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#1
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Hi,
I'm wondering if anybody else made some experiences (good or bad) with the R7 cushcraft vertical antenna. I bought such an antenna second-hand some days ago, but never used a vertical antenna for HF before. vy 73 de Lorenz -- Fritz Lorenz Born, HB9DTN E-Mail: f=lbo=rn@sw=iss=onli=ne.=ch -- sed 2,4s/=//g signature "I hate spam!!" |
#2
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I'm wondering if anybody else made some experiences (good or bad) with
the R7 cushcraft vertical antenna Hi Lorenz. The R7 will work, needs a ground radial system to work well, and will be difficult to get a good match on multibands. Never used one myself, just commenting on multiband verticals in general that I have used. 73 Gary N4AST |
#3
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Fritz,
I have an R-7 currently laying in the yard. I'm not a big vertical fan, but have to say that it did work as advertised. Unfortunately, the fibreglass insulator used to hold the antenna on the 'base' doesn't last forever if it's in the sun very much (mine was). It wasn't really all that hard to tune, just follow the recomendations. Don't expect much bandwidth on 40 meters! It's also fairly sensitive to 'where/how' you mount it. I tuned mine on a fence post, then tried to move it to the top of my house. Worked great on the post, terrible on the roof. Too lazy to re-tune, so just mounted it on the post. Still not a vertical fan, but I think I got my money's worth out of the R-7 (10-15 years?). 'Doc |
#4
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f=lbo=rn wrote:
Hi, I'm wondering if anybody else made some experiences (good or bad) with the R7 cushcraft vertical antenna. I bought such an antenna second-hand some days ago, but never used a vertical antenna for HF before. vy 73 de Lorenz -- Fritz Lorenz Born, HB9DTN E-Mail: f=lbo=rn@sw=iss=onli=ne.=ch -- sed 2,4s/=//g signature "I hate spam!!" I picked one up used. I checked out all the mechanical connections in the traps, then set it up according to instructions manual and am terribly pleased with it. I did arrange for the 40 meters to be set to the low end where I operate, other than that, I get great results with it using QRP. If you do a Google search you will find that some people have experienced problems, but nothing that can't be fixed using the information available on the net. I have mine sitting on a 12 foot piece of pipe just to lift the radials over the garage roof. Irv VE6BP -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/ Visit my very special website at http://members.shaw.ca/finkirv4/ Visit my CFSRS/CFIOG ONLINE OLDTIMERS website at http://members.shaw.ca/finkirv5/ -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
#5
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Well the R7 Cushcraft antenna is NOT your Fathers quarter wave vertical --
it is a half wave end fed antenna thus it needs no radials. It is fed at a high impedance point by virtue of the matching black box at the antenna feedpoint. In fact the addition of radials will really screw it up --- read the manual see URL: http://www.cushcraft.com/support/pdf/r7.pdf "THE R7 SHOULD NOT BE CONNECTED TO A GROUND RADIAL SYSTEM". I ignored this (as an experiment) and found Cushcraft knew what they were talking about. The four 49 inch rods at the antenna bottom are counterpoises designed to isolate the antenna from ground and not long enough to be resonant on any band. The bandwidth and efficiency on 40M, I found to be poor. But it works well enough on the other bands, covering full bandwidth on all bands except 40M and 20M. You will have to choose the portion of the band you want to operate on for these two bands. Tuning the R7 was easy, following the manual instructions. Be careful of running high power into this antenna for an extended length of time -- particularly if you horse it beyond resonance with a tuner -- several here have frazzled the traps when doing this. Using an R7 I was able to work a lot of DX, it does seem to have a low angle of radiation -- Cushcraft claims 16 degrees. For more opinions --see url: http://www.eham.net/reviews/detail/518 This opinion is not to engage in a debate of 1/4 wave vs 1/2 wave verticals save that for another thread. -- Incognito By Necessity (:-( If you can't convince them, confuse them. - - -Harry S Truman "JGBOYLES" wrote in message ... I'm wondering if anybody else made some experiences (good or bad) with the R7 cushcraft vertical antenna Hi Lorenz. The R7 will work, needs a ground radial system to work well, and will be difficult to get a good match on multibands. Never used one myself, just commenting on multiband verticals in general that I have used. 73 Gary N4AST |
#6
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Well the R7 Cushcraft antenna is NOT your Fathers quarter wave vertical --
it is a half wave end fed antenna thus it needs no radials. It is fed at a high impedance point by virtue of the matching black box at the antenna feedpoint. In fact the addition of radials will really screw it up --- read the manual see URL: http://www.cushcraft.com/support/pdf/r7.pdf "THE R7 SHOULD NOT BE CONNECTED TO A GROUND RADIAL SYSTEM". I ignored this (as an experiment) and found Cushcraft knew what they were talking about. The four 49 inch rods at the antenna bottom are counterpoises designed to isolate the antenna from ground and not long enough to be resonant on any band. The bandwidth and efficiency on 40M, I found to be poor. But it works well enough on the other bands, covering full bandwidth on all bands except 40M and 20M. You will have to choose the portion of the band you want to operate on for these two bands. Tuning the R7 was easy, following the manual instructions. Be careful of running high power into this antenna for an extended length of time -- particularly if you horse it beyond resonance with a tuner -- several here have frazzled the traps when doing this. Using an R7 I was able to work a lot of DX, it does seem to have a low angle of radiation -- Cushcraft claims 16 degrees. For more opinions --see url: http://www.eham.net/reviews/detail/518 This opinion is not to engage in a debate of 1/4 wave vs 1/2 wave verticals save that for another thread. -- Incognito By Necessity (:-( If you can't convince them, confuse them. - - -Harry S Truman "JGBOYLES" wrote in message ... I'm wondering if anybody else made some experiences (good or bad) with the R7 cushcraft vertical antenna Hi Lorenz. The R7 will work, needs a ground radial system to work well, and will be difficult to get a good match on multibands. Never used one myself, just commenting on multiband verticals in general that I have used. 73 Gary N4AST |
#7
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I have used one for many years, right after it first came out. NO PROBLEMS. I
have it on a telescoping TV mast. The bottom of it is about 20 feet up. On 40 it is adjusted for CW portion, and use built-in AT in rigs for a match there. Elsewhere it has acceptable SWR for each band. 73 de Jack, K9CUN |
#8
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Same here, have had mine up and going after fixing it last summer, went thru
winter very well, not a sign of detoriation at all. Still works like a top. Now I don't know if anyone else did check the antenna with an antenna tuner (mfj 259 or whichever) Did check mine out last year will doing the installation and found the antenna to resonant not to badly at all on 6 meters, and also on 80, where it would be a real compromise antenna. A bit hight on swr , but in a pinch i am sure it could be use with a tuner on at least 80 meters. Someday will check it out on the air on 80 meters to really find out what is what with it. Just some feedback about R-7. de Jean-Guy/ve9buf "JDer8745" a écrit dans le message de ... I have used one for many years, right after it first came out. NO PROBLEMS. I have it on a telescoping TV mast. The bottom of it is about 20 feet up. On 40 it is adjusted for CW portion, and use built-in AT in rigs for a match there. Elsewhere it has acceptable SWR for each band. 73 de Jack, K9CUN |
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