K2 and wire antenna
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This is a test message and a question. If the message gets through, that
part works fine. Now for the question: My current QTH is a city lot that has several large oak trees in the back yard. The trees have been there over 30 or 40 years and I will not be able to do much more than trim a very few limbs that get too close to other structures. My HF antenna at present is an inverted V configuration hung from one of the trees at about 40 feet off the ground (also the yard is not level, there are several slopes) and the end points tied to another tree on one side of the yard and a fence on the other side. The antenna was cut for 40 meters. The feed line is an unknown length of 300 ohm television twin lead coming into the attic then through a closet to the radio. My current radio (not an Elecraft) has an MFJ-941B tuner between the antenna connection and the actual feed line. Would the K2 with an internal ATU be able to work with this antenna/feed line combination? Thank you, Jim KD5VXH _______________________________________________ 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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On Sun, 2008-01-06 at 15:27 -0600, Jim's mail wrote: > Would the K2 with an internal ATU be able to work with this antenna/feed > line combination? Probably, but you will need a balun. ELecraft make one that is switchable 1:1 / 4:1 I use an MFJ switchable balun and find I can match pretty much anything in one position or the other. 73 Brendan EI6IZ -- Don‘t complain. Nobody will understand. Or care. And certainly don‘t try to fix the situation yourself. It‘s dangerous. Leave it to a highly untrained, unqualified, expendable professional. _______________________________________________ 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 Jim's mail
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In reply to this post by Jim's mail
I have had very good luck tuning various antennas with my
KAT-100/K2/100. In most instances, I have used a 4:1 balun. - David Wilburn [hidden email] K4DGW K2 S/N 5982 On Sun, 2008-01-06 at 15:27 -0600, Jim's mail wrote: > This is a test message and a question. If the message gets through, that > part works fine. Now for the question: My current QTH is a city lot that > has several large oak trees in the back yard. The trees have been there > over 30 or 40 years and I will not be able to do much more than trim a very > few limbs that get too close to other structures. My HF antenna at present > is an inverted V configuration hung from one of the trees at about 40 feet > off the ground (also the yard is not level, there are several slopes) and > the end points tied to another tree on one side of the yard and a fence on > the other side. The antenna was cut for 40 meters. The feed line is an > unknown length of 300 ohm television twin lead coming into the attic then > through a closet to the radio. My current radio (not an Elecraft) has an > MFJ-941B tuner between the antenna connection and the actual feed line. > > Would the K2 with an internal ATU be able to work with this antenna/feed > line combination? > > Thank you, > Jim KD5VXH > > _______________________________________________ > 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 Jim's mail
I use the KAT2 and BL2 with 2 different antennas. One is the Cobra Ultralite (www.k1jek.com) and the other is a 40 meter inverted Vee fed with 300-ohm twinlead. The tuner/balun has been able to match the first antenna on 160 to 10 and the second antenna on 40 to 10 (and even 80 but I never use it there). The balun has always stayed in the 4 to 1 position. I try to keep the piece of coax from the balun to the rig as short as possible, and sometimes use the male-to-male BNC adaptor that Elecraft sells.
