11 Jun 2009

10m (and 15m) DSB rig ideas

The GQRP club sell xtals for 24.906MHz for £2 each. They also sell 3.58 and 3.68MHz ceramic resonators at 50p each. Now, mix 24.906 with either 3.58 o 3.68 with an NE/SE602 and you end up with a stable and simple mixer-VFO (when the ceramic resonator is pulled in a VXO) covering two very useful parts of the 10m SSB band or the 15m SSB band. All it needs is a filter on the output to select 10m or 15m injection. I have ordered the xtals and ceramic resonators and will start on the mixer-VFO when the parts come.

My idea is to use the VFO with a simple DSB TX and DC receiver. Such an arrangement will give a simple 10m (or 15m) DSB transceiver covering very useful parts of either band, but with few parts.


Paolo said...

Roger I'm afraid you will have a hard time filtering out the 12m fundamental and 3.58 harmonics. They're too close to your wanted signal, you'd need a very selective filter. Better use 2 x 14.318 MHz resonator.

- ik1zyw

Roger G3XBM said...

You may well be right Paulo.Using an NE602 mixer should help reduce both of these components by some 20-30dB or more and further bandpass filtering on the NE602 output may get enough rejection to be workable in a simple rig.

I do have a 14.3MHz ceramic resonator and will try this x2 and VXOed first as this would be simpler, easier and cleaner.