Page 1 of 1

Ahhhhhh RFI That won't Go Away!

Posted: 06 May 2015, 15:11
by radiogaga
Why me! It's driving me up the wall this one.

Having moved and got the shack all set up as I want it I now have to battle an RFI problem.

Antenna is a long wire (I know :oops: :oops: ) set off against an earth rod, 9:1 Balun and an RF Choke in to the shack. Now here were go into LPF and 2 way switch though removing those two items makes no difference. The 897 and 590 display the same problems. All or some of the USB devices on my Windows PC disconnect and occasionally reconnect but more likely require unplugging and plugging back in again. Feed is 213 MIL.
High Power on 2m has the same problem. That is a Tri-Band Collinear again fed with 213MIL.

No matter what ferrite I add I still have the same problem. Only seems to affect 12/11/10/2m. Power doesn't really seem to make that much difference and all voice modes cause the problem, as well as PSK31.

The obvious answer seems to be to sort the KB and Mouse for something better but surely that's not the solution?

Re: Ahhhhhh RFI That won't Go Away!

Posted: 06 May 2015, 15:31
by Barnbilly
I would start by using a dummy load to see what happens then add to that to see whats happening

Re: Ahhhhhh RFI That won't Go Away!

Posted: 06 May 2015, 16:51
by andymuza
Make sure you plug your PC in to a separate socket to your radio PSU in case it's RFI via the mains. Also, any surplass cable wrap up and add some clamps.

Start your PC with just the keyboard connected and then add components to see which one or which cable is causing the issue. Your monitor may also be part of the problem with the RFI getting through that or your PC PSU. Tidy all cables and make them as short as possible.

Make sure your coax doesn't run near the PC or any connected devices.

How far away is your antenna from your PC and how far away is the feed point?

You may need better screened USB cables.

Re: Ahhhhhh RFI That won't Go Away!

Posted: 06 May 2015, 17:33
by radiogaga
My Mac (Hacintosh) is about 2' away from the radios. The affected Windows PC is about 1' away. Feed point is 20' away on to the antenna at that point.

I'll give the separation of mains a go in a mo and see how that goes.

Cheers chaps!

Re: Ahhhhhh RFI That won't Go Away!

Posted: 06 May 2015, 19:12
by Samalex
Check see if its coming via you modem / down the phone line?
Disconnect everything from the pc except keyboard mouse and monitor see if it shows anything then add usb to see if its the usb cables or modems.

Do you get anthing in your audio or speaker on the radio?

Re: Ahhhhhh RFI That won't Go Away!

Posted: 06 May 2015, 22:14
by Adriano9966
:think: this may or may not help

http://www.repairfaq.org/REPAIR/F_CompRFI.html :idea: but I hope its useful kind regards Adrian