500 kHz transmit permit

Today I received a permit for experimental transmissions on the 500 kHz band, 501.000 - 504.000 kHz.

Now I will need to build a transmitter, I will most probably go the way Joachim proposed, using a 27 MHz crystal on the fundamental frequency (9 MHz), then dividing by 9 with a 4017, then by 2 with a flip-flop, followed by a "buffer amplifier" , and later an IRF510 as power amplifier.

The hard part will be the antenna, it needs to be compact, so a "magnetic loop" is probably the only way to go here.

Rock-mite kits

A discussion with Joachim today made me go buy some more kit stuff.

The Rock-mite kits look very suitable for a simple QRSS modification , as seen on Joachim's blog.

I ordered the 80 and 30m versions, one of each.

The best thing is that it is useful as both a grabber receiver and a QRSS MEPT - and the price of $32 a piece to have it sent here should not discourage anyone from doing QRSS.

The Rock-mite is a simple crystal controlled CW transceiver and can be used as such. It is a single frequency device with a crystal as the input filter and another one as (VXO) local oscillator/TX oscillator.

QRSS transmitter under construction

In talks with Joachim, PA1GSJ we decided to build the simplest possible (construction wise) transmitter for 28MHz.

Using a "canned" - in my case IC-like housing - oscillator on 28.322 MHz and a 74HC(T)240 as the "power amplifier" it is possible to get an output of around 50 mW, sufficient for a QRSS MEPT.

Joachim already has his model working, and I am in the process of building mine. The oscillator is there (duh)and the "PA" is just about wired, now I need to make the keyer , will be using a PICAXE processor, and the output matching circuit/low pass filter.