GDO

[Yorkie]

Same here - opened fine.

I took the easier route and made the soild state PW FET GDO, ('Gate Dip Oscillator' rather than 'Grid Dip'), many years ago. Nice to make a valved one though, in keeping with vintage radio.

I've used it very little since I lost interest in amateur radio, but it used to be handy when I did such things as making home-brew traps for trapped dipole antennas and the like. You can't of course rely on the dial, but if you loosely couple the GDOcoil to a frequency counter you can read of the actual frequency that way. I've attached a pic. The coils are wound on paxolin tubes, terminated with DIN plugs. I made a little 'storage rack' into which the unused coils are plugged. The coil in the foreground is s 7.1 MHz test coil to ensure that the oscillator is working and to check the dial accuracy, not that the accuracy is too important when it can be checked in seconds on a counter.

Commercial dip oscillators aren't very well built, and are very expensive for what they are, and what use they can be put to.