Q: I have a Talk–back unit model PD600D which I purchased several years ago. I would like to change frequencies so that I can use it in an OB vehicle I have. I have attached a photo of the transmitter module which is made by W&D. Can you give me some information on this model?
The transmitter and receiver modules used in the PD600D were made by W&D but the Talk-back unit was manufactured by Drake and sold as a PD400 or a PD600 depending on the frequency. Both the transmitter and receiver modules were crystal controlled, whereas the later modules are synthesized. To change frequency on these modules you will have to purchase the crystals, which have a 4-6 week lead time due to the aging process in the manufacturing of the crystals. Once the crystals are available it will take a couple of hours to retune the modules.