Jim,
It's a wonder Tom didn't add a "by the way" saying, scopes and dip
meters are very inaccurate and should never be used. : ) At least he
answered you by e-mail, he never would me.
If a scope is calibrated properly, or a dip meter the same, they
can't lie. They can only show you the truth. If a dip meter shows a
resonance, there is a resonance at its tuned frequency. Forget
reading the freq off the dial, simply couple it to a known accurate
freq counter, it will show the truth if you want precision. A
calibrated scope can only show a waveform that it produces from what
it sees at the input jack. The only way to make it lie is to not
calibrate it or set a control properly. If using a Tek or other
quality scope, your viewing something pretty accurate. I still think
a scope is one of the better ways of measuring output power while
monitoring the signal for over-modulation and cleanliness. This
method has been used for years.
I have an old book by Sylvania that they sold with their old tube
type scopes showing all the ways of measuring the output power
including the trapezoid pattern. I actually have a scope here made by
Wawasee Electronics that uses the trap display, and it works pretty
darn good. It's a combination wattmeter and scope. I also have one by
Heathkit, but it really requires a connection to the modulation
circuitry to work. The Wawasee one uses a yoke (electromagnet) to
pull the trace over making the trap pattern. This doesn't require
that connection and runs soley off the RF coming in. Either way, they
both show the same pattern.
Best,
Will
--- In ham_amplifiers@..., "pentalab" <jim.thomson@...>
wrote:
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
RICH SEZ.... W8JI's censorship is quite rational, Bill.
R L Measures, AG6K, 805.386.3734
r@..., , rlm@, www.somis.org
#### I had sent an e-mail to Rauch re: this PEP vs Average
nonsense on the "other reflector". Other's had mentioned
texts
where they depict 14.5 db peak to average ratio in the male
voice. I looked it up... it's also in "SSB sytems and
circuits"... same deal.. 14.5 db. What every one missed was
they are talking about absolute peak... as in ur 100 watt rms bulb
is actually 200 peak.... and your 120 vac is actually 169.7 V.
Peak
V / dc resistnace = peak current. Peak current x peak V =
peak watts.... that kinda peak.
### Reading though some audio engineering notes.. it was pointed
out that a pure sinewave had a ... 3db peak to average ratio....
then the light bulb went on ! I tried the same experiment on
my Behringer DEQ-2496 built in RTA... and sure enough, a sine wave
has exactly 3db peak to rms ratio. When talking on my RE-27
mic... and looking at the raw audio on the RTA [b4 processing it
with EQ, compression, split band limiter's, etc] I get EXACLY
14.5 db peak to rms ratio. This rta will hold the highest
peak too... and in 1/10 db increments.
### How does this relate to ssb + linears ? While looking
at my L4B's plate current meter.... with a dead cxr.. reads 800
Ma. While talking, it averages around 350-370ma... and 400-420
ma with the processing on. Looking at the Coaxial Dynamic's
wattmeter... with a dead cxr... reads 1250 w. [whether meter is
switched to average OR pep] While talking.[processor
OFF]..and meter on average.... meter reads aprx 175- 200 w .
Switch to pep.... reads 1400 w. With processor ON... pep readings
are the same 1400 w pep. Switch to AVERAGE... and meter reads
250-265 w 1400 w pep / 250 average = 7.48 db IE: the
average power output [250 w], is 7.48 db down from pep...
and 7.48 db = 14.96 db peak. 14.96 db peak is virtually
identical to the 14.5 db peak to rms ratio I measured on my audio
rta in the 1st place !!!!!
### Imo.... the confusion arises between interpreting plate
current readings while talking [with varying meter response time
constants between different brands of linears/plate meter's]....
and interpreting wattmeter readings, while talking... and
wattmeter switched to "average". Of course, you can take 5 x
different brands of wattmeter's... calibrate em all so they all
read exactly 100 w with a dead cxr. Feed ssb into em [all 5 x
wattmeter's on average... and all wired nose to tail]... and they
all indicate differently ! Flip the processor on and off, and
some average reading wattmeter's will show the increase in
average more than other's ! Probably to read true average, a
RF
thermocouple ammeter would be the ticket.
### Below is Tom Rauch's response.
Hi Jim,
Please don't attempt to be civil to my face and a horse's ass in
public about me on that Google amplifier hate group.
