Topband: Fw: T vert feed
- Original Message - From: "Brian Mattson" To: "Guy Olinger K2AV" Sent: Monday, January 30, 2012 9:22 PM Subject: Re: Topband: T vert feed > Let me see if I have this right. With an unfortunate length of coax (half > wave or multiple thereof), the house ground rod appears as a 1.7 ohm > impedance at the base of the antenna feed. Why not avoid the tuned coax > complication and put a ground rod right at the vertical feed point. With a > 1/4 wave vertical at 36 ohms and a 1.7 ohm ground rod, efficiency is > better than 95%! I'm impressedand who said a ground rod isn't much > good for verticals? Just think, you can pull up all those radials & sell > them for scrap copper... > > Brian K8BHZ > > - Original Message - > From: "Guy Olinger K2AV" > To: "Roy" > Cc: > Sent: Monday, January 30, 2012 5:32 PM > Subject: Re: Topband: T vert feed > > >> Oh, yeah. It will. If you are unlucky and it is presenting a current >> node >> at the antenna connection. All the MORE likely if you have a really good >> ground at the house entry point. Get used to it. Each little wire >> running >> off from the center is a **DRIVEN** element in the system, and if the >> coax >> shield is not blocked, the coax shield is an element DRIVEN with power >> from >> the base of the antenna. >> >> It can be that low, it's insulated, it has a very large surface, and >> because there are miscellaneous distributed and specific terminations at >> the other end, you CAN very definitely have current nodes if it's driven >> with power at the antenna end. That is where you can get VERY low >> effective series resistances. Maybe you particularly will, maybe you >> won't, with your SPECIFIC piece of coax and routing, grounding, yada, >> yada. >> But the warning of the 50/50 possibility has to remain. I'm really quite >> sure some of you out there ARE lucky in this very miscellaneous regard. >> Carry on. Enjoy life. Kiss a pretty woman. Work rare DX. As for the >> REST of you. >> >> The trick is to remember that without a block you are driving that shield >> with counterpoise power, the same as each one of the radials >> individually. >> >> 73, Guy. >> >> On Mon, Jan 30, 2012 at 1:53 PM, Roy wrote: >> >>> This is the part I'm objecting to: >>> >>> "the coax will carry HALF >>> the counterpoise current and waste most of that power, besides being a >>> link...(etc.)" >>> >>> No, no, nertz. Where did that notion originate? >>> >>> Roy K6XK >>> >>> >>> >>> ___ >>> UR RST IS ... ... ..9 QSB QSB - hw? BK >>> >> ___ >> UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: T vert feed (Roy)
Roy, you said: <"Whaaat??? Where did that 1.7 ohm figure come fromspace?"> Three cheers for you!!! And for Jeff! I was beginning to think that everyone was joining in a conspiracy of silence so that if a lot of people would buy into the baseless prattle that has been going on for months, there would be less QRM on the band. If we can get lots more stations to replace their radials with a folded counterpoise, for instance, the level of competition will drop off significantly. For such a high degree of pontification to exist, one would expect the pontificators to have some understanding of how an antenna works. There has been little indication of that during this latest thread of nattering. My advice to myself is follow a couple simple precepts. First, only take financial advice from rich people. Second, only take antenna advice from people with very loud signals. One of my friends always reminds me "Do not argue with an idiot... he will drag you down to his level and beat you with experience." 73, Barry ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: T vert feed
-Original Message- From: topband-boun...@contesting.com [mailto:topband-boun...@contesting.com] On Behalf Of Roy Sent: Monday, January 30, 2012 1:53 PM To: topband@contesting.com Subject: Re: Topband: T vert feed >This is the part I'm objecting to: >"the coax will carry HALF >the counterpoise current and waste most of that power, besides being a link...(etc.)" >No, no, nertz. Where did that notion originate? When I read your message I keyed on this, >> Where did that 1.7 ohm figure come fromspace? This led me to believe that you were wondering where the 1.7 ohm figure came from. :-) 73..de John/K4WJ ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: pace...@aol.com Subject: understanding 160 meter propagation
It sounds like classic "spotlight propagation," Larry. Happens a lot on 160. I feel lucky to have experienced it several times over the last 58 years on topband. The most memorable one for me occurred about 8 years ago on a Saturday evening. I called CQDX about sunset and didn't expect much because the usual early spots by East Coasters were not showing up on the "Summit." Several Russian and eastern European stations answered me. Reports were 579 to 599 both ways. It continued until sunrise in the British Isles as I worked my way across the continent. By that time reports were more like 449 to 569. I worked about 100 stations. I hardly heard any stations east of the Mississippi work any EU that night. On Sunday morning I had an eMail from John, ON4UN asking me what I was running last night because the only strong stations he was hearing was me and K9DX. Well, for me it was a spotlight propagation burst... for John, K9DX it was that fantastic layout he had. I was running an OMNI 6+ and a TenTec Hercules solid state amp at 500 watts into a 520' horizontal loop at 50'. Boy, was that fun! 73, Barry ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: T vert feed
Oh, yeah. It will. If you are unlucky and it is presenting a current node at the antenna connection. All the MORE likely if you have a really good ground at the house entry point. Get used to it. Each little wire running off from the center is a **DRIVEN** element in the system, and if the coax shield is not blocked, the coax shield is an element DRIVEN with power from the base of the antenna. It can be that low, it's insulated, it has a very large surface, and because there are miscellaneous distributed and specific terminations at the other end, you CAN very definitely have current nodes if it's driven with power at the antenna end. That is where you can get VERY low effective series resistances. Maybe you particularly will, maybe you won't, with your SPECIFIC piece of coax and routing, grounding, yada, yada. But the warning of the 50/50 possibility has to remain. I'm really quite sure some of you out there ARE lucky in this very miscellaneous regard. Carry on. Enjoy life. Kiss a pretty woman. Work rare DX. As for the REST of you. The trick is to remember that without a block you are driving that shield with counterpoise power, the same as each one of the radials individually. 73, Guy. On Mon, Jan 30, 2012 at 1:53 PM, Roy wrote: > This is the part I'm objecting to: > > "the coax will carry HALF > the counterpoise current and waste most of that power, besides being a > link...(etc.)" > > No, no, nertz. Where did that notion originate? > > Roy K6XK > > > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: T vert feed
