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Author Topic: Telephone RFI complaint/issue  (Read 7033 times)
AA4PB
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Posts: 14282




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« Reply #15 on: June 13, 2017, 11:01:55 AM »

I have VTech cordless phones and don't have any RFI issues with them. However, my tower and antenna is located 100-feet from the house and the coax is underground.

Most of the new phones are digital technology in the upper UHF range so I seriously doubt that their RF links are affected by HF ham radio. It's more likely that the phone line going to the base unit is acting as an HF antenna, picking up your RF signals and feeding it into the analog audio circuitry in the base. The place for an RFI filter would be on the phone line very close to the base unit.

It'll be next to impossible to fix if you don't have access to try things and run tests. Phone techs typically have no experience with or understanding of RF. Their first response will typically be that it's the ham's fault. The customer usually reasons that he doesn't have the interference when the ham isn't transmitting so it must be his fault and the solution is simple - just don't transmit  Cry
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KL7CW
Member

Posts: 239




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« Reply #16 on: June 13, 2017, 11:12:49 AM »

If you have a not too expensive phone in your house which is not affected by your transmitter, offer to let them take it home and plug it into their phone jack.  If they still have RFI, then the problem is probably in their wiring or their telco wires.  So their or their telco need to address the problem.  You are probably off the hook.  If there is no RFI with the loaned phone, then the problem is probably with their phone.  Tell them this and even offer to give them the phone.  They may even be able to buy a phone, try it out, and then return it.  Many retailers will refund purchases with no questions asked.
    I used the word probably several times so do keep an open mind.  Strange things can happen with RF.  For example the RF field at their house could be stronger than at your house directly under your antenna. The RFI they experience could be a combination of both a defective phone and wire or telco problems.
    Usually a telco has a jack right at the customer/telco demark point...they could plug a known good phone in at this point and determine on which side of this point the problem exists.  
    I would use caution before doing anything in a "hostile" neighbor's or even a cooperative neighbor's house.  Occasionally some of us have ventured inside to help a "good" neighbor, but as stated this could backfire on you.
               Rick  KL7CW            
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KH6AQ
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Posts: 7677




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« Reply #17 on: June 13, 2017, 11:31:11 AM »

Except for telephones connected to a public network the "FCC requirements" do not require radiated or conducted immunity. Telephones connected to a public network must have some specified immunity in the AM BC band.

In the EU there are RF immunity requirements; see IEC 61000-4-3 but the frequency range begins at 88 MHz - no testing in the HF range.

So, perhaps purchasing consumer equipment that is CE Marked (for the EU) is a way to ensure some RF immunity.
« Last Edit: June 13, 2017, 11:35:51 AM by KH6AQ » Logged
KC4ZGP
Member

Posts: 1261




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« Reply #18 on: June 13, 2017, 11:45:32 AM »


See folks. Multi-band antennas cause, multi-problems.

Single band, not a single problem.

Anything else with which I can help?

_ _ ... ... _ _

Kraus
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W8JX
Member

Posts: 12039




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« Reply #19 on: June 13, 2017, 02:03:04 PM »

If you have a not too expensive phone in your house which is not affected by your transmitter, offer to let them take it home and plug it into their phone jack.  If they still have RFI, then the problem is probably in their wiring or their telco wires.  So their or their telco need to address the problem.

Guess again. It is not the telco's problem. Their house wiring is not required to be RFI hardened. Rules or not the finger points back to ham because without him and his kw+ power there is no problem. Trying to pass buck is not the solution here. Maybe if another ham moved next door that that ham and ran a KW and wiped out his telephone or other electronics he would be a little more understanding that he is causing problem and needs to mitigate it not try to pass bick.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
W4KVW
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Posts: 68




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« Reply #20 on: June 13, 2017, 10:22:08 PM »

Given the current litigious state of our populace, don't do anything but suggest fixes. You touch it you own it.

KF7CG

AMEN & AMEN!  Shocked

Clayton
W4KVW
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W8JX
Member

Posts: 12039




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« Reply #21 on: June 14, 2017, 04:09:18 AM »

Given the current litigious state of our populace, don't do anything but suggest fixes. You touch it you own it.

KF7CG

AMEN & AMEN!  Shocked


Bad idea as it goes back to finger pointing and blaming others for a problem you, like it or not,  are causing. One needs to stop passing blame or responsibility and mitigate problem or shut down transmitter because if you upset neighbor enough they may shut it down for you in a costly manor.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
N0YXB
Member

Posts: 1049




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« Reply #22 on: June 14, 2017, 09:40:18 AM »

One needs to stop passing blame or responsibility and mitigate problem or shut down transmitter because if you upset neighbor enough they may shut it down for you in a costly manor.

