On 20 Sep 2006 02:53:13 -0700, "Telstar Electronics"
wrote:

+++
+++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!
+++
+++www.telstar-electronics.com
***************

Below about 1 KW, PCBs are adequate. In the 10 to 20KW range forget
laminates. You would have to plate at least 3 ounce if not 4 ounce
copper. Beisdes most laminates will have tremendous problems with RF
currents at these power levels. AIr dielectric or even ceramics
provide a better solution.

Also I believe Frank never mentioned the actual power out of his
design.

james

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.

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.

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)

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.

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?

Steveo wrote:
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)

FETs like the MRF173 (or similar) have certain advantages. They also
have several disadvantages... one is cost! Franks proposed design
already looks to have a hefty price tag as described.

www.telstar-electronics.com

On 20 Sep 2006 04:28:52 -0700, "Telstar Electronics"
wrote in
.com:

Steveo wrote:
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)

FETs like the MRF173 (or similar) have certain advantages. They also
have several disadvantages... one is cost! Franks proposed design
already looks to have a hefty price tag as described.


That's because I don't make cheap, disposable crap. Never have, never
will. But the use of FET's is at the discretion of the builder. The
amp can be built with either FET's or bipolars. No other modifications
are necessary, just a variation in the initial alignment.

On a sunny day (20 Sep 2006 04:28:52 -0700) it happened "Telstar Electronics"
wrote in
.com:

Steveo wrote:
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)

FETs like the MRF173 (or similar) have certain advantages. They also
have several disadvantages... one is cost! Franks proposed design
already looks to have a hefty price tag as described.

www.telstar-electronics.com

http://www.sphere.bc.ca/test/rf-semis.html

On 20 Sep 2006 04:28:52 -0700, "Telstar Electronics"
wrote:

+++Steveo wrote:
+++ 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)
+++
+++FETs like the MRF173 (or similar) have certain advantages. They also
+++have several disadvantages... one is cost! Franks proposed design
+++already looks to have a hefty price tag as described.
+++
+++www.telstar-electronics.com
**********

Prefer FETs even with their cost. They suffer less from thermal
runaway as bipolar designes do. Bias network is easier to design.

Major disadvantage to FETS are the inputs are very static sensitive.
SO some means of ESD protection is needed that wont h inder RF
performance.

james