Zetron 4010R

ffighter_94 · Post by **ffighter_94** » Wed Dec 31, 2003 1:37 am

here I sit at work, bored out of my mind, when what do I hear, the local 1240 AM station playing Tejano. Now here is the strange part, it is not being logged on my Dictaphone Freedom Call Check recorder. The units in the field cant hear it, and it is only heard at 2 of the console positions. It comes over my speaker when units are talking, when they are not talking, when ever it wants. I dont know about anyone else, but I dont ahve a clue as to what they are singing about.............. Maybe they are trying to tell me how to get rid of this problem............ There are 2 4010R and 2 4010 consoles, the 4010R's have the added Tejano option. Suggestoins?

radiomidwest · Post by **radiomidwest** » Wed Dec 31, 2003 3:33 am

If it's just the 2 rack mount 4010's and the desktop units are not doing it, then my first quess is the grounding of the unit. Remove the the unit and any associated expansion panels from the cabinet and see if it's still their.

Are all the posistions programmed the same? How close is that AM transmitter? Either additional grounding or isolation will correct the problem.

ffighter_94 · Post by **ffighter_94** » Wed Dec 31, 2003 4:14 am

problem just appeard tonight all of a sudden. the units are all programmed differently, but all for of them do have that particular VHF channel in common, the AM transmitter is about a mile from the water tower that has our repeater on it. It is tone remote to dispatch, which is another mile away or so. Who knows. Now another console has crapped out completely..... Sounds like my local Big M shop is gonna get a wakeup call today.....

RKG · Post by **RKG** » Wed Dec 31, 2003 5:29 am

You should promptly notify the station engineer of the AM station. It sounds like they are pumping RF into their ground, and are probably exceeding their station specs. It is the AM station's obligation to fix the problem. If they don't respond very quickly (which would be unusual), contact the District Engineer of your local FCC office.

radiomidwest · Post by **radiomidwest** » Wed Dec 31, 2003 6:30 am

4010's don't just crap out. If you are hearing it on just the one channel and just on the 4010R's, programming the "Mute Idle Channels" will mute any noise on the line that is under the VOX threshhold. Doesn't eliminate the problem. Just gets rid of the audio from being thier all the time.

If you don't hear it at all on the other consoles, even when someone is talking, then the problem is right there at the console and not at the tower. If you do hear it on the others, it may be a phone line problem.

Did that other concole just quit working on the one channel or all channels? If its just the one channel, I'm thinking it's the phone line.

ffighter_94 · Post by **ffighter_94** » Wed Dec 31, 2003 1:36 pm

The 4010 lost tx/rx functions, but now has appears to have cross channel mutng turned off for some reason. The switch is on, but it is off. There are 8 channels in this one, and they are all down. Of the 4010R's with the Tejano option, only one of them is constant, the other comes and goes, I am thinking it is not a tower problem, but an onsite wiring problem. By the way, Mute Idle Channels is programmed. Our office is in the Verizon C.O., so there techs were already checking the phone lines when I left at 0700 today. It should be fixed by now, I hope. I will be back at 2300 tonight and find out.....

Thomas

ffighter_94 · Post by **ffighter_94** » Wed Dec 31, 2003 3:50 pm

All fixed now, problem was on KTAM end. Several well placed chokes on our side on the phone lines should keep any future problems away. Seems we lost a card in the one 4010, and for some reason, we lost a card in a 4010R 2 weeks ago, these consoles are at most 2 years old. Seems pretty unusual to me. The first card to go was for a different pair of channels than had the interference. I am not sure which card we lost last night, I will find out at 1900 or so.

Jim202 · Post by **Jim202** » Thu Jan 01, 2004 6:09 am

I have a couple of comments to pass along. First, the cards you lost, were they line cards connected to the phone line and did you have any lightning storms come through? The first thought that comes to mind is that you need to have good surge protection on the phone lines.

Second thought is do you have any surge protection on the AC power line. By any chance did you spend some money for a UPS feeding the console equipment? This is always a good investment. It not only catches most of the power line spikes, but will carry the console over till the generator kicks in.

Third, the problem with hearing an AM station on your equipment can come from a variety of reasons. The AM station can have a problem with their antenna tunner. A shift in the water content of the soil is enough to create this problem. They could have an antenna problem that causes the transmitter to go out of tune. They too could have taken a lightning strike that caused some damage.

You may have to put some RF chokes and bypass caps on all the phone lines going to the console to remove any of the RF that may get on the lines. You may have to run some shielded audio cables to replace the regular JK type wiring (jacketed 2 pair cable) the phone company likes to run.

Make sure that all the console equipment including any remote cabints are all grounded. This means to the same ground source. These grounds need to be BIG low inductance type grounds. You need to have a good building ground system that both the telephone and electrical systems are both tied to. The NEC (National Electrical Code) gives the enforcement to have all these grounds tied together at a communications facility. We do this all the time at cell sites and Public Service Answering Points (PSAP) and dispatch centers.

You may get a small hassle from the local wiring inspector. If this is the case, politely ask him to go back and research the NEC where it pertains to the communications facilities. What your doing is telling him he doesn't know the code and had better go back to the office and learn it before giving you any more flack. Be politically correct in the way you walk through the land mines on this one. You will be right and he will be wrong, but he also carries a big stick.

One good place to start looking is NEC 800-40-d. NEC 800-21 also covers grounding of antenna masts to the same ground electroid as the electrical service. Then there is the NEC 250 section that covers grounding in general.

Jim

ffighter_94 · Post by **ffighter_94** » Thu Jan 01, 2004 7:30 pm

Well, the whole PSAP is on UPS, (CAD, RMS, Muinicipal Court Warrant Database, Status Monitors, Sentinel 911, etc) and we are located in the Verizon C.O., so you would think that there would not be any power issues. But, we all know how that goes. Yes, all the cards that were lost were connected to phone lines. No, we have not had any lightening storms in some time. The night we lost the first card, somehow the leaseline to the tower site had been disconncected somehow in the switch in the telco building. The cabeling is not JK, it is brought to the back room in one of several 100 pair cables as well as a fiber line. We did install a boat load of chokes to get rid of the rf interference.

ffighter_94 · Post by **ffighter_94** » Fri Jan 02, 2004 9:38 pm

Ok, so if I would have been more awake when i posted this thread originally at 03:37, i wouldnt have posted it at all. Seems as if a card was not dead, seems the 25pair cable that runs to the back room was slightly unplugged........ Gee, I guess that means it has to be pluggd in to work right. Thanks for all the suggestions and help.

nmfire10 · Post by **nmfire10** » Sat Jan 03, 2004 6:50 am

ffighter_94 wrote:Ok, so if I would have been more awake when i posted this thread originally at 03:37, i wouldnt have posted it at all. Seems as if a card was not dead, seems the 25pair cable that runs to the back room was slightly unplugged........ Gee, I guess that means it has to be pluggd in to work right. Thanks for all the suggestions and help.

Whoops!