Posted by Kerwin on August 25, 2001 at 15:37:56:
In Reply to: Re: vehicle extenders? posted by MM on August 23, 2001 at 03:05:28:
This describes a WSP extender setup back in the mid 1980's.
This is based on a brief chat with a trooper in the Seattle North detachment who had one, and from my own monitoring of the UHF link between the car and the portable.
I don't know how WSP may be doing things NOW with regards to extenders, other than some cars have them. I have heard a few on the Bremerton area freq, they have a distinctive "audio signature".
As I recall many of the WSP cars at the time had an 8 ch VHF mobile. This was prior to the Syntor X-9000 radios they had later. Some had a pak-rat" Moto UHF portable and vehicular repeater system either on the 453.475/458.475 or 453.925/458.925 frequency pair. The mobile VHF microphone MAY have had a 2 mode ptt switch. Something like push IN and transmit on AREA, push DOWN and transmit on another selected ch like STATE or LERN. (can anyone verify if there was a mike like this?) The radio was preset for the district it would be assigned to. Area dispatch was the priority ch for both rx and tx. The buttons on the control head selected the "other" ch. This was probably simular to several of the radios in the King County Police (now Sheriff) SAR Comm Van in the mid '80s. The selected transmit freq was also the rx priority in scan mode on those radios.
Listening to the UHF OUTPUT of the vehicular repeater, you would hear everything the VHF mobile was receiving when the extender was turned on.
I recall being able to hear car to car traffic on 155.970 being repeated over the uhf, with a distinct "put, put, put, put" sound
about every 1/2 second as the mobile VHF radio in priority scan checked the dispatch ch. EVERY time there was traffic on 155.58 the mobile VHF would lock onto it and it would repeat over the uhf WITHOUT the "put,put" sound. If the trooper keyed up the portable it transmitted back to the car on UHF and the VHF would key up on 155.58. Only a few of the troopers had extenders.
You all remember how District 2 was a big Experiment for WSP?
Roll Call, cars with BLUE reflective markings etc! And the automatic morse ID that used to key up even when a mobile was transmitting?
King County Medic One had UHF extenders that used DTMF keypads on the portable that could change which freq the mobile was on.
It could even switch between the VHF dispatch and the UHF Med Com!