Date: Mon, 24 Oct 94 04:30:15 PDT From: Ham-Ant Mailing List and Newsgroup Errors-To: Ham-Ant-Errors@UCSD.Edu Reply-To: Ham-Ant@UCSD.Edu Precedence: List Subject: Ham-Ant Digest V94 #354 To: Ham-Ant Ham-Ant Digest Mon, 24 Oct 94 Volume 94 : Issue 354 Today's Topics: ### Advice needed for loss in BNC<->SO-239 connector Beverage antennas (3 msgs) Elnec Antenna Program Send Replies or notes for publication to: Send subscription requests to: Problems you can't solve otherwise to brian@ucsd.edu. Archives of past issues of the Ham-Ant Digest are available (by FTP only) from UCSD.Edu in directory "mailarchives/ham-ant". We trust that readers are intelligent enough to realize that all text herein consists of personal comments and does not represent the official policies or positions of any party. Your mileage may vary. So there. ---------------------------------------------------------------------- Date: 20 Oct 1994 16:12:52 GMT From: s2202629@np.ac.sg (Teh Aik Wen) Subject: ### Advice needed for loss in BNC<->SO-239 connector I'm at present trying to homebrew an antenna. It's the first time I'm doing it, and parts aren't exactly the easiest for me to find, especially since I'm not very sure what I'm looking for. (Yes, I'm very new, and I don't have a xceiver or anything for that matter). Whats the antenna for? Thats a different story altogether. Anyway, I've been trying to make this antenna featured in Sept'94 CQ. (Anyone else doing it/has done it, care to email me?). I didn't read it carefully enough, and bought a BNC connector instead of a SO-239 for the antenna. Not difficult I thought, just go look for a 'single-hole, rear-mount SO-239 socket'. But I didn't seem very successful in finding it. What I did find however was a connector that was a BNC to SO-239. I was wondering, how much 'losses' would I face if I went ahead and used the BNC, followed by this connector? Reason why I want to do this is because I'm having difficulity in finding the SO-239 (single hole, rear mount). Just a note, the 'other side' of the SO-239 socket was supposed to be a lenght of RG-58/U that is some 2" and then connected directly to the twin lead (that makes up the antenna). Thanks. ------------------------------ Date: 19 Oct 94 22:29:42 From: Dave.Headland@f725.n635.z3.fidonet.org (Dave Headland) Subject: Beverage antennas Has anyone come up with a convenient way of remotely varying the resistance of the termination to earth from the far end of a beverage antenna, from the receiver end? I've been playing with an idea of using photocells, controlled by LEDs, but have come up with a problem of too much resistance in the antenna wire. The beverages I've been using varying from around 750 metres to around 2000 metres in length. Using twin-flex cable the resistance is roughly 45 ohms per 250 metres, so at 2000 metres you have roughly 360 ohms - too much resistance for several (approx 5) LEDs to operate from a 12 volt battery. Resistance in antenna approx 360 ohms. o----------------/\/\/\/\/\/\/\----------------o-------o | | Receiver (& 12 << BEVERAGE ANTENNA >> LEDs Photocells volt battery) | | o----------------------------------------------o | ----- --- - Rather than use additional batteries to boost the voltage, I'm after a circuit that could perhaps take advantage of the high resistance and adjust the bias of a transistor (controlling the LEDs) at the terminated end. The 12 volt battery doesn't necessarily have to be at the receiver. Sooner or later I will be restricted to using single core cable for the antenna, and will need to control the LEDs with a return circuit through the ground back to the receiver. I am not sure what resistance this involves but I suspect several hundred k-ohms, if not meg-ohms. If anyone has overcome this problem I am interested to hear your comments. I've tried radio controlled servos controlling potentiometers, but without a great deal of success.... -- FidoNet: Dave Headland 3:635/725 Internet: Dave.Headland@f725.n635.z3.fidonet.org ------------------------------ Date: Sun, 23 Oct 1994 23:48:22 GMT From: jeffrey@kahuna.tmc.edu (Jeffrey Herman) Subject: Beverage antennas Dave.Headland@f725.n635.z3.fidonet.org (Dave Headland) writes: > The beverages I've been using varying from around 750 metres to around > 2000 metres in length. Using twin-flex cable the resistance is roughly What's their average height above ground, Dave? .73W, Jeff NH6IL ------------------------------ Date: 23 Oct 1994 23:50:01 -0400 From: jimkd0av@aol.com (JimKD0AV) Subject: Beverage antennas In article <321_9410221145@unique.pronet.com>, Dave.Headland@f725.n635.z3.fidonet.org (Dave Headland) writes: > The beverages I've been using varying from around 750 metres to around >2000 metres in length. Dave, you may want to consider shortening them as they become pretty inefficient after 3 wave lengths...i.e., 480 meters on 160. 'That would go along way in dropping ur resistance. 73, Jim KD0AV ------------------------------ Date: 22 Oct 1994 22:43:23 -0400 From: z004391b@bcfreenet.seflin.lib.fl.us (John W. Wilson) Subject: Elnec Antenna Program I have been using the ELNEC program since the Dayton Hamfest last year. I found it to be a well written program and an excellent tool for some antennae but has problems with Quads. The author admits this drawback but the program is worth the money anyway. I also have the ARRL MicroSmith program which accepts the ELNEC output. Together these programs can analyze and ultimately provide design information that would take time consuming experimentation otherwise. 73, John, KN4HX -- John W. Wilson z004391b@bcfreenet.seflin.lib.fl.us ------------------------------ End of Ham-Ant Digest V94 #354 ******************************