[Boatanchors] Intelligibility on SSB

[Gary Schafer]

If you talk the amp up to 1/2 the plate current I can assure you that you
are overdriving it and flat topping. That used to be the old way of doing it
but the peaks are much greater than a 2:1 ratio to what the meter reads.
If you look at a scope and watch the output and talk it up to where the
peaks just barely hit the maximum output level and then note the meter swing
I will bet that the meter will just barely flicker. Actual flat topping is
hard to see on the scope until it gets well into it. If you actually see
flat topping on the scope you are well beyond where it will splatter.

The 10B, 20A type exciters will pass very high audio frequencies as they had
no low pass filtering in them at all. I was on the air one time using my 20A
and a JT30 mike that went bad and it was dishing out trash over 100Khz on 80
meters.
I used one many years with a D104 mike like Karl, they sure sound good that
way.

73
Gary  K4FMX

> -----Original Message-----
> From: boatanchors-bounces at mailman.qth.net [mailto:boatanchors-
> bounces at mailman.qth.net] On Behalf Of Ken
> Sent: Thursday, March 13, 2008 5:38 PM
> To: Todd, KA1KAQ; boatanchors at mailman.qth.net
> Subject: Re: [Boatanchors] Intelligibility on SSB
> 
> Hi Todd,
> 
> A good phasing type SSB generator is capable of beautiful
> audio. I'm not talking about Hi-Fi to 15,000 cycles but good
> audio natural sounding.
> I do not use and have never used a "processor" and have no
> use for them what-so-ever!
> I even unplugged the clipper module from my 100V and
> used a tube base with a jumper to substitute in place of it.
> A good rule of the thumb with my 100V and 600L linear
> is to check momentarialy the maximum plate current just
> for a split second, observe maximun plate current then
> back off the carrier input, switch to ssb and kick 600L
> plate meter only half way. If the max cw input current
> to the 600L was 300 mills, then kick the meter up to only
> 150 mills, in other words, half way. The meter cannot
> follow the voice peaks fast enough so when you kick
> it up to 150 mills the voice peaks are really hitting 300
> mills. NO overmodulation!
> I have never had a report of carrier with the 100v which
> has a metered "null" reading, far superior to trying to
> null by sound, etc.
> I have never had a report of overmodulating either.
> 
> Leave those darn processors OFF and watch you
> modulation peaks - no problem.....
> Take care,
> 
> Ken   N5CM
> 
> ----- Original Message -----
> From: "Todd, KA1KAQ" <ka1kaq at gmail.com>
> To: "jeremy-ca" <km1h at jeremy.mv.com>
> Cc: <boatanchors at mailman.qth.net>; "Harold Hairston" <k4hca at alltel.net>;
> "Ken" <n5cm at rtconline.com>
> Sent: Thursday, March 13, 2008 9:49 AM
> Subject: Re: [Boatanchors] Intelligibility on SSB
> 
> 
> > On Thu, Mar 13, 2008 at 1:26 PM, jeremy-ca <km1h at jeremy.mv.com> wrote:
> >
> > I've heard a lot of good things about the rigs that generate SSB via
> > phasing..
> 
> > And Ken - I'm still looking for those straight-line caps. Spring is
> coming!
> >
> > ~ Todd,  KA1KAQ
> 
> 
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