grumpyroger's profile

New Member

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11 Messages

Tuesday, April 26th, 2022 2:28 AM

Ham Radio knocking out internet system while talking on 3.953 KHZ

Trying to figure out why my Ham Radio is knocking out my Internet signal while transmitting on HF Freq. 3.953 KHZ. I use a Di-Pole antenna (12 ga Wire Center fed) does this with or without the Amp. There is a world of difference in the freq. ranges between KHZ and GHZ. Anyone ever experience this or have a suggestion? The Tech they keep sending out knows nothing about it. When he did my install, he just dropped the Internet antenna ground wire to the dirt, not even hooked up. I hooked it up but no difference.

my thoughts

Employee

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19.9K Messages

9 months ago

Internet antenna ground wire?

Suggests you have fixed wireless internet installed by a DirecTv tech.

If this is the case, no hardwired internet service from pole or ground terminal, your looking as cellular service hotspot.

New Member

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11 Messages

9 months ago

According to reg. NEC 10, installed antennas must be grounded to a grounded surface to help avoid RF and lightening strikes. Nothing on this install is grounded. He's got the upper wire connected to a painted mounting post. And you are correct on stating it was A direct TV tech. When I call customer service they keep telling me I need to do a reset on my Server. That does Nothing for me but waste time. I have even installed Ferrites on each and every cable including my radio station. Nothing changes

(edited)

New Member

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11 Messages

9 months ago

You say,

"Internet antenna ground wire?

Suggests you have fixed wireless internet installed by a DirecTv tech.

If this is the case, no hardwired internet service from pole or ground terminal, your looking as cellular service hotspot."

What exactly is meant by this? Are you saying that I have just a hot spot connection and no true internet? What can be done to remedy this situation?

New Member

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2 Messages

3 months ago

I am having the same issue but on 3.965. I have grounded everything including the ATT box. I have installed ferrite snap on chokes on every wire going to the main box and the power box for the antenna. My station has proper grounding with individual paths from the radio, the amp, the tuner, etc to ground. I have even installed a choke at the output of the tuner. Nothing seems to work. I was able to use the radio with the older wired internet from ATT but the speed was so slow that I had to change to the fixed wireless. I may have to go to a cell phone hot spot and drop ATT if they cannot help me with this. It is clearly a fault with their equipment.

New Member

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11 Messages

3 months ago

Mine only does this on 75/80 m. If I use 40m, 20m and so on it doesn't affect it at all. I've just gotten use to unplugging it when on 75m. I too am properly grounded. It's this Old DSL junk modems they are issuing. 

(edited)

New Member

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6 Messages

2 months ago

Interesting. I am having similar issues with transmissions on the 20m ham band. No issues on 40m; haven't checked 80m; no issues on 160m even with 500w amp; 15m also OK. Installed Mix 31 split ferrites on all leads (power & cat5) into modem and POE injector. No joy. Also installed same everywhere on ham equipment. Again, no joy. I then noticed that the power LED on the POE injector was pulsing in sync with my CW. I could also hear a clicking sound (sort of like a relay cycling) coming from POE injector when I keyed the rig. Hmm. Disconnected cat5 cable from POE injector to modem. No joy. Disconnected cat5 from POE injector to ATT external antenna. No pulsing power LED, no clicking. Put 4 Mix 31 ferrites on this cable and reconnected. No joy. I think the culprit may be the POE injector, and more specifically, RF pickup in this cable or the external antenna itself. I looked at the label on the rear of the POE injector to see if it is Part 15 compliant. Though there is an FCC logo on the label, no mention is made of Part 15 compliance. The same is true for the label on the external antenna itself (FCC logo; no reference to Part 15). However, looking on the ATT fixed wireless website I found a page that discusses RFI issues with their fixed wireless equipment, and this page claims that the equipment is Part 15 compliant. I have my doubts though, based on my experiences and those of other hams on this forum. I note also that labels on both the external antenna and POE injector say these items are designed in Australia. Do Australian RF engineers understand what is required with respect to RFI immunity for Part 15 compliance? I wonder. Notably, prior to installation of the ATT fixed wireless system here at N1OKL, I was using a terrestrial microwave internet system from a local provider. Their access point is on the same tower as the ATT broadband antennas I am currently using and my antenna for this system was a Ubiquiti half-meter dish with integrated 2.4 GHz microwave transceiver and modem at the dish feedpoint. The POE injector for this system was located in the room with my ham equipment and I never once experienced RFI issues with this system. (Poor service due to an over-subscribed backhaul link and aging access point equipment that had become unreliable were why I dropped their service after 8 years.) But again, absolutely zero RFI issues with the Ubiquiti equipment they provided. I note that the ATT POE injector uses POE 802.3af, Mode A to supply 48 vdc power to the antenna. I looked this up and discovered that POE Mode A supplies DC power on the same cat5 conductors as the TX/RX signals: 1, 2(+), 3, 6(-). Reading more about POE Mode A, it appears as if this mode is principally for use with gigabit ethernet systems. One wonders why ATT would use POE Mode A to supply DC power in a system that will never achieve gigabit speeds? (I have a sneaking suspicion that this POE Mode A may be the RFI culprit here.) I have decided to relocate the ATT POE injector out of the radio room and to the attic where the cat5 cable from the injector to the antenna can be shortened to 10 ft. or less. It will be interesting to see if this solves the problem. If not, I plan to formally challenge ATT's assertion that their fixed wireless equipment is Part 15-compliant. I see no ferrite chokea on any of the AC or DC  power cables connected to the ATT devices, so I have my doubts that anything was done in engineering the modem, antenna or POE injector for RFI immunity. More to come... 

(edited)

New Member

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6 Messages

2 months ago

UPDATE from N1OKL -- I moved the POE injector from the radio room to the attic. I also moved the cat5 cable from the ATT antenna so that it enters the attic via the ridge vent, which shortened this cable to about 10 ft. This configuration change eliminate the RFI problem in the POE injector when transmitting at 100w on the 20m band. However, when using 200w, the problem remains, as before. For now, I can live with this, though it is not a long-term solution. My sense is that the ATT Model POER0-35 Antenna Power Supply has no RF immunity provisions in its circuitry. This is something ATT engineering should address as it renders the ATT Fixed Wireless Antenna system non-compliant to FCC Part 15 regulations for unlicensed transmitters.

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