Antenna wire gauge efficiency
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Hello all. I know this is somewhat off topic, but there is a lot of knowledge here, so I will ask. I am in the process of erecting two wire antennas and wondered, for stealth reasons, how small I can go in wire gauge for these antennas and still have an effeicient radiator. I know in general bigger is better and copper glad is prefereable. I will be running anywhere from QRP to 400 watts. It seems like I have seen tables in the past that are good general reference guides for this question. Any thoughts and yes my K2 is a great rig? Paul NN5G
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Re: Antenna wire gauge efficiency
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Paul, I am certain you will get more responses, and since I do not have the
formulas in my head, I suggest you wait for the more knowledgeable folks to weigh in. However, if you plan on going up into the hundreds of watts, I would be thinking in the 14 gauge area. Personally, my antennas are 12 gauge, but that was because ... A) I used it as much for its added strength as for its electrical characteristics ( I live in heavy woods) B) It was the wire I had lots of on hand. (Application of the Cortina Economic Applications of Existing Resources) One more thing I might add is that in case you had not planned on doing this, use a system of pulleys (I use marine pulleys) so that as the trees (I assume you are erecting the antenna between trees) sway, the antennas will give. If you need more info on this, contact me off list. I will be happy to send you a graphic of how I do this. Best of luck. Vin Cortina KR2F K1-4 s/n:1977 KX1 s/n:1476 ----- Original Message ----- From: "Paul Kelly" <[hidden email]> To: <[hidden email]> Sent: Thursday, August 10, 2006 10:25 AM Subject: [Elecraft] Antenna wire gauge efficiency > Hello all. I know this is somewhat off topic, but there is a lot of > knowledge here, so I will ask. I am in the process of erecting two wire > antennas and wondered, for stealth reasons, how small I can go in wire > gauge for these antennas and still have an effeicient radiator. I know in > general bigger is better and copper glad is prefereable. I will be > running anywhere from QRP to 400 watts. It seems like I have seen tables > in the past that are good general reference guides for this question. Any > thoughts and yes my K2 is a great rig? Paul NN5G > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: Antenna wire gauge efficiency
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The biggest factor (if you are running less than 100 watts) is the strength
of the wire. Whilst 26/28 gauge and other lightweight wires will radiate properly at these levels, it's the tensile strength that is the main point. I use 28 gauge teflon wire for portable operations but at my home station I use 12 gauge. According to the NEC, wire antennas must be a minimum 12 gauge, so if you want to be perfectly legal run 12 gauge. Gregg R. Lengling, W9DHI, Retired K2/100 SN 3075 http://www.milwaukeehdtv.org ----- Original Message ----- From: "Vin Cortina" <[hidden email]> To: "Paul Kelly" <[hidden email]>; <[hidden email]> Sent: Thursday, August 10, 2006 9:54 AM Subject: Re: [Elecraft] Antenna wire gauge efficiency > Paul, I am certain you will get more responses, and since I do not have > the formulas in my head, I suggest you wait for the more knowledgeable > folks to weigh in. However, if you plan on going up into the hundreds of > watts, I would be thinking in the 14 gauge area. Personally, my antennas > are 12 gauge, but that was because ... > A) I used it as much for its added strength as for its electrical > characteristics ( I live in heavy woods) > B) It was the wire I had lots of on hand. (Application of the Cortina > Economic Applications of Existing Resources) > > One more thing I might add is that in case you had not planned on doing > this, use a system of pulleys (I use marine pulleys) so that as the trees > (I assume you are erecting the antenna between trees) sway, the antennas > will give. If you need more info on this, contact me off list. I will be > happy to send you a graphic of how I do this. > > Best of luck. > > > Vin Cortina KR2F > > K1-4 s/n:1977 > KX1 s/n:1476 > > > ----- Original Message ----- > From: "Paul Kelly" <[hidden email]> > To: <[hidden email]> > Sent: Thursday, August 10, 2006 10:25 AM > Subject: [Elecraft] Antenna wire gauge efficiency > > >> Hello all. I know this is somewhat off topic, but there is a lot of >> knowledge here, so I will ask. I am in the process of erecting two wire >> antennas and wondered, for stealth reasons, how small I can go in wire >> gauge for these antennas and still have an effeicient radiator. I know >> in general bigger is better and copper glad is prefereable. I will be >> running anywhere from QRP to 400 watts. It seems like I have seen tables >> in the past that are good general reference guides for this question. >> Any thoughts and yes my K2 is a great rig? Paul NN5G >> >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by nn5g
