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G5RV
Looking to buy a G5RV for 80 and 40 mtrs and maybe able to tune other bands
lots of diff brands of this antenna can anyone suggest a manufacture or maybe another alternative thanx howard |
G5RV
On Thu, 25 Sep 2008 18:06:15 -0500, "Howard Kowall"
wrote: or maybe another alternative Hi Howard, Build a dipole, and with the money you save, invest in a tuner. 73's Richard Clark, KB7QHC |
G5RV
Howard Kowall wrote:
Looking to buy a G5RV for 80 and 40 mtrs and maybe able to tune other bands lots of diff brands of this antenna can anyone suggest a manufacture or maybe another alternative The G5RV is a 4-band antenna, 80m, 40m, 20m, and 12m. If you care about the other 4 bands, don't go with a G5RV. -- 73, Cecil http://www.w5dxp.com "According to the general theory of relativity, space without ether is unthinkable." Albert Einstein |
G5RV
yes i have built a dipole and it works good with the manual tuner
BUT now my new rig has a built in tuner and of course it wont tune it the dipole i built was cut for 3.747mhz and works great without a tuner but with the auto tuner it wont tune anyware but 80mtrs is there a magic number for a dipole to make it tunable on 80 and 40 thanx howard "Howard Kowall" wrote in message ... Looking to buy a G5RV for 80 and 40 mtrs and maybe able to tune other bands lots of diff brands of this antenna can anyone suggest a manufacture or maybe another alternative thanx howard |
G5RV
On Thu, 25 Sep 2008 18:33:11 -0500, "Howard Kowall"
wrote: yes i have built a dipole and it works good with the manual tuner BUT now my new rig has a built in tuner and of course it wont tune it the dipole i built was cut for 3.747mhz and works great without a tuner but with the auto tuner it wont tune anyware but 80mtrs is there a magic number for a dipole to make it tunable on 80 and 40 thanx howard Howard, Before you go sailing off into space on the GRV check this out. http://www.degendesigns.com/Downloads/TheEasyWay.PDF Danny, k6mhe |
G5RV
No magic numbers, sorry 'bout that. Try hanging a 40 meter dipole
from the same feed point as the 80 meter, fed with the same feed line. Tune/trim for use near the 40 meter frequency you want, then use that tuner. The same thing will work for any other band you want to add to it, and will certainly be better than a 'G5RV'. - 'Doc |
G5RV
Danny Richardson wrote:
... Howard, Before you go sailing off into space on the GRV check this out. http://www.degendesigns.com/Downloads/TheEasyWay.PDF Danny, k6mhe Now that paper is an odd mix of fact and fantasy ... first time I have ever seen that particular brand of obsfucation ... Regards, JS |
G5RV
On Sep 25, 7:06*pm, "Howard Kowall" wrote:
Looking to buy a G5RV for 80 and 40 mtrs and maybe able to tune other bands lots of diff brands of this antenna can anyone suggest a manufacture or maybe another alternative thanx howard I have found with my G5RV that I still need to 'tune' so that my transceiver doesn't throttle back in power due to approx. 3:1 SWR on 40/80/20 (and maybe 12). I can also tune 15, 17 and 10. However, as mentioned elsewhere, it is only good on 80/40/20/12. The SWR on 10 without a tuner is very high and 10 with a tuner is still unusable (also G5RV is ng for 17m). |
G5RV
"Howard Kowall" wrote in message ... yes i have built a dipole and it works good with the manual tuner BUT now my new rig has a built in tuner and of course it wont tune it the dipole i built was cut for 3.747mhz and works great without a tuner but with the auto tuner it wont tune anyware but 80mtrs is there a magic number for a dipole to make it tunable on 80 and 40 thanx howard I am the only one I know who is doing this, so it may be a risky practice: tandem tuners. I have an autotuner in my Kenwood TS-870 and I feed some antennas through an MFJ tuner set on "BYPASS," usually. If I encounter a situation where the internal autotuner balks, I flip the selector to the "TUNED" side and get it close by quickly and casually peaking the received noise (or sigs). Then I give the autotuner another crack at it and always seems to get a match. The coax runs are all short and I seem to be getting away with it. I am putting up more and better antennas ASAP, but there are still some freqs I can't cover properly, so I cover them improperly :-) |
G5RV
"John Smith" wrote in message ... Danny Richardson wrote: ... Howard, Before you go sailing off into space on the GRV check this out. http://www.degendesigns.com/Downloads/TheEasyWay.PDF Danny, k6mhe Now that paper is an odd mix of fact and fantasy ... first time I have ever seen that particular brand of obsfucation ... Regards, JS I had a hard time separating what he actually thought from what he was complaining about. I find that even if go to great pains to be extremely clear and eliminate all distractions from a document, and write for a 6th grade reading level, only 10% will actually get it. Some will cling to a word that has special meaning to them and go on a wild tangent and some will only get 3 or 4 words out of it, throw away the context and quote those words. |
