[ARC5] Modulation for ARC-5 transmitters.

[D C _Mac_ Macdonald]

I am reasonably sure that was the circuit I used to modulate a pair of 807s in parallel that I built up from a QST and Handbook article.  I used it until I managed to find the parts to build a plate modulator using a pair of 1625s.  Sold that whole rig at Brownfield, TX hamfest somewhere around 1965 or 1966.
  
* * * * * * * * * * * 
* 73 - Mac, K2GKK/5 * 
* (Since 30 Nov 53) * 
* k2gkk hotmail com * 
* Oklahoma City, OK * 
* USAF & FAA (Ret.) * 
* * * * * * * * * * * 
 

> From: kgordon2006 at frontier.com
> To: arc5 at mailman.qth.net; vk2bcu at operamail.com
> Date: Thu, 8 Oct 2015 16:56:30 -0700
> Subject: [ARC5] Modulation for ARC-5 transmitters.
> 
> Leslie:
> 
> There was an article some time ago in Electric Radio Magazine on 
> controlled-carrier AM modulation which I found to be a very well-done article, 
> and it explained a lot.
> 
> There was also a recent article in ER on the same subject, but I was very 
> "under-whelmed" by that article. I found it very difficult to follow.
> 
> My first transmitter, a Heathkit DX-35 used CC modulation, and I have 
> always liked that mode ever since.
> 
> You might also consider this modulator:
> 
> http://www.w7ekb.com/glowbugs/projects/SimplestModulator.pdf
> 
> Which plugs into the key-jack of any cathode-keyed transmitter. I tried one of 
> these once and was very pleasantly surprised at how well it worked and how 
> good it sounded.
> 
> Here is another article on that same modulator with different info:
> 
> http://www.w7ekb.com/glowbugs/projects/SimpleGridModulator.pdf
> 
> Using CC modulation, you should be able to achieve output equal to the full 
> plate dissipation capability of your final amp tubes, which in the case of a 
> pair of 1625s, should be close to 60 watts. (807/1625 has 30 watts PD rating 
> in ICAS)
> 
> Also, CC modulation works extremely well when fed into a modern linear 
> amplifier, unlike straight plate modulation, which must be "dialed back" 
> severely to prevent the following linear from being overloaded.
> 
> Ken W7EKB