72, John W2XS K2, KX1, and K3 (due in April) |
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In reply to this post by Jim's mail
Probably it will work. A 50 or 75 ohm feed line would
be a better choice for this antenna. I have had good results over the years with feeding a dual inverted vee, one vee cut for 75 or 80 meters and one cut for 40 meters. It will load well on about 100 to 150 khz of 80, all of 40, all of 15 and most of 10 meters. It doesn't load well on 20 and only fair on 17 and 12, but is a pretty good antenna. It doesn't need a tuner at all on 80, 40, 15 and 10, but an automatic tuner will get the other bands easily. You will need a separate dipole for good results on 20 meters. Touching a branch probably will not kill the antenna, but may cause some noise, especially in rainy weather. Cookie, K5EWJ --- Jim's mail <[hidden email]> wrote: > This is a test message and a question. If the > message gets through, that > part works fine. Now for the question: My current > QTH is a city lot that > has several large oak trees in the back yard. The > trees have been there > over 30 or 40 years and I will not be able to do > much more than trim a very > few limbs that get too close to other structures. > My HF antenna at present > is an inverted V configuration hung from one of the > trees at about 40 feet > off the ground (also the yard is not level, there > are several slopes) and > the end points tied to another tree on one side of > the yard and a fence on > the other side. The antenna was cut for 40 meters. > The feed line is an > unknown length of 300 ohm television twin lead > coming into the attic then > through a closet to the radio. My current radio > (not an Elecraft) has an > MFJ-941B tuner between the antenna connection and > the actual feed line. > > Would the K2 with an internal ATU be able to work > with this antenna/feed > line combination? > > Thank you, > Jim KD5VXH > > _______________________________________________ > 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 Jim's mail
At 04:27 PM 1/6/2008, you wrote:
<cut> My HF antenna at present is an inverted V configuration hung from one of the trees at about 40 feet off the ground (also the yard is not level, there are several slopes) and the end points tied to another tree on one side of the yard and a fence on the other side. The antenna was cut for 40 meters. The feed line is an unknown length of 300 ohm television twin lead coming into the attic then through a closet to the radio. Would the K2 with an internal ATU be able to work with this antenna/feed line combination? Thank you, Jim KD5VXH JIm, I have had very good performance from an inverted V hanging from an oak tree at 30 feet to the center with my K2. My inverted V is actually a three band unit with wires cut for 40, 30 and 20 meters all fed at the center with 50 ohm coax. I used an antenna analyzer to trim the wires, starting with the 40 meter section first, for minimum SWR at my operating frequencies. I had very little problem getting a match for each band and I did not need an antenna tuner. The 40 meter section can also be used for 15 meters but I found that the match was up near the top of the band and an antenna tuner (I use the KAT2) is needed to prevent the K2 from cutting back on the power due to the higher SWR at the lower end of the band. Larry AG4NN _______________________________________________ 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 John W2XS
John W2XS wrote:
> I use the KAT2 and BL2 with 2 different antennas. One is the Cobra Ultralite > (www.k1jek.com) and the other is a 40 meter inverted Vee fed with 300-ohm > twinlead. The tuner/balun has been able to match the first antenna on 160 > to 10 and the second antenna on 40 to 10 (and even 80 but I never use it > there). The balun has always stayed in the 4 to 1 position. I try to keep Especially in the 4:1 configuration, this sort of configuration will only work if the antenna is close to resonance. If the antenna is well off resonance, the path of least resistance for the RF will through the balun windings, which are a DC short, and will be an RF short if their reactance is not greater than that of the antenna. Such a configuration may appear to tune, but won't actually put much power into the antenna. > the piece of coax from the balun to the rig as short as possible, and > sometimes use the male-to-male BNC adaptor that Elecraft sells. > > 72, > > John W2XS > > K2, KX1, and K3 (due in April) -- David Woolley Emails are not formal business letters, whatever businesses may want. RFC1855 says there should be an address here, but, in a world of spam, that is no longer good advice, as archive address hiding may not work. _______________________________________________ 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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David
Do you mean "close to resonance" or close to 200ohm impedance ? This is where the truly balanced matching units come into their own, but does anyone make them? David G3UNA Cobra Ultralite >> (www.k1jek.com) and the other is a 40 meter inverted Vee fed with 300-ohm >> twinlead. The tuner/balun has been able to match the first antenna on >> 160 >> to 10 and the second antenna on 40 to 10 (and even 80 but I never use it >> there). The balun has always stayed in the 4 to 1 position. I try to >> keep > > Especially in the 4:1 configuration, this sort of configuration will only > work if the antenna is close to resonance. If the antenna is well off > resonance, the path of least resistance for the RF will through the balun > windings, which are a DC short, and will be an RF short if their reactance > is not greater than that of the antenna. Such a configuration may appear > to tune, but won't actually put much power into the antenna. > 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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