Gentleman,
Happy New Year. I want to take this time to let everyone know that my efforts to install a Beverage have met with success and thank all those who took the time to aid in my efforts. One person in particular John G3PQA spent a large amount of time working with me via email. His efforts wont soon be forgotten. Now for what I found. In the way of a refresher the antenna I installed is a two wire 490ft long system. I used the canned transformers described by ON4UN but it didnt seem to perform correctly nor did the SWR flatten out. After some measurements I decided that the Receiver end transformers were working and matching fine but that it was the termination transformer that was outta wack. With this in mind I constructed a special transformer. It was the one similar to the one described by ON4UN but had taps on the ground end of the secondary. I connected the ground to the taps in turn until the SWR flattened out. Why did this happen.. Heck I dont know but I suspect that it had to do with the ground resistance. It could be that my ground was either lower or higher than normal. My money is on higher and at one time I considered adding extra ground rods but unfortunately there are way to many tree roots to bury connecting wires and leaving it on the ground would have been a hazard to the deer. Anyhow it works great now.. Tomorrow I will run the second cable out to the receiver end so that I have boths directions for direct comparison and front to back measurements. This is what makes this list great. Thanks Tree for your efforts and to those who help with oppinions, technial knowlege and encouragement. Again many thanks.. Jim WA3MEJ ----- Original Message ----- From: [email protected] To: [email protected] Sent: Tuesday, December 27, 2011 3:01:09 PM Subject: Topband Digest, Vol 108, Issue 79 Send Topband mailing list submissions to [email protected] To subscribe or unsubscribe via the World Wide Web, visit http://lists.contesting.com/mailman/listinfo/topband or, via email, send a message with subject or body 'help' to [email protected] You can reach the person managing the list at [email protected] When replying, please edit your Subject line so it is more specific than "Re: Contents of Topband digest..." Today's Topics: 1. Re: K2AV 160m Folded Counterpoise Antenna (Charles Moizeau) 2. Update Information Sought: "Topband Bad Frequencies" OpAid (Jeff Maass) ---------------------------------------------------------------------- Message: 1 Date: Tue, 27 Dec 2011 00:31:49 -0500 From: Charles Moizeau <[email protected]> Subject: Re: Topband: K2AV 160m Folded Counterpoise Antenna To: Topband <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset="Windows-1252" I should like to offer comments on and some alternative recommendations for the described construction of the 66-foot long FCP. It has already been pointed out that the commercially manufactured ?450-Ohm open-wire line? is not suitable for the counterpoise. That is indeed true. A yardstick will quickly show that with less space for ?windows? than ?panes? that black stuff measures 58 percent closed. Hardly ?open-wire?! The surge impedance is around 390 Ohms dry and less when wet. ?Nuff said. I homebrew my open-wire feedlines, using #14-gauge solid copper wire, either enameled, or bare wire that is roughened and then painted gray. Spaced 2?, the surge impedance is very close to 500 Ohms. I use solid copper wire, not copper-clad steel. First because my feedlines are not under mechanical stress and therefore steel?s greater strength is unnecessary. Second, and importantly, because one antenna when used on multiple bands will almost certainly have standing waves on its feedline, and it has been my experience that, with standing waves present, the feedline suffers permeability losses if itsr conductors contain iron or steel. In fact, I have also experienced permeability losses when using steel or steel-cored conductors in matching stubs. And I would expect similar losses in any impedance transforming device, balun, transformer, etc. Please spare me any lectures about skin effect and how the rf just whizzes along without attenuation. Let me assure you that when an rf conductor, albeit with its unquestioned skin effect, is in intimate contact with another substance it WILL BE affected. For example, it is perhaps not widely known that the intimate contact between pvc insulation and house wire will change the velocity factor of a single conductor (although to a much lesser extent than does the insulation of a coaxial cable). And just as with a conductor?s insulation,"intimate contact? certainly prevails between a conductor's surface and its core. Therefore, in your FCP use solid copper wire, bare or enamel-insulated, not stranded (which has higher losses because over time an outdoor environment will change the Ohmic relationship of the individual strands to one another, and thereby may also intensify the inductive effect of the spiraled strands). By all means avoid copper-clad steel. 