Amp Design Concept -- Preliminary
 

On Tue, 19 Sep 2006 18:09:10 -0700, Frank Gilliland
wrote in
:

However, know that if FET's
are used for power transistors then most of your 25/100 watt drive
would be wasted.


Come to think of it, that power wouldn't be wasted at all. I just
remembered a neat little power splitter circuit I designed a few years
ago; using that I can tap off a signal for the amp and the rest can be
rectified, filtered, and fed back into the power supply. So nothing is
wasted except in conversion.

Amp Design Concept -- Preliminary
 

Frank Gilliland wrote:
On Tue, 19 Sep 2006 18:09:10 -0700, Frank Gilliland
wrote in
:

However, know that if FET's
are used for power transistors then most of your 25/100 watt drive
would be wasted.

Come to think of it, that power wouldn't be wasted at all. I just
remembered a neat little power splitter circuit I designed a few years
ago; using that I can tap off a signal for the amp and the rest can be
rectified, filtered, and fed back into the power supply. So nothing is
wasted except in conversion.

Waste not want not.

Amp Design Concept -- Preliminary
 

On 20 Sep 2006 01:13:01 GMT, Steveo wrote in
:

Frank Gilliland wrote:
On 20 Sep 2006 00:26:10 GMT, Steveo wrote in
:

Frank Gilliland wrote:
Enough of that cheap one-board crap..... this amp is MODULAR!

Cool. How about a high drive portable to go behind an HF rig? Variable
input 25/100w.

The intent is to drive this from a stock CB, but if you want scale it
up then it's an easy design modification to the input module. I can
include that as an option in the design. However, know that if FET's
are used for power transistors then most of your 25/100 watt drive
would be wasted.

Are FET's the most economical transistors, or are are there other choices
for a 10 meter portable amp? The high drive would make it a bit more legal
too, wouldn't it? (dunno, just curious)


Bipolars are better for higher drive, but the more efficient setup
would be an FET amp with a low-power exciter.

Amp Design Concept -- Preliminary
 

Frank Gilliland wrote:
On 20 Sep 2006 01:13:01 GMT, Steveo wrote in
:

Frank Gilliland wrote:
On 20 Sep 2006 00:26:10 GMT, Steveo wrote in
:

Frank Gilliland wrote:
Enough of that cheap one-board crap..... this amp is MODULAR!

Cool. How about a high drive portable to go behind an HF rig?
Variable input 25/100w.

The intent is to drive this from a stock CB, but if you want scale it
up then it's an easy design modification to the input module. I can
include that as an option in the design. However, know that if FET's
are used for power transistors then most of your 25/100 watt drive
would be wasted.

Are FET's the most economical transistors, or are are there other
choices for a 10 meter portable amp? The high drive would make it a bit
more legal too, wouldn't it? (dunno, just curious)

Bipolars are better for higher drive, but the more efficient setup
would be an FET amp with a low-power exciter.

Gotcha. What about the legal part of the question?

Amp Design Concept -- Preliminary
 

On 20 Sep 2006 01:23:28 GMT, Steveo wrote in
:

Frank Gilliland wrote:
On 20 Sep 2006 01:13:01 GMT, Steveo wrote in
:

Frank Gilliland wrote:
On 20 Sep 2006 00:26:10 GMT, Steveo wrote in
:

Frank Gilliland wrote:
Enough of that cheap one-board crap..... this amp is MODULAR!

Cool. How about a high drive portable to go behind an HF rig?
Variable input 25/100w.

The intent is to drive this from a stock CB, but if you want scale it
up then it's an easy design modification to the input module. I can
include that as an option in the design. However, know that if FET's
are used for power transistors then most of your 25/100 watt drive
would be wasted.

Are FET's the most economical transistors, or are are there other
choices for a 10 meter portable amp? The high drive would make it a bit
more legal too, wouldn't it? (dunno, just curious)

Bipolars are better for higher drive, but the more efficient setup
would be an FET amp with a low-power exciter.

Gotcha. What about the legal part of the question?


What about it?

Amp Design Concept -- Preliminary
 

Frank Gilliland wrote:
On 20 Sep 2006 01:23:28 GMT, Steveo wrote in
:

Frank Gilliland wrote:
On 20 Sep 2006 01:13:01 GMT, Steveo wrote in
:

Frank Gilliland wrote:
On 20 Sep 2006 00:26:10 GMT, Steveo wrote
in :

Frank Gilliland wrote:
Enough of that cheap one-board crap..... this amp is MODULAR!

Cool. How about a high drive portable to go behind an HF rig?
Variable input 25/100w.

The intent is to drive this from a stock CB, but if you want scale
it up then it's an easy design modification to the input module. I
can include that as an option in the design. However, know that if
FET's are used for power transistors then most of your 25/100 watt
drive would be wasted.

Are FET's the most economical transistors, or are are there other
choices for a 10 meter portable amp? The high drive would make it a
bit more legal too, wouldn't it? (dunno, just curious)

Bipolars are better for higher drive, but the more efficient setup
would be an FET amp with a low-power exciter.

Gotcha. What about the legal part of the question?

What about it?

Does the 25 watt -in- requirement make it anymore legal, or no? ( I really
don't know)

Amp Design Concept -- Preliminary
 

On 20 Sep 2006 01:30:33 GMT, Steveo wrote in
:

snip
Does the 25 watt -in- requirement make it anymore legal, or no? ( I really
don't know)


A ham could probably confirm this, but I think the minimum is 50 watts
input (with a license, of course..... without one it's no more legal
than having 5 watts input). Regarding -compliance- with the law, just
follow the leadership example set by our president and Congress.

Amp Design Concept -- Preliminary
 

Frank Gilliland wrote:
On 20 Sep 2006 01:30:33 GMT, Steveo wrote in
:

snip
Does the 25 watt -in- requirement make it anymore legal, or no? ( I
really don't know)

A ham could probably confirm this, but I think the minimum is 50 watts
input (with a license, of course.

Well yeah a guy is supposed to know CW to transmit voice on 10 meters...of
course. (I thought it was 25w or maybe they've up'd it since then?)

.... without one it's no more legal

Right, and a legal one would be a whole lot easier to advertise so the
bottom line should be better. (just throwing my two cents in fwiw)

than having 5 watts input). Regarding -compliance- with the law, just
follow the leadership example set by our president and Congress.

Do I have to? That's nasty.

Amp Design Concept -- Preliminary
 

On 20 Sep 2006 01:49:32 GMT, Steveo wrote in
:

snip
than having 5 watts input). Regarding -compliance- with the law, just
follow the leadership example set by our president and Congress.

Do I have to? That's nasty.


LOL!!!

Amp Design Concept -- Preliminary
 

Frank Gilliland wrote:
No PCB = no cracked traces, copper seperation, no burnt boards, better
heat dissipation, more efficient conductors, etc, etc. Let's face it:
replace the power transistors more than twice on a PCB and your board
(and therfore your amp) is garbage. Not only that, but it also allows
the flexibility to use transistors of different physical sizes and
styles; i.e, the amp can be upgraded or retrofit as desired.

You're losin' it... no PCB at RF frequencies means wires and
uncontrolled inductances / resonances all over the place causing
instabilities... resulting in oscillations. Why don't you think any
commercial amps are built your way.
Great idea Frank... LOL... you're truly a great engineer!

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