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+--- Thread: 2M transmission shuts computer down (/thread-480.html)
2M transmission shuts computer down - VK4WDM - 10-01-2018
Here is a strange problem. When I transmit on 2m (max 50W) my computer shuts down. It only happens on that band. It has just started happening but no changes have been made to any wiring and no new equipment has been added. Ideas please.
73
Wayne VK4WDM
RE: 2M transmission shuts computer down - VK3LU - 11-01-2018
Hi Wayne,
Is your computer a desktop or a laptop?
If it is a laptop, disconnect everything, mouse included, and run it on battery only. If that's OK then reconnect things one by one and see if the problem still happens.
If it's a desktop then obviously you must have power connected. You may be able to run it without the monitor but the procedure is basically the same.
It sounds like a job for trying out clip on ferrites to solve the problem. Also, check for loose plugs etc.
Jaycar on Ingham Rd usually have them.
Cheers
Nev
RE: 2M transmission shuts computer down - VK4WDM - 11-01-2018
Hi Nev
I have a lot of ferrites in the system already and there has been no problem until a couple of days ago. What is weird is why only 2M? No problem with any other band. It is power dependent. If I drop it back to 5W the computer (desk top) is not effected. I will do as you say and check out all the plugs and try more ferrites.
Wayne VK4WDM
RE: 2M transmission shuts computer down - VK3PY - 11-01-2018
Wayne,
You haven't given much of a description your your station layout or computer set-up, but here's a suggestion. Could it be that you have a loose connector or poorly-terminated connector on the 2m feed line, either "upstairs" or in the shack? This could result in plenty of RF floating around in the shack if the co-ax shield is not making good contact.
Chas
VK3PY
RE: 2M transmission shuts computer down - VK4WDM - 12-01-2018
(11-01-2018, 04:16 PM)VK3PY Wrote: Wayne,
You haven't given much of a description your your station layout or computer set-up, but here's a suggestion. Could it be that you have a loose connector or poorly-terminated connector on the 2m feed line, either "upstairs" or in the shack? This could result in plenty of RF floating around in the shack if the co-ax shield is not making good contact.
Chas
VK3PY
Hi Chas
You were right, but firstly I will describe my system.
Antenna is a log periodic yagi covering 6m to 23cm. A single flexible coax line attaches to a length of heliax down to the shack wall where it connects with another flexible coax line (via lightning protection) through the wall to a coaxial switch and patch line to the FT847 and the 23cm transverter.
I checked the antenna a couple of weeks ago and the connectors, switch and lines inside the shack yesterday - no problems found. When I checked the connector between the heliax and the line going through the wall I found that the inside of the plug was lightly corroded. Attached a new one and the problem with the computer was resolved
6m (100W), 2M (50W) 70CM (50W) and 23cm (10W) RF power all passed through the same plug but only 2m caused the problem. The other interesting point is that there was no discernible change in 2M SWR.
Funny stuff RF!
Wayne VK4WDM
RE: 2M transmission shuts computer down - VK3LU - 12-01-2018
Hi Wayne,
Glad you solved the problem. Yes, RF is weird stuff.
You mentioned that you have a multiband log periodic antenna. Is it home brew or commercially made?
Sounds interesting.
Cheers
Nev
RE: 2M transmission shuts computer down - VK4WDM - 12-01-2018
(12-01-2018, 06:52 PM)VK3LU Wrote: Hi Wayne,
Glad you solved the problem. Yes, RF is weird stuff.
You mentioned that you have a multi-band log periodic antenna. Is it home brew or commercially made?
Sounds interesting.
Cheers
Nev
I had several unsuccessful tries at home brewing an LPY and decided to by the Create CLP-5130-1N from DX Engineering. It was quite expensive even when the Aussie dollar was high, but excellent quality. Assembly is a bit tricky but no extra tuning was required.
Obviously it only has a few elements on each band and cannot be compared with band specific yagis but I like the convenience it brings. Have worked into JA, KH6 and all over VK and ZL on 6m and some interstate Dx on 2m. It is also very good on the air bands which is another interest of mine. Just got my 23cm transverter to work so I will see how it goes on that band.
73
Wayne VK4WDM