ZLPLL

I built my 2m transverter with the intention of using it primarily for EME (JT65), driving either my 2m PA or at some point in the future as the IF for one or more microwave transverters.

To ensure that I was actually operating on the frequency I was tuned to and my received traces were not drifting across the screen during extended transmit periods, I wanted to lock the 116MHz local oscillator (LO) to a GPS-disciplined oscillator (GPSDO). At the time I built the transverter I had no means of doing this so I simply added a Murata Posistor crystal heater. Calibration was carried out using GB3VHF and this gave perfectly acceptable results running JT65B on 2m.

With my interests also moving towards the GHz bands, I built a 10MHz GPSDO and obtained a SG-Lab TR1300 23cms transverter. The TR1300 (V2.3) is capable of accepting a 10MHz reference to lock the LO and I was soon using the Anglian transverter as the IF to the TR2300. I did some extended WSPR tests on 23cms and with its long transmit periods and occasional back to back transmissions it proved to be an excellent stress test for my system.  The tests showed that my WSPR transmissions were not running nice and straight; the extended WSPR transmit periods were highlighting some slight drift on the 2m side. I had not seen this before running JT65b.

I ordered the ZLPLL board from Wayne, ZL2BKC and specified that I intended to use it with the Anglian transverter. Wayne configured it for 116MHz and provided a very quick turnaround with excellent communication, advising on shipment details, ETA and answers to my question on the 10MHz reference signal level. The board arrived very quickly, 7 days door to door  🙂

I chose to put the ZLPLL board in a screened box with an additional regulator to drop the 13.8V down to 9V. This fitted nicely inside the transverter case.

This slideshow requires JavaScript.

 

The 2m and 23cms setup is now locked to my 10MHz GPSDO and stress testing shows a very nice series of straight traces  🙂

 

Acknowledgements:

Wayne, ZL2BKC for his excellent ZLPLL board and customer service.