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#1
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I want to make a 2m Yagi out of stainless steel, partly because of the
corrosion resistance but mostly because I have the materials on hand. Some of my friends have tried to tell me that the higher ohmic resistance of SS will make for a poor antenna. Frankly I do see that it would make any significant difference. While SS has several times the resistance of AL I figure we are just comparing micro ohms to milliohms.at worst, probably more like micro ohm to tens of micro ohms. I am a correct on these assumptions or should I listen to my friends. |
#2
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![]() "Jimmie" Gfender@carolina dot.rr.dot com wrote in message . com... I want to make a 2m Yagi out of stainless steel, partly because of the corrosion resistance but mostly because I have the materials on hand. Some of my friends have tried to tell me that the higher ohmic resistance of SS will make for a poor antenna. Frankly I do see that it would make any significant difference. While SS has several times the resistance of AL I figure we are just comparing micro ohms to milliohms.at worst, probably more like micro ohm to tens of micro ohms. I am a correct on these assumptions or should I listen to my friends. If you have the materials go ahead and make the antenna. SS is just harder to work with for most people and weighs more. YOu will loose some gain but unless you are into very weak signal work it will not be too noticable. I have an 8 element quagi for the 220 mhz band I made using SS welding rods for the directors. It works beter than a 6 element beam I had up in the same place. It also works much beter than the 11 element CC antenna that was also in the same place. |
#3
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Use the SS. I just finished building a dual band J-Pole 2m/70cm and
used SS. It works just fine. 2m SWR ranges from 1.0:1 to 1.4:1 and I have had great success hitting distant (40 miles) repeaters on ~5w at only 20' AGL at my location, but about 5' BELOW average ground level for the entire city... Go figure, I bought the place in the bottom of the hole! ![]() On Wed, 16 Jun 2004 18:03:58 GMT, "Jimmie" Gfender@carolina dot.rr.dot com wrote: I want to make a 2m Yagi out of stainless steel, partly because of the corrosion resistance but mostly because I have the materials on hand. Some of my friends have tried to tell me that the higher ohmic resistance of SS will make for a poor antenna. Frankly I do see that it would make any significant difference. While SS has several times the resistance of AL I figure we are just comparing micro ohms to milliohms.at worst, probably more like micro ohm to tens of micro ohms. I am a correct on these assumptions or should I listen to my friends. |
#4
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go for it - the added R may increase bandwidth a little
"Jimmie" Gfender@carolina dot.rr.dot com wrote in message . com... I want to make a 2m Yagi out of stainless steel, partly because of the corrosion resistance but mostly because I have the materials on hand. Some of my friends have tried to tell me that the higher ohmic resistance of SS will make for a poor antenna. Frankly I do see that it would make any significant difference. While SS has several times the resistance of AL I figure we are just comparing micro ohms to milliohms.at worst, probably more like micro ohm to tens of micro ohms. I am a correct on these assumptions or should I listen to my friends. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.707 / Virus Database: 463 - Release Date: 6/15/2004 |
#5
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On Wed, 16 Jun 2004 18:03:58 GMT, "Jimmie" Gfender@carolina
dot.rr.dot com wrote: |I want to make a 2m Yagi out of stainless steel, partly because of the |corrosion resistance but mostly because I have the materials on hand. Some |of my friends have tried to tell me that the higher ohmic resistance of SS |will make for a poor antenna. Frankly I do see that it would make any |significant difference. While SS has several times the resistance of AL I |figure we are just comparing micro ohms to milliohms.at worst, probably more |like micro ohm to tens of micro ohms. I am a correct on these assumptions or |should I listen to my friends. | Listen to your friends. |
#6
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On Wed, 16 Jun 2004 19:38:43 -0400, "Hal Rosser"
wrote: |go for it - the added R may increase bandwidth a little Yep, and while you're at it, add a 20 dB resistive pad at the feedpoint. The bandwidth will be super. |
#7
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Ralph Mowery wrote:
"Jimmie" Gfender@carolina dot.rr.dot com wrote in message .com... I want to make a 2m Yagi out of stainless steel, partly because of the corrosion resistance but mostly because I have the materials on hand. Some of my friends have tried to tell me that the higher ohmic resistance of SS will make for a poor antenna. Frankly I do see that it would make any significant difference. While SS has several times the resistance of AL I figure we are just comparing micro ohms to milliohms.at worst, probably more like micro ohm to tens of micro ohms. I am a correct on these assumptions or should I listen to my friends. If you have the materials go ahead and make the antenna. SS is just harder to work with for most people and weighs more. YOu will loose some gain but unless you are into very weak signal work it will not be too noticable. That's correct - especially the last part. In typical yagi designs, resistive losses in normal aluminum elements are on the order of a percent - which is negligible. There are many grades of SS, of course, but again a typical value might be a few percent. In Europe there is a successful range of 'Flexa-Yagis' of very lightweight construction using elements made from thin, springy SS wire. These yagis are only about 0.5dB down in gain compared with ali elements at 144MHz, and maybe 1dB at 432MHz. A few years down the line, when ali elements may have corroded, the SS elements may even come out ahead. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
#8
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![]() "Jimmie" Gfender@carolina dot.rr.dot com wrote in message . com... I want to make a 2m Yagi out of stainless steel, partly because of the corrosion resistance but mostly because I have the materials on hand. Some of my friends have tried to tell me that the higher ohmic resistance of SS will make for a poor antenna. Frankly I do see that it would make any Look at all the mobile antennas. For the most part they are SS. Mainly because of the stiffness of the material. The antennas for the low bands are usually not SS. Part of it is that the short for wavelength antennas can not stand much resistance where it becomes a large part of the overall "radiation resistance". When the antenna is aproaching a 1/4 wave or more the resistance of the material it is made of is less important. |
#9
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The loss in a stainless steel whip antenna in comparison with the TOTAL
loss, including that in the ground, is always small enough to be neglected, regardless of length of the antenna. |
#10
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Ralph Mowery wrote:
The antennas for the low bands are usually not SS. In one of the CA 75m mobile shootouts, Wally, WA6JPR, entered a bugcatcher with an SS Fortex Coil. It was 4 dB down from his copper loading coil (no hat) and 6.5 dB down from the top rated screwdriver (with hat). Of course, most stingers on HF mobile antennas are SS and are located at the high voltage - low current end of the mobile antenna. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
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