Cell phone tower equipment?

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If it is not empty it might have some microwave stuff or possibly a Rubidium frequency standard that you could use to calibrate frequency counters or resell.
Reply to
Spehro Pefhany
The six big cylinders with the adjustment knobs & rods are diplexers, from which I deduce that the four boxes with heat sinks on the four cylinders are amplifiers of some sort -- probably power amplifiers.
This does _not_ look to be the right size for GHz-band diplexers -- those look more like the 146MHz diplexers that I'm used to seeing for amateur repeater use. If I'm right then someone was piggy-backing on a cell tower -- probably a 150-ish MHz band commercial repeater, although the actual repeater is missing. If the stuff can be modified to work at amateur radio frequencies there's definitely a market for it; there may even be interest from a commercial radio operator.
Reply to
Tim Wescott
They look big for cell phone spectrum to me too. You'll have to get numbers off the decals to be sure. Those coax connectors alone used to go for ~$20 a pop, probably superflex type too. A lot of techs don't like to re-use old coax connectors, but if the price is right...
It may have gotten whacked by lightning too, something to keep in mind if you try to sell it.
Reply to
Leon Fisk
Ah, okay, my telecom guy says they are cavity resonators use to share signals- probably lower than cell phone frequencies as others have said (he mentioned 560 MHz or something like that, for which they had installations).
He doesn't think there is much market for that stuff these days because cell phones have replaced most of the 2-way radios.
Reply to
Spehro Pefhany
Btw..they make really marvelous gun cabinets...ahum..
Political Correctness is a doctrine fostered by a delusional, illogical liberal minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.
Reply to
Gunner Asch
English translation for Iggy: Diplexers allow you to connect multiple transmitters and receivers to one antenna (or one array of phased antennas, like a Turnstile used for TV and FM.)
When you have proper channel spacing (to get the TX and RX frequencies seperated by a few MHz) they allow multiple full-duplex transmitters and receivers on one antenna. Hopefully, without blowing up any of the associated gear by excess RF energy getting where it shouldn't go.
And if you don't coordinate the frequencies right and adjust those little plungers and sliders right, you'll watch a lot of very expensive Magic Smoke happen...
Reply to
Bruce L. Bergman
Translation translation. They are VERY sharp RF filters; so you can have a receiver and a transmitter [or multiples thereof..] sharing one tower or antenna array. Think of them as tuning forks in the RF octave, vice Middle C.
They must be kept in a stable-temp room or they will drift off frequency. They are tuned with the knobs you saw; they run the shaft into the cavity; changing its volume ergo its resonant frequency.
They are usually used in two modes. First is a pass filter, tuned to the desired frequency; the receiver has one set on its frequency to it hears ONLY that, and the transmitter has one on its, so it emits only that [no off-freq splatter].
Then the receiver will have a shunt one set to the transmitter freq. so as to divert any of that signal to ground; and the ditto the transmitter on the rx freq.
This cabinet seems to have multiple output amps but that's solely a guess. I look forward to knowing what all the labels and PN's say.
Reply to
David Lesher
The idiots who built one UHF TV station in Dayton, ohio put their diplexer above the drop tile ceiling to hide it. That required it be aligned at least twice a year. I think it was Ch.. 22 but it's been 25 years since I interviewed for the job. I was told later that the chief engineer was two years from retirement, and I knew so much about the equipment in the station that he was afraid he would be fired if I was hired. He didn't believe in a strict preventative maintenance program so when he saw the letter of commendation from the US Army for the one I implemented at the AFRTS station in Alaska he told me the interview was over.
Reply to
Michael A. Terrell

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