VK Logger Ham Radio Forum Archive

hi all, just wondering if anyone else has had this problem. When I transmit on HF our internet drops out and takes about a minute to come back on. I am running 100W into a fan dipole which has a 1:1 balun connected. I have wound all leads going into the router around toroids. The router is a standard type supplied by Telstra. Anyone have any other ideas on how to fix this
regards Wayne VK4WTN

gday

I only have 254 feet 11 inches of wire for 160 and 80 metre bands with a tuner.

Other bands yagis or verticals etc.

When i tx even with 5 watts, on 80 or 160 my dsl modem actually walks across the table in pure disgust at the RF up its rear end.

I did a few tests with a 12 volt battery... sealed lead acid... feeding the modem and it was a bit happier but not much.

I disconnected the phone line and it was a litle bit happy

I fitted a KY filter to the phone socket on the modem and it was much happier.

http://www.ky-filters.com/

I think this is a comb filter.

BUT i gave up on 80 and 160 except transmitting 5 watts into a dummy load in the tuner and work locals no problem

Have a close look at the KY filter.

vk6ro

e&oe

Yes, I've had this problem for years. Doesn't happen on all HF bands but as far as I can remember it happens on 10m and 40m, possibly others.

ADSL sync drops out, then reconnects. I have wrapped several turns of telephone cord around a ferrite rod just as it comes out of the wall but it did bugger. I've just learned to live with it.

Thanks guys, I have bookmarked the K-Y filter. I may look at a different modem or moving the modem to the other side of the house away from the antenna
Any other ideas will be appreciated
regards Wayne VK4WTN

I did initially have problems on 40M, but after putting the line from the telephone socket to the modem thru quite a number of toroid turns, all seems to be okay now.

VK4GJW wrote:I did initially have problems on 40M, but after putting the line from the telephone socket to the modem thru quite a number of toroid turns, all seems to be okay now.

May I ask which toroid you used?

Hi all.
I recently solved this problem with snap on toroids around all cables in and out of the modem. The band in use was 6m, every JT65 transmission would drop me off the net.
Problem solved.

73
Mark.

Don't have the internet problem but if I go on 80M, the TV turns on. Have not worked out which band the use to turn it off with!

I have touch lamps in the kids bedrooms. Every time I transit the house lights up !!

I found the best solution was 7 meters of RG58 wound on a 90mm plastic stormwater pipe. Plastic cap for each end . all up $5 from Bunnings.

Before I sealed it I slid 3 or 4 ferrite beads over the coax (from Jaycar).

A very good looking ugly balun , with ferrite option !!


Works, most of the time. Some frequencies still set them off.


Brian

Yeh had that problem years ago with a G5RV. Also would set the house alarm off on 10m.

On 40m when I tax laptop shuts down, pulled out the usb mouse and it stopped doing it. Leadspluggrdinto modem are little antenna. When my wife got a pacemaker I took my work radiation monitoring device and walked around the house while keying up on cow, Evey bit if metal in the house had secondary re-radiation. Picture and curtain rails, the metal shower door frame, everything even at low power levels. I think my radios amps and cables leak like a seive.

I found several good designs for low pass filters on the net so I will make one and put it on the phone line where it goes into the modem. 40M is a real problem it is even interfering with foxtel which is a surprise. Have to go back to 6M no RFI there.

hi all just a followup. After rerunning phone cables and fitting toroids on just about everything to no effect, I made up a low pass filter that rolls off above 2Mhz. It fits between the modem and phone line.Problem solved, no problems anymore with internet drop outs.
Wayne VK4WTN

Don't underestimate the importance of using braid breakers in stubborn RFI situations.

The shielded cables that often run between pieces of equipment when added together, make excellent antennas that can conduct RF into the equipment's critical components.

Most of the modems and other devices connected to them have a minimum of shielding, surrounded by plastic - the shielding within the devices only serves to shield the various low level signals between the components and certainly not stray RF being conducted into the units by the cable shields.

Braid breakers using balun toroids of appropriate permeability and number of turns, are easy to fabricate.

Cheers

Peter VK3QI

Further to my previous post, the issue of shielded cables not being properly connected to equipment is also related to what is often called the pin 1 problem.

An excellent tutorial by Jim Brown K9YC on this issue is available at: http://www.k9yc.com/GroundingAndAudio.pdf

Jim Brown is an acknowledged expert in this field, having been involved in various US standards committees on Audio Engineering through his career.

His extensive website: http://www.k9yc.com/publish.htm is well worth looking at, either as an amateur or a professional.

When you look at the current crop of WIFi modems and laptops that are being rolled out and the way in which limited shielding is used, you can see why they are so susceptible to and likely to cause interference. Also the manner in which most of the big brand Amateur Radios connect their microphones and other peripherals is the reason why there are often issues when strong RF fields are present.

Cheers

Peter VK3QI

Try an MF radio site like Dooen 50kw rf even trips our mast light breakers. Its all in the elimination process.
My new ASUS modem for ADSL2 has none of the issues of the previous Telstra white box.
Also have really short lead to phone socket.
And its all wifi now.