sundance-communications.com/forum Forums TDM Business Telephone Systems Mitel Telephones & Systems Radio on all my ext.

I have and SX-50 and the majority of the analog extension are getting a christian rock station on them. I have installed Chokes on all of the extensions but it makes no difference. Any Ideas?

Find out the radio station and have them check their SWR and grounds. If they are all legal then you need to add filters for their frequency. Are the analog phones a standard passive phone or electronic? It maybe the phones not the system or wires.

Remember to ground properly. That's #1.

Then find out the frequency and get a filter for the frequency. Sandman has some good products, but you must know the frequency.

A filter that I have found useful in your situation is a model PORFF. Don't know who makes it. Used to get it from Graybar. Here it is on E-bay.

https://cgi.ebay.com/RADIO-FREQUENCY-NOISE-SUPPRESSION-FILTER-RFI-PORFF-/160538381244

As I recall the asking price ain't bad. I believe the last time I bought some they were a couple of dollars more. Also, do you have the clamp-on ferrite filters in place on the 25 pair cables? AND CHECK THAT GROUND, SPARKY SOMETIMES DOESN'T DO TO GREAT A JOB.

As Merritt pointed out, it 'can' be the telephones. Also, no matter what you do, it may not seem to have any noticeable affect until you are almost done. Ground Spare pairs, and if someone ran shielded cable to 'prevent RF interference', they may not have grounded the shields. OOPS, one great antenna! That will keep you out of trouble for the time being. Remember, 'idle hands are the devil's workshop'. Let us know what you've tried and what eventually works.

Check out Sandman's article on RF. That will give you some insight on the whole problem. Sometimes it ain't so easy. https://www.sandman.com/rf.htm

As a telephone technician and a broadcast engineer maybe I can give a few suggestions.
You are probably very close to the stations transmitter site, most likely an A M station. The telephone wireing in the building is acting like a big antenna.
Sometimes chokes in line at the phone system will help but I have had better luck using bypass capacitors on all lines going into the system. Normally I use .01 UF disk ceramic capacitors. Be sure they are rated to handle at least 100 volts. You can get these at most electronic supply stores. you will need 2 for each extension. Connect one side of the cap to each line and the other side of the cap to a GOOD ground. Keep all leads as short as you can. I have often soldered one of the capacitor leads to a bridgeing clip and just push it on the 66 block.This seems to be the easiest way.
If your phones are wired with the old untwisted pair cable then rewireing with a good twisted pair cable or shielded cable may help.
Be sure all of your grounds are tied together near the system. Power ground and telco ground should be connected together. Also have you tried another make of phone? Some of the cheaper phones are good phones but just can't be used near a radio transmitter.
Getting the RF or radio interference out of a system can be a nightmare. There is no sure fire way to do it. Sometimes the suggested cures I listed above can make it worse. You just have to try and see what happens.
You may try to talk to the engineer at the radio station. He may be able to give you some suggestions. Don't try to blame it on the station. There is a very small chance that they have anything wrong that is causing this problem.
I hope something in this long post helps.
Good Luck
Robert

A couple more thing.. I see LH also said this but I am going to repeat it. Ground all unused pairs.
The filters others said try work too. I have just always tried to homebrew my own.