G5RV
On Fri, 26 Sep 2008 15:16:47 GMT, "JB" wrote:
I had a hard time separating what he actually thought from what he was complaining about. I have yet to read what problem he's trying to solve. There has to be a reason for all that effort. I find that even if go to great pains to be extremely clear and eliminate all distractions from a document, and write for a 6th grade reading level, only 10% will actually get it. Some will cling to a word that has special meaning to them and go on a wild tangent and some will only get 3 or 4 words out of it, throw away the context and quote those words. I think a 10 year old level is more appropriate. It's roughly what TV shows try to target. Topic drift is a problem, but boilplate solutons are what drive the technical newgroups and mailing lists. Whenever someone asks a question, the vocal experts are usually first to misinterpret the question and provide their favorite boilerplate answer. In my case, it doesn't matter what antenna problem you're having, a computer model will provide the answer. Lots of other approaches (careful measurement, ignore VSWR and use a field strength meter, etc) that vary with the person providing the analysis and boilerplate. OF course, the answer never completely solves the original problem, so the discussion drifts off into optimizing the computer model, instead of fixing the antenna problem. My guess is about 3 back and forth postings and the original topic is lost. Kinda like this posting. Anyway, I've never used or built a G5RV, know nothing about the antenna type, and propose building a computer model of the antenna, supporting structure, and nearby buildings, that will solve any problem with a G5RV, including operating it on bands for which it was never designed. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
G5RV
On Thu, 25 Sep 2008 18:33:11 -0500, "Howard Kowall"
wrote: yes i have built a dipole and it works good with the manual tuner BUT now my new rig has a built in tuner and of course it wont tune it the dipole i built was cut for 3.747mhz and works great without a tuner but with the auto tuner it wont tune anyware but 80mtrs is there a magic number for a dipole to make it tunable on 80 and 40 A popular antennas over here in the UK is a centre fed doublet, 80 to 100 Foot top with 450 ladder line feeder into your ATU. You will need a balun near the shack end if your ATU is coax only input. This makes feeder access into the shack easier than balanced feeder coming in. DX Engineering makes excellent baluns for this purpose. This antenna will work all HF bands, 80m and up. At the moment I have an 80m inverted V dipole and a 40 metre one fed with the same RG213 coax (about 60 feet of the stuff). These antennas work worldwide DX very nicely, even though the apex is only up at 32 feet. NO atu needed :-)./ However I'm shortly going to erect the doublet described abovce so that I can work all the WARC bands as well. I already have a 3 el beam for 10/15/20m. 73 Peter G3PHO |
G5RV
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G5RV
Owen Duffy wrote:
Modelling suggests that the efficiency of such an antenna degrades quickly for dipole lengths less than about 35% of a wavelength. Walter Maxwell agrees. In "Reflections", he suggests the minimum length for a dipole should be 3/8WL. -- 73, Cecil http://www.w5dxp.com "According to the general theory of relativity, space without ether is unthinkable." Albert Einstein |
G5RV
On Sep 25, 5:55*pm, Danny Richardson wrote:
On Thu, 25 Sep 2008 18:33:11 -0500, "Howard Kowall" wrote: yes i have built a dipole and it works good with the manual tuner BUT now my new rig has a built in tuner and of course it wont tune it the dipole i built was *cut for 3.747mhz and works great without a tuner but with the auto tuner it wont tune anyware but 80mtrs is there a magic number for a dipole to make it tunable on 80 and 40 thanx howard Howard, Before you go sailing off into space on the GRV check this out. http://www.degendesigns.com/Downloads/TheEasyWay.PDF Danny, k6mhe Danny, Thanks for sharing this link. I found the article very well written and some very good information on SWR and suggestions on antenna design. Looks like the author is SK, so probably no way to follow up with questions, as suggested in the article. I'm curious as to when the article was written. I am just getting back on the air after several years of inactivity. I am trying to decide what type of antenna to put up in a 1/3 acre city lot without any tall trees. I'm thinking about an off-center fed dipole. Looks like an 80 meter dipole fed with ladder line and using a good antenna tuner would work on all bands. I don't have room for a full half-wave 80 meter dipole, but could do a bent off-center fed dipole. The Carolina Windom is probably what I'm thinking about, but hate to pay their price for something that could probably be home built. Also considering an all- band vertical, mounted on the roof of my home. Thanks again Vee W7IBB – Utah |
