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New to HF and looking at antenna options.

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#21
I've compared the resonant EFHW to a center fed dipole the same size, at the same location on many occasions and so have countless others. Exact same performance to a full size half wave center fed dipole, can't tell the difference. All the current is flowing in the antenna wire minus a tiny amount in transformer loss. Just because you don't understand how or why they work doesn't mean the don't work really well and better than many other type antennas of the same size.

So tell me Paul, how many resonant EFHWs have you built or tested side by side to other known antennas? Maybe you should call MyAntennas and tell them their flagship antenna cant work. I'm sure Danny will be kind enough to enlighten you on the subject.

AC or DC, there has to be two "terminals" or current doesn't flow. That second terminal may not be user supplied, or apparent, but it's got to be there. Antennas are the same way or no current f2fglow so no radiation. That's about as simple as it gets.
 
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#22
One nice thing about the ZS6BKW is it has a good match on many bands, unlike its cousin the G5RV which was designed as a 20m antenna. That means less coax loss from the coax operating under high mismatch conditions. On 80m the match will be above 5:1 but within the tuning range of most modern tuners built into radios.

If you were local I would probably give you the heavy duty version I built but took down a few years back.


I do appreciate the suggestion of the ZS6BKW antenna. I do like the specs on it and I have found so many 5 star reviews on it at eham.net and Amazon. I think that in my situation that I won't be able to get it much higher than 25 to 30 feet high in an inverted V setup. The supplied coax will be more than long enough to reach it's destination. I like the fact that I will not need an external antenna tuner with it as well.

I have researched so many antenna options in the last few days that my head hurts. :giggle: I hope that this one will fit my needs. I found it for $69 including shipping. Amazon wants $147 for it. :eek: I hope it will work well at that height and that I do not get too much interference from all of the nearby power lines but I guess I will cross that bridge when I get to it.
 

W5lz

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#23
Please show me where I have said anything about the performance between an end fed 1/2wave and a center fed 1/2 wave antenna. The subject has been about end fed antennas and how they are fed. Using the term "other half" was probably a mistake I made when trying to describe where that second terminal (so current would flow) came in. Mea Culpa...
The fact remains, there still has to be that second terminal. In most cases that amounts to the feed line, transformer or not.
 

graywoulf

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#24
One nice thing about the ZS6BKW is it has a good match on many bands, unlike its cousin the G5RV which was designed as a 20m antenna. That means less coax loss from the coax operating under high mismatch conditions. On 80m the match will be above 5:1 but within the tuning range of most modern tuners built into radios.

If you were local I would probably give you the heavy duty version I built but took down a few years back.
I hope that someday I will have the knowledge and experience to build my own antennas. The mechanics of the construction I would not have any problem with as I have been a tinkerer and a DIYer most of my life. The design and technical aspects are yet to be learned. I did help a friend build a three element beam when I was 13. That was back in my early CB times. It worked well and was fun to build.
 
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#25
Your past posts should answer that, I have nothing else to add.

Please show me where I have said anything about the performance between an end fed 1/2wave and a center fed 1/2 wave antenna. The subject has been about end fed antennas and how they are fed. Using the term "other half" was probably a mistake I made when trying to describe where that second terminal (so current would flow) came in. Mea Culpa...
The fact remains, there still has to be that second terminal. In most cases that amounts to the feed line, transformer or not.
 
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#26
Building antennas is probably the most fun I have in amateur radio. The End Fed Half Wave that has been mentioned in your thread here is really easy to build and it makes a great DIY project. You can build a tiny one that will handle 100W for just a few $ and even though you chose something else for home, its great for travel, camping, etc. I can point you to some plans if your interested.

I hope that someday I will have the knowledge and experience to build my own antennas. The mechanics of the construction I would not have any problem with as I have been a tinkerer and a DIYer most of my life. The design and technical aspects are yet to be learned. I did help a friend build a three element beam when I was 13. That was back in my early CB times. It worked well and was fun to build.
 
