I would like to play around with openBTS/yateBTS (experimental, no 24/7 run). What I would like to do is to modify a UMTS/GSM module or mobile phone so it operates in a frequency that can be used with a HAM license.

I looked around and think in my location, Austria, I can use this frequency because in my area there are no active hams that use ATV: 1272,0 – 1290,994 MHz. Has anybody ever done this before? Does anybody know a good module or phone where this can be archived?

I first thought about just replacing the crystal and bypassing the filters, but i can't access them all, because some of them are in the chip. Another idea was to use a mixer to offset the output frequency and place filters behind this.

So the questions are:

• Is it okay to use an ATV frequency when I am sure no other ham gets disturbed?
• How should i modify an existing chip/mobile phone?
• Is one of the ideas above good enough for experimental usage?