Enough of that cheap one-board crap..... this amp is MODULAR!

Modular design allows easy repair and modification, as well as ease of
construction and interchangeability between different amps. It also
allows seperation of functions both electronically and physically. The
modules include:

* Input module. Includes variable attenuator and dummy load which
provides adjustment of input power without 'tweaking' anything inside
the radio.

* Control module. Board that controls keying, bias & cooling fan.

* Sensor module. Board with circuits that take measurements from
various locations throughout the amp and sends them to a meter. Meter
function selection can be by rotory switch or by LCD display simply by
swapping the board (module). Meter functions may include:

- RF input power, Fwd
- RF input power, Ref (for matching amp input to radio output)
- Base current
- Emitter voltage, (RMS)
- Emitter voltage, (peak)
- Emitter current
- RF output power, Fwd (RMS)
- RF output power, Fwd (Peak)
- RF output power, Fwd (Peak & hold)
- RF output power, Ref
- AF input (Ext. mod. function, AM only, see below)
- DC supply voltage, amp
- DC supply voltage, radio
- DC supply current, amp
- DC supply current, radio

* Power Amplifier Module. The module will consist of the amplifier
circuit, heat sink and cooling fan, constructed inside an enclosed
sub-chassis designed for forced-air cooling. Flying in the face of
convention, the power amplifier circuit will -not- be mounted on a PC
board. Instead, the components will be chassis-wired with heavy-guage
copper, except for the transistors which will be wired with strips of
copper sheet having rounded edges and corners. This allows easy repair
and modification, as well as more secure and robust connections.
Circuit will be an ultra-linear, broadband, AB push-pull design
(details at a later date).

* Output module. Includes matching network and output connector, the
type of which depends on the desired output method: balanced or
unbalanced. The reason is that an unbalanced output is fine for mobile
amps where the amp is mounted to an adequate RF ground, but that is
rarely the case with base amps. So an option is provided for balanced
output; the line can then be run to a point where a good RF ground can
be found (e.g, a ground rod right outside the window) where it is
coupled to a coax with a balun, or simply run balanced right to the
antenna. The user now has these choices and they are built right into
the amp!

* Power supply module (optional). Power transistors that are designed
for higher voltage are more linear and -much- more reliable than those
designed to operate on 12-14 volts. This switching power supply bumps
up the voltage to 28 or 50 VDC and allows the use of such transistors.


Additional features:

* An external modulation function can be included, allowing the amp to
function as a Class C modulator. Audio input is via a terminal strip
on the back and fed from a common 8-ohm audio amplifier. The base bias
is then adjusted (with a screwdriver through a hole in front panel) to
Class C operation for higher efficiency. This works only in AM mode.
There is no provision for audio filtering, so hi-fi (wideband) AM is
possible if desired.

* Connections for remote operation:
- Key ground
- Key on ground
- Key on high (=+5VDC)
- Key function select 1 (amp in/out)
- Key function select 2 (key auto/manual)
- Key function select 3 (AM/SSB)


I am open to any comments or suggestions, provided they are limited in
scope to the design concept and desired features.

"Frank Gilliland" wrote in message
...

I am open to any comments or suggestions, provided they are limited in
scope to the design concept and desired features.

Yes, what are you going on about? Are you talking about an amp that exists,
something you would like to see or something you want. You have just quoted
a load of nonsense.

On Tue, 19 Sep 2006 22:51:37 +0100, "malc" wrote in
:


"Frank Gilliland" wrote in message
.. .

I am open to any comments or suggestions, provided they are limited in
scope to the design concept and desired features.

Yes, what are you going on about? Are you talking about an amp that exists,
something you would like to see or something you want. You have just quoted
a load of nonsense.


This is a project to design and build an amp. Once the preliminary
design is complete it will be built, tested and refined. All final
design parameters will be released for public use. Feel free to
contribute.

Modular design has its benefits but it also has at least two
disadvantages.

1. Initial cost

2. Problematic connections/connectors between high current modules.

Frank Gilliland wrote:
Flying in the face of
convention, the power amplifier circuit will -not- be mounted on a PC
board. Instead, the components will be chassis-wired with heavy-guage
copper, except for the transistors which will be wired with strips of
copper sheet having rounded edges and corners.


No PCB!... transistors wired with strips of copper... sounds like a
Davemade... better known as a "prototype"... LOL

www.telstar-electronics.com

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 Tue, 19 Sep 2006 18:56:34 -0400, wrote in
:

Modular design has its benefits but it also has at least two
disadvantages.

1. Initial cost


Good point. And the final product costs will also be somewhat higher
than single-board designs. But that extra expense may be offset when
considering the product's usable lifetime. IOW, single-board designs
are so cheap they are frequently considered to be 'disposable', while
the sevicable lifetime of modular designs are limited only by the
availability of parts. I'll have to see if there's enough info
available to do an objective cost-benefit analysis.


2. Problematic connections/connectors between high current modules.


Connectors are a necessity, but they are only problematic if you make
them problematic. And since I haven't specified what connectors will
be used and where, don't you think you are jumping the gun a bit?

On 19 Sep 2006 16:54:16 -0700, "Telstar Electronics"
wrote in
om:

Frank Gilliland wrote:
Flying in the face of
convention, the power amplifier circuit will -not- be mounted on a PC
board. Instead, the components will be chassis-wired with heavy-guage
copper, except for the transistors which will be wired with strips of
copper sheet having rounded edges and corners.


No PCB!... transistors wired with strips of copper... sounds like a
Davemade... better known as a "prototype"... LOL


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.

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)