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M3GXQ > EMC 10.09.04 09:13l 35 Lines 1328 Bytes #999 (0) @ EU
BID : B10031M3GXQ
Read: GUEST DK5RAS
Subj: 40m & Intruder Alarms
Path: DB0FHN<DB0MRW<DB0ERF<DB0FBB<DB0GOS<ON0AR<ON0AR<7M3TJZ<F6CDD<I0TVL<
CX2SA<WU3V<W1NGL<GB7LGS<GB7YFS<GB7HOL
Sent: 040909/1952Z @:GB7HOL.#22.GBR.EU #:32829 [Holbeach] FBB7.00i $:B10031M3GX
From: M3GXQ@GB7HOL.#22.GBR.EU
To : EMC@EU
Hi All,
I have an ongoing problem with my neighbours Intruder alarm & 40m.
It seems that anything over 10w PEP on 40m will trigger the alarm. This
wouldnt be so bad, but the alarm system has a telephone dialler attached,
and when it activates, it alerts 2 members of his family, and they come
running at high speed, thinking a burglary is happening.
The system itself is quite old, and only has 1 PIR detector. I know that
some of the older PIR's are quite susceptible to RFI, and the European EMC
directive only calls for an immunity to a field strength of 5v/m or
similar. I know that there are some detectors oput there that will quite
happily handle upwards of 30v/m.
CW is the worst mode, and sometimes just 10w will trigger the alarm, all
down to the fact that these PIR's work on a pulse count, and my keying
speed must be near the pulse count.
My neighbour hasnt suspected me yet, but is talking of getting a new
detector, as he thinks the present one is beginning to fail.
Can anybody recommend a PIR that has a good RFI immunity? as I have told
him that when he does decide to purchase a new PIR, I will pay half of the
costs, to prevent any future problems when I get my intermediate license,
and thus be able to run more power.
Many thanks and 73's,
James M3GXQ
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