In a message dated 1/21/2010 11:56:01 P.M. Pacific Standard Time, roy.dyball@... writes:

Also remember if you are dynamically tuning your loopstick by unwinding turns or repositioning it, that with every change you make to the loopstick you must steep off the frequency you are on and then steep back again, this gives the Si4734 a chance to update its varactor and choose a new corresponding value for the change you just made.

Cheers Roy.  

Hello Roy,
 
Thanks for mentioning this. In the dynamic tuning of the PL-380 "stealth models" (a 40/44 Litz wire coil of about 433 uh inductance on the stock ferrite bar), I found this was very true. In both of my two models, the original coil of about 500 uh had an Si4734 varactor lock-up issue on the high AM band frequencies, and coil turns needed to be subtracted one by one until the radio had a sudden boost of sensitivity on 1700 kHz. (There was no option to use a Slider coil for loopstick tuning purposes, since the flat stock ferrite bar was geometrically unsuitable as a Slider coil base).
 
After the sudden rush of increased 1700 kHz sensitivity on the PL-380 when the inductance was lowered to 433 uh, it was necessary to move off of the frequency and then back to 1700 kHz, to judge the final RSSI increase after the modification. The dynamic signal "turn-subtracting" strategy (to lower the coil inductance to a level acceptable to the varactor) was a weird idea that ended up giving great results.
 
73, Gary