Serendipity, Marconi Day and Some noise help

22 Apr

This morning I woke up again during the wee hours before dawn. I secretly love this time of day because, as a parent with kids for a very long time, it was the most peaceful time of day and allowed one some precious “thought” time. It also is a wonderful time to discover unsuspected radio surprises. This morning I happened across a P29 station operating very weakly on the 30 Meter band at around 1140Z. He was very weak and lots of stations were calling. I eventually worked him or at least I think I did because it was not the cleanest exchange in my career and put him my logbook. Later my wife came out for coffee and asked if I had worked anything rare or exciting and I related to her my P29 story. She became animated as wives are sometimes prone to do as if to say I had just done something wonderful and deserved some recognition or something like that. I had to explain that the thrill for me the discovery and not so much the doing. Just the joy of  discovery, appreciation and enjoyment of doing  something that is as free as the air we breath is exhilarating. Finding nuggets where you do not expect them is a big part of it as well. The log entry is secondary-at least to me.

Please do not forget to support Marconi Day this weekend. Ships and Shore Stations around the globe will be active and in fact KSM has published a series of frequencies they will be guarding during this years celebrations. You can find them posted on their web site here. There are even instruction on how to call and behave as if you were a ship calling in for traffic service during the days of marine radio commercial traffic. Enjoy!

Every so often I see an email or RF noise posting on the RFI reflector that could benefit from the affected party having access to a wonderful way to find RFI. It is called a B Field loop antenna and is extraordinarily easy and inexpensive to build. I first came across it via W1HIS and he was kind enough to send me a hand drawn diagram. I have asked permission in the past to share and so am again offering it here. This antenna coupled with a small portable shortwave radio ( I use a cheap Yacht Boy with external antenna jack) becomes a lethal weapon in the continuing fight against RFI. Switching everything should be banned but they are not yet so the fight goes on. I will post a copy here for use should anyone want to try them out. So many guys are walking around with large and bulky 2 meter yagis and trying to locate RFI on 2 meters….this Current Sensing loop works on the frequencies you are actually being interfered by so no 2 Meter proxy is required. Simply lay the long edge along a bundle of suspect wiring and locate the source. I sometimes hold it by the handle and walk about pointing it variously in the vertical and horizontal planes to see which is more active. The switcher noise (di/dt) attached to AC mains is devastating as the house wiring make a wonderful antenna. Sometimes these things are so loud ferrite is not enough; good AC line filters like Corcom must be used on the AC mains side of the switcher along with substantial Mix 31 Ferrite on both AC as well as DC or low voltage sides. The absolute worst case so far was shared with me by a fellow blessed with a what are called solid state transformers. Horrid beasts! Pray you dont encounter one of those.

B Field Loop with YachtBoy radio

W1HIS Sniffing Loop

Dead simple to construct and inexpensive too boot!

Thanks for reading my Blog. Best, Chas W5PG

1 Comment

Posted by on April 22, 2010 in Maritime, Radio, Stuff


One response to “Serendipity, Marconi Day and Some noise help

  1. André, M0JEK

    April 23, 2010 at 1:16 pm

    Thank you for sharing, I will indeed find this “sniffer” useful.



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