Radio Boy

Tuning the BFO on your Grundig Satellit 700 (Reproduced from Gary Sawyer's website (now closed) with permission)

Improve your reception by carrying out this simple task (Thanks to Donald Reeve)

Firstly a word of warning, please don't attempt this if you are not sure of what you are doing. Neither myself, Gary Sawyer or Donald Reeve can take any responsibility for what you might do to your radio - if you do this, you do it under your own volition and we accept no responsibilty for what may happen. Having said that, I find it hard to imagine getting in such a mess that you can't get out of it again, as long as you use the right screwdriver and only touch the trimmer/pot shown, there's no need to remove the case or warm up your soldering iron!

A word of warning! If you have tuned all your utility frequencies in off frequency to allow for the BFO offset, you will have to program them in again spot on frequency!

All we are trying to do is adjust the BFO circuit to give no hum when you use USB/LSB on an AM bradcast station. This centres the BFO circuitry and allows you to enter a frequency dead on and just select USB/LSB. Mine was so far out that I couldn't tune the BFO to the station unless I tuned off frequency.

The Radio (back view):

Back of the 700

There are three holes in the back of the set where you can adjust what's under them. The one we are interested in is the one circled in green, to the left of the tilty stand thing no-one uses. Tune the radio to one of the big boys in your area, a frequency you can trust that will be bang on (I chose Deutsche Welle, you can use BBC, RCI - anything as long as its a decent signal and one you can trust is on frequency). Make sure the BFO fine tune roller is in the centre (dented) - This is very important, also, as Donald points out, it's better to have the Bass turned right up, helps you hear the note better, then:

Switch to USB or LSB whichever gives you the best note.

Carefully put your jewellers screwdriver (maybe a plastic handled one would be best but it doesn't seem to have any capacitance effect)

Turn left/right until the note lowers and finally dissapears.

Switch to the opposite sideband mode (USB if you used LSB) and check that there is no tone there. And, that's it!

Note. The top right adjustment seems to adjust the gain for the pre-amplifier, all the way left is high, right is low. (Not that I propose changing it!)

That's it. The thing doesn't wander and on my set really helped bring in the stations and seemed to improve reception generally. Donald says that the hole on the right seems to adjust the pre-amp and doesn't have a great effect, the hole under the stand effects the FM scanning (badly) and the S-meter.

 

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