Mod For popping & AGC on Argosy
Sun, 16 Jun 1996 18:38:04 -0700
Steve Ellington wrote:
> Questions on this mod.
> 1. Since I don't have the diagram nor the Argosy, what is the function of
> that capacitor?
> 2. Does it in any way affect the recovery time of the receiver? Could the
> reason for less popping be because it takes longer to recover thus slowing
> the qsk?
> I'm working on the same symptom with the Omni 6. Although there are
> several cures, all so far have slowed the super fast qsk which us cw nuts
> don't want to do. Thusfar, it seems that the popping originates in the
> 9mhz IF stage and is due to a mixing of the T voltage with the IF signal
> in the crystal filters. Replacing the filter with a capacitor totally
> eliminates all popping and of course all selectivity (brilliant eh?).
> I've tried using capacitors to block the dc to no avail. Next, I shall try
> totally isolating the filter from both the T signal and ground. That
> T signal is a square wave, rich in harmonics of course. Combine that with
> your puney little 9mc IF signal in a tight crystal filter then amplify it
> about 50,000 times and no telling what you're gonna wind up with! It
> reminds me of my cat when the vacuum cleaner is fired up. He heads for the
> pet door full tilt and POPS outside with his hair on end.
> > Change C40 on the audio/IF board from 1 Mfd to a 10 Mfd will stop the
> > popping when You return to Receive, Your ears will love it. This takes
> > about 10 to 15 minutes.
> Steve Ellington N4LQ@IGLOU.COM Louisville, KyI did this mod on the Argosy II and it seemed to bring the recovery
time to about the same as the Omni V and the paragon. I got this Mod
from another ham and I had to play around with the cap size, I used
another size than a 10 but don't remember what it was. This mod came
from what is used on the corsair II for slow Qsk. I have never had a
problem on either .I have had 2 of the Argosy II s and really love
them for a CW rig, The Cw and Audio cw filter system on them is second