pac unit

pete633 · Post by **pete633** » Wed Dec 05, 2001 1:44 pm

i am looking to buy a pac vhf unit, if i hook this up to a syntor x will i then have a vhf repeater or is this only a crossband unit?

i am not familiar with a pac could someone briefly explain??

tnx pete

CHEFA2001 · Post by **CHEFA2001** » Wed Dec 05, 2001 2:07 pm

Pete the pac units as in pac-rt & pac-pl were gen. made for cross band use as in UHF to VHF, vice versa, and sometimes from 800 to VHF/ or UHF but I don't believe that one can be made to a "normal" in vehicle repeater. You might be able to hook it up some how w/ a duplexer and such but I am not sure as there is alot involved with that and the rf output of the pac unit is about 2 watts so I dont know if that would suit your purposes.

I'm sure there are others who will commment on this and steer you in the right direction.

Good luck

pete633 · Post by **pete633** » Wed Dec 05, 2001 2:16 pm

thank you for your help

pete

Post by **HumHead** » Wed Dec 05, 2001 5:05 pm

Does anyone know of a good source of information on the PAC-RTs? I've also been curious about playing with them, but haven't found any good information on tuning, set-up, etc. yet.

Also, has anyone ever played with linking two units together to create a low-power cross band link? I can't see why it wouldn't work.

Thanks!

Vern · Post by **Vern** » Wed Dec 05, 2001 9:26 pm

The 450-470 PAC RT theory manual is part number 6881010C20-0. Motorola or MDM or some of these places may have one lying around.
The receive sensitivity on these is not as good as a "regular" radio. They were only designed to receive from portables located in the immediate vicinity. Power output ranges from 250 mW to several watts, depending on the users needs.

CHEFA2001 · Post by **CHEFA2001** » Wed Dec 05, 2001 10:29 pm

I have a service manual new as hell since it is still in plastic which I kept it in for safe keeping since getting my first one about ten years ago.
If anyone wants me to copy the entire manual, I can scan each page in my computer and send it to you for the cost of the postage. Please, only people who plan on working with it, as I am more than willing to help out a fellow bat but dont want to have to make 40 copies of the manual.

kens · Post by **kens** » Thu Dec 06, 2001 11:21 pm

Motorola supplied UHF Micors with Pac Rt's that were also UHF for the old "HEAR" system which was made to enable ambulances to communicate with hospitals. They used a "flat pack" which resembled a duplexer but was actually 2 sets of pass/reject filters connected to 2 separate antennas. It worked on very low power (less than .5 watts) and used ht220 slimlines as companion ht's

raymond345 · Post by **raymond345** » Fri Dec 07, 2001 2:18 am

Hi there on vhf we used them in the old days
for the police.It was all vhf only.
When car on pac-rt the rx of the portable
was on a different simplex freq. then it run into the normal car radio.It had a duplexer
installed for the close freq. 5 mhz split
between portable and car radio.They
had very close operating range only.
Raymond eMail [email protected]

Post by **HumHead** » Sat Dec 08, 2001 6:49 am

Thanks to all for the information so far.

I'm actually looking to repeat a single VHF channel over to a UHF low power channel, so that I don't have to lug two radios around my facility when I'm working.

I generally have no trouble talking around the facility on a UHF HT1250 on 1W out, so I don't think output or sensitivity will be a problem. If I can manage to tie a VHF and UHF unit together, and not tie up a "real" radio, so much the better.

Can anyone educate me on:
1) The difference between the PAC-RT and the PAC-PL?
2) Just what the heck is a vibrasponder? (Sounds kind of naughty, doesn't it?) I gather that they were the predecessors to the PL reeds or active paging filters, but the values that I see for the units on eBay are well out of the CTCSSS tone range. Are they used in the PAC-RT for single tone access or something similar?
3) Are the units simplex, or can you set them up for repeater access?

CHEFA2001- I sent you a private message.

Thanks!

Cowthief · Post by **Cowthief** » Sat Dec 08, 2001 12:39 pm

Hello.

Vibrasponder is the RX reed,
Vibrasender is the TX reed.
This is the case in 2 way as well as paging,
anybody remember the old pageboy/bellboy, 2 full size vibrasponder reeds in the bottom of the radio sized pager.
The PAC-RT system will need the radio to generate a confidence tone, this is used trigger the watchdog in the PAC-RT unit, this was used to prevent the unit from keying on other than the intended user, this was because there could be more than one PAC-RT on the scene, and having several transmitters key at the same time tends to be a problem.
If you have only one PAC-RT to deal with, you can set the watchdog to disable.

Thank You.