GP300 438-470MHz - a few questions

[g8tzl2004]

I have recently acquired a UHF 438-470MHz GP300. The unit is a European set which was manufactured on 3rd Dec 1993 (93/12/3 ) and has 8 channels.

I am aware of the "shift key" trick and was planning on programming the radio between 430.850MHz and 439MHz. I am also aware of the 16 channel mod which I might do at a later stage. I have a few questions:

- I originally attempted to use "European" RSS (Version R01.00.00) dated 31 Oct 1994. However , this did not work. When attempting to read the codeplug , all I got was "connecting to serial bus" (...or something similar). The RSS seemed to hang and I had to power down the laptop to exit. I am using pure DOS on an old 486 machine. Does a European version of the RSS actually exist (ie R01.00.00) which is dated 31 Oct 1994??

- I then checked out some "Americas" RSS (Version R07.00.00) dated 31 Oct 1994. This worked OK and I was able to read the codeplug . I then tried to program the GP300 using the "shift key" trick. When I inputted 430.85MHz , a message came up saying maximum range 433-480MHz. So I can only input freqs above 433.000 MHz. Is this normal with the "shift key" trick? Can I not get below 433.000 MHz using "standard" RSS?

- Using the service menu , I turned the squelch down to "1"(previous setting was 7). I originally noticed that the SQ threshold on exactly 433.000MHz was still higher than on other freqs such as 433.075MHz. I thought that this might be something to do with "433.000" being the band edge. However, after powering up/down again , the SQ threshold on 433.000MHz was then back to the same as the other freqs. I'm not sure why? Maybe the RX VCO is on the verge of going out of lock? Anybody any idea of the "typical" maximum frequency coverage of a 438-470Mhz GP300? Is it really only 433 MHz or will it get down to 430.000Mhz without going out of lock?

At 433.000MHz , the GP300 is still exceptionally sensitive!!

Thanks