G5RV
Vee wrote:
Danny, Thanks for sharing this link. I found the article very well written and some very good information on SWR and suggestions on antenna design. Looks like the author is SK, so probably no way to follow up with questions, as suggested in the article. I'm curious as to when the article was written. I am just getting back on the air after several years of inactivity. I am trying to decide what type of antenna to put up in a 1/3 acre city lot without any tall trees. I'm thinking about an off-center fed dipole. Looks like an 80 meter dipole fed with ladder line and using a good antenna tuner would work on all bands. I don't have room for a full half-wave 80 meter dipole, but could do a bent off-center fed dipole. The Carolina Windom is probably what I'm thinking about, but hate to pay their price for something that could probably be home built. Also considering an all- band vertical, mounted on the roof of my home. Thanks again Vee W7IBB – Utah This paper takes the view that the final stage(s) in a PA is/are very much like a power generating plant. And, in a very simple comparison, it/they is/a http://www.degendesigns.com/Downloads/TheEasyWay.PDF However, that power generating station has carbon piles to sink the power into and maintain a correct draw for the power the plant is producing--until generators can be slowed or dropped off line to match "the impedance" of the load being presented to it. The power plant has switches and breakers to cut part of its' load to maintain a "correct match" (or, correct impedance) being presented to its' load, etc. In our PA's, we do not have such niceties ... the antenna must present and hold a proper "draw" upon this power being generated in our tubes/transistors/tank-circuits. If not, either too much current is drawn, voltage dips, the design parameters of devices and components are exceed and "something gives." If the load draws too little power, voltage(s) spike, current drops, and the voltage rating of the devices/components are exceeded and "something gives." While the paper, in a round-about-way, does present this in an convoluted view, it expounds on this/these events to build a case for obsfucating SWR, forward power, etc. But then, in old arrl literature, such inconsistencies abound ... indeed, they can still be found in current material from this source (arrl) ... Regards, JS |
G5RV
John Smith wrote:
... Regards, JS Yanno, every time I read that 10 PAGE PAPER! it just peeves me off ... Take his statement, "If a mismatched antenna causes power to be reflected back down the line, they reasoned, this power obviously wasn't radiated by the antenna." He is using this to "poke fun at dummies who don't know what they are taking about", this gives you the hope that "this dummy" is going to simplify, explain and dispel your ignorance on this subject--however, during the next several pages he does NOTHING in this direction. That statement can be stated more accurately as, "The LOAD is reflected back down the line!" DUH! However, it can be pictured as power being "reflected", because it sure as heck doesn't get to the antenna where it is anywheres near useful! It sure as heck is going to cause stress and heating in devices and components. A simple FSM will prove this to you in short order! And, just touch those finals to prove the stress and heat. The guy could state it, stupendously more, accurately in two pages, max--the paper is only a disclosure of the fact he doesn't understand what he is proposing to "teach" others ... If you can't make a SIMPLE statement (or paper), on a concept, which an average layman can understand, you probably don't understand the concept(s) yourself ... end of story. The paper stands in tribute to that mans ego ... sad, but true ... :-( Regards, JS |
G5RV
John Smith wrote:
... Regards, JS This BS is ALL the way through this paper of his ... reading and re-reading this paper is going to give me little sleep this night. Take this on baluns: "Next, he puts a 1:1 ferrite- core transformer-type balun up at the feedpoint of the antenna. What happens? His swr comes down to 1.5:1 at the band edges. Boy, that balun really solved the problem. Right?.....WRONG! In this case, if his rig would load up (or if he used a transmatch) he would be much better off without a balun." YES, that balun did solve his problem! Now the feedline is not the major element in his antenna, and giving God knows what radiation pattern! AND, in NO case would "he" be better off without a balun (well, unless "he" had designed the feedline to be part of "his" antenna. Or, the antenna was "perfect" and would always remain in that state, theoretically ... ) I mean this ALL just galls me ... and then new guys coming along read this crap, take it as "the holy word" since it has "arrl" attached to it, and it ALL begins again ... ALL over. Regards, JS |
