Icom External Keypad

In the past I’ve designed and built external keypads for triggering the REMOTE input on an Icom mic connector [1] & [2].  These both were designed to add an auto repeat feature to the in-built Icom voice keyer for older radios by monitoring the radio’s PTT state (the duration of the voice recording) then adding

144MHz 1.25Kw SSPA Amplifier

Winner in Craftsman category of the RSGB Construction Competition 2014 Waw, what a device.  The Freescale (and NXP) SSPA parts are quite incredible. The part I’ve used is the MRFE6VP61K25H, which is a 1.25Kw device with peak gain and efficiency figures of 26dB and 78% respectively at 144MHz, that means for 1Kw output the drive

DTMF Keypad (and more) Explanation

Wow, I just realised I created this project back in May 2008… I think the principal and technique used for the keypad is worth explaining however so I’m publishing it now. When my local repeater GB3PY started providing Echolink access my shack radio was an Icom IC-910 which does not support DTMF to control Echolink.

70MHz Transverter Mk5 – Nacton

I’m a sucker for continually re-building, I’ll have you believe *improving*, my 4m transverter, the first I built in 2010.  The Nacton variant is the Mk5 iteration in as many years!  The transverter is essentially the same, 28MHz IF and > 50w output (300w peak in later versions) on 70MHz and all in the same

144MHz Harris Amplifier

Modification of the Harris Amplifier is not the reason for this article, there are many documents on the web covering this [Site 1, Site 2 part1 & Site 2 part 2], I followed Mark GM4ISM’s as Mark was the source of my Harris amplifier bits. I actually purchased a Harris amplifier ‘pallet’ from Mark, this

23cm Masthead System (Remote RX/TX Amp)

Most people know coax has loss, the higher the frequency the greater the relative loss.  You can go buy better coax with less loss – however every coax has loss and once the signal is lost, it’s lost. This is more prevalent on receive as in reality loss in the receive system equates to noise,

BXF Azimuth Rotator Controller

  I decided to build a new rotator controller to replace my Yaesu G400RC controller (but my design was made to work with virtually any rotator) to give me additional futures beyond the sole analogue position feedback of the G-400RC. I wanted the new design to be digital, have integrated PC control, hands off operation

PICAXE-18M & MXD2125 Based Elevation Module

One of the aspects of amateur radio I enjoy is EME.  When I was active on 2m (144MHz) EME I built my own elevation system using a jack-arm but I then needed a way to feedback the angle.  I tried many ways in the past such as potentiometers then Sam G4DDK introduced me to the

LVB [Tracker] Extender

I started using an LVB Tracker by G6LVB (also of FunCube Dongle fame) to control my Yeasu G400RC and KR-5400 rotators which have my directional antennas on them – The G400RC + homebrew jack-arm elevation was mainly for EME and the KR5400 was for satellite work.  I had to built an elevation feedback circuit, I