[ARC5] "Curing Chirp in Command Transmitters"

[Jim Falls]

The Password is: Power-supply. 

I always "over design" my PSUs using the highest current power transformer I can get at for the particular application. 

I had so many fits getting my BC-375 to behave: yooping on CW, FMing in phone even when neutralized as best as I could. Drove The Net Guys a bit nuts. 

The power transformer I had was running warm right at its design limits w/no breathing room whatsoever. A colleague (Dennis W7QHO) gifted me a bigger transformer w/200 mA to spare, explained Critical Inductance to me, and the problem went away once I retrofitted the old one. Now I have 8% regulation at key down; about the same as the PE-73. 

My 1929 Hartley w/two parallel 27s, runs sweet and clean at 300V because the PSU can deliver 100mA, and it only uses 60. Check it out on my Flickr listing. 

Sometimes for me, beef is the easier solution. Feed these Mil-babies what they were designed to run on, and they are generally well-behaved, at least so far, hihi! 

Cheers!
Jim K6FWT
CBLA #37

> On Oct 5, 2014, at 10:36, Kenneth G. Gordon <kgordon2006 at frontier.com> wrote:
> 
>> On 5 Oct 2014 at 10:46, Bill Cromwell wrote:
>> 
>> Whooping, yooping, and drooping are very poor practice.
> 
> I ABSOLUTELY agree...and it is totally unnecessary to boot.
> 
>> That musical fifth will qrm other qso's in progress as will more serious,
>> slower drift.
> 
> Yes...and the drift is unnecessary also.
> 
>> On the other hand having some "character" can help us sort out
>> the signals in a busy band because they stand out.
> 
> Again, yes....but that is "some" character, not some horrible sounding crap.
> 
> What has never ceased to bother me and I don't understand it, is that some 
> old timers LIKE to hear those horrible signals. Many of the really-OT in the 
> Antique Wireless Association have expressed such thoughts, and, again, I 
> don't understand their thinking.
> 
> It is prefectly possible to make, for instance, a 1929 TNT sound at least as 
> good as a modern rice box....or even a little better.
> 
> Ask Carl KM1H: he made DXCC using such a rig, and no one whom he 
> contacted even bothered to ask him what he was using except ONE 
> contact...who then expressed considerable surprise and asked many more 
> questions.
> 
> W7QQQ Jack Meadows routinely uses a pair of 809s in a TNT configuration 
> on both 80 and 40 meters. I have worked him and can assure you that his rig 
> sounds literally beautiful: no chirp, no clicks, no drift and a beautiful almost 
> bell-like tone with a very little "character".
> 
> If it can be done with a 1929 design, it sure as heck can be done with an 
> "ARC-5" transmitter, and it SHOULD be done!!!
> 
> IMHO, there is simply no excuse for crappy sounding signals.
> 
> And, IMHO, there is no need for fancy "chirp reduction techniques" with the 
> rig either. :-(
> 
> Ken W7EKB
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