Steveo wrote:

"Telspam Electronics" wrote:

http://cg/spam


Things must be slow.
didn't he get booted off a provider for spamming?

jim wrote:
Steveo wrote:

"Telspam Electronics" wrote:

http://cg/spam


Things must be slow.

didn't he get booted off a provider for spamming?

Rumor has it.

"Steveo" wrote in message
...
jim wrote:
Steveo wrote:

"Telspam Electronics" wrote:

http://cg/spam


Things must be slow.

didn't he get booted off a provider for spamming?

Rumor has it.

Very good layout PC board, that takes allot of work. Hope he sells them
all day to CBers, I don't care where they go.
Some of the so called BIG amps( Dave Mades, ect ) look crappy inside because
the designers are not very bright.Some look like they were
built in a cow barn.

From: (JSF)
"Steveo" wrote in message
Very good layout PC board,

By whose standards?

that takes allot of work.

Actually, it takes the ease of locating one who produces a quality
board.

Hope he sells them all day to CBers, I

don't care where they go. Some of the so

called BIG amps( Dave Mades, ect ) look

crappy inside because the designers are not

very bright.Some look like they were

**built in a cow barn.

When an amp maker takes to bashing another amp, they feel they have to
sell their product for whatever reason. A quality made amp sells itself.

JSF... you're right about those "big amps". They are nothing but
hay-wired prototypes, mostly designed and constructed by persons having
no electronic background. I have looked at many of them over the years
and have found that they have major flaws such as inadequate cooling,
improper tuning, and instabilities/oscillations caused by improper
layout and long wires running around all over inside. Because of these
issues, their owners must keep a steady stream of expensive output
transistors flowing through them... if you know what I mean... LOL

www.telstar-electronics.com

On a sunny day (22 May 2006 04:45:06 -0700) it happened "Telstar Electronics"
wrote in
.com:

JSF... you're right about those "big amps". They are nothing but
hay-wired prototypes, mostly designed and constructed by persons having
no electronic background. I have looked at many of them over the years
and have found that they have major flaws such as inadequate cooling,
improper tuning, and instabilities/oscillations caused by improper
layout and long wires running around all over inside. Because of these
issues, their owners must keep a steady stream of expensive output
transistors flowing through them... if you know what I mean... LOL

www.telstar-electronics.com

Hi, I am reading on your website
http://www.telstar-electronics.com/S...Amplifiers.htm
about efficiency and conductingangle.
My question, has anyone ever attemped a class D (pulse width) modulated amp
with MOSFETS for 27Mc?

The limit would be the switching time, say if we have 1nS switching FETS,
and 37 nS period time, we use a bridge, so per 37 nS we switch 4x = 4nS

We dissipate any power (not counting Rds-on losses), could we achieve 80%
efficiency?
There are also losses from transformer and Pi filter of course.
And perhaps you would need a switchmode to get a higher operating voltage,
mmm that would bring it down to .8 x .8 = 64 % + filter and other losses....
But it COULD take you into the kW range with cheap FETS?

Whatdoyouthink? ;-)

Jan,

Sure you can run class D at 27MHz... the problem is distortion. Class D
is very efficient but is really only meant for digital signals.

www.telstar-electronics.com


Jan Panteltje wrote:
On a sunny day (22 May 2006 04:45:06 -0700) it happened "Telstar Electronics"
wrote in
.com:

JSF... you're right about those "big amps". They are nothing but
hay-wired prototypes, mostly designed and constructed by persons having
no electronic background. I have looked at many of them over the years
and have found that they have major flaws such as inadequate cooling,
improper tuning, and instabilities/oscillations caused by improper
layout and long wires running around all over inside. Because of these
issues, their owners must keep a steady stream of expensive output
transistors flowing through them... if you know what I mean... LOL

www.telstar-electronics.com

Hi, I am reading on your website
http://www.telstar-electronics.com/S...Amplifiers.htm
about efficiency and conductingangle.
My question, has anyone ever attemped a class D (pulse width) modulated amp
with MOSFETS for 27Mc?

The limit would be the switching time, say if we have 1nS switching FETS,
and 37 nS period time, we use a bridge, so per 37 nS we switch 4x = 4nS

We dissipate any power (not counting Rds-on losses), could we achieve 80%
efficiency?
There are also losses from transformer and Pi filter of course.
And perhaps you would need a switchmode to get a higher operating voltage,
mmm that would bring it down to .8 x .8 = 64 % + filter and other losses....
But it COULD take you into the kW range with cheap FETS?

Whatdoyouthink? ;-)

On a sunny day (22 May 2006 07:47:53 -0700) it happened "Telstar Electronics"
wrote in
.com:

Jan,

Sure you can run class D at 27MHz... the problem is distortion. Class D
is very efficient but is really only meant for digital signals.

www.telstar-electronics.com

Hi, you know class D audio amps exist I suppose?
There are even class D power amp chips for audio.
These use PWM (pulse width modulation).
You can make any output waveform with PWM (as long as the switching frequency
is much higher then the output frequency).

This links shows some basics for a modulator (driving class D for example):
http://www.netway.com/~stevec/ham/pd...lid_state.html

I can also think of a 'digital' solution, say you have 8 RF amps,
1W, 2W, 4W, 8W, 16W, 32W, 64W, and 128W,
now simply switching these on with an 8 bit digital audio signal (one on each
bit) and summing the RF output together, will give you a 255W AM modulated
transmitter with less then 1/255 (0.4 percent) distortion (have not tried)?
Since these RF amps can be class C (no need for A, AB, B, any linear!!) you
should get good efficiency.
The stages are only 'on' or 'off'.

So, maybe someone could combine some :-)
Nice for experiments....
hehe

Telstar Electronics wrote:

JSF... you're right about those "big amps". They are nothing but
hay-wired prototypes, mostly designed and constructed by persons having
no electronic background. I have looked at many of them over the years
and have found that they have major flaws such as inadequate cooling,
improper tuning, and instabilities/oscillations caused by improper
layout and long wires running around all over inside. Because of these
issues, their owners must keep a steady stream of expensive output
transistors flowing through them... if you know what I mean... LOL

www.telstar-electronics.com

Kind of like building an amp and running it with class C bias?

You know what that means?

"Lancer" wrote in message
m...
Telstar Electronics wrote:

JSF... you're right about those "big amps". They are nothing but
hay-wired prototypes, mostly designed and constructed by persons having
no electronic background. I have looked at many of them over the years
and have found that they have major flaws such as inadequate cooling,
improper tuning, and instabilities/oscillations caused by improper
layout and long wires running around all over inside. Because of these
issues, their owners must keep a steady stream of expensive output
transistors flowing through them... if you know what I mean... LOL

www.telstar-electronics.com

Kind of like building an amp and running it with class C bias?

You know what that means?

I think some of those Amps are getting close to class D now, they drive 250
Watt amps with 5 watts in to a 50 watt driver 10- 13 DB gain then a pair of
finals with 10-13 DB of gain, no bias on the base , I can just see the crap
the poor transistors go through. Then they mod their radios to give SWING
which does nothing but make the wattmeter swing like SSB but their no
louder, but I will say it helps keep the poor finals cooler.

In the new Commerical Broadcast AM transmitters their Audio is Class D audio
amps driving the finals saving allot of AC power.