QRP Accessory box, update (Long)

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From: Paul Beltrani (beltrani@mango.aloha.com)
Date: Fri May 05 1995 - 01:57:28 EDT


(I apologize in advance if this msg has already made it to the
list. Unfortunately, my internet service is not always reliable
and I have reason to believe my original posting was never
sent. As I have seen neither my original post nor any possible
replies, I am resending this.)

Here is an update on my project to build one unit that contains
the extras we usually add to a rig, antenna and power supply.

For those of you that missed the original, this unit should be
small, light and easily reproduced. All active circuits can be
switched off to conserve power.

If there is enough interest, I will make plans and a schematic
available to the list.

----- -----
I plan to include the following circuits and would appreciate
any suggestions for improvements or additions.

Case: I would like to go with the Sierra case. I have to check
with Wilderness Radio or NorCal to see if there is convenient
source. (Unit must be easily reproducible, no difficult to get parts)

AF Amp: a simple LM386 based audio amp that will drive
headphones or an internal speaker.

SWR/Pwr meter: I plan to use the Roy Lewallen design on page
217 of the ARRL QRP Classics book (also Feb 90 QST). The
circuit is simple and designed to be accurate at QRP levels.

Dummy load: if there is room, I will include a simple 5w dummy.

Straight Key Jack: basically just an easy way hook up paddles
   and a SK at the same time. This will just connect to the
   keying output jack.

Iambic Keyer: I had planned on a Curtis 8044ABM based keyer.
   However several people have suggested the CMOS II contest
   keyer. I am leaning towards the CMOS II because it is no larger
   than a full featured Curtis, is a simpler circuit, and it has the
   added feature of memories. However I am concerned about the
   price that it would add to the project.

TransMatch: I am considering the "Z-Match" circuit for three reasons.
     1) It is simple. It does not have a switched/roller inductor
        There are only two tuning adjustments.
     2) It works with both Balanced and Unbalanced lines.
     3) It covers a fair range of Z mismatch

   For more info on the circuit, check out Bill Orr's "Radio Fun" cols
   in the Aug 93 - Oct 93 issues of CQ. (For those who are interested,
   email me and I'll try to email back an ASCII version of the schematic)

   I would appreciate the input from the group on the suitability of this
   circuit for QRP work.

Power input jack:
Regulated power out jack:

There isn't room for much more, though suggestions are welcome.
----- -----

   - Paul Beltrani
                    beltrani@aloha.com
                    ah6nu@nh6yw.hi.usa.oc Amateur Radio Packet


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