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rahul,

do go ahead with the schematics. i have no 'property claims' on the design. i am right now doing a bit of upgrading of the design myself. i ill probably share this with the group as soon as i have made some progress.

this time around, i am make a rig for my personal use. hence, i am expending more effort on this piece as well as slightly higher cost. my main areas of imporvment are the following:

1) high amount of shielding between stages especialy the oscillators and the filters.

2) i am using FET based VFO for lower oscillator phase noise, tuning it with a bank of four 1N4001 diodes with a 10 turn potentiometer for good slow motion drive.

3) digital binary counter for low counter noise (thanks hans! ur site is a treasure).

4) the RF front-end mixer changed to doubly balanced configuration (one more coil to wind).

5) the detector/modulator connections are reversed as discussed previously in the group.

6) reworked the entire audio from detector onwards. the new audio pre-amp is based on w7el design of a common base stage directly coupled to a common emiiter stage. both the stages decoupled by an active decoupler. the audio amp, though not done yet, will be a class-A amplifier with low distortion (instead of the LM386).

7) two IRF510s in push-pull to deliver 10 watts pep (The legal limit for qrp).

8) switching for 7MHz/14Mhz bands, making it a dual-band transceiver.

the low-sensitivity that some have complained about, according to my analysis, is due to the mismatch between the detector and the audio pre-amp.

hence the rework on the audio.

as an aside, are planning to attend the hamconvention in bangalore in october? if you are, we might have an eyeball.

- farhan