STL
I recently discovered 2.4 GHz STL systems, which seems like an excellent way to link up multiple transmitters and cover a large area.
Is anyone doing this?
I found a place that charges about $600 for the transmitter and I think it includes one receiver.
I'd appreciate any links or information about companies that sell STL equipment.
ive been meaning to get some onfo for folks:
www.active-robotics.com has the 2.4ghz modules (send and recieve) for 16.00 BP and 15.00 BP .. you can NOT beat this anywhere.
Thanks mlr, but the link didn't work. Could you check it?
Thanks for the new link.
I saw a video 2.4 GHz setup at this link: http://www.active-robots.com/products/accessories/compact-video.shtml
But I couldn't find anything for radio. I need a transmitter that can be omnidirectional and go for about three miles or more. Do they have something like that?
2.4 Ghz wireless is good if you have a clear line of sight to each transmitter. Access point with omni-directional antenna can be had for under $300.00. Subscriber units (that's what you need at each transmiter site) for about $200.00.
A better and easier distribution way is subcarrier audio on an FM carrier. You would have to get friendly with an commercial FM station and lease an audio subcarrier. With an special SCA radio you can pick up your signal wherever you can hear the "big" FM station.
Ralf Black
Shoreline Communications
STL is usually point-to-point and semi-fixed. What are you thinking of that would require omnidirectionality?
The STL system equipment I saw had directional and omnidirectional capeabilities. I think the omniderctional had a range of about three or four miles, or less if there is no line of sight.
I was thinking that if I needed more transmiters to cover my area properly, I would set up an omnidirectional STL transmitter in the center of town, with several transmittes distributed throughout the town, which would all be at various directions from the STL transmitter.
Ok: The one at active-robots.com (sorry for the bad link) is actually good for about 6miles with an omni.
2.4ghz SS - the fcc gives you a full watt you can play with. These are half watt units.
Omni for a link? Because you might want multiple transmitter sites.
Why the AV unit? because you wouldnt need a PLL at each slave transmitter site. 🙂
A plain whip works.. but at a loss (you'll get about 2.5 miles) on the transmit side. The recieve side needs a good (29.00 USD) directional.
This is being done right now at Stanford University in "testing and research" mode. Once the research is done, it will be what I use for my linking.
🙂
Sorry for terseness - I'm just doing way too many things and have not had the time I wish I did for lengthy posts, getting back to the good people who have called me, etc.
Hey MLR - I can understand you OK.
Probably better than broadcastman can understand my disjointed ramblings...
Just when I may have found an affordable STL (Studio Transmitter Link) to experiment with, the changing rules may take it away. I just read in Pro Audio Review that wireless mics operating above 700 MHz will be banned after the June 12 analog TV shutdown. The devices I'm looking at are 900 MHz wireless mics, Sony WCS-990, which cost just over $100 from MCM Electronics.
My history with these units goes back a few years when I did on-location video. We have a good Lectrosonics at 184 MHz which will still be legal, and I bought the Sony out of curiosity. With its supplied mic it sounded worse than a telephone call, but I attached a high quality lapel mic and amazingly had a professional sounding microphone that matched the Lectrosonic for area coverage.
These are switchable on two frequencies so there's your stereo, just use two sets.
By merely adding an attenuator circuit these could accept line-level and the final question is their ultimate point-to-point long-range.
Is it known what will happen to the 900 MHz range? These use 912.6 and 916.2 MHz.
Looking more closely at the device, Sony WCS-990, it is labeled "This device complies with Part 15!" And checking 15.245, 902 - 928 MHz is open for intentional radiators with a limit of 500 mV/meter
Maybe it's also of some importance to consider that if the device were employed as a program link it would not be regarded a wireless microphone.
I'll go ahead with testing and let this Forum know about results.
By the way, the newer version is WCS-999 and has three selectable frequencies.
A better and easier distribution way is subcarrier audio on an FM carrier. You would have to get friendly with an commercial FM station and lease an audio subcarrier. With an special SCA radio you can pick up your signal wherever you can hear the "big" FM station.
i have had this idea for years. you are at the mercy of the big fm station though. should they consider you competition your done.
also make sure your 900 mhz, 2.4 or 5.8 ghz options carry an fcc id for part 15.
i also recommend 900 mhz fhss over the other bands. it's quieter these days and has better propagation.
SCA would be terrific in some cases. In this city all of the subcarriers of full power stations are filled, but a few LPFMs might do some good. And now with HD maybe somebody isn't using all their capacity and could sub-let a channel.
The Sony WC-990 contains FCC ID: AK8WCS990R