Cheap Computer's and Walkie Talkie's Don't Mix

themuzicman

Well-Known Member
Joined
Apr 27, 2007
Location
On Tour
Well, technically nothing went wrong yet. Our play opens next weekend, and I caught this problem in a rehearsal.

About 8 or 9 months ago, our telex system suddenly broke. We narrowed it down to some bad wiring in the walls, as our base unit runs fine as long as we string our own cable. The school has been slow to fix it, and has even said now that the problem cannot be fixed. For our current show, we needed a fast fix. Our sound designer found an old arts center willing to lend us their walkie talkies. They are older, but still better than the cheap motorola's that every family has, but look very much like the one's the school admin's carry around, and can send and receive anywhere on the school grounds.

Our school came with a Horizon Lighting System on the cheapest computer than can find. It is an eMachine of some variety, I never bothered to check the model because it sucks. Anyway, this board is prone to crashing, having cues jump out of order, and random lights will merge into every cue. For the last two weeks, more odd things than usual had been happening, but I really gave no notice. I would turn around to talk on my walkie talkie, and when I turned back around a blackout would have been cued, or something like that. One day during our last rehearsal I was running board and I noticed that every time I would tx on the walkie talkie, the house lights would raise a little bit, and when I released the button they would go off.

In short, there is no shielding around the computer, or just enough to protect it from itself. The extra output from the walkie talkie throws it out of whack and either every light it is connected to raises to around 10%, or cues will trigger, or menus will flash up. Either way, it sucks. I ended up having to wrap the computer in a roll of aluminum foil just to provide it some reenforcement. Now when people ask why it is like that, I tell them the aliens are trying to probe it, and hand them an aluminum foil hat.


unrelated to the problem: because our walkie talkies look very similiar to the schools (but are on completely different bands), certain teachers have taken to yelling at us for stealing school equiptment, and one even went as far as to say, "only people who shoot schools carry things like that around" and tried making me hand it over to him. These situations tend to be very humorous.
 

Pie4Weebl

Well-Known Member
Fight Leukemia
Joined
Feb 22, 2006
Location
New York City
computers don't need shielding but the dmx cable out of the computer does, I don't the type of the computer is the issue.
 

themuzicman

Well-Known Member
Joined
Apr 27, 2007
Location
On Tour
My friend and I assumed it was the DMX first, but then we came back to the fact that when the walkie talkie is tx'ing, we can see the channel percents rising within the program. Anyhow, both are now shielded :)
 

Van

CBMod
CB Mods
Premium Member
Joined
Jul 27, 2006
Location
Portland, Or.
The Issues you are describing seem much more computer related, than Horizon related. First and foremost is using an E-machines pc as anything other than a doorstop, they are complete and total POS's. Check a couple of thing on the computer; First I hope you're not using a wireless keyboard and/or mouse with this setup. To many potential areas for disruption. Second, make sure Horizon is the only thing < other than XP> on your computer. DO not under any circumstances run anything besides just Horizon. Remove it from any network it may be hooked up to whenever you're running a show, make sure no one has install a dozen different "chat" programs, IM interfaces or whatever. E-machines uses really crappy components, it would not surprise me too much if the memory, or other ICs were being overloaded by EM interference. Check the BIOS on the computer, make sure ECC error checking is enabled, it slows performance on some games, but you don't have games installed right? Also make sure "Spread Spectrum Clock" is Disabled this will help reduce some of the EM interference coming from the Processor itself.
And lastly make sure everything is properly grounded.
 

icewolf08

CBMod
CB Mods
Joined
Jan 11, 2007
Location
Lititz, PA
To second van, you should definitely check the grounding. Make sure are plugged into a grounded surge suppressor and outlet, and that no one has damaged the ground pins on anything. Like Van said, make sure there is nothing else installed on the computer, and you should never have it on a network (unless it is a separate network only to connect other Horizon boxes). If you have other things on the computer or if it has been on a network, then you should reformat and reinstall only the software you need.

It may be interesting to get one of your schools admins to come and talk on their radios near the computer and see if they have the same effect. You could then possibly narrow down the culprit frequencies.
 

mbenonis

Wireless Guy
Administrator
Premium Member
Joined
Sep 1, 2003
Location
Chicago, IL
The fact that the levels on the screen rose a few percent means that the problem is definitely NOT in the DMX or the computer. Being all digital, an analog noise source would not cause them to rise in level in a logical fashion - rather, I would expect to see random error issues if that were the case. My best guess as to the problem would be in the submaster wing (I think y'all have one). Essentially when you TX on the HT (walkie-talkie), the signal gets coupled into the faders and causes them to "ghost up" in level a bit, which is read by the software. Try disconnecting the panel and see if that doesn't fix the problem.

Also, themuzicman, check your PM folder...I sent you one today.
 

Van

CBMod
CB Mods
Premium Member
Joined
Jul 27, 2006
Location
Portland, Or.
You know Mbenonis is correct, I missed that part when listing issues. The wing panel is most likely the culprit as it is really the only only area, other than the keyboard/mouse that's going to be doing D/A conversion for data. Do All that other stuff I said, and make sure the wingpanel is grounded. It could be a bad shield on the wing panel cable, or possibly the cable could have gotten crimped in some way.
 

mbenonis

Wireless Guy
Administrator
Premium Member
Joined
Sep 1, 2003
Location
Chicago, IL
You know Mbenonis is correct, I missed that part when listing issues. The wing panel is most likely the culprit as it is really the only only area, other than the keyboard/mouse that's going to be doing D/A conversion for data. Do All that other stuff I said, and make sure the wingpanel is grounded. It could be a bad shield on the wing panel cable, or possibly the cable could have gotten crimped in some way.
Agreed. A properly shielded and grounded device will not have these problems.
 

bobgaggle

Well-Known Member
Joined
Nov 19, 2007
Location
Philadelphia, PA
Well, matt...anything you touch breaks anyway....hahaha jk...but not really. We gotta talk Gilligan into buying us a new machine. The school can use the e-machine for their crap assemblies and we can use the nice one.
 

avkid

Not a New User
Fight Leukemia
Joined
Feb 17, 2004
Location
Lakewood, NJ
Well, matt...anything you touch breaks anyway....hahaha jk...but not really. We gotta talk Gilligan into buying us a new machine. The school can use the e-machine for their crap assemblies and we can use the nice one.
Put the CPU in a lead lined, water cooled box.
:lol::lol:
 

Lightingguy32

Active Member
Joined
May 2, 2006
Location
New York
Ahh, E-machines, my advice is to immediately put together a budget box computer that has the capabilities needed for horizon and has a good processor and at least 1 GB ram. Other than that, shield the DMX cords. But really, get rid of the E-machine and get something better than it (try a dell optiplex or dimension computer)