• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

WiFi STL - Is anyone doing is successfully on 900MHz or 5.8GHz?

B

bmcglynn

I'm looking into the possibility of running an IP-based STL over a long-range WiFi connection. I've done some research on units such as Ubiquity and Engenius and based on the specifications and claims of the manufacturer, it looks like a workable solution.

The station's that would be using the STL equipment have an FM and AM transmitter location that are line of sight to the main studio. The FM link is approximately 8km with the AM being 1KM.

It looks like it would be feasible to put a base-station style link at the FM transmitter tower with a parabolic receiver at the studio and at the AM tower (pointed to the FM tower). I would imagine that 900MHz would give some advantages over vegetation blockage (should it be an issue at some point). The only issue I see with 900MHz is that the gear is substantially more expensive.

Additionally, what sort of codecs are people using? With a proposed throughput of 10MB/s, I would imagine that raw PCM audio could be fed to both sites.

I'm looking for some info on experiences with WiFi STL configurations. Thanks in advance for the information.

Brian McGlynn
Genesee Media Corporation
 
The only 'home-brew' STL I have made was with 2.4 GHz.
I successfully set up a link using two dishes and a modified digital audio sender. (note 'audio', not 'AV').
I tested it over 20 km line of sight and it was rock solid.
The TX can shift frequency, and the receiver will follow automatically (meaning a trip to the TX site isn't needed).
The most important mod I did was to uprate the RF final in the TX.
I see no reason why you shouldn't be able to do something similar on 5.8 GHz or 900 MHz.
I'm not sure if 900 MHz is licensed for 'WiFi' as such, although if you had a licensed frequency there you may be
able to use digital data mode on it. I guess it would depend on the terms of the license.
The only other WiFi link I have done was also on 2.4 GHz but used two PCs running wireless cards, into amplifiers and up
to dishes on the roof. There is software you can get online which allows audio streaming over LAN, and this worked
quite well over the WiFi link.
 
I have an STL setup using Nanostation M'5 and Barix 500's running pcm 44.1.Rock solid..Comrex,Tieline, Worldcast Silver all do a good job.On the longest link you might want to use the Nanobridge.All of these have built in antennas.as far as freq I would use 5.8,or 900 ,both are license free of you may try the newer licensed 3.65.You can scan the freqs to see what's the best for your application.Maybe my eng friend Stephen will chime in.He's a whiz on this stuff!!
 
I would also suggest that you look at the Mikrotik routers and point-to-point radio links. I use this brand for all my sites (no STL though) and the equipment is rock solid. As I mentioned in another post, one of my deployed routers has just passed the two YEAR mark of 24/7 service (plugged into a UPS, not a single reboot) and hasn't slowed, hanged, or otherwise needed any attention.

The Mikrotik brand is marketed to the ISP industry, so it's definitely reliable; it's Cisco industrial grade quality at consumer Linksys prices. They do have various radio links that will probably suit your needs.

I'm not affiliated with the company, only a huge fan after years of use.

http://routerboard.com/

http://www.mikrotik.com/index.html
 
I'll say to be careful with 900MHz ISM, VERY noisy in most places unless rural. I run a wireless ISP by day and engineer 2 stations after hours.

One of the stations is on a t1, cisco 2610 routers on each end, comrex BRIC link on each end doing audio duty, works great, had some issues with the circuit at first, ATT got it fixed and have had 0 downtime in well over a year.

the other station is on a tranzeo tr-902 link. There is only one slightly usable channel here, had to go down to 5mhz wide, scala STL dish on one end, long yagi on the other, tried smaller antennae first, too much interference. Got signal up to -38dbm, still catch a glitch occasionally from interference. I'm colocating my internet service on the tower of this station in the near future, going to move the STL into our network.

In my ISP experience, I'm running UBNT rocket radios on 2' dishes for all my P2P links with great results. the longest link I have functioning in P2P is 3.5 miles, its absolutely flawless, TCP throughput is > 90mbps both ways in a 40MHz channel.

On P2MP in 5GHz, I have a client out 5.5 miles, seeing 50+mbps in 20MHz channel width. for short links with the big dishes, you will have to turn the tx power down on both ends, UBNT radios do NOT like signal above about -50dbm. when I initially fired up the 3.5 mile link, I had tx at 28dbm, signal -35dbm at both ends, it was NOT happy.

I will also second mikrotik routers, we use them for our core network, at every tower site as well as the stations I take care of and the owners home all have mikrotik routers. I have an x86 mikrotik box supporting ~160 internet customers and never breaking a sweat, 1-2% cpu at most.

