This is topic fm transmitter in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=003526
Posted by Phil Radosevich (Member # 508) on 06-02-2002, 10:37 PM:
does anyone know what kind of FM transmitters that are in use in drive ins
Posted by Steve Kraus (Member # 476) on 06-02-2002, 11:16 PM:
Mostly illegal ones, no?
Posted by Paul G. Thompson (Member # 655) on 06-03-2002, 12:25 AM:
Phil, There are several FCC approved FM transmitters that can be used in the drive-ins. I think around 100mw or so......Just strong enough to keep it on your property.
Posted by Paul Mayer (Member # 355) on 06-03-2002, 01:25 AM:
Does anyone market those loop antennas (the kind where the signal is receivable only inside the loop) for drive-in use? Seems to me like that would be a perfect application of the technology...The Non-Weenie-Wielding Paul
Posted by Gordon McLeod (Member # 33) on 06-03-2002, 05:48 AM:
Decade in Montreal Canada makes an excellent stero FM transmitter that is DOC approved. They also supply the correct antenna for it as well
Posted by Josh Jones (Member # 447) on 06-03-2002, 06:36 AM:
Most of the stuff out there is made for pirate radio use. Speaking from a former pirate's view, you have the following options(undoubtivly I've missed a few):Veronica FM www.veronica.co.uk/
Uk based comapny with a good PLL, some consider it the standard, FM kit.
Broadcast Warehouse www.broadcastwarehouse.com/
Ramsey kits www.ramseyelectronics.com/
makers of the famous FM25 stereo transmitter.
If you do go this route, make sure the kit you get is compliant with FCC rules and does not exceed 100mW. it is also necessary that you put out a clean signal, or the feds will be on your ass in no time at all.
Josh
------------------
"Film is made of silver, video is made of rust"
'nuf said
Posted by John Anastasio (Member # 607) on 06-03-2002, 06:58 AM:
I don't have the URL handy right now, but do a search on LPB. It's a Pennsylvania company (Easton, I believe) that manufactures broadcast consoles and low-power (legal) transmitting equipment. I've worked on their stuff for years and it's excellent. If you're going to do an installation, you might as well do it right.
Posted by John T. Mellor (Member # 468) on 06-03-2002, 07:38 AM:
Marble sells one that is legal and complete with antena for Drive in use
Posted by Barry Floyd (Member # 385) on 06-03-2002, 10:05 AM:
The Broadcast Warehouse TX-1 is an excellent transmitter (although too much power for FCC Part 15). I beleve the output power can be turned down, but I might be mistaken.I personally have a Ramsey FM25 that I got from an old defunct drive-in. It came in a crappy little plastic case which did not shield it from any stray RF signals and noise. I bought a single space standard 19" rack mount chasis from Par Metal Products (www.par-metal.com), and mounted the circuit board inside the new chasis. It works great and my interference issues went away. I put a couple of ferrite coils on the 12volt power supply line and that helped too.
------------------
Barry Floyd
Floyd Entertainment Group
Nashville, Tennessee
(Drive-In Theatre - Start-Up)
Posted by Ken Layton (Member # 133) on 06-03-2002, 10:16 AM:
Actually for drive in use, the Ramsey Electronics FM-100 is the best, but here in the USA you have to assemble it yourself (it's sold fully assembled only for shipment outside the USA). It's a professional unit (and in a nice metal case with digital display of frequency). Be sure to buy the companion TM-100 antenna to go with it.
Posted by Josh Jones (Member # 447) on 06-03-2002, 01:18 PM:
If the output power is too high, you can always make an attenuator to reduce the power. old FM exciters work great for drive ins too, just require more maintainance.Josh
Posted by Paul G. Thompson (Member # 655) on 06-03-2002, 05:40 PM:
Yeah, Josh. They do. However, they are too powerful. 10 watts will do an excellent job on coverage of a whole city. Just exactly what FCC gets a little horny about. 
Posted by Matthew Bailey (Member # 601) on 06-03-2002, 06:15 PM:
How about ordering a C. Crane FM stereo transmitter? PLL,digital tuning,,FCC approved. www.ccradio.com
Posted by Josh Jones (Member # 447) on 06-03-2002, 07:14 PM:
well, then put an attenuator on it.
Posted by Mike Jones (Member # 522) on 06-04-2002, 06:39 PM:
Hey Paul, what are you holding? i hope its just a hot dog.
nice to me back working again,
mike
Posted by Thomas Procyk (Member # 1170) on 06-04-2002, 09:01 PM:
I purchased and assembled a Ramsey FM-25 a year ago, (they come as a kit) and it works great, except for the interference that Barry mentioned. In their latest catalog however, I noticed that they fixed the problem with the DC hum in their "New Improved" model. As for broadcast power, it could easily (and legally) cover a drive-in parking lot. I don't know what kind of transmitter the drive-in over in Lake Worth uses, but if we leave their station on as we drive off, it begins to fade about 2 miles down the road.
=TMP=
Posted by Will Kutler (Member # 770) on 06-04-2002, 11:09 PM:
The DeAnza Drive In in Tucson, AZ (IATSE booth) is a four screen that uses FM transmission...
Posted by John Pytlak (Member # 331) on 06-05-2002, 08:21 AM:
Some links: FCC Rules
Guidelines for Unlicensed Low Power Transmitters
FCC Parts 2 and 15
------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion