17 Jun 2009

6m (4m?) distraction

OK, I'm about 40 years out of date with my technology, so if I live to be 100 you may just find me getting excited by SDRs and the like when the rest of you are busy with thought and matter transfer. Who cares, it keeps me happy and doesn't cost a lot :-)

This last week I have had a spurt of creative (?) energy and have been building. Firstly I started work on the 10m DSB rig. The RX is fully working using the Neophyte as a basis. Next I tried the 14.3MHz ceramic resonator-doubler idea for the LO but was disappointed that I couldn't get it to reliably pull down to a useful part of the 10m SSB band. The plan was to look at a mixer-VFO and then put the whole breadboard together with the DSB TX. But I got distracted....

Instead, I built a simple super-regen AM RX for 6m (or 4m), which works well using T37-6 toroids. All that I need to do is arrange for the RX tuning across the chosen band with a varicap. Next I built a simple series modulator (even simpler than the Fredbox one) and now I've started on a very simple AM TX strip and small linear. The idea is to do a Heathkit Lunchbox "Sixer" AM transceiver replacement but in a very simple solid state and no-IC design. The design is likely to produce around 100mW of AM and can be completed for either 6m or 4m. I haven't decided which yet.

There is not a lot of AM on 6m, but a bit in pockets on 70.26MHz. I know 100mW is not much. But, this is a project I've just wanted to do for years and you'll have to bear with me. When this is done I'll get back to the serious stuff - the proper DSB transceiver that is!


Anonymous said...

Could I place a vote for a 4m version? The super regen would be very useful in it's own right as a band monitor.

73, Dave GW8JGO

Roger G3XBM said...

Thanks Dave. Let's see how things go. I could easily do versions for BOTH bands as there would only be about 6 tuned circuits (2 RX and 4 TX) to change between bands.

Anonymous said...

Hi Roger,

That would make sense. Leave it up to the home brewer to choose which band to construct for.

Your comments in another post about 10m activity was interesting. A few days ago the 11m CB band was full of strong AM/FM/SSB - 10m? Nothing! Even with my indoor dipole I heard many beacons. Does make one think.

73, Dave GW8JGO