At their own peril. Video surveillance is your friend.
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W8JX
Member

Posts: 12039




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« Reply #23 on: June 14, 2017, 09:54:44 AM »

One needs to stop passing blame or responsibility and mitigate problem or shut down transmitter because if you upset neighbor enough they may shut it down for you in a costly manor.

At their own peril. Video surveillance is your friend.

Once again trying to pass buck. If you were my neighbor and causing me RFI grief I would shut you down one way or another  if you were being a ass about it. Get far more with sugar than salt but some think salt is better....
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Ham since 1969....  Old School 20wpm REAL Extra Class..
KL7CW
Member

Posts: 239




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« Reply #24 on: June 14, 2017, 11:05:03 AM »

I was never suggesting that you not assist a neighbor.  If you can help him identify the problem it would be a great first step.  If he wants to work with you, together you could explore various possible solutions.  I never said you should never touch his equipment...just gave you a heads up that you may open a can of worms.  Decades ago I even installed new TV antennas and twin lead, hi-pass filters on their equipment.  However go there knowing you could have liability.  However sometimes folks will not accept advice, free filters, or even agree to do a simple test to just see if you are the cause and on which equipment and bands.  I always tried to be polite and extend the offer.  Back in the 1950's a neighbor said he had TVI.  I had a 60 ft tower a few hundred feet away, but always ran 100 watts or less, usually on CW.  One summer I was out of the state and country for about 3 months.  My father had frequent battles with him all summer, the man was sure my tower was the cause.  The ham club TVI committee and another neighborhood ham all offered to even help him work on the problem...he refused.  He even refused to log some of the times he experienced the TVI, so myself and the other neighborhood ham could try and see if it was tied to either of our operations.  The other ham ran a KW and was closer to him and operated many hours each evening.  The other ham had a mostly hidden wire antennas.  We were very successful working together to cure or reduce other RFI issues in the neighborhood.  So just do what you can, and be polite.  Do not flip him the bird or tell him where he can go.
                       Rick  KL7CW                         
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W9IQ
Member

Posts: 1534




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« Reply #25 on: June 14, 2017, 01:06:49 PM »

Quote
Get far more with sugar than salt

Wow, John that seems strange coming from you. Are the prevailing winds shifting?

- Glenn W9IQ
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- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
K0UA
Member

Posts: 885




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« Reply #26 on: June 14, 2017, 05:05:44 PM »

I have VTech cordless phones and don't have any RFI issues with them. However, my tower and antenna is located 100-feet from the house and the coax is underground.

Most of the new phones are digital technology in the upper UHF range so I seriously doubt that their RF links are affected by HF ham radio. It's more likely that the phone line going to the base unit is acting as an HF antenna, picking up your RF signals and feeding it into the analog audio circuitry in the base. The place for an RFI filter would be on the phone line very close to the base unit.

It'll be next to impossible to fix if you don't have access to try things and run tests. Phone techs typically have no experience with or understanding of RF. Their first response will typically be that it's the ham's fault. The customer usually reasons that he doesn't have the interference when the ham isn't transmitting so it must be his fault and the solution is simple - just don't transmit  Cry


I was a phone tech for several decades, and a ham for longer than that. Then a Telecom Engineer for 15 years.  So you can take what I have to say with a salt grain.  BUT the poster I quoted above, seems spot on to me.   Have you tried a DSL filter on the base unit?.  I don't have any problems with my 5.8 Ghz Uniden cordless system, but I don't a Kilowatt either.  The maximum fire I can put into the wire is 100 watts.  The DSL filter is quick and easy and low cost.
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W8JX
Member

Posts: 12039




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« Reply #27 on: June 15, 2017, 04:49:27 AM »

 Have you tried a DSL filter on the base unit?.   The DSL filter is quick and easy and low cost.

This is actually a pretty good suggestion!  Smiley
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Ham since 1969....  Old School 20wpm REAL Extra Class..
WB4SPT
Member

Posts: 443




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« Reply #28 on: June 18, 2017, 07:08:20 AM »

Martin;  The low pass filter (DSL) is an easy and good idea.   Also, have you done an estimate of the V/meter lets say, to the middle of the victims house?  Most light duty CE marked equipment should be compliant to 3V/meter field strength and 3V@150Ohm ref of conducted RF on wiring. 
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KF7CG
Member

Posts: 1187




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« Reply #29 on: June 20, 2017, 10:48:30 AM »

Slight stretch but another "good neighbor" interference problem and issue. What do you do when your neighbor shells out a ton of money to have a new room added to their house and the electrical system brought to code and then have whole rooms of lights and wall sockets go out every time you get on the air, even at 100 watts? No problem until their remodel.

How do you square this one if they don't want to Eaton or other AFCI manufacturer replace breakers in their new electrical panel? As house are remodeled and more new houses popup I see this as the public relations nightmare of the decade for us. See the AFCI post for more. I just thought I would mention this one since one's responsibility to be a good neighbor has been flying around here.
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