G5RV
John Smith wrote:
If you can't make a SIMPLE statement (or paper), on a concept, which an average layman can understand, you probably don't understand the concept(s) yourself ... end of story. Here's a simple statement he could have made about reflected power not being lost: In a conjugately matched system using lossless transmission line: Source Power = Forward Power - Reflected Power = Load Power -- 73, Cecil http://www.w5dxp.com "According to the general theory of relativity, space without ether is unthinkable." Albert Einstein |
G5RV
Cecil Moore wrote:
John Smith wrote: If you can't make a SIMPLE statement (or paper), on a concept, which an average layman can understand, you probably don't understand the concept(s) yourself ... end of story. Here's a simple statement he could have made about reflected power not being lost: In a conjugately matched system using lossless transmission line: Source Power = Forward Power - Reflected Power = Load Power Cecil: Conjugately? Gawd man, that terms reminds me of yesteryears (Cecil, that term was an antique when I came along--your age is showing ;-) ... ) lol However, the wife and I do get along, conjugately, from time to time--but, THAT IS a story for another day ... EVIL GRIN I believe so, that "reflected power", is certainly causing some of the heating of the semiconductors (finals.) And, some of the "loss" due to SWR is not "lost" (as heat) at all--you can count the power radiating from the transmission line as "power delivered", I suppose ... but I will agree with "him" on one point, it darn sure well ain't endin' up in "SWR heaven!" ROFLOL At extreme power and extreme SWR I have seen the dielectric of coax puncture and burn ... seemingly, gloriously, dramatically, instantaneously. And, yet, another reason why a balun may be a good idea ... if you grab hold of your coax and it feels warm, suspect dielectric heating and major loss(es) ... Another thing, with the "correct" transmatch, a couple of coat-hangers can be made to look as right as rain ... at 160m! That don't mean it is right ... that paper burns me bum. Regards, JS |
G5RV
Cecil Moore wrote:
Here's a simple statement he could have made about reflected power not being lost: In a conjugately matched system using lossless transmission line: Source Power = Forward Power - Reflected Power = Load Power Let's face it Cecil, that man was obviously "being paid by the word"--in our capitalistic society--I can understand that! (However, this paper appears to have been done to "justify" "his antennas" which he was selling at the time. Indeed, it reminds me, very much, of how db has been abused ... I'd say, in this regard, he did a nice job of "Barnum-ing it!" And, was wholly motivated by financial gains. LOL ) And, in that "reality", 100 words are worth 10x as much as 10 words ... and, any inaccuracy will just be justification for more words (and more profit) on another day ... or, more obsfucation ... Regards, JS |
G5RV
Howard Kowall wrote:
Looking to buy a G5RV for 80 and 40 mtrs and maybe able to tune other bands lots of diff brands of this antenna can anyone suggest a manufacture or maybe another alternative thanx howard Howard, I made a homebrew using ARRL information and some advice from this group...pretty inexpensive and it continues to work well after 2 yrs. With a decent ATU, you should get most bands. Mine won't tune 30M. My G5RV is cut for 40M but does fairly well on 80M also. There is a longer version cut for 80M. Mine is copper wire, 300 Ohm window line for the feed and no balun. This comports with the original design, I think. You can buy center and end insulators from many suppliers, including DX Engineering (or just make your own: short pieces of PVC, for eg...spray painted blk for UV protection). One thing I might add to my G5RV (after listening to this group) would be some ferrite beads on the coax at the end of the measured window line feed. For me, Building is more fun than Buying. Good luck and 73 John AB8O |
G5RV
Jim Higgins wrote in
: .... Which "RG-8" is the author referring to? Belden 8237, Belden 8267 or Belden 9913? His cited loss figures are way too low for Belden 8267 (RG-213), probably the most common coax in use by hams on HF and high for Belden 9913, a spiral wound largely air dielectric coax that's a bitch to keep dry in outdoor use. He only cites the loss at 4MHz. Loss at 14 MHz is almost 3dB and at 28 MHz exceeds it. I'll fix the antenna before I'll use a tuner to fool the transmitter. When they does get down to some hard numbers they can be wanting. Re your example above, they say "Since a 10:1 swr on 100 feet of RG8U at 4 Mhz increases loss by less than 1 db, don't worry...". The loss on 100' of RG8/U at 4MHz with a 50+j0 ohm load is 0.35dB, the loss with a 5+j0 ohm load is 1.64dB (a bad case of load end VSWR=10), some 1.3dB higher and clearly not less than 1dB higher as he explains. Since it is not clear, some readers might even think