Hello all,
Many thanks to all who responded to my troubles re the
above.
When my son and colleagues arrived for work ( They run an on
line retail business) this morning and read the deluge of e mails they
shut all systems down and we turned off the mains power supply. Fed
underground.
The phone lines are also fed underground but fixed about
25cms above ground for about 25m to the input socket.
Using the main transmit antenna, 14mm top loaded vertical,
and using a battery operated receiver the noise had disappeared completely.
GI4DPE’s beacon was S7. Only just detected it previously.
I thought we had been through this procedure before
but with old age and failing memory I now recall this was done in relation to
80 m noise some time ago.
Switching power back on we then went through the laborious process
of shutting down the large amount of equipment—Server and network systems
and numerous PC terminals printers etc.
2 devices are causing the problem.
Firstly-fairly minor, a power supply to an HP 750 printer. Produces
a carrier across the band.
Secondly-- an internal telephone system. 20 line - 4 in use,
Panasonic KXT 61610BE—“ Electronic Modular Switching System”
The reason I associated the interference with broad band
adsl was that using a portable RX placed anywhere near the telephone line
produced massive QRN, even to the extent that I could detect it under ground.
I can only conclude that somehow this wonderful Electronic
Modular Switching System is feeding back down the phone lines. I am not
knowledgeable enough to know if this is possible but it certainly seems the
case.
I am greatly indebted to all who offered solutions and
secured the co operation of “ workers” this end.
I just hope some other gremlin does not appear again
73s
Mike GW4HXO.
PS Anyone know of an internal phone system –QRM free ?
or a possible filter solution ?
