audio*. The thing
> sounded very, very good. The only thing that was used from the original
> Apache audio section was the modulation transformer, which isn't a bad
> piece of iron.
>
> *This is what the audio section looked like:
>   -push-pull tube type audio output xfmr with 8 ohm speaker winding as
> audio input from external audio amplifier capable of at least 5-8W
> output. (original) high-Z primary ends go to 6146 modulator tube screen
> grids, and center-tap of this winding goes to ground.
>   -6146 modulator control grids tied to about -5V bias, well bypassed
> for audio and RF, to put the operating point for the modulator tubes in
> a good place.
>   -6146 plates to each end of mod tranny primary per usual arrangement.
>   - voila! quick and easy good audio for the Apache!
>
> Having said that, though, I agree with Rob about focusing on the antenna
> first, and spend some time on AM before deciding what the  "upgraded" AM
> station will be.
>
> Here are some AM nets up here in the Northeast you might be interested
> in checking into:
>
> AM Carrier Net, Sundays at 8:30AM on 3835 KHz
> Antique Wireless Association Sunday PM AM net, Sundays at 4:00PM on 3837
> KHz.
> Gray Hair Net, Tuesday evenings at 8:00 PM EST (or 8:30PM EDT) on 1945 
> KHz.
>
> 73 and we'll be looking for you Jerry,
> -Larry/NE1S
>
> _