Paul Kelly wrote:
> I am in the process of erecting two > wire antennas and wondered, for stealth reasons, how small I can go > in wire gauge for these antennas and still have an effeicient > radiator. I know in general bigger is better and copper glad is > prefereable. I will be running anywhere from QRP to 400 watts. As long as it is strong enough to stay up, the wire gauge won't affect the efficiency too much with a full-size antenna. For example, I ran EZNEC for a dipole at 40 feet with no. 12 and no. 28 (probably too weak to stay up long) copper wire. The difference in gain was only 0.24 DB! If you have a shortened antenna, the effect is greater. A half-size dipole showed a difference of 0.76 DB. And really small antennas like small loops would show much greater effects. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: Antenna wire gauge efficiency
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In reply to this post by nn5g
Paul, as Vin suggests I also use a system of marine pulleys to avoid problems when the trees sway. I would like to add that because most trees tend to grow over any object such as a rope that is hanging over a limb, it is worthwhile to loosen up occasionally the ropes that go over the trees to the pulleys, say once every 9 - 12 months. This will prevent the ropes becoming stuck. For wire I use plastic covered Flexweave approximately #12 for reasons of strength and ease of handling, plastic covered because the many local birds perch on the antennas. 73, Geoff GM4ESD ----- Original Message ----- From: "Vin Cortina" <[hidden email]> To: "Paul Kelly" <[hidden email]>; <[hidden email]> Sent: Thursday, August 10, 2006 3:54 PM Subject: Re: [Elecraft] Antenna wire gauge efficiency <snip> > One more thing I might add is that in case you had not planned on doing > this, use a system of pulleys (I use marine pulleys) so that as the trees > (I assume you are erecting the antenna between trees) sway, the antennas > will give. If you need more info on this, contact me off list. I will be > happy to send you a graphic of how I do this. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Vic K2VCO
Hello All:
What is the proper way to set AGC in the K2? The manual suggests adjusting R1 for 3.80V at U2-5 as a starting point, but then gives no other information. TNX, Paul N8NOV Houston _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: Proper Adjustment of K2 AGC
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Paul,
You are correct, there is no well defined procedure, and part of the real procedure depends on 1)whether you set the pre-amp on or off, 2) the band that you use to optimize the AGC, and 3) the sensation in your ears as you listen to the result - An AGC Threshold setting that is higher than necessary will tend to reduce the gain of your receiver even with no signal present, and the AGC Threshold adjustment can be used to avoid that condition. Here is how I do it: Do this adjustment only after the reciever is fully built and aligned. Set the receiver to 40 meters, the PreAmp OFF, CW mode, Bandwidth at 700 Hz, and be certain the RF Gain is at the full clockwise rotation. Listen to the reciever noise (use a speaker and turn the audio gain up a bit high). Turn the AGC alternately ON and then OFF (press PRE/ATT and AGC buttons together) while listening to the noise level. Lower the AGC Threshold voltage gradually while doing that - when the AGC ON noise is just a tiny bit less than the AGC OFF noise, you have found the proper point. Go no lower than 3.6 volts or you may likely have trouble with the S-meter limits that must be adjusted afterward. Do CAL S Lo and CAL S HI (in that order) as instructed in the manual - go through this adjustment cycle a couple times and double check with the wide filters (SSB OP1 filter if installed). If you use the XG1 or XG2 to check the S-9 level, you may have to make some compromises in the CAL S Hi setting to get the S-meter readings satisfactory to your eyes and ears - there are no exact requirements, it is all in the S-meter action that you want to see, so set it as you like - the K2 receiving performance is not changed by the CAL S Hi and CAL S Lo, only the s-meter readings change. 73, Don W3FPR > -----Original Message----- > > What is the proper way to set AGC in the K2? > The manual suggests adjusting R1 for 3.80V at U2-5 as a starting > point, but > then gives no other information. > > TNX, > Paul N8NOV > Houston > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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