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#1
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#2
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![]() "Mike Knudsen" wrote in message ... In article , (Scott Dorsey) writes: [...] I used to listen to WWVB on a huge old Navy regen RX (RAL or the like?) and could get it day or night on a Sloper antenna. Nothing I own now is sensitive enough down there to pick it up. [...] Be careful with this. I haev an ICOM 706 which I have been listening to 350kHz beacons and I suspect sensitivity is not an issue. The receive is not selective enough to keep out much noise. Below about 200KHz I heae locam AM broadcase stations. Some kind of IM or something. I want to build some kind of a low / band pass filter to see if it makes a diff. The specific antenna can also make a diff. I'm using a 40M dipole. -- Regards, Steve N, K,9;d, c. i My email has no u's. |
#3
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On Tue, 9 Mar 2004 14:01:40 -0600, "Steve Nosko"
wrote: Be careful with this. I haev an ICOM 706 which I have been listening to 350kHz beacons and I suspect sensitivity is not an issue. The receive is not selective enough to keep out much noise. Steve - You suspect correctly. That is why the antenna preamp for the HP 117A VLF Comparator incorporated a magnetorestrictive 60 kHz filter with a half-power bandwidth of 30 Hz. Dale H. Cook, Chief Engineer, WWWR Roanoke VA, WCQV Moneta VA, WKBA WZZI Vinton VA, WKPA WLNI WZZU Lynchburg VA, WMNA/WMNA-FM Gretna VA http://members.cox.net/dalehcook/starcity.shtml |
#4
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In article , "Steve Nosko"
writes: Be careful with this. I haev an ICOM 706 which I have been listening to 350kHz beacons and I suspect sensitivity is not an issue. The receive is not selective enough to keep out much noise. Below about 200KHz I heae locam AM broadcase stations. Some kind of IM or something. I want to build some kind of a low / band pass filter to see if it makes a diff. The specific antenna can also make a diff. I'm using a 40M dipole. Pretty sure that the best antenna is a loop -- a big one with lots of turns, and a fat cap to resonate it to 60 KC. Maybe not practical. Or use a big ferrod loopstick and wind LOTS of turns on it. And like you say, many RX suffer from intermod and images from the BC stations. A low-pass filter would probably help a lot. A resonant loop would of course eliminate all that stuff. I haven't cracked my Rat Shack clock open, but I suspect there's some kind of loop antenna inside. --Mike K. Oscar loves trash, but hates Spam! Delete him to reply to me. |
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