On Sat, 20 Aug 2005 18:36:32 GMT, james wrote
in :

On Fri, 19 Aug 2005 19:51:36 -0700, Frank Gilliland
wrote:

+On Fri, 19 Aug 2005 23:08:10 GMT, the self-proclaimed "CB Amp God"
+Bill Eitner wrote in
m:
+
+
+
+Jay in the Mojave wrote:
+ Hello All:
+
+ Yes this had to run in someone's mobile, I would think it took way over
+ 200 amps to run. This really has to be one for the hall of fame!
+
+ It would take nearly 20 amps just to
+ keep it on standby.
+
+
+Closer to 10 amps.
+
******

Closer to 15 amps. The filaments, with (6)6LR6s and (3) 6KV6As alone
are over 10 amps. Then add in the switcing transisitors. If I remember
correctly the original output tubes were 6LF6s. The amp is three tubes
to drive 6.


Closer to 10 amps -- it has a standy mode that reduces the current
through the filaments and shuts off the inverter. Besides, I ran one
across the bench a few years ago and measured the standby current.


+
+ .....A DC pig it
+ definitely is. However, as far as
+ output, by todays standards, it isn't
+ that big a deal. A daily-use 8-pill
+ is easily its equal.
+
+ I saved the photos on a disk. Where would you put this monster in a car
+ or truck?!??!!??!?! Hehehehhehehehe
+
+ On the floor, in the trunk, or in A
+ custom box in the bed. In those days
+ the radios didn't have the frequency
+ coverage that is common today. That
+ means that once it was tuned it could
+ be left alone.
+
+
+What a load of hogwash. This amp has a tuned pi-tank output that you
+can clearly see in the pics; i.e, you need to retune if you change
+freqs. Tube amps can be designed to be broadband just like solid-state
+amps, and solid-state amps can be built with tuned output tanks. But a
+broadband amp -- tube -or- transistor -- eliminates the tuned output
+tank, the result being harmonics that increase with non-linearity. The
+only difference between 'then' and 'now' is that ampheads these days
+don't give a rat's ass about harmonics bleeding all over the spectrum.
+

Tuning was not as critical for that amp. When there was only 23
channels, you set it at channel 12 and it pretty much was adequate for
the whole 23 channels. You only had a span of 300 KHz. Granted it
maynot have been optimum at the band edges, but was useable. For 40
channel operation that maybe stretching it a bit.


Quite a bit.


I agree toaday most could care less about harmonics. The further the
meter goes to the right the happier they are.


Unfortunately, that's all too true.


+And as far as frequency coverage is concerned, the range of bipolars
+is generally narrower than power RF tubes, the latter being usable
+from 0 Hz all the way through to their maximum frequency. In fact,
+most are rated in their data sheets for use as audio amps. Even
+smaller RF tubes like the 6146 have been used in guitar amps. You
+can't do -that- with a 2SC2290.
+
****

Come on, crossover distortion at 12 volts is horrible compared to 450
volts. For audio, Tubes of FETs are superior to bipolar transistors.


Again, true story. Where did I say anything different? You need a
feedback loop in order to reduce crossover distortion in a bipolar
push-pull, but you can't put a feedback loop in an RF amp.


+
+ And WHAT mobile antenna would hold a full KW, other than a 102 inch
+ stainless steel whip ?
+
+ A Firestick (heliwhip), the Francis
+ whips, or even a K-40 or an Avanti
+ Mobile Moonraker that was tuned right.
+ It has to be realized that when all was
+ well that unit was good for 600 dead-key
+ and 1200 peak.
+
+
+More like 300 dead-key (RMS/AM) and 1200 PEP (SSB). And to think that
+after all these years you -still- haven't learned the difference. Go
+crawl back under your rock, Bill.
+
+
******

Almost all of the sweep tubes ran in cathode driven more linearly
wqith much less carrier output than most CBers like. Judging by using
4 6LQ6s in cathode driven configuration with some bias on the contrrol
grids,I saw between 80 and 120 watts as the maximum carrier pwoer for
good linearity. For this amp more like 120 to 180 watts carrier. Sweep
tubes are not the best fore AM amplification. They perform adequately
for SSB. There you can realize more power out.


Sweep tubes aren't very linear to begin with..... at least not when
driven as hard as they are in these RF amps. The pi-tank is almost
essential but does nothing to improve linearity. I've never heard one
sweep-tube amp that didn't noticably distort the audio.

But my point was that PEP @ 100% mod = 4 x carrier, a fact which
befuddles voodoo CB techs like Bill the self-proclaimed CB Amp God.


The again output power and life expectancy of sweep tubes are
inversely proportional. The more out, the shorter the life span.


That's pretty much true with all power devices.








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