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graywoulf

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#27
Building antennas is probably the most fun I have in amateur radio. The End Fed Half Wave that has been mentioned in your thread here is really easy to build and it makes a great DIY project. You can build a tiny one that will handle 100W for just a few $ and even though you chose something else for home, its great for travel, camping, etc. I can point you to some plans if your interested.
Yes, thank you for that offer. I would be interested to see those plans. I was thinking of playing around with some 2m antenna plans that I saw on YouTube as well. I have heard some wild tales of all kinds of objects and materials being used for antennas including gutters and window screens. I have even started looking at everyday objects and wondering about the possibilities of them being converted to antennas. I recently purchased one of the DBJ-1 J pole antennas from Ed Fong. An amazing antenna that looked so simple to make. I might like to try making one for portable use in the future. Thanks again.(y)
 
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#28
Here is one of the better articles on making the transformer for an EFHW, scroll down the pdf to the "high impedance UNUN for EFHW" and follow the instructions carefully. For 100w SSB portable use, get an Amadon FT-114A-43 ferrite core and wrap with 22ga up to 16ga wire. Enamaled magnet wire is good and stranded Teflon is also good. You will need a small disc capacitor between 100pf and 150pf with a 100v rating being ok for 100w.

http://gnarc.org/wp-content/uploads/The-End-Fed-Half-Wave-Antenna.pdf

I fit these small transformers in a tiny box a little bigger than a Zippo lighter with a BNC connector. Then get the largest plastic chalk line reel you can find at Home Depot, take out the string and roll up about 64ft of wire inside, then you can use some of the chalk line string attached to that as guy string. Wind up as much string as will fit in the reel, which will be about 40ft.

What you now have is a really portable HF antenna that covers 40.20, 15 and 10m without a tuner. You pull all the string and wire out of the chalk line reel and the empty reel is now your throw weight to toss over a tree, etc. When your done just disconnect the wire from the transformer and wind up all the wire and string with the crank handle on the chalk line reel.

Here are some pictures of some of the half wave end feds I've made. I included a Zippo lighter in the pic to show the size of the small transformer. The larger box is a dual core I use with a 600W amp when portable. The small spool of coax is RG-316 teflon with a 1:1 choke made with a #31 mix ferrite bead. These are just two of the dozens of EFHW antennas I've made.

Here is a link to the ferrite core for a 100w version. FT-114A-43

If you make a larger version using the FT-240-43 cores in the article, about 64ft of wire will give you 40,20,15 and 10m and 133ft of wire will give you 80m on up plus a few other bands.


end feds.jpg




Yes, thank you for that offer. I would be interested to see those plans. I was thinking of playing around with some 2m antenna plans that I saw on YouTube as well. I have heard some wild tales of all kinds of objects and materials being used for antennas including gutters and window screens. I have even started looking at everyday objects and wondering about the possibilities of them being converted to antennas. I recently purchased one of the DBJ-1 J pole antennas from Ed Fong. An amazing antenna that looked so simple to make. I might like to try making one for portable use in the future. Thanks again.(y)
 
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graywoulf

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#29
Thank you very much for all of this. This looks like a good start for me to study antenna design and construction. I just got my MFJ-259B analyzer today and I am learning how to use it. I must say that I am enjoying learning all of this new technical stuff. I'm 63 and proof that you can teach an old dog new tricks. :D
 
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#30
You got a year on me. Congrats on the antenna analyzer, it will open a new world with understanding how antennas behave, and it will also give you fits not understanding how antennas behave.

If you make an EFHW for 40m on up, hang it in the air and tune it for the best match on roughly 7.125 to 7.150, which will also land it around 14.250 to 14.300 on 20m and so on. All the bands will be harmonically related.

If you make a 133ft long 80m version tune it the same as a 40m version and forget about 80m. Turns out 80m is not harmonically related to the other bands and it will have the best match around 3.6Mhz and the match in the 3.8-4.0Mhz range will be high but it will still radiate really well.

Thank you very much for all of this. This looks like a good start for me to study antenna design and construction. I just got my MFJ-259B analyzer today and I am learning how to use it. I must say that I am enjoying learning all of this new technical stuff. I'm 63 and proof that you can teach an old dog new tricks. :D
 

graywoulf

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#31
One nice thing about the ZS6BKW is it has a good match on many bands, unlike its cousin the G5RV which was designed as a 20m antenna. That means less coax loss from the coax operating under high mismatch conditions. On 80m the match will be above 5:1 but within the tuning range of most modern tuners built into radios.
I have been reading up on the ZS6BKW antenna and I have a question. The specs on this antenna state that it needs to be at least 40' or higher and it also states that it needs a minimum of 70' of 50 OHM coax to be effective.

My situation is that I barely could attain that height but I can get very close. But between the 40' of ladder line and the 70' of coax, I am going to have a lot of left over coax to deal with as this antenna is going to have to be mounted on a mast which is going to be attached to the chimney on my house. I have no other options for mounting a dipole which is why I was considering the EFHW antenna. So, my question is that is it still possible that this is a good antenna option for me?

Thanks.
 
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#32
Those don't sound like the specs from the designer, probably from one of the commercial mfrs. I've built a bunch of them and they have been used at all different heights with excellent performance.