14-gauge wire is perfectly adequate; the extra expense of 12 gauge is not warranted, nor is the extra weight desirable. One does not need spreaders made out of small diameter pvc tubing with end caps and weep holes. The weight, bulk and expense of such spreaders is not justified. I have read, but not verified, that bamboo has a more favorable strength-to-weight ratio than steel. Regardless, it is wonderful stuff for making open-wire spreaders. At an Asian food market I bought 200 bamboo chopsticks for five dollars. Snooping around I?ve found bamboo skewers in various lengths and diameters for very little money. For 14-gauge wire I use bamboo skewers that are about 3/16? diameter. I look over the chopsticks or skewers and discard the misfits, about 10-15 percent of the lot. Here?s how I make my spreaders for the 500-ohm feedline mentioned above: I measure 2.5? lengths. At the cut marks I use a compact tubing cutter to scribe a groove all the way around the skewer. I cut with a fine tooth hand saw. Using a divider set to 0.25? I make a prick mark at that distance from each end. I use a naked hacksaw blade to cut a slot to a depth of 0.25? in one end of the spreader. Placing a piece of cardboard in that slot, and with the spreader in a bench vise, I visually align my hacksaw blade at the spreader?s other end with the cardboard, and again cut to a depth of 0.25?. In this way I achieve a spreader with two parallel slits. At the base of each slit, I use a #50 drill bit secured in a pin vise to make a circular hole through the sawn slit. I then widen only the slit using a couple of naked hacksaw blades taped together and/or a small file. The slit should be just wide enough to tightly pass the 14-gauge wire and the hole should grip it tightly when the slit ends of the spreader are pinched together. Spreaders are baked in a <180 degree oven for 24 hours, and while still warm dipped in diluted gray exterior latex paint. I stretch the two parallel 14-gauge wire conductors between two trees. For bare wires, I rough up their surface by running a piece of coarse sandpaper along them. The Eastwood Company also sells an acid etch that would probably do the same thing. I paint the bare wires with the same gray paint used on the spreaders. Then I snap the spreaders on to the wires and adjust their spacing, which can be anything between 9 and 15 inches. I secure the spreaders using 50-lb. test Dacron kite line with a constrictor knot at each spreader?s tip. Another technique is hot glue applied with a gun and then pinching the spreader tips with spring clamps while the glue sets. After the spreaders have been fastened, I paint them thoroughly with gray latex paint. If you wish to have the described 4? spacing for the 160m folded counterpoise, you should start with 4.5? long bamboo skewers. 73, Charles, W2SH ------------------------------ Message: 2 Date: Tue, 27 Dec 2011 09:07:11 -0500 From: "Jeff Maass" <[email protected]> Subject: Topband: Update Information Sought: "Topband Bad Frequencies" OpAid To: "Topband Mailing List" <[email protected]> Message-ID: <004201ccc4a0$d51757b0$7f460710$@com> Content-Type: text/plain; charset="us-ascii" Topbanders: Seeking the collective experiences from you. Some years ago, I assembled an OpAid for myself providing guidance in selecting operating frequencies on 160 meters. In building it, I asked (on this Reflector and others) for input on bad frequencies in various areas of the World, and general band usages. Eventually, it was published online. It's been revised a few times with input sought again on Reflectors, the last time three years ago. It has been suggested to me that it is time to update this "Topband Bad Frequencies" OpAid once again. You can review the current version at: http://www.k8nd.com/Radio/Planning/CQWW160/TopbandBadFreqs.pdf Please look it over, and provide me with corrections/enhancements. The "Bad Frequencies" should be those affecting others over a large area, not your neighborhood-generated noise. Broadcasts, beacons, birdies, and other band noises that make a frequency difficult or impossible to use should be included in your report. The band allocations notes are broadly general: there are many exceptions, and there may have been some changes. Please provide corrections to these if something is incorrect that might affect operating decisions on the band. And while there is no formal "DX Window" recognized any more, I leave it noted as many still respect the 1830-1835 range as a reserve for working stations in other continents. You may send your corrections/comments to me directly. I may seek confirmations here on the Reflectors once I accumulate some changes. Thanks! 73, Jeff K8ND ------------------------------ _______________________________________________ Topband mailing list [email protected] http://lists.contesting.com/mailman/listinfo/topband End of Topband Digest, Vol 108, Issue 79 **************************************** _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
