I have been using an old AOR AR8600 with a stabilized LNB (indoor reference oscillator on 25MHz). This is essentially a glorified scanner receiver with SSB capability.
This works OK, but is far from ideal.
The filters for SSB are cheap ceramic filters. Those are quite wide, and lacks some good suppression of the opposite sideband. This was noticed when I operated at a frequency with interfering stations . The wanted station were sometimes weak, and were swamped by the neighbouring stations.
So what to do to improve the situation? The AR8600 does have an output for the IF band, used for add-ons like a TV demodulator. Maybe that could be used together with an old fashioned HF receiver. I located a suitable cable for the experiment and set things up, with an easy-to-read frequency.
Oops! No.
The conversion in the AR8600 inverts the down converted IF band. Further, the IF output only works with the AR8600 in WFM (wideband FM) mode. The second part could be eliminated by a minor modification of the radio. The inverted band is annoying, however. I could live with using the other sideband, but the frequency readout goes "backwards" , so I have to recalculate the frequency.
What do I do now?
First option would be an up-converter, converting the band up to 19,29,39 etc MHz, using a local oscillator above both frequencies.
There may be another option. the HF radio is my IC7600. That model has a transverter input(/output). There is one drawback with that. There is no setting for ah"high LO" , i.e. I cannot invert the band frequency readout once more. More oops.
Update:
I used it today, and it does work, even if it is inconvenient.
This leaves a second converter with high LO.
Yet another project to add to the already long list. This is no longer a very simple solution, but neither is it a very large project.
No comments:
Post a Comment