I have not yet used any mikrotik wireless as we settled on ubnt airmax early on, I understand mikrotik has nstreamv2 which is their TDMA protocol thats not compatible with ubnt. I'm very impressed with airmax so far, we have a 2.4 GHz omni site that could barely pass traffic with all the interference from consumer routers, turned on airmax it was like moving to a clear channel. We're seeing 30+mbps TCP throughput on our 2.4 stuff and perfect voip quality. Works surprisingly well, I though the noise would be worse than it is with the sectors at 280ft.

I will also say the Barix instreamer/exstreamer boxes are great on a stable network, doing audio in the station LAN or on a stable wireless link they can be flawless. Don't try to use them for realtime low delay audio over the public internet though, the fixed buffer does not play too kindly.

I'll offer up whatever help I can through text, oldiesstation can vouch for me, I assisted him in configuring his ubnt radios for his link. Once he got LOS, everything was great. LOS is a must for 5GHz, ubnt M series MIMO gear in 2.4GHz is very impressive on foilage penetration. I tested a link the other day about 1.2 miles from the tower, through mostly solid treetops, still managed to see -71dbm, throughput was somewhat slow but stable, no packet loss even though the data rate was dropping to 6mbps.

Latency is low on ubnt gear too, airmax is 1-2ms round trip, non airmax is < 1ms round trip. we have seen more jitter on non airmax than airmax. We typically see 2-5ms round trip though 2-4 hops of wireless.

Stephen
 
A snooty texas town wouldnt let my buddies station put up a stl tower/dish so we had to be creative. We are using Demarctech 2.4ghz wireless bridges over a 4 mile two hop run. The hop handover takes place at a municipal water tank where we put a solar panel and deep-cycle battery that will run the system for approx two weeks without sun. System has been rock solid with very low latency. Cant remember all the systems specs right now.
 
Dumb question maybe, but I'll ask. We're using Ubiquiti 5.8 GHz and Tranzeo products. They work rock-solid, just get them line-of-sight, point them precisely.

Curious about 2.4 GHz. Same band of WIFI that will be compatible with laptops' WIFI cards, etc?

The 5.8 GHz needs solid line-of-site. Is the 2.4 GHz better able to penetrate some buildings and get through some trees?

Thanks in advance.
 
2.4gHz happens to be the resonant frequecy of water, making the band relatively susceptible to rain fade. Nobody really wanted that band commercially which is why it was given to unlicensed public use. It's also the frequency of microwave ovens, which is why they boil water so effectively.
 
Kmagrill said:
2.4gHz happens to be the resonant frequecy of water, making the band relatively susceptible to rain fade. Nobody really wanted that band commercially which is why it was given to unlicensed public use. It's also the frequency of microwave ovens, which is why they boil water so effectively.
Click to expand...

Back in August, I attended a county fair where our station was doing the traditional remote broadcast. In the "Rural Museum" at the fairgrounds, there's a nice replica of an old doctor's office, and in the corner, I spotted a 60+ year-old Raytheon "Microtherm" diathermy machine, basically a microwave oven without the cavity. It uses a 150 watt magnetron that operates in the 2.4 GHz band, with the RF output fed to a corner reflector antenna which can be positioned over any part of the body requiring "deep heat". My immediate thought: Someone could wreak big havoc with WiFi with one of these -- not to mention the warm feeling of sticking one's hand in front of the antenna.

How times have changed. The FCC now limits FM stations to an RF power density of 200 microwatts per square centimeter at locations accessible to the public, but these machines were permitted to exceed that radiation level by many, many times. Search "Raytheon microtherm" in Google for more background.
 
Hi!
I had been doing successfully 5.8 GHz Link covering distances from 15 to 50 Km.
The key for good signal and coverage is the radios and antenna gain.
Radios: Ubiquiti Rocket M with 5GHz AirMax 2x2 PtP Bridge Dish Antenna.
Audio: Codec Barix 100 with 192Kbps
For better quality Barix 500 PCM quality.
The sound is much better then 950 MHz Links.
I hope this Help.
 
Speaking from experience, using the Ubiquity Bullets and 5.8g connections in Afghanistan, we had no problems at all with them as STL's. We were using the Digigram Iqoya STL systems along with the Bullets and consistently shot through buildings, trees and everything else, and never had an issue with drops, fades, or any other anomalies that you'd normally get. One of our hops were shooting close to 50km and still had no problems. Like a previous post mentioned though...they have to be aimed dead on or you will have problems.
 
Use the Microtik routers and point to point radio links to relay a T1 around 19 miles, reliable and trouble free. Does need to be line of sight and aimed correctly. Once does, superb. Why not?
 
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.


Back
Top Bottom