The Mini-HotSpot Board
If you don't need the standalone repeater mode (which is the
case if you use the board with the HotSpot software), then you can use the
new Mini-HotSpot board, which simply is a smaller, trimmed-down version
of the original Node Adapter design. It does not have the second
processor and its supporting circuits, and, therefore, cannot be used in
standalone-repeater mode.
Designed by Mark Phillips G7LTT, the
original Mini-HotSpot PCB only measured 2.5 x 2.75 inches, and
ran the original Version 4.XX family of firmware, written by Satoshi
Yasuda JK1ZRW. It is no longer being offered for sale as the PCB had some design errors.
A direct result from the co-operation between Mark and Fred van Kempen PA4YBR,
the new version of the Mini-HotSpot board is a little larger than the original
version (3.6 x 2.1 inches) and now uses a somewhat cleaner placement of the
various LED's, jumpers and connectors, at the cost of a board that is slightly
larger.
You can order this board in our Web Shop.
which is also the place to go to order our firmware for it.
A kit is now available as well, containing the PCB itself and all parts that go on
it, except for a radio interconnection cable, or an enclosure.
If you'd like to know more about it, you can download the
schematics here, which also includes the BOM (Bill Of Materials, also known as the
Parts List) and the parts placement drawing. Also, if want to make a board for yourself
or some friends, you can also download the board files
(Gerber format) here.
The
Construction and Reference Manual (version 1.10) describes how to build your board into a working Mini-HotSpot
system. It also contains a parts list in case you want to buy your own
parts, as well as a detailed parts placement drawing so you can easily
what-goes-where. Lastly, it even contains a simple operating manual for
those who wish to have all that in a single document.
The people at the
Yahoo!
GMSK_DV_NODE group will be more than happy to help you with any problems you
might run into- after all, it is the same board that is run by many
others on that group.
NEW: Digital COS !
After some discussion on the Yahoo! group, it was
requested that Andy G4ZSM's Digital COS circuit be added
to our board. This circuit uses the RSSI value generated by the CMX589A
modem chip to determine if there is a valid signal being received or not,
and this result is then used as a COS signal to the board.
Especially with systems that have to deal with both
analog (FM Voice) as well as digital (GMSK D-STAR) signals, using the
GMSK quality indicator gives better results for determining whether to
enter analog or digital mode. Dual-mode repeaters will obviously
benefit from this !
The new Mini-HotSpot PCB with the
Digital COS added to it (and some other minor cleanups, as set out
for Rev.A01.) You can see the extra RSSI LED's (the yellow ones)..
during reception, these LEDs will indicate the relative signal strength.
If the signal strength exceeds a level set by the user, the circuit will
raise the COS line, and the green LED will light, indicating we have a
valid signal at hand.
This signal adds another jumper switch (SW2);
it selects between Analog COS (the signal from the radio, polarity being
selected by SW1 and SW3) or Digital COS, which is our new signal.
All this fun obviously requires space on the PCB, so
we had to make it a little larger. Not a lot, only about 10mm or so; its
length remained the same. We could have muddled with smaller trimpots,
but to keep things clean and simple, we decided to just make the board
larger- this also allowed us to place the extra LEDs, and add the
jumper.
This new Revision B board has been tested, and
it works as expected. Depending on how many people request (order) it,
we will make a batch of these boards sometime in December 2009. If too
few orders are received, we will not make any of these boards.