I have noticed several times that people talk about being able to put up a full .250 wavelength vertical and I have wondered why almost never do they think about making it .270 wavelength instead of .250 wavelength. The little extra length gives a feed point impedance of 52 ohms with some inductive reactance which can be canceled with a series capactor. This gives a more efficient feed than a .250 wavelength and using an inductor to get a match. I designed my 75/80m vertical this way and with 65 radials ( odd number 'cause that's all the wire I had) it has allowed me to work 280 entities with100 watts, all SSB. (Blasphemy I know, I have an ear condition which made 13 wpm almost impossible for me).
I also use this antenna on 160m by using linear loading and an inductor for matching. Linear loading seems to be overlooked in a lot of discussions of antennas on this list and I wonder why. Am I missing a downside to these matching systems? If so I would like to hear about it. Pat Armstrong KF5YZ Heart of Texas On Tue, Dec 20, 2016 at 12:00 PM, W0MU Mike Fatchett <[email protected]> wrote: > https://www.dxengineering.com/search/product-line/dx-enginee > ring-160-meter-thunderbolt-vertical-antennas?autoview= > SKU&keyword=160%20vertical&sortby=BestKeywordMatch&sortorder=Ascending > > > On 12/20/2016 10:24 AM, Petronel Postolache wrote: > >> I can't find the Vertical from DX Engineering. If you can send me a link >> it will be great. >> One solution might be top hat vertical, similar with >> http://dl2kq.de/ant/3-1.htm . Not sure how much power is lost in the >> matching unit L1, C1. >> >> I would love a Waller Flag too. Imposible to buy one from here (too >> expensive) but I might wanna try build one. Preamp will be the biggest >> problem. >> >> Petronel >> YO8SEP / YP8W >> >> On Mon, Dec 19, 2016 at 9:30 PM, W0MU Mike Fatchett <[email protected] >> <mailto:[email protected]>> wrote: >> >> Check out DX Engineering. They sell a vertical that uses 3 top >> hat wires. Sloping back down is ok. For 80/160 you need to stop >> the 80m energy with a coil/trap My 80 uses a very fast taper and >> the top is only 3/8 inch or less so It cannot support a coil or t >> wires. I probably should have planned that out better. I was >> also going to try to phase two 80 elements over time but that will >> not happen any time soon. >> >> With all the metal in the yard the AY loop may not work very >> well. Waller Flag on the roof maybe. I would love one. >> >> W0MU >> >> >> On 12/19/2016 12:24 PM, Petronel Postolache wrote: >> >>> I can try to put a 21-22m (68-70 foot) telescopic aluminium pole, >>> made from pipes 2" to 1" diameter. >>> It will be a bit too long for 1/4 on 80m. I can put a T top hat >>> or run an InvL, but probably need to slope it from 70 foot to >>> about 40 foot. What will be better ? and will I be able to >>> match/use the antenna on 80m also ? >>> >>> About K9AY, I understood that the loop is influenced by close >>> metal objects, and the property is full of wire fences, vineyard >>> rows and other "metal" structures. That's why i was thinking >>> about using some flag/loop at 10 feet or more above ground. >>> >>> 73, Petronel >>> YO8SEP >>> >>> 160 and 80 will be difficult. Can you get another vertical up >>> about 60 feet? You can top load that with a trap for 80 and have >>> "t" wires at the top that also act as guy wires. You can also >>> bottom load for 160 and maybe that will be good enough for you. >>> Radials whatever you can do will help.An Inverted L with about >>> 50ft of vertical will work ok....If you can keep the horizontal >>> end up in the air around the same height or more. It doesn't >>> sound like you have any tall trees to work with.For receiving I >>> have been very impressed with a K9AP loop. 25 ft up and about 15 >>> feet out at the corners. It does not take up much space and you >>> can reverse the direction easily with a relay. A flag or pennant >>> will work too. You can never have enough rcv or xmit antenna! HI! >>> Welcome to the club! >>> >>> W0MU >>> >>> >> >> > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
