Converting 800 Mobile Duplexers???
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Converting 800 Mobile Duplexers???
I am in need of a 900 mobile duplexer. I see a lot of 800 duplexers around. Has anyone had any luck with converting an 800 to 900 Ham band??
800-900 mobile duplexer
Hi Bob,
I've messed with two different 800 mobile duplexers - one went OK (the screws stuck out a long way - but I guess you could cut 'em off..) the other didn't quite make it.
If you have a tracking generator/spectrum analyzer setup, it doesn't take long to figure out if it'll work. The problem will be the 927 end, of course! Also, keep in mind the T - R spacing is much smaller for the 902 ham band than the original 800 band, which can cause problems with some designs.. If you don't have the fancy setup and you're tuning for best reject, try moving the "pass low- reject high" section to notch 927 mHz - if it goes, you have a winner.
Short story - it IS possible, but I wouldn't invest much in the 800 duplexer (unless you can trade it back!)
73 DE Hartley
I've messed with two different 800 mobile duplexers - one went OK (the screws stuck out a long way - but I guess you could cut 'em off..) the other didn't quite make it.
If you have a tracking generator/spectrum analyzer setup, it doesn't take long to figure out if it'll work. The problem will be the 927 end, of course! Also, keep in mind the T - R spacing is much smaller for the 902 ham band than the original 800 band, which can cause problems with some designs.. If you don't have the fancy setup and you're tuning for best reject, try moving the "pass low- reject high" section to notch 927 mHz - if it goes, you have a winner.
Short story - it IS possible, but I wouldn't invest much in the 800 duplexer (unless you can trade it back!)
73 DE Hartley
Have done several. AS makes a duplexer that will not do 900 mhz. Sinclair 800 mhz duplexers will go quite nicely into the 900 mhz band. for the upper portion, I took the cavity apart, removed all the tuning poles, and cut approx 1/8" off each pole. Worked excellent, I was able to exceed original specs because I was tuning for 1 frequency, not a 20 mhz spread.