Heh, heh, I can see Frank there in the white suit holding a CO2 extinguisher at the ready now...
I also found balanced antennas superior in apartments for indoor antennas. I did occasionally use an end fed wire and never had any trouble, but I was careful to isolate the rig from the mains (a ferrite choke or two over the power lead does that) and use a 1/4 wave 'radial' or 'counterpoise' that held the rig at ground. Not only is that important to avoid RFI, it's critical for efficiency too. I was and remain convinced that when limited to a small antenna (a *physical* half wave or less) a balanced antenna is easier to make efficient. I say "physical" because while a short wire can be loaded to "look" longer electrically, it still suffers all the limitations of any physically-small antenna: very low feed impedances and relatively high currents. I used a small purpose-built link-coupled balanced ATU for my indoor doublets and they worked very well indeed. I managed to be on the top (second or third) floor in the buildings where I lived and that helped a lot! (We start counting floors with the first floor at ground level here in the USA). I don't know from experience about potential RFI problems with unbalanced antennas, but I am convinced that it's easier for me to keep RF under control with a balanced system, and easier to build a more efficient antenna. My love affair with doublets isn't just for apartments either. At my present QTH I have an outdoor doublet fed with true open wire line (two #12 conductors separated 3 inches by a limited number of high-quality insulators) that connects directly to a purpose built QRO balanced tuner sitting above my K2, runs through a header at the window directly behind the tuner and up the mast holding the center of the antenna. This tuner will handle a kilowatt under most conditions. There's a picture of my shack on QRZ.com with the tuner above the K2. The relative sizes of the units shows why more compact single-ended tuners are so popular, but in half a century of using doublet antennas I've not seen a singled-ended tuner/balun combination work efficiently with doublet across the HF spectrum. (Okay, give me some room, Frank. I'm putting my asbestos suit on. Got a spare extinguisher?) Ron AC7AC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
