[Premium-Rx] Powering receivers away from electricity grid

[DANIEL HIGGINS]

A bit late to join the thread, but here are my experiences both from 
deploying premium receivers with generators and from doing portable contests 
with the local radio group.

Determine whether the noise from the generator is radiated or conducted down 
the power line.  This isn't always easy to determine since conducted 
interference will radiate from the power line.  We always use a heavy duty 
power cable with a good screen, grounded properly at both ends.  Heavy duty 
cable means we can get the generator a good distance away from the antenna 
and receivers (about 80 feet).  The grounding rods we use are heavy duty 
ex-military ones about 3 feet long made from solid galvanised steel.  It 
takes a heavy sledgehammer to get them properly into the ground.  They have 
a hollow centre with bleed holes down the length of the rod so that water 
can be poured down the centre if conditions are dry.

Power line filters are effective, but often the good ones have so much 
capacitance across the power lines that they cause Residual Current Circuit 
Breakers to trip.  A very effective RF choke can be made by winding the 
power line round a 6 inch diameter hollow plastic core for a length of about 
2 feet.  Filters are probably more effective at the generator end since the 
will stop radiation from the power cable.  A good ground connection is 
important for power line filters.

For receive only use, a loop antenna is quite immune to interference pick 
up, especially if you can arrange to steer a null in the direction of the 
generator.  A balanced antenna is better than a vertical if you don't like 
loops.  Consider separate receiving and transmitting antennas.

One thing always missing from all of the Racal premium receivers (and 
probably many more) is any form of noise blanker.  Didn't they suffer from 
the Woodpecker back in the 1970s?  A good noise blanker is useful for 
getting rid of impulsive interference.

Hope this helps,

Danny
G3XVR