> The DDS is moved 0.1Hz per change of 1 deg C. When I noticed the
frequency
> downward drift I went down and opened the door of the transmitter shed -
> hence the reversal of frequency drift.
John Andrews said
And here I was...waiting for an explanation about how the cesium beam lost
collimation. I do feel the tiniest bit let down. <g>
What you really need is a GPS-controlled shed door opener.
The idea of the GPS-controlled shed door opener seemed attractive but I felt
it might lock me out when I wanted to get in. A different hi-tech approach
was needed.
It came in the form of a small transparent plastic storage box large enough
to contain the DDS, keyer/driver, a 15watt lamp, a thermometer and a fridge
thermostat. This produces a micro climate of around 10 deg C and a nice
stable signal.
While transmitting last night for KL1X, Laurence saw a signal on my
frequency but doppler shift caused by the polar propagation path made the
keying unreadable. What was needed was some frequency variation!
To do this I needed heat, which was provided by XYL Erica's hair drier.
(another hi-tech solution).
When I was challenged as to what I needed a hair drier for in the garden
shed in the early hours of the morning she found the explanation
unconvincing.
One day I will have the DDS in the house shack, with a divide by 10
driver/keyer to get much better stablity and 0.1Hz resolution - but it wont
be as much fun.
Peter G3LDO
| 