[CQ-Contest] strange noise problem

Ronald Stuy pa3ewp at zonnet.nl
Sat Dec 4 16:40:00 EST 1999

Hello guys,

We have a strange problem (big noise/static) at the location of PI4COM.
Let me explain our situation.

On 40 meter we use an 3 elements M2 at 27 meters up. As soon as we are 
transmitting and went back to the receive mode we get this strange
It seems that it is a sort of static or decharging of a capacitor.
The noise is there for approx. 30 seconds and than it is gone.
After the next transmission the noise is back again.
The noise is not equal strong in all the directions. So it seems it is
an external source?!
When we are transmitting on a dipole or the virticale whe don't have
this problem.
And on the beam we can listing without this noise.

So this is not it, on 80 meter this noise was also available, only when
40 meter was transmitting. (We got the same problem during the SSB
contest between 40 and 10 meters).

We checked a lot of items during the contest to locate this problem but
we couldn't find it. We even changed the amplifier. 
Running about 300 watts the noise was not available.

What extra information: approx. 1 KM away from our location is a BC at 
828 Khz. running 20 KW.
The fieldstrength of this station is big at our location. On our 160m
verticale we have all the time 10 Watt reflected power from them.

Next weekend we will check the coax-cable and the beam to see if there
is something wrong. 

Have anyone an idea what source could generated this strange noise?
All information is welcome.


Ronald Stuy (PA3EWP)

Member	: 	PI4COM (Contestgroup Oude Maas)
Homepage:	http://www.muurkrant.com/pi4com/index.html

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