The KA9FUR Delta RIB
Design by Dave Karr, KA9FUR
Construction commentary by Jeff Depolo, WN3A
Last edited 7-Dec-2002
Click here for a PDF
version of the schematic for the RIB.
Pay attention to the four caps' values; three of them are 0.1 uF, one of
them is 1.0 uF.
The schematics show 2N3904 for the four transistors, but you can use 2N4401,
2N2222, or whatever small-signal NPN silicon you have around should work
You can substitute 1N914 or whatever other switching diode you want for
I'd recommend that you make a programming cable with *only* the wires connected
that are on the schematic; cut off the ones that aren't needed. You can't
have a control head connected to the programming cable - wire only what
it shown on the drawing. Do not connect up the high-current DC lines.
On the newer radios, you have to remove J707 during programming (it's to
the rear of the EEPROM), and then reinstall it when you're done programming.
On the older radios, you'll hear the T/R relay click during programming.
On the newer radios it won't click. Have no fear.
I was able to build the electronics onto a snipped-off piece of PC board
(Radio Shack ring-hole perfboard) that was small enough to fit inside the
radio connector. Once you get rid of all of the wires that you don't
need, it's easy to make it fit inside the connector shell. Wrap it
in electrical tape or something to ensure nothing shorts out to the radio
In order to get the contacts out of the radio plug, you need two *small*
paperclips and a little patience. You stick the paperclip into the
front of the connector where the little rectangular areas are on the sides
of each contact's hole. With the paperclips shoved all the way in
you can then pull out the contact from the rear. The paperclips have
to be shoved along the side of the contact such that they're pushing in
on the little wings that hold the contact into the connector shell.
Once you get one of them out you'll see what I mean and then it will be
obvious. Obviously for the pins that aren't needed you can just cut
off the wires rather than trying to remove the contacts. For the
high-current DC pins you can use two greenies instead of paperclips; the
paperclips probably won't be stiff enough to work. You can still
order the pins from GE if you need them ($2.80 for a pack of 10 of the
low-current pins), but if you're going to order some, I'd suggest you do
it sooner rather than later since the Delta series is on end-of-life.
GE part number 19A701376P1/10, (800) 368.3277 menu option #2.
If you mess up the interface you could blow out your parallel port, so
I'd recommend testing it out on some old POS computer you have laying around
(or at least a computer that has the parallel port on an cheap ISA card
rather than the motherboard).
Since this is a TTL parallel port interface, you should keep the cable
length short and/or use low-capacitance shielded cable. I'd suggest
using the shield's drain wire as the ground connection. Make sure
you tie pins 18 through 25 together at the COMPUTER end of the cable, and
then just run a single ground wire from the computer end over to the interface
board ground and to pin 21 on the radio.
1 DB25 Male w/hood
1 Radio connector w/contacts
1 100 ohm 1/8 watt
2 4.7K 1/8 watt
2 10K 1/8 watt
4 2N4401 or equiv
4 1N4148 or equiv
3 0.1 uF monolythic ceramic
1 1.0 uF electroloytic (10WVDC or more)
1 7-conductor+shield cable, 5 feet max
1 small piece of perfboard
Good luck and may the force be with you.