The ZS6BKW is no different than any other HF wire antenna as far as height is concerned. For most people in a residential environment I think about 30 to 35ft is a good compromise. This will get the antenna about a half wavelength high on 20m for a good shot at low angle takeoff. Its also about 1/4 wavelength high on 40m giving the most gain upward for NVIS and its a reasonable height for 80m NVIS. I had mine about 30ft high and could get into some coast to coast evening nets on 80 and 40m with only 100w.

You feed this antenna with 50 ohm coax with a good 1:1 choke balun at the junction of the coax and ladder line. The least amount of coax is best. The match on most bands 40m on up is good and easily handled with an internal radio tuner that will tune a 3:1 mismatch. On 80m it will be worse and you will need a tuner that can do up to 10:1, but of the coax run is short you will have very little overall loss and the high VSWR on 80m wont degrade the performance much.

If you put a 94ft long ZS6BKW up against a full size 80m 133ft tuned dipole at the same height, the difference between them is not much. Probably less than 2dB not counting feedline loss.

I have been reading up on the ZS6BKW antenna and I have a question. The specs on this antenna state that it needs to be at least 40' or higher and it also states that it needs a minimum of 70' of 50 OHM coax to be effective.

My situation is that I barely could attain that height but I can get very close. But between the 40' of ladder line and the 70' of coax, I am going to have a lot of left over coax to deal with as this antenna is going to have to be mounted on a mast which is going to be attached to the chimney on my house. I have no other options for mounting a dipole which is why I was considering the EFHW antenna. So, my question is that is it still possible that this is a good antenna option for me?

Thanks.
 
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W5lz

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#33
The "absolute" minimum height is what will keep the ladder line off the ground. The real one is whatever you can manage so that ladder line isn't on the ground coiled, or doubled back onto it's self. From there, get all you can get. The length of the ladder line (minus a bit depending on location) is the minimum height that practical.
 

w2xq

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#34
I used PVC pipe in the ground to get my balanced feedline out of the house and to a spot about 50 feet from the house. Balanced feedline tuner, 100w input, good for about 220 countries and all (at the time) 3076 USA counties. No need for a tower, beam or amplifier. I don't think I spent more than $40 on any antenna. Wire, feedline, insulators and rope. A hunting slingshot and cheap spinning rod were one-time purchases to toss ropes over 50-100 foot trees. KISS principle. Good luck.
 

graywoulf

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#35
Thanks for the information guys. I was beginning to wonder if ANY antenna was going to work for me but I am seeing the light at the end of the tunnel. Thanks w2xq for reminding me of the KISS method. ;)
 
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#36
Ladder line can also go sideways. I had a G5RV then a ZS6BKW at work with the ladder line going sideways horizontal into the building where it changed to coax but still 90deg to the antenna wire. Whatever works to keep it off the ground.

Thanks for the information guys. I was beginning to wonder if ANY antenna was going to work for me but I am seeing the light at the end of the tunnel. Thanks w2xq for reminding me of the KISS method. ;)
 

graywoulf

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#37
Ladder line can also go sideways. I had a G5RV then a ZS6BKW at work with the ladder line going sideways horizontal into the building where it changed to coax but still 90deg to the antenna wire. Whatever works to keep it off the ground.
So, back to the ZS6BKW antenna, if I can get the center to 30' or so, can I pull the ladder line horizontally across the roof of my house and then use maybe 20' of coax to my radio? Or does the ladder line have to be straight down at the 90deg angle for sure?
 
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#38
You can pull the ladder line sideways and horizontal to the roof but try to keep it 90deg to the main antenna. I would keep it off the roof and I used concrete cinder blocks with a two foot long chunk of PVC pipe screwed to it to suspend the ladder line above the roof. I then slit the open top of the PVC pipe to stick the ladder line in then a PVC pipe over that to lock the ladder line in the pipe. I had a cinder block every 15ft or so until the ladder line transitioned to coax then that laid right on the roof. The cinder blocks are nice because you can move them around as needed and they stay put.

You must use a good choke balun at the ladder line/coax junction. You can make an ok one with a $7 ferrite toroid that approaches 30dB of common mode isolation but I would recommend this one for over 40dB of common mode isolation. CMC-130S-3K - MyAntennas.com

So, back to the ZS6BKW antenna, if I can get the center to 30' or so, can I pull the ladder line horizontally across the roof of my house and then use maybe 20' of coax to my radio? Or does the ladder line have to be straight down at the 90deg angle for sure?
 

W5lz

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#39
Any dog will like you if you feed it and scratch it's back every now and then. