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Author Topic: COMPUTER CRASHES on 7.026 cw when phased array is pointing SW  (Read 5928 times)
W3HKK
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« on: March 24, 2014, 04:54:54 AM »

This is driving me crazy!

This is a single frequency problem.  When I am on or very near  7.026.5, and have the 2 el phased array switched SW, my logging program hangs up 95% of the time and the computer sometimes crashes when I transmit on cw.

When I am switched NE, there is no such problem.  Nor is there a problem on any other 40m frequency or any other band.

The station consists of  an IC7600 to a Tentec Centurion amp, and Tentec  tuner. Output is  in the 500-700w range.  The phased array is 150 ft east of the shack.

Ive rearranged the station several times with no success.

Suggestions would be appreciated.
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K5LXP
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« Reply #1 on: March 24, 2014, 06:25:06 AM »

Standard procedure - determine the power level where the problem happens.  Then change something - put ferrites on the PC cords, add a choke unun to the feedline, whatever, then run the power level test again.  If the problem still happens at the same power then you know what doesn't work and you try something different.  If there is an effect you know you're in the right area and can hone in on the remedy.

Mark K5LXP
Albuquerque, NM
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WA2ISE
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« Reply #2 on: March 24, 2014, 09:08:43 AM »

Also check that all the side and top panel case screws on the PC are tight.  It could be RFI leaking into the motherboard, or a disk drive, video board or such.   

Is SW also the direction the beam points towards your shack? 

And RFI is a two way street, once you solve it, RFI from the computer should also be reduced. 
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NK7Z
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« Reply #3 on: March 24, 2014, 09:29:19 AM »

This is driving me crazy!

This is a single frequency problem.  When I am on or very near  7.026.5, and have the 2 el phased array switched SW, my logging program hangs up 95% of the time and the computer sometimes crashes when I transmit on cw.

When I am switched NE, there is no such problem.  Nor is there a problem on any other 40m frequency or any other band.

The station consists of  an IC7600 to a Tentec Centurion amp, and Tentec  tuner. Output is  in the 500-700w range.  The phased array is 150 ft east of the shack.

Ive rearranged the station several times with no success.

Suggestions would be appreciated.

Go buy some ferrites and start adding them one at a time...  I had exact same issue...  Added some ferrites, and it was gone...
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Thanks,
Dave
For reviews and setups see: http://www.nk7z.net
WX7G
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« Reply #4 on: March 24, 2014, 10:00:06 AM »

A good supply of type-31 ferrites are the thing to use. DX engineering stocks these.

http://www.dxengineering.com/search?keyword=ferrite&SortBy=BestKeywordMatch&SortOrder=Ascending

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W3HKK
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« Reply #5 on: March 24, 2014, 02:36:59 PM »

Thanks for the tips.  I did the  "reduce power thing" last night, and last night, at least, the threshold was 400w.   

Ive already  used a half-dozen  ferrites on the coax  before and after the tuner, with no success.  There are so many wires behind the desk, plus getting back there is a challenge.

Looks like I need a more methodical, thorough approach, and will  work on the power cords next.
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K5LXP
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« Reply #6 on: March 24, 2014, 08:08:38 PM »

Odds are the fix will be on the PC.  All I/O is suspect.  You can try and surgically determine if it's keyboard, power cord, internet, etc but I would shotgun the whole PC and check for effect.  An extra ferrite where it isn't needed isn't going to hurt anything and testing all the possible iterations can get annoying.

Mark K5LXP
Albuquerque, NM


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W1JKA
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« Reply #7 on: March 25, 2014, 06:09:37 AM »

Re: W3HKK

  Have you tried using a different computer to see if you have the same problem?
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W8JX
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« Reply #8 on: March 25, 2014, 02:59:43 PM »

Re: W3HKK

  Have you tried using a different computer to see if you have the same problem?

Good suggestion. He definitely has a RFI saturation problem. Also it is likely that 7.026.5 mhz or a harmonic of it is interfering with a critical system clock causing crash.
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--------------------------------------
All posted wireless using Win 8.1 RT, a Android tablet using 4G/LTE/WiFi or Sprint Note 3.
WA2ISE
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Posts: 158




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« Reply #9 on: March 25, 2014, 08:33:04 PM »



.... Also it is likely that 7.026.5 mhz or a harmonic of it is interfering with a critical system clock causing crash.

Many computers use 14.318MHz, half of which, 7.159MHz, is pretty close to the trouble frequency 7.0265MHz. 
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KD0REQ
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« Reply #10 on: March 26, 2014, 04:14:21 PM »

until the fix is found, 9 out of 10 doctors say, "don't DO that!"

the 10th doctor has a boat payment due
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W3HKK
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« Reply #11 on: March 26, 2014, 05:28:30 PM »

1. don't have another computer to try.
2. Upon further investigation,  I crash the computer from 7.025 up to about 7.100, with 400+ watts out.  Above 7100 Im ok.

I will work on  the computer  power cord and input wires this week.

Tnx.
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ZENKI
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« Reply #12 on: March 28, 2014, 07:57:57 PM »

Issues like this can be fixed by bonding all your PC equipment and then tie them to a single point ground on your desk.

Dont forget to check all your stations cables and feedlines for common mode issues. There is no point in putting the cart before the horse.
If you are using antennas and other practices that causes common mode issues  these should be fixed first before attempting to fix the problems
on other equipment like PC's Fixing common mode also reduces  noise from things like PC's, keyboards and mice. The new generation of mice/mouse seem to be bad qrm generators.
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