Don’t know if its practical, but its a great experiment even if it only makes it to proof of concept. A project to create a mouseless mouse.
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Don’t know if its practical, but its a great experiment even if it only makes it to proof of concept. A project to create a mouseless mouse. The 160 Inverted-L is about 160 feet of wire. To get a good match there is a series capacitor in line with the wire. The bandwidth for any useful value of capacitance is about 40kc. The object is to use a set of relays to switch in or out additional capacitors. That will allow the antenna to be tunable across most of the band – from 1800kc to 1930kc. There is also a 1.5:1 unun at the feed point, followed by a coax cable choke. This lowers the SWR to a very nice 1.1:1 over the useful range. The rig is very happy at resonance, and a good match will be a dial click away. Currently the capacitance in the system gives a nice 1:1 SWR at 1825kc. Using the autotuners, either radio [K2, FT-920] can work from 1800 to 1875. The goal is to be able to turn off the tuners and feed the antenna directly. Maybe I’ll pick up a few extra QSO’s with a good match on the antenna end of the feedline. After several other projects using relays and the 3kv Panasonic capacitors for the band pass filters, enough extra parts are in the parts bin to make it happen. So, why wait? A handy nearby line previously shot into a nearby biological antenna support provides an opportunity for expansion. The line seems well placed to add an INV-L element for 80m. One additional relay for switching bands. Judicious choices for the capacitance values may allow […] Continue reading Inverted-L Matching Getting home from vacation a couple of weeks back, a huge branch was found in the rear area of the antenna farm. One ginormous limb had fallen from one of the white oaks holding the north-south 40 meter dipole. It was on the opposite side from that antenna, but must have crossed paths with the 80 meter folded dipole on the way down. The bad news is that the 80m antenna was on the ground, as well as six or eight radials from the nearby inverted L for 160m. The good news was that only the line holding the antenna itself had failed, and not the line over the branch, and the nearby 40m vee was not effected. On most of these hard to hit branches, the approach that usually works best is to use two lines for the center load-bearing supports. Once a pilot line is shot over a branch, a heavy line is run up and over to make a loop. At the joint in the heavy loop line, a pulley is attached. The actual antenna support line is then run through the “pulley”. Haul the pulley up to the desired height, paying out antenna support line as it goes up. Note: The “pulley” is usually just a simple welded steel ring, attached to the heavy loop with a swivel. Real pulleys often bind – never a problem with the simple steel rings, although the steel ring may cause the line to break more often. The swivel […] Continue reading Wind Damage To The Biological Antenna Support Structures Had fun again for Field Day with N4YDU. Always do. Even though it was miserably hot and humid this year. Operated this year under the NC Contesters call NR3X. We had a crew of ‘ringers’ on 40m CW. W0UCE, N3ND, and K2AV ran up a nice QSO count on 40Cw. Other operators were AA4XX, K4CZ, N4GU, N4YDU, and W4KAZ. With the extra operators on hand we operated class 3A. AA4XX and K4CZ were only available for the first few hours, so in the end we wound up with about seven or eight hours of idle time on two of the stations. Gotta sleep sometimes. With one station dedicated to 40m CW, the other bands/modes were spread between the other two stations. Station one was 40m ssb plus 10m/15m. The second station handled 80m CW and 20m CW, plus 20m SSB. A late afternoon thunder storm chased me out of the 20m CW shack for just over an hour at about 4:00pm local on 06/26. To hell with that! I like operating, but not enough to die for. Also had a couple of computer problems early on with the setup for the 20 CW station. Piddled away some time resolving those. (Problems: N1MM has a faux “Elecraft K2” radio option that does not work [MUST use “Kenwood”], and when the laptop went idle its power saver caused N1MM to hang up when using its function key macros [solution re-boot laptop. Better Solution: Use writeLog]) The 80m/20m CW station had dipoles for […] Continue reading Field Day 2010 as NR3X |
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