> With respect to using the GE MII mobile frame for repeater > applications: > > 1. Can you say categorically that there is sufficient TX/RX > shielding to prevent any desense at any power level the > conversion is capable of operating?
Depends on the pa power level. You can easily test for desense both external and "in cabinet". > 2. When these converted mobiles operate with reduced TX power, > what happens to the output impedance of the TX? Is it still > 50 ohms? Depends a lot on the pa circuit, it's laytout and how you reduce the power output. > If not, does this affect the physical length of the half wave > interconnect cables often suggested between the TX and an > isolator and/or the cavities? The practical answer... Again it depends on the above mentioned and how nit picky you are. Most people say the tx or pa to circulator cable length is not critical. I say it is for my own reasons and experience. Keep in mind you can easily match non 50 ohm outputs to 50 ohms using special coax values/lengths or various combos there of. > 3. If the output of the TX is other than 50 ohms as a result of > a power level change, does it upset the adjustment of the > downstream isolator that has been tuned by a tracking generator? The answer you're probably looking for is yes... but again each case is specific to the respective hardware, circuit and all the related factors. An adjustable Circulator/Isolator is best setup under actual rf power... tracking generator will not often give the best adjustment... sometimes only close. Lunch hour... food... time to go, back later. cheers, skipp
