Sunday, January 25, 2009

1000Km contact on home brew 80m DSB rig

rig.jpgWell, I'm absolutely stoked! I've just had a 30 minute contact with Peter, VK3EPW, who's in Melbourne.

Both of us running home brew transmitters. (He's running a home brew receiver too, but I'm not quite at that point).

Peter gave me pretty good reports, I'm around S8 to him, sometimes fading to S7 when I'm hard to read and sometimes peaking at S9 where I'm easy to hear. There's a fair bit of static from storms around tonight for both of us but we had a fine contact and my simple transmitter apparently sounds very good. "Sounded like a bought radio".

One question that came up for both of us, and I'll have to research the answer is: can a direct conversion receiver receive a double sideband transmission?

Feeling very positive about home brew radio tonight, but now it's time to go sleepy ni nis and dream of the next project.

5 comments:

Anonymous said...

Nice one, I think I need to get onto 80m asap.

Cheers
Kevin zkb

Peter B Marks said...

It was 10pm summer time, despite some electrical storm noise the contact was solid.

Amazing communicating over such distance with a box of bits on the bench.

I guess SSB is twice as effective but DSB is so simple I like it.

Alan Yates said...

I'm so glad to hear it worked well for you Peter. Nothing quite like having a QSO with a piece of homebrew gear.

I like your idea of using the same basic RF amp scheme with switched filters to cover the lower part of HF. Drew has a design that uses some gain-levelling feedback to cover all of HF with IRF510s or similar MOSFETs, not just to 20 metres. I've seen one bloke using them on 6 metres. The power gain is 14 dB per module and it delivers 500 Watts from a relatively small and light package:

http://www.frenning.dk/OZ1PIF_HOMEPAGE/50MHz_IRF510.htm

Peter Parker said...

Peter, A DC receiver can receive DSB but I found it helps if it's very stable (more so than for SSB reception).

Peter B Marks said...

Thanks Peter, I have a simple DC receiver under construction, I'll crystal lock it to the same frequency and see how we go.