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Category: Technology

DIY USB CAT control cable for TS-850

My recently newly acquired TS-850 is a great radio. But what’s even more,
it comes with the proper serial ICs built in to hook it up to a PC for CAT
control. There are various ready made cables available on eBay to accomplish
this, but I really can’t get myself to spend $40 on a cable which can be built
for a lot less.
The serial connection on the back of the TS-850 (ACC2) provides inverted
TTL level signals. So all that is needed is a inverter and then a TTL to RS-232
conversion. At first I built the following circuit which I found here:

This is a straight forward circuit using the 74LS04 to invert the TTL signals
and then the good old MAX232 for TTL to RS-232. One could leave it at that
and use a USB-serial dongle to connect to the PC.
I went a step further and simply feeding the signals from the hex gate (74LS04)
into a FTDI USB interface. Total cost in parts ~ $15 and the satisfaction of
having built it yourself . Adafruit has a USB to TTL cable for just $9.95 which
would also work. I just had the other interface already on hand.
This is what my fancy design looks like:

One thing to note is that I did not use RTS/CTS which for some reason did not work.

More Arduino fun on Sunday

What better way to spend a Sunday afternoon than to debug some code in your project.
Got around to hooking up the Adafruit LCD display via I2C bus to save some connections,
and also got rid of the garbled text when load was applied to the relays (a 10uf cap did the
trick). In addition I also solved the reset issue when rotctl re-connected (another 10uf cap)
and now need to figure out where some of the weird readings come from and how to make
the buttons work for manual control. Progress is being made.

Elecraft K1 – Day 3

Progress is being made … but organization comes first.

K1 day3 organized

I can just highly recommend sorting parts first. Especially when you have parts where the numbers are hard
to read because of their size. This makes the build process go much smoother.

K1 day3 mainboard

Managed to get some parts mounted on day 3 of the build on the RF board. This will be a longer process. This
is fine though, as building this little radio is half the fun. More to come.

Elecraft K1 – Day 2

Yesterday was the easy start of building the K1. It starts of with the filter board which
doesn’t have too many complicated components, so it’s a good getting used to item.
Today I started to work on the front panel board and figured I’d finish it tonight. Well,
it went smoother and quicker as planned so it’s already done while working on it
during lunch time and a bit this afternoon.

The top side of the front panel board

K1 day2 frontpanel board

The rear

K1 day2 frontplate rear

And the final minus the knobs which are mounted as well.

K1 day2 frontpanel


Next up is the RF board which is the more complicated one and will take longer than one night. But still fun. 
In the meantime I can spend also time testing to make sure no cold solder points creeped in and also to learn
more CW so that I can actually make use of this little thing :).


73 Mike K5TRI


Elecraft K1 – Day 1

So I decided to go a complete different route in amateur radio than before. As I mentioned 
somewhere else, for me the most important part of the hobby is the building of radios and
antennas. Everybody can buy a radio, pick up the microphone and speak into it. Not a real
challenge IMHO so not my cup of tea. I find it rather boring to tell the truth.

Enter stage left the Elecraft K1. A nice 2,4 or 6 band QRP kit one has to build first before
powering it on. Now that is exactly my cup of tea even though I usually drink coffee in the

K1 overview

This is what awaits you once all the contents are removed from the packaging. Nicely sorted by function are the 
parts in various bags. Even a nice touch that each bag contains a slip with the name of the person who packed
it. The manual is pretty thorough and straight forward. Nothing is left out and one can follow it easily step by step.

The K1 is certainly not a project to be completed in one night. That would be too easy and quite frankly I am looking
forward to the build process as much as operating it. I reckon it’ll be done by the end of the week and then the first
smoke test will be conducted.

K1 filterboard

The first board which will be built is the filter module for the bands I chose when I ordered the kit. I went the cheap
route and only ordered the 2 band kit for $299 to see if I like it. If I do, the next order may be the K2 which covers
from 160 – 10m.

Building the first part was not very difficult (if you know how to hold a soldering iron) and after about an hour I had
all the parts on the board. Make sure you get a loupe. I tried without and eyeballed it. May have to go back to
troubleshoot should I have guessed wrong on some of the capacitors :).

Next up will be the front panel board. But that’s for another night.

73 Mike K5TRI