This message came up on the Lowfer list but I thought that
it might be of interest here.
Marko of PCS Electronics says that he could easily modify the
card to work on 136kHz, if there is the demand, of course.
He says that its just a matter of a software change and a small
modification to the unit which can be done very easily.
We would of course need much finer steps than 100Hz.
73s Tracey
-----Original Message-----
From: [email protected] <[email protected]>
To: [email protected] <[email protected]>
Date: 04 December 2000 20:08
Subject: [Lowfer] New PC based 1750 Meter Transmitter (Product)
For those of you who have been looking for an inexpensive 1750 Meter
transmitter may be interested
in a new product called the "LW-MAX" designed by PCS Electronics.
Photos of
the board and more information
can be found at:
http://www.pcs-electronics.com/Products/hams.shtml
The transmitter is based on their PC-MAX FM transmitter concept, it
that it
uses an IBM PC
and a PSA slotted card as the transmitter. Software totally controls
the
operation of the card,
making it easy to upgrade and add modes, features, etc.
I've been working with the circuit designer to test both hardware and
software, having put a working
prototype board on the air already. The software drivers is already
available for download and
evaluation from their main index page:
http://www.pcs-electronics.com/
The file is very large at over 7 Megabytes, and is undergoing revisions
as
we speak, so you may want to
delay trying it out. It will function without the card installed for
those
who want to look at the operation
of the unit.
The transmitter currently supports CW operation at speeds of up to
12wpm
and also QRSS operation
in three modes, including one that allows the user to select the "dash"
length and then the software
will automatically adjust dot length, character spacing, etc.
Another nice feature is the ability to use the software to "power step"
your beacon. For instance, you can
transmit for 1 minute at full power, then 1 minute at half power
(500mw), 1
minute at one quarter power (250mw),
etc. This allows listeners to evaluate band conditions. Very nice!
The unit comes fully assembled, with software included. You need to
connect
the transmitter to
your lowfer antenna using a coaxial cable. While the unit will operate
this
way, to be legal you'd
need to construct a final amp to mount at the base of the antenna.
(such as
Lyle's simple push
pull amp).
Some who are aware of this project have already pointed out that it is
not
totally legal to "make" a
1750 meter transmitter, even as a kit. We won't debate that...but I
will
say that never stopped others
like Palomar Engineers, Curry Communications, LF Engineering, etc.
Using the LW-MAX you still have to build the loading coil, antenna, and
ground system...so it's
hardly plug and play, but it will get you on the air quick. Selling
price
is $120 plus shipping.
I am expected arrival of the final hardware within a few days, and will
post a review of the unit
then. The prototype performed well, with some problems noted in the
output
filters. Marko assures
me that these have since been corrected.
Future software revisions may support BPSK operation...and PCS
Electronics
has promised to
make the source code of the driver freely available so that those like
Bill
de Carle can modify
it as they wish.
While this product is based on my original idea, I am not financially
or
legally involved in the project.
I am working with PCS Electronics to test both hardware and software,
and
have contributed to
the writing of the manual.
Les Rayburn, N1LF
4919 Cox Cove
Helena, AL 35080
XMGR 189.500khz
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