With the band specific capacitors replaced, Ive managed to peak the transmit output of the PF8 up to about 170mW. This is still a far cry from the specified 500mW. Likewise, the receiver barely peaks higher than -85dBm.
In order to make certain this was a filter issue, I have bypassed the 3-pole input helical filter - and the receive sensitivity shot up!
But now I have a big problem. Not only are the correct filters simply not available, but the ones fitted cannot be modified to work better either. In fact, its near impossible to remove them anyway without destroying them (as I found when attempting to take one off my 'donor' unit!)
So, what to do? Well, pretty much all I can do is either find some 2- and 3-pole helical filters for 430MHz that will fit, probably impossible, or at least prohibitively expensive, or think up some way to replace the helical filters with small home brew band pass filters.
All this just so I can own a working, genuine Bodie and Doyle CI5 walkie-talkie!
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