VK Logger Ham Radio Forum Archive

I've built one inside the both my FT-817 microphones using the Picaxe 08m2 chip. As well as the roger beep/pip (mine is 60mS long), if you give three presses on the PTT it goes into 'beacon mode' where it generates a tone with a CW ident every 30 seconds (useful for peaking microwave dishes). It reverts to normal if you press the PTT again. There's also a 5 minute timeout.
73
Iain

Nice one Iain..Very useful..
Cheers de Lloyd VK4FP

VK5ZD wrote:I've built one inside the both my FT-817 microphones using the Picaxe 08m2 chip. As well as the roger beep/pip (mine is 60mS long), if you give three presses on the PTT it goes into 'beacon mode' where it generates a tone with a CW ident every 30 seconds (useful for peaking microwave dishes). It reverts to normal if you press the PTT again. There's also a 5 minute timeout.

A great idea Iain, would like to do the same with my 817 mic.
Can you provide a link to the schematic, or perhaps post it here as an attachment, along with the PICAXE code?

Hi

This is a short article I wrote for our club newsletter which has the schematic and Picaxe code.
Don't forget to change the callsign in the code
As an alternative you could use the tone switch on the back of the microphone to activate the beacon by connecting it to the spare pin (C.4) on the Picaxe and altering the code accordingly. Obviously you lose the option of changing the tone setting but I never alter it anyway.
73
Iain

Hi all

Just a few extra thoughts for this project...

I also use a 'beacon generator' board in my 817. I don't use a 'roger beep' but opted to use the switch on the back of the mic to turn on a beacon transmission to aid in finding my signal during dish alignment etc.

My 817 came with a (non functional) speech compressor board wired into the mic and activated using the switch. Whoever built the board left out an audio coupling cap so it never ever worked!!!

I removed that and rearranged the wiring to incorporate a small picaxe circuit similar to Iains but using different code. When I switch it on, it will run indefinitely until the mic button is pressed, which terminates the program.

It must be switched off and back on to restart it. Rather than generating a single tone, it generates a very distinctive 'hee-haw" tone much like emergency vehicles use! It cannot be mistaken for a spur or heterodyne in the receiver!!
This is interupted around every 20 seconds or so with a 'standard' CW CQ call (using my callsign of course).

Rather than just feeding the near square wave output from the picaxe to the mic circuit, I opted to add a simple RC lowpass filter which results in a more triangular wave output. This sounds 'smoother' on air than the square wave.

Cheers

Tim VK5ZT