Please be one way or the other. I have a rule where i treat people
exactly the same behind their backs as I do in their face. I expect
the same.
Thanks,
Tom
### Apparently Tom reads the posts here... and myself and other's
must have either (a) pissed him off (b) he doesn't like
criticism leveled at him (c) doesn't like "bad mouthing" about
his Ameritron/ Heath/ Dentron /Amp supply/ MFJ 'engineering' or
(d) doesn't like the idea that he will never post here, and
can't do his own rebuttal (e) can't defend the superb
engineering of Ameritron products.... like the AL-1500's 8 x
lytics being run at their MAX + voltage ratings... then
saying "that's ok" .... "just make sure the bleeder eq
resistor's don't ever open up, or the lytics WILL start blowing
up en masse" [If u ran the lytics at the prescribed 75%
max V rating the manufacturer's recomend, they will NOT blow up,
if
the bleeder EQ resistor's open up.]
### Heck... anybody can read the posts, without being a member...
they just can't post.. or see photo's, etc. He could log in
with
ANY user name... and ANY hotmail address. My guess is... he is
probably among us right now.
### Here's my reply to Tom... dated a few day's ago.
### agreed. The other group isn't any hate group.... it runs
just fine since day 1. You are free to join in any time you
want. Loads of pix on there too.
### I use some of your insights as examples from time to time...
like the test jigs for testing 3-500Z's for shorts... tripped
leds the next AM..stuff like that.
### In the case of poorly designed Palstar /Ameritron / anybody
else's products... they are fair game.
### we all know who the secret administrator is now.... it's Joe
Subich W4TV.... blatantly obvious now.
### Nothing is behind your back.... it's a public forum.... with
136 members.. and growing in leaps and bounds.
### If member's can't freely disagree or discuss things...
what's the point ?
Take care.... Jim VE7RF
####### On the surface, this doesn't appear to be a .. "Google
amplifier hate group". This Tom Rauch scenario appears to be
nothing more than... 'sour grapes'. Me, I could afford to go
out and buy 6 x Ameritron's right now, cash.... but don't. If
they were any good, I'd have a few of em here in 4 day's
flat.
I'm tired of fixing this crap for other fellows. I got fed
up with what's available for amateur radio... decided to
build
it myself. Next trick was most of the various handbooks lack
detail. I found 38 mistakes...so far [mostly typo's] in Orr's
23rd and latest edition [and still available]. And that's
only a fraction of that book. The 2006 ARRL handbook has a
poorly written section on tube amplifiers. Bought a few
engineering text's as well. The fellows who wrote the latest
edition of "SSB sytems and circuits" obviously have a 'hate
on' for GG linears. If it's not grid driven, it's no good..
per the Collins engineers. [who wrote the book].
### gave up on standard texts... and decided to undertake a long
drawn out study of every last component in a GG linear, it's
function, calculated peak/average voltage + current of
everything.... do a series of bench tests... and prove one way or
another new concepts. Several idea's were tried, some
discarded, some although they work superbly, are way too
complex,
and would make construction, implementaion, and trbl shooting
and
repair more difficult. I call the 'whittling down'
process...'the elimination program'. Don't stick 4 x
sockets/tubes/chimney's/anode suppressor's in an amp..... when
just one socketless tube will do the job. You don't stick 4
x
engines under the hood of a car... u get a bigger engine to start
with. Trying to split the drive 4 x equal ways, ditto with
airflow, then 4 x independently adjustable regulated bias
supplies... + 5 x switchable plate current shunts [individual +
total] amounts to a nightmare in progress. [you require
separate fil xfmr sec's as well] Trying to trbl shoot a multiple
tube amp with one bad int tube is a horror show.
## The short of it, with a HB amp... or at least a modified
commercial unit... you can get some satisfaction from the
process. When u light the wick on a HB amp for the 1st time,
get any bugs resolved... and watch the wattmeter get blown off the
scale.. it's a feeling of imense personal accomplishment and
achievement. You don't get that with stock commercial units.
### I'm trying to convince W7IUV to resurect his 'amp pix
page' from years ago. That alone inspired more people than
anything else imo. It had 10's of thousands of hits from around
the planet... including US signal corps, Nasa, and other's. It
really showcased what ham's were doing in their work shops...
and
no two looked alike.
Outa here... stay tuned...... Jim VE7RF
