Wireless mic's.

RCVMO · Post by **RCVMO** » Mon Jun 16, 2003 6:07 pm

I don't have a special wattmeter to meaure the output of some wireless mic's, but what is the usual output? I have been working on some mic's for the in-car video cameras and have some that are questionable and don't have the range as compared to the same model on the other cars.
The usual RX in the video systems are normal police scanners, but I have seen some use the rx'r of P-50's. This particular model I'm working on is a wide band TX and WB rxr. Range is maybe 20 feet. The model is a Telex, and the antenna is embedded in the microphone cable.
Any ideas?
Thanks.
Jimmy

PRR · Post by **PRR** » Mon Jun 16, 2003 8:33 pm

Wireless mic TX power varies with make, model and frequency band; anything from 10mW to 250mW. According to the spec sheet, the Telex PB-1 is rated at 35 - 45mW, while the PR-1 receiver's 12dB SINAD sensitivity is .65uV. Both units really need to be checked as well as the RX antenna and coax, along with the transmitter's mic (as it's the TX antenna).

Henry

RCVMO · Post by **RCVMO** » Tue Jun 17, 2003 12:05 am

Thanks for coming back./ Years ago, I worked with another local dept. that used the input of their DPW rptr ( 450 mhz) for their mitter channel. If memory serves me correct, this Mitter appeared to be the TX portion of an Mt500, using the same crystal oven as well. That one worked great as it had at least 1/2 mile range. Bad thing about it was they were using an old Regency mobile to recevie. We later talked them into a BC760 with tape outs for gathering evidence.
Batterries don't last very long in these especially on a long run, but for the in-car video, the SOP is to turn them off when the TS is complete and secure. Some of the mic's end up staying on, batterrries run down, and the time you really need it, it's not there for you.
Thanks.
Jimmy