As for ESD....Someone here suggested going barefooted. I've verified this. It works. Socks are not allowed! This also lets you run "barefoot" while running the amp. Replacing carpet with wood flooring helps too but a bit more expensive.
Your RFI problems sound like common mode current on your feeder. I would try changing the length. My final solution here was to put the MFJ-998 1.5kw auto tuner out at the antenna "130' inverted L" and run coax into the house. Steve N4LQ ----- Original Message ----- From: "Jerry T. Dowell" <a...@sbcglobal.net> To: "'callen1155'" <callen1...@yahoo.com>; <elecraft@mailman.qth.net> Sent: Thursday, February 25, 2010 12:58 PM Subject: Re: [Elecraft] K3/100 -Second floor- no RF ground ?? > Chuck, > > I operate a K3/100 from a 2nd story shack and have significant RF ground > problems. I do have a good powerline ground, but that is irrelevant. My > antenna is a 100 ft sloper, centerfed with over 100 ft of 450 ohm window > line (perpendicular to the antenna for 75 ft). It will "load up" on all > bands 160M through 6M, with varying degrees of effectiveness. I cannot run > my amplifier (Alpha 78) at more than 200-300 watts on most bands without > significant RF problems, including tripping GFIs. I intend to try to > alleviate the problems with a tuned ground, using a series-tuned resonant > circuit in a counterpoise system hanging out the window, an arrangement > similar to the MFJ 931. (If you look inside one of those, you will see > that > it is very cheaply made. You can do much better with your own coil, > capacitor, and RF ammeter.) By the way, I can operate the K3/100 barefoot > without apparent adverse effects due to the bad RF grounding. > > Another issue only distantly related to grounding is that the K3, like the > K2, is extremely susceptible to ESD strikes. That is a huge problem for me > in the dry, high desert of Nevada. You cannot touch anything here without > drawing a significant spark, any time of year. I quickly caused expensive > major damage (destruction of firmware, etc) to my K2/100 by touching it, > even though it was carefully grounded to power system ground. The K3 is > upset by such strikes also. I try to avoid damage by using an operating > table with conductive paint (Walmart) and a good (DC) ground system, so > that > I can continuously discharge myself before and while operating. The reason > for the ESD susceptibility of the K3 and K2 is flawed shielding design and > (apparently) lack of ESD mitigation in the circuitry/layout. > > Jerry AI6L > > -----Original Message----- > From: callen1155 [mailto:callen1...@yahoo.com] > Sent: Wednesday, February 24, 2010 2:19 PM > To: elecraft@mailman.qth.net > Subject: [Elecraft] K3/100 -Second floor- no RF ground ?? > > > > Hello guys, > > I'm planning on purchasing a K3/100 but am concerned about my second floor > shack and RF problems. > > First of all: > 1) I don't have an RF ground (don't really want to drill thru the house > and > siding for the ground strap) and > > 2) my antenna is a semi-indoor/attic dipole (HOA). > I'm running a coax from the second floor radio to the attic where i attach > to a dipole (no balun) and the dipole runs the length of the house each > way > and out the eaves where both wires run out about 35 yards to the trees. > > I'm using my K2/15 and don't have problems but previously with my old Knwd > TS 830 at about 100 watts the vibroplex bug would 'bite' me. I'd also get > some RFI on the TV (didn't try any filters to prevent it). > > I know both of the above arrangements are potential sources for RF > problems. > What I don't know is whether RF problems (both the 'burn' and RFI) are > radio > related; i.e. are some radios more prone cause issues and how is the > K3/100 > in this regard as compared to the TS 830? (this may be a non-question-- i > just don't have enough experience with different radios to know). > > So I'm wonder if any of you operate a K3/100 from a second floor shack, > with > no RF ground, (guess it's too much to ask about a semi-indoor antenna) and > if you're experiencing RF problems? > > Also, if I experience RF problems with the K3 do any you have any > experience > with an "Artificial RF Ground" such as the MFJ-931? > > Sorry about being long winded. > > Hope I'm not 'destined' to order a K3/10 instead. > > thanks again. > chuck > af4xk > -- > View this message in context: > http://n2.nabble.com/K3-100-Second-floor-no-RF-ground-tp4628979p4628979.html > Sent from the [K3] mailing list archive at Nabble.com. > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html -------------------------------------------------------------------------------- No virus found in this incoming message. 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