Testing rf at public service mic connector
Moderator: Queue Moderator
Testing rf at public service mic connector
I have what I believe to be a working public service mic on my XTS3000 however in checking rf power out from mic connector I get no power reading. I am using the the proper mic and rf adapter. Part numbers Mic#NMN6247A, RF Adapter# NTN8327. This seams to defy logic. Can anyone tell me if this is possible?
XTS PSM
I read somewhere awhile back in moto documentation that rf power measurements are not possible from the PSM antenna connector, after encountering exacty what you speak of. Ill see if i can find it for ya.
Last time I opened up a new PSM box there was a little tag attached to the mike that idicated it was not possible to perform measurements fron the Mic antenna connector.
I just opened up my JEDI PSM, and the center conductor from the Co-ax goes to the whole antenna jack, and the sheild braid goes to a conductive coating on the inside of the whole microphone. I guess the mic head acts as a ground plane.
I just opened up my JEDI PSM, and the center conductor from the Co-ax goes to the whole antenna jack, and the sheild braid goes to a conductive coating on the inside of the whole microphone. I guess the mic head acts as a ground plane.
-
Tom in D.C.
- Posts: 3859
- Joined: Tue Sep 04, 2001 4:00 pm
- What radios do you own?: Progreso soup can with CRT
Antenna changeover...
Ken:
Your XTS probably works much the same as my older Sabers in which there is an internal hybrid module that senses whether or not an external antenna has been connected. Without the antenna connected to the PS mic the circuit stays connected to the radio's antenna, and if you connect a wattmeter to the PS mic you're not providing the proper resistive load to make the module change to the PS mic antenna port.
On the much older MT500 and HT220 radios when you connected the PS mic one of the mic connector pins actually and physically pushed in one of the connector points which actuated an internal relay that changed over the antenna.
Anyway, that's my best guess as to what's happening.
Your XTS probably works much the same as my older Sabers in which there is an internal hybrid module that senses whether or not an external antenna has been connected. Without the antenna connected to the PS mic the circuit stays connected to the radio's antenna, and if you connect a wattmeter to the PS mic you're not providing the proper resistive load to make the module change to the PS mic antenna port.
On the much older MT500 and HT220 radios when you connected the PS mic one of the mic connector pins actually and physically pushed in one of the connector points which actuated an internal relay that changed over the antenna.
Anyway, that's my best guess as to what's happening.
Tom in D.C.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.