[ARC5] 10 meter BC-454 a bit more

[D C _Mac_ Macdonald]

Until I built a full plate modulator (pair of 1625s) 
for my home brew pair of 807s, I used a cathode 
modulator plugged into the key jack. I don't know 
how "well" it worked, but it did "sorta" work. 
 
My Globe Scout 65 (first commercial xmtr) used the 
Heising system for modulation. I was told that it 
developed maybe 35% positive modulation and close 
to 100% negative modulation. I sure had no way to 
tell what it was doing. 
 
* * * * * * * * * * * 
* 73 - Mac, K2GKK/5 * 
* (Since 30 Nov 53) * 
* k2gkk at hotmail.com * 
* Oklahoma City, OK * 
* USAF & FAA (Ret.) * 
* * * * * * * * * * * 
 
 
> From: kgordon2006 at frontier.com
> To: geoffrey at jeremy.mv.com
> Date: Thu, 7 Mar 2013 09:52:40 -0800
> CC: Arc5 at mailman.qth.net
> Subject: Re: [ARC5] 10 meter BC-454 a bit more
> 
> On 7 Mar 2013 at 9:29, Geoff wrote:
> 
> > Now all you need is a 6CW4, 6GM6 or 6EH7 (or SS) preamp to find
> > another layer of signals and crank the 12SG7 gain back a bit.
> 
> Sure. I should continue to make a silk-purse out of this hog's ear. ;-)
> 
> > Im not at all surprised at the 454 performance since it is missing all
> > the loss associated with a bandswitching receiver.
> 
> Well, not having (yet) had your experiences with receivers, I must insist that I 
> am quite surprised at the results of this job. I had about half expected its 
> performance to be about on par with my S-41G at 10 meters: i.e. dismal.
> 
> It most certainly is not.
> 
> > All you need now is a simple AM/CW TX to enjoy the coming 10M E season
> > DX. Time to hack an ARC5 TX maybe?
> 
> Well, I still have a DX-35. I'd bet that would work well. However, I also have 
> several badly modified ARC-5 transmitters here. All are unrestorable, IMHO. 
> All have significant holes in various places, and many missing parts, and 
> added parts. I suppose I could use one of those.
> 
> > A carrier control audio stage can
> > be built right in.
> 
> SInce the time of my first DX-35, I have always had a great liking for 
> controlled-carrier AM modulation. There was an article in ER magazine some 
> time ago which went into great detail on that method.
> 
> I also like so-called "cathode" modulation. There were several articles in QST 
> magazine and in the Handbooks on it. One was entitled, "The Simplest 
> Modulator". It simply plugged into the key jack of any cathode-keyed 
> transmitter. It is actually a combination of cathode and grid modulation. 
> 
> I tried it once and it works very well indeed for being so simple.
> 
> One advantage to controlled-carrier AM is that it drives a linear amp much 
> more "kindly" than straight plate modulated AM.
> 
> Another is that if used properly, it can sound like SSB (actually DSB) to 
> someone on SSB.
> 
> Ken W7EKB