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eHam Forums / Elmers / RE: RF in the shack
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on: September 22, 2012, 11:25:51 AM
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The antenna's too close.  Ditto. I have an SWL antenna outside my bedroom that just happens to resonate on 20 and would make a pretty darn good antenna if it was more than 12' off the ground. I didn't put it up for DX'ing, it's just a quick & dirty 66' of #18 wire fed a quarter wave from the end nearest the house. It loads well enough that I can hear myself in the bedroom stereo through a large pair of three way speakers if I run more than ~50 watts. Did I mention the stereo does not need to be turned on? Tis' true. The speaker wires alone pick up enough RF to give me plenty of volume through both speakers with the left side being the loudest. That's what I call RF coupling, and yes, the left speaker is closest to the antenna. Like maybe 4' - 5' if I had an X-Ray tape measure. The antenna does have a 1:1 balun at the feed point and is a clean install by an experienced amateur with above average intelligence and exceptional good looks. It's just too damned close to the speakers, and the answers I'm sure you'll get about ferrites on the power cords and such address the symptoms............. Not the cause. Either crank the power down or get the antenna away from the house where it belongs. It's an outdoor toy. Agreed, it's an out door toy, however my Icom had no problem getting out on both 10 and 20 meters using that 20m dipole and the built in tuner. SWR on 10m was a litle over 1.5, the Icom was a great radio and I wish I had it back!  |
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eHam Forums / Elmers / RE: RF in the shack
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on: September 22, 2012, 11:23:48 AM
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A 20 meter dipole (about 33') presents an impedance of roughly 2000 ohms on 10 meters. The VSWR on your coax is 40:1 and that is not a good thing.
How is the RFI on 20 meters?
The 10 meter contact was using the built in tuner in the Icom 746Pro, this test was on 20m using the Yaesu, should have been fine but the SWR went up near 5, it was shut down after that. The person I had here was Extra class so he did the test on 20m (not giving out his id though). With no tuner used it put out near nothing with full power applied, the red high swr led never turned on either. I realize I have a lot to learn since I have been out of the hobby a few years and I'm reading a lot so hopefully I get better at this. |
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eHam Forums / Antenna Restrictions / RE: Attic Dipole = Shack RF = GFI Issues And More
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on: September 21, 2012, 06:10:35 PM
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Like many hams, I live in a covenant-restricted "snooty" neighborhood, and like some, I have turned to my attic to hide my antennas. Of course, there are consequences - shack RF, among others. I keep my RF power output down as a result, and test as required. I discovered that on certain frequencies (20 & 40M) and at certain wattage outputs (when I kick my low power linear on), there can be enough RF crawling through the wiring to trip my GFI's. I was popping my XYL's whirlpool tub GFI in my main panel, and popping my kitchen and bathroom outlet GFI's. Research indicated that this is especially likely in homes built before 2004. After that year, electrical standards changed and GFI's were built to be better insulated from RF. After upgrading my 1998 GFI's to modern versions, no more problem. I hope this helps other newbies in the same situation.
I'm causing my expensive LCD TV to reset and my computer monitors to start beeping, I'm keeping output to around 100 watts now but need to get my antennas outside some how as well... should be fun! |
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eHam Forums / Computers And Software / RE: Someone Thought This Was A Good Idea...
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on: September 21, 2012, 05:34:44 PM
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It's probably better than my new Dell desktop or my new Dell laptop but even a good old Tmex Sinclair would beat any Dell anyday.
Oh I dunno, I'd agree I wouldn't buy any of their consumer gear but the Precision series is one of the best company made computers I have ever used outside what I build. Been running 4 years almost 24x7 and is stable, fast and still going! |
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eHam Forums / Elmers / RE: RF in the shack
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on: September 21, 2012, 05:05:51 PM
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I did forget to mention this is also a different 20m dipole, I gave the Radiowavs 20m dipole with 1:1 Balun away with the Icom, this new dipole uses the same RG8X feedline but I'm now using a different 20meter dipole with 1:1 Balun. I am looking into getting an MFJ 269 analyzer as well to check things out.
I'm going to go for the General soon so I can get onto more bands and do some real testing of this rig and antenna set up.
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eHam Forums / Elmers / RF in the shack
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on: September 21, 2012, 11:29:44 AM
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While testing my Yaesu FT-1000MP Mark V on 10 meters it killed my Samsung 8000 (the power led was flashing and the screen all screwed up) TV forcing me to turn it off and back on to straighten it out and it also caused 2 of my computer monitors to blank out so they had to be shut down and turned back on.
I realize whats causing it but not sure what I can do about it. If I cut back power to 100 watts or elss there doesn't seem to be a problem but going above 100 there is. SWR is fine. The antenna is in the attic and the coax runs up the middle of the house to the attic for now until I can get the antenna outside.
I'm a newb as well, I got my ticket in 2008 but was not active between late 2008 through AUgust of 2012 due to family illness. I have to study the antenna book and get back in the saddle fully. I see people showing pictures of their shacks with mugh higher power and I have to ask myself if it's because the antenna being in the attic or the coax running through the house, or heck both.
My Icom 746Pro never had this issue but then it was 100 watts...
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