Monday, 12 December 2016

There is no heat in my workshop (or how I remoted my IC7100 radio)

Icom RS-BA1 Remote Control Software

Icom IC7100 rear panel
 At the moment all my antennas come into a brick built workshop in my back garden.
The workshop has minimal heating so it does not get used during the winter months.
To remedy this situation I bought a used IC7100 on eBay from W&S. I already had
an Ethernet cable going from the house to the workshop, so it was fully networked.

I had an old Belkin Ethernet to USB hub which I connected to the workshop
network and then plugged the USB2 port on the IC7100 into it. Also connected I
have an LDG AT200PC. The AT200PC is no longer made but has an RS232
control port which was ideal for this application. The 2m/70 cms port on the IC7100
is connected to a Diamond Diplexor which splits the output so it can connect to a
2m and 70 cms  yagi. The HF port of the radio goes into the LDG which as well as
being an antenna tuner also is an antenna switch which I can control remotely allowing
me to switch between an HF antenna and a 6m/4m beam. The ATU will be controlled
by a simple Windows dialog application I am writing (the app can currently only read
the version number of the ATU's firmware but that shows it has comms).

Initially the Belkin would not work with my Windows 10 machine
(it worked fine on Win7). After some Googling I found that while
Bekin don't support it on Windows 10 (their tec support said it could not be done)
it is possible to use under Win10 by downloading updated drivers from the
chip manufacturers website (Silex Technology).

Now using Icom's RS-BA1 remote software I can fully control my radio and use PC
connected headphones and microphone with it from the warmth of the main house.
To the RS-BA1 software the radio appears to be locally connected via USB2.

To rotate the VHF/UHF antennas I used my homebrew Arduino based rotator
controller. It appears as a command line application on my desktop and allows
me either to input a bearing or a QRA locator. I have blogged about the rotator
controller before.

I also have plans to add a multi-mode TNC to the set-up so I can use legacy modes
like Pactor and Amtor remotely. There are still some spare USB2 sockets left on the

Digital Beam Forming on 70 cms
70 cms Turnstile antenna
Above is the 70 cms turnstile antenna I bought from a company in Europe.
My current thoughts are to use 16 of these antennas connected to phase/time
locked Lime SDRs to produce a Digital Beam Forming demonstrator. This will
allow the tracking of multiple Cubesats / balloons simultaneously. Unlike a conventional
antenna which can only point in one direction at a time this can have multiple
receiver channels each pointing at a different satellite. It can also steer nulls in the
radiation patterns to null out interferers on each of the beams (It is only maths).
Ideally I would like many more than 16 antennas but there is a limit to the
space and money I have available for this project.

The signal processing will be done using CUDA C and NVIDIA graphics cards
allowing for potentially hundreds of independent beams. I am happy to collaborate
with others on this project.

So that is it for this month. I hope you enjoyed my thoughts.


  1. I'm not much of an antenna person. I wonder though if the antenna could be simplified by using a back screen as the ground plane. Well I assume the bottom elements is just a ground plane. Maybe use some kind of conductive screen.

  2. I am sure it could as could bending the elements down slightly to improve the radiation pattern and match. The problem I have is that I intend to use 16 antennas in the array and making those myself would simply take too long so I wanted a commercial source. I am more of a software person than a mechanical one anyway.