DRAKE TR7 Service Manual download pdf (Page 12)

In conclusion

The N4YG VFO is a reasonably priced approach to solving the PTO problems of the TR7, including

stability and tuning rate. The installation is non-trivial and it would be easy to get into trouble while

making the modification if you don't have the required skills and experience. These problems can be

completely avoided by installing the VFO in an external cabinet (re-use an old RV7). If you don't

already have an external enclosure, Tentec makes an excellent line of cabinets that would serve well.

One thing you lose with the TR7 internal installation is the ability to read out the frequency to the tens

of kiloHertz. If you happen to have a TR7 without the digital board installed, it appears that you could

mount the VFO LCD display in the location intended for the TR7 digital readout.

The variable rate tuning takes some getting used to, but that's the best answer to the requirements of a

slow tuning rate along with rapid tuning to another part of the band. The DDS VFO solution based on

the IQPro is a bit better in this respect as it offers a FAST button that applies additional acceleration to

the tuning for large frequency changes, while retaining the slower fixed rate tuning. But, the IQPro

solution will cost you at least $100 more. At the time this was written (February 27, 2012) the VFO

cost for the TR7 was $139.95 and that included the wired and tested board, encoder, all connectors and

wires.

Floyd Sense, K8AC

February 27, 2012

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DRAKE TR7 Service Manual Page 12