Topband: Topband Most-Wanted Suirvey
This is a reminder to presumably the most-dedicated of topband DXers---those on this list--- that there is an active new Topband Most-Wanted Survey that needs the participation of all serious topband DX-chasers. The survey is at _TopBand2011.hamdocs.com_. All 340 current DXCC counters are listed; all that is required is to check the ones you consider as needed. Normally this means you have either not worked or not confirmed the counter on 160m. So far, the heaviest response --unsurprisingly-- has been from North America, with Europe a distant second. We need more participation to ensure that the survey will accurately reflect the needs of all serious and not-so-serious topband DXers. Therefore, submissions from EU and JA, as well as SA and VK/ZL are specifically solicited. Also, if you know of lists/sites in EU/JA/VK/ZL that are relevant, please send them along to me, or forward this email to them. With the close of the winter season in the Northern Hemisphere, completing this survey just might have a positive effect on your DXCC totals for next season. If you have not yet submitted, please go to _TopBand2011.hamdocs.com_ at your earliest convenience. Right now would be optimal. And repeat announcements in the relevant newsletters and topband-specific sites would also be helpful. End of drum-beating--for now. Results will be published in late summer. 73 Garry, NI6T ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Asymmetric radials for GP antennas; Just in case others seek what I've just found...
Cormac other Topbanders, In the new June 2011 issue of QST, page 42 there is an article about a vertical with only two radials on one side of a vertical radiator, and the directivity one gets by having losses in other directions with a very limited radial field or ground plane. If you can model your situation, you can get a pattern that will tell you about your compromise of having good radials only over 180 degrees. One of the W1-land DXers said he did very well with a good set of radials over 180 degrees and very little on the other 180 degrees due to site constraints. One of the W8's has a vertical near his house and has put radials across the ceiling of his cellar to fill in the ground plane. I did that at my first QTH as well, with elevated radials across the ceiling joists of a one-story house that seemed to work OK for me with random length elevated radials anywhere from 50 to 100 feet long behind the house to the trees and fencing at the perimeter of the lot. I have heard of others running radials through crawl space where there a house was built with no cellar and raised maybe 3 feet above ground level. Good luck, 73, George K8GG All, I've been searching for clarity and hard data on the effects of asymmetric radials on radiation patterns and efficiency of a vertical as I'm installing a 21m vertical for 80/160 and will have to live with a radial system that is significantly compromised over a 180 degree sector. I was a bit surprised to not find this subject dealt with in any clear decisive way in e.g. the ARRL Antenna Book or ON4UN's otherwise excellent Low Band DXing book (Did I miss it in either publication? If so, just send me a your an idiot email and I'll crawl back under my cabbage leaf suitably chastened). I was surprised as I had always assumed it is something many hams have to deal with unless they are prepared to go on stealth missions in the dead of night to lay radials on or under neighbours property (I don't recommend this course of action by the way; I attempted just such a thing once and got caught. As a mental exercise to occupy you during those quite times when calling CQ on a dead 160m, try explaining your way out of that one). On the basis that there might be one/some/many out there, who, like myself, are installing verticals with radial systems that are compromised directionally as well as length-ways, I just thought I'd share what I found; N6LF's excellent (if not exactly encouraging) summary of the consequences of asymmetrical radials at http://rudys.typepad.com/files/qex-ground-systems-part-7.pdf . It's well worth the read. I hope to hear you all on the far side of the Summer... -- Regards Cormac (EI4HQ) [Cork/UTC+1] http://86.43.106.118/ei4hq/ http://www.corkharbourweather.ie ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: The Dallas Files
Some of The Dallas Files containing most of the information about Top Band receive only antennas is currently available at http://groups.yahoo.com/group/thedallasfiles/ 73, Dallas ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Asymmetric radials for GP antennas; Just in case others seek what I've just found...
Christman has written a number of excellent articles on this subject. Some of which are in the ARRL book Vertical Antenna Classics. FWIW, I have been using a base loaded 60 foot vertical on my urban lot in San Jose, CA for the past 6 years. The base of the vertical is elevated about 3 feet and uses 12 elevated radials on 160 and 4 on 80. Since the vertical is located very near one side of our 12,000 sq. ft lot, and right next to the house, most of the radials are on the roof and cover less than 180 degrees of the compass (more like 120 degrees). From what I have read on the subject, there is some directivity in the direction of the radials, and a loss of signal strength in those directions with no radials. I have been able to work all over the globe, in every direction, including the Pacific and Europe where there are no radials. I often get excellent signal reports from Asia (my most compromised direction). While the signal reports would be better if I had radials in those directions, I have learned that those of us with constraints must simply do the best we can and work within our limitations. Beyond that, we get on the air and have fun. My advice to all those similarly situated is do not be discouraged! Make the best of your situation, and then don't worry about your limitations (this is not directed to Cormac, as I understand his post was an observation about what information is available on this subject of asymmetrical radial systems). Too all others who might be considering 160, do not let the compromises which must be made prevent you from getting on the air and enjoying 160. Good (and very good) success can be had from a small urban lot - even with major compromises in antennas and ground systems. The signals won't be as strong as they would in an optimal antenna system, but don't let the fact you can't do what's best prevent you from doing the best you can! Good luck and 73, Bob/AA6VB Cormac Gebruers wrote: I've been searching for clarity and hard data on the effects of asymmetric radials on radiation patterns and efficiency of a vertical as I'm installing a 21m vertical for 80/160 and will have to live with a radial system that is significantly compromised over a 180 degree sector. I was a bit surprised to not find this subject dealt with in any clear decisive way in e.g. the ARRL Antenna Book or ON4UN's otherwise excellent Low Band DXing book (Did I miss it in either publication? If so, just send me a your an idiot email and I'll crawl back under my cabbage leaf suitably chastened). ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
