Wednesday, 19 October 2016

Further Restoration of the Pye PF8

With G-QRP Clubs Rishworth convention just around the corner, ive decided some long standing projects need to be brought back to the fore.

One of these is the Pye PF8 restoration. As of my last post on this subject, some time ago, the PF8 is working and crystalled for 433.500MHz, but, it is working poorly.

The reasons for this are that 433.5MHz falls within the T1 band 405-440MHz, but this radio was built for the U0 band 440-470MHz. Many of the tuning components are at their extremes in trying to bring the radio down to 433MHz.

One thing that can be done though, is to change the band critical fixed capacitors for the correct values for T1. By a stroke of good fortune, ive been able to obtain three of these from my spare PF8 'donor' chassis. If I cant find the other two amongst my junk boxes, then hopefully these can be found on saturday at Rishworth.

Changing these capacitors is only half the modification really needed, but im not able to swap the variable inductors, as I dont have a T1 chassis to find them on. But 433MHz is very close to the lower edge of the U0 range, so im hoping that by fitting T1 capacitor values, it will kind of fudge the set into being a T1-U0 hybrid. The PF8 is only capable of 500mW output and has an internal antenna - so every little helps!

I also could do with finding some modern batteries for it!

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