modem losing sync

Has anyone who has DSL AND is a Ham radio Operator had success with any DSL modem regarding immunity from r.f. overloading, especially from a

160 meter transmitter.

I lose sync with 5 watts output. All shielded, including phone line, all cables, r.f. filters, chokes on transmitter leads, etc.

Looking for an r.f. proof modem.

Currently using Netopia 3300(3341) series Cayman device on Centurytel.

Thanks for the Help.


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I can't help with a modem recommendation but over the years I have seen cases where trying to shield phone wires actually increases the RF pickup.

Reply to
Ken Abrams

The problem is the fact that the 160 Meter band (1.8 - 2.0 MHz) is using frequencies pretty close to the spectrum that DSL uses. It's going to be

*very* difficult to keep the two from interfering with each other.

My suggestion would be to try and keep the modem and transmitter as far apart as possible.

I would also suggest that you install a whole house filter (sometimes called a splitter) at the Telephone NID. Then run a short home run to the DSL modem, keeping the modem as far away from the transmitter as possible.

What you're trying to do is introduce as much separation as possible between the DSL modem and the RF signal. The filter keeps any RF that is getting coupled into your house phone wiring from interfering with your DSL signal.

Do a Google search for DSL Splitter and you should have plenty of sources.

Good luck, but I really think you're in for some trouble with that 160 Meter signal. 8-(


-- John Dearing A+, Network+, Server+

Reply to
John P. Dearing

"Capt. James. T. Kirk" wrote in message news:99uQe.45$

I would try it both with the shield grounded and with the shield unconnected. I have definitely seen cases where grounding the shielding makes things *much* worse, though I suspect it's largely because the ground is poor.


Reply to
David Schwartz

I highly recommend a outdoor DSL filter to be located at the demarcation point (where your house line meets your phone co. line in a box).

Then route shielded wiring (don't forget to ground its shielding) from the outdoor DSL filter to where your modem is located. This limits the pickup length to just between your modem and the grounded phone jack junction box.

Keep your antenna away from this setup.

Works for me.

Reply to
Capt. James. T. Kirk

If you *do* decide to ground the shield, only ground *one* end. Preferrably the end at the NID which should already be grounded and bonded. You only ground one end to avoid "ground loops" where each end of the ground is at a slightly different electrical potential causing current to flow in the ground conductor. In addition to be unsafe, it also greatly reduces the effectiveness of the ground.

Let us know how you make out!!


Reply to
John P. Dearing

OK, I got someone at Centurytel to listen.

Tech brought me a Westel modem to try instead of the Net(less)opia I was using.

IMMEDIATELY, I could run 85 watts on 160 meters.

Installed splitter at demarc and ran shielded twisted pair home run to DSL modem(55 feet away).

Grounded all unused pairs in regular phone circuits through splitter box.

Now using 500 watts with no issues.

Thanks to all for your advice.

BTW, tech came back to check on my progress and said he was surprised modem change helped at all. He had given me the DSL splitter and was real helpful. He saw that I was all shielded and graounded and choked at his initial visit so he must have figured I wasn't totally inept.....this was a pleasant experience, all in all.

best regards, Mark K8VF

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