[Lowfer] UWL station pics and measurements

[jrusgrove at comcast.net]

No slings and arrows ... just constructive comments. You probably know most of the following already 
...

While it may be possible to get lucky and hit resonance with a few taps and no moveable variometer 
coil it's not likely (at least I've never been that lucky). A decent loading coil will be of high 
enough Q that tuning will be very sharp. One would have to hit the correct tap position - probably 
within an 1/8 of a turn or less! That's one reason why there needs to be some form of adjustment. 
Also, water, ice and changes in the immediate environment will shift the resonant point. Since the 
moveable variometer coil is much smaller than the main coil it provides the fine adjustment that's 
needed. I'd suggest reinstalling the one you have.

For tuning, start with the variometer at a 45 degree angle (coils series aiding - not opposing) and 
check for resonance using one of your existing fixed taps. One simple and quick way to find 
resonance is to replace the transmitter with a general coverage receiver (IIRC you have an R-75?) 
and spin the dial noticing at what frequency the background noise peaks. That's resonance. By 
observing the resonant frequency using other existing taps on the main coil you should be able to 
predict (roughly) the correct position of the tap for your desired transmit frequency. The correct 
tap point is where the receiver noise peaks at your desired frequency and the moveable variometer 
coil is at roughly 45 degrees (series aiding - not opposing).

Once the antenna is at resonance the next step is to couple power to the antenna. It looks like 
there might be a link coil wrapped around the bottom of the main coil ... if not, what method of 
feeding power to the antenna are you using?

Jay