This is the part I'm objecting to: "the coax will carry HALF the counterpoise current and waste most of that power, besides being a link...(etc.)" No, no, nertz. Where did that notion originate? Roy K6XK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: T vert feed
Would not each one remain 100 ohms? If the analysis is correct, they are in parallel and that does not add linearly based on the individual wire values as would a series connection. 73/jeff/ac0c www.ac0c.com alpha-charlie-zero-charlie -Original Message- From: Charles Moizeau Sent: Monday, January 30, 2012 12:37 PM To: royan...@ncn.net ; Topband Subject: Re: Topband: T vert feed Nope. With 100 Ohms per radial and 60 of them all the same and in parallel with each other, one gets 1.6 Ohms; close enough. 73, Charles, W2SH > From: royan...@ncn.net > To: topband@contesting.com > Date: Mon, 30 Jan 2012 12:15:10 -0600 > Subject: Re: Topband: T vert feed > > 'Twas stated: > > "Feedline coax shield 1.7 ohms. > > The single 1.7 ohms lowers the voltage and even in this case of what > appears to be an excellent ground radials system, the coax will carry HALF > the counterpoise current and waste most of that power, besides being a > link...(etc.)" > > > Whaaat??? > > Where did that 1.7 ohm figure come fromspace? > > The size (gauge) of radial wires has very little effect on their > effectiveness as radials, according everything I've ever read. Also, > effective resistance to ground, due to such intimate coupling to earth > when > radials are at the surface or buried, evens out their equivalent > resistances > and reactances, rendering them "un-tuned." Not comparable to elevated > radials at all. Voltage and current nodes on surface or buried radials > are > smoothed and averaged out rendering them un-problematic. > > If no balun, including a choke-type, is used at the feedpoint of a > vertical > then the coax braid simply counts as another radial, averaged in with the > many. Ferrites at the shack end can attenuate any residual RF on the braid > if it is troublesome there (unlikely). > > 73, Roy K6XKIowa > > > > > > > > > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: T vert feed
Nope. With 100 Ohms per radial and 60 of them all the same and in parallel with each other, one gets 1.6 Ohms; close enough. 73, Charles, W2SH > From: royan...@ncn.net > To: topband@contesting.com > Date: Mon, 30 Jan 2012 12:15:10 -0600 > Subject: Re: Topband: T vert feed > > 'Twas stated: > > "Feedline coax shield 1.7 ohms. > > The single 1.7 ohms lowers the voltage and even in this case of what > appears to be an excellent ground radials system, the coax will carry HALF > the counterpoise current and waste most of that power, besides being a > link...(etc.)" > > > Whaaat??? > > Where did that 1.7 ohm figure come fromspace? > > The size (gauge) of radial wires has very little effect on their > effectiveness as radials, according everything I've ever read. Also, > effective resistance to ground, due to such intimate coupling to earth when > radials are at the surface or buried, evens out their equivalent resistances > and reactances, rendering them "un-tuned." Not comparable to elevated > radials at all. Voltage and current nodes on surface or buried radials are > smoothed and averaged out rendering them un-problematic. > > If no balun, including a choke-type, is used at the feedpoint of a vertical > then the coax braid simply counts as another radial, averaged in with the > many. Ferrites at the shack end can attenuate any residual RF on the braid > if it is troublesome there (unlikely). > > 73, Roy K6XKIowa > > > > > > > > > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: T vert feed
'Twas stated: "Feedline coax shield 1.7 ohms. The single 1.7 ohms lowers the voltage and even in this case of what appears to be an excellent ground radials system, the coax will carry HALF the counterpoise current and waste most of that power, besides being a link...(etc.)" Whaaat??? Where did that 1.7 ohm figure come fromspace? The size (gauge) of radial wires has very little effect on their effectiveness as radials, according everything I've ever read. Also, effective resistance to ground, due to such intimate coupling to earth when radials are at the surface or buried, evens out their equivalent resistances and reactances, rendering them "un-tuned." Not comparable to elevated radials at all. Voltage and current nodes on surface or buried radials are smoothed and averaged out rendering them un-problematic. If no balun, including a choke-type, is used at the feedpoint of a vertical then the coax braid simply counts as another radial, averaged in with the many. Ferrites at the shack end can attenuate any residual RF on the braid if it is troublesome there (unlikely). 73, Roy K6XKIowa ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Solar Activity & Topband
On 1/28/2012 11:07 AM, Eddy Swynar wrote: > Hi Guys, > > I'm hearing of all kinds of disruptions& negative effects that the recent > outbreak on ol' Sol's visage has been having upon the higher bands... > > Yet, conditions for transcontinental QSOs here during this weekend's ongoing > running of the CQ 160 WW test have been very good...so far, anyway. > > And the level of activity seems to be considerably "up", too... > > ~73~ de Eddy VE3CUI - VE3XZ > My experience here in way Western MA was Friday had very few Europeans being heard. I did hear more South Americans than normal. Saturday there was a huge increase in European stations being heard and worked. My 2 cents. 73, Tom, W1TO ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