that the statements apply to indicated VSWR at the source end of the line. When they get some things that are easy to check quite wrong, it does cast doubt on the credibility of the paper. Their point in this case about band edge VSWR is probably fair if qualified for usual configurations... but it needs qualfication and the premise they use to support the assertion is plain wrong. Why didn't they just correctly state the increased loss at VSWR=2 in support of their argument (it is about 0.1dB)? You could pick through the technical content of the paper in this way, and try to discover if there is any real value to the name dropping... but it is a mix of good stuff and not so good stuff. There is still a place in the world for text books. Nevertheless, I sympathise with them trying to find good reviewers... it is a challenge. Owen |
G5RV
In article , Cecil Moore
wrote: John Smith wrote: If you can't make a SIMPLE statement (or paper), on a concept, which an average layman can understand, you probably don't understand the concept(s) yourself ... end of story. Here's a simple statement he could have made about reflected power not being lost: In a conjugately matched system using lossless transmission line: Source Power = Forward Power - Reflected Power = Load Power Hello, and in a general case one has to be careful in dealing with the concepts of "forward" and "reflected" when talking about power. It can become an issue when source impedance, tranmission line characteristic impedance, and load impedance all have different values. The "matched" value corresponding to no reflections might not be the value for maximum power transfer from source to load. In this general case incident (forward) voltage or current from the source becomes a function of mismatch between the source and the reference impedance (e.g. 50 ohms) and the mismatch between the load and reference. When the source is matched this dependency vanishes and the incident power is the same as the "available" power (Vsource^2/(4 * Real part of source impedance)) from the source. The source can be "matched" to the input of the transmission line feeding the load but not be conjugately matched to the transmission line/load combination. Conversely, we can have reflections present at the source-line interface for conjugate match conditions. Sincerely, and 73s from N4GGO, John Wood (Code 5550) e-mail: Naval Research Laboratory 4555 Overlook Avenue, SW Washington, DC 20375-5337 |
G5RV
J. B. Wood wrote:
Cecil Moore wrote: In a conjugately matched system using lossless transmission line: Source Power = Forward Power - Reflected Power = Load Power The source can be "matched" to the input of the transmission line feeding the load but not be conjugately matched to the transmission line/load combination. Note that I specified an ideal lossless transmission line. In a lossless system, if a conjugate match exists anywhere, a conjugate match exists everywhere. My assertion was a conceptual statement about an ideal example. Conversely, we can have reflections present at the source-line interface for conjugate match conditions. I was also assuming a 50 ohm source with a 50 ohm Z0-match in a lossless system. I should have specified such. Here is what I had in mind. XMTR---50 ohm coax---+---1/8WL 300 ohm twinlead---(97.3-j283.8) There is a (close enough) 50 ohm Z0-match at '+' :-) -- 73, Cecil http://www.w5dxp.com "According to the general theory of relativity, space without ether is unthinkable." Albert Einstein |
G5RV
Cecil Moore wrote:
... Note that I specified an ideal lossless transmission line. In a lossless system, if a conjugate match exists anywhere, a conjugate match exists everywhere. My assertion was a conceptual statement about an ideal example. ... Cecil: I believe so ... However, you have been lifting weights with your brain. These things look elementary to you; your only mistake is you do not strive for even a simpler example, to let those wishing to, catch that first step ... The lossless line is a key. Remember those lines of force around a magnet which can be seen with some iron powder and a paper? These are being stored within the ether; you are seeing the only feeble proof of the ethers existence--magnetic lines of force, in that simple experiment. Remember the plans to store energy in a superconductor configured in an endless loop? Where do people think that energy is being stored? In the electrons and other particles? Naaa ... it is being stored within the ether--in magnetic lines of force ... You lossless line has no loss, simple. 100% of the power being stored in the ether is being gotten back from the ether (and your lossless line is a superconductor.) And, when that condition exists, the workings of the antenna become a bit more clear (visible) ... Art says some of this in his "ramblings", most just don't look for it .... Art just obsfucates beyond recognition (or fubar!) Regards, JS |
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