Re: Topband: PL 259 for RG6
I've used lots of RG-6 over the years for transmitting. It handles full power fine, even through F connectors (got that tip years ago from KM1H) for various antennas 160-10m. Though most of mine is hard-wired. Mine wasn't new either -- most scrounged from dumpster at local CATV company in the '80s or picked up at flea markets. 73/Jon AA1K On 10/9/2011 8:15 PM, Mike Waters wrote: On Sat, Oct 8, 2011 at 3:40 PM, Jim Brownj...@audiosystemsgroup.com wrote: ... you should be using ONLY coax with a heavy copper braid shield for transmitting on the HF and MF bands. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: New list member intro
Hi, ..and thanks for including me on the Top Band reflector. My interest in electronics generally and ham radio in particular goes back to the 1950s although I didn't get my license until 1980. No elmers were available and life had other things taking too much of my energy for a lot of years. I did listen to the ham bands a lot and even home brewed some gear for it - just no transmitting. Now the farm is gone and with it the space for large antennas. I used to have a very large antenna for 80 meters way up in old growth trees and ran traffic but now my lot is 100 by 100 feet and no possibility of routing antennas beyond my own property line. At least there are no antenna covenants here! I have yet to transmit on the 160 meter band and the only thing holding me back is a suitable antenna. I have reviewed some information about the 160 meter band and I am encouraged for the most part. Before there were two meter FM repeaters everywhere the 160 meter was one of the bands used for mobile communication. Now antennas for mobile use are really *puny* on 160 meters! Hams still managed to communicate with very modest power levels in mobile operation. I suspect I can get on 160 and 80 meters with a combination of a helically wound mast and top, horizontal wire (along with the ground that I already have in place). Something like that should easily outperform any mobile antenna. I used a helically wound vertical on higher frequency HF bands in the 1970s and it worked well for me. Rhombics and such are just out of the question for me and now that I'm in retirement and rebuilding a compromised heart I won't be going back to those salad days. I will be doing antenna construction as an autumn project and with any luck I'll have my 160 and 80 meter bandswitches in use here. A modest 100 foot loop with a balanced line and a Johnson tuner is serving me well on 40 through 10 meters. I have a couple of receivers and a couple of transmitters that will get the job done as well as a transceiver that can give me QRP through ~100 watt operation including a Johnson Ranger and a Heath DX 100. The Atlas 180 will give me SSB as well as portable operation. I hope to join you on the air soon. 73, Bill KU8H ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Beverage Transformer?
Ive been using BN73-202 cores on 2 wire reversible Beverages in the 500-900' range. They work fine down to 150KHz with surprisingly good directivity on the LF BC stations as well as NDB's They are wound as isolated winding transformers with Teflon sleeving to minimize interwinding C which has resulted in excellent FB. I would think that similar attention to detail would help a single wire unidirectional Beverage also. Turns calculations were done with 500KHz and performance is good thru 30M. Even 20 shows directivity which is surprising considering the many wavelengths of wire but its lossy, likely not helped by a very poor 250 Ohm RF ground resistance on this hilltop rock pile. Carl KM1H - Original Message - From: Tracey Gardner tracey.gard...@talktalk.net To: topband@contesting.com Sent: Sunday, October 09, 2011 2:43 PM Subject: Topband: Beverage Transformer? I would be grateful for some advice on the type of transformer to use on a Beverage antenna that I am in the process of erecting. I have been reading the latest (5th edition) of ON4UN's Low Band DX'ing and, on Pages 7-67 and 7-68, he discusses the types of cores to be used and comes out strongly in favour of the binocular core type BN 73-202. He states that test results for transformers using toroidal cores with type 75 and 77 material turned out to be significantly inferior to what was obtained with the other two cores. Now my problem lies in the fact that I want to use the Beverage on 1.8MHz and down to 150kHz. I'm concerned that a transformer wound using the BN 73-202 core will not perform satisfactorily down to 150kHz. The comments that ON4UN makes about the use of type 75 material have me puzzled as there is an excellent, lengthy article by Bill Bowers, the late John Bryant and Nick Hall-Patch, VE7DXR which comes out clearly in favour of 75 type material for transformers for use between 100kHz and 7MHz. http://www.dxing.info/equipment/impedance_matching_bryant.doc I presume that I would have to significantly increase the number of turns on the binocular core in order to get it to perform down to 150kHz? Is my presumption correct? Many thanks Tracey G5VU ___ UR RST IS ... ... ..9 QSB QSB - hw? BK - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1410 / Virus Database: 1520/3943 - Release Date: 10/07/11 ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Phased Vertical Dipoles
Hello All, I am working on improving my TB ability this season. I have installed 2 sloping ½ wave dipoles. Is there anyone on this reflector that is using the Comtek ABC-4 with a phased pair of antennas that I might take advantage of there experience and ask them some pointed questions? Rich K7ZV rich_k...@gphilltop.com mailto:rich_k...@gphilltop.com ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: PL 259 for RG6
As per the VK1OD website chart RG-6 has less loss than anything else shown. Matches RG-213 at 1.8 Mhz the place we are all looking at. I can see where perhaps my twenty year old RG-6 could be improved upon by using the quad shielded variety perhaps. Maybe more help on receive than transmit by changing out the Coax over to the quad shielded type. Antenna system here is what you would call a K8UR version of a 4 square array. Each feedline is 3/4 wavelength electrical length of plain Garden Variety RG-6. It uses F connectors crimped at the Phasing Box end with adapters to PL-259 to get into the box. The box and all is inside an enclosure so weather isn't a consideration inside that box. The antenna end of these feedlines is just pigtailed out with added copper wire to the shield side. Connections to the antenna wires is done with Wire Nuts. I do put NoAlox inside the wire nuts before they are screwed onto the connections. I live in Northern Indiana in what is often referred to as The Black Hole I hold the first all 40 zones on 160 award issued from the USA. My present 160 meter dxcc total is 306. I too would nearly kill for an additional 1/4 dB of receive ability or transmit ability on 160. It seems to me that RG-6 is pretty good coax for our purposes. John k9uwa On 10/9/2011 3:33 PM, John K9UWA wrote: can you tell me why one would NOT want to use the common variety of a RG-6 that has a few strands of braid.. and foil + foam insulation and the usual single wire center for an Antenna on 160 meters? 1) LOSS. Significant if it's a long run for flimsy shields. Also, copper clad steel is pretty lossy on the lower bands as compared to solid copper or copper clad Aluminum. If you're only going 25 ft, it doesn't matter. 2) SHIELDING If you've got much RF noise around you, you could benefit from a much more robust shield that what's on the cable you describe, especially on an RX antenna. Shielding is strongly dependent on the resistance of the shield, and foil shields aren't worth much until you hit VHF. BTW -- one thing that can be less than wonderful about those crimps is the resistance (and reliability) of the shield connection. 3) Define almost nothing. :) I know guys (N6LF is one) who will go to extremes for less than half a dB when they're already maxed out on TX power and everything else in their system. I certainly agree that the loss in 25 ft of almost any coax on 160M doesn't matter. 73, Jim Brown K9YC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK John Goller, K9UWA Jean Goller, N9PXF Antique Radio Restorations k9...@arrl.net Visit our Web Site at: http://www.JohnJeanAntiqueRadio.com 4836 Ranch Road Leo, IN 46765 USA 1-260-637-6426 ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
