Thursday, March 19, 2015

Locking the 2m Anglian Transverter to an external reference

G4DDK had mentioned it was possible to Injection lock the 116MHz oscillator of the Anglian Transverter by Injecting 116MHz into the LO port of the Transverter module. In my parts collection I found an early 116MHz DFS module, similar to the design used on 96MHz described at  at http://g4fre.com/dfs9096.pdf  except it used (10MHz * 11)+(3 * (10MHz/5)) and three 116MHz crystals. The output level was ideal at +3dBm While monitoring GB3VHF it was found to put the transverter onto the correct frequency as opposed to the free running frequency.

Having proved it worked, I then mounted the DFS116 inside the box. A slider switch (less likely to get damaged portable than a toggle switch) was used to remove the 13V from the DFS when there is no external 10MHz applied. The output from the DFS did not need disconnecting from the transverter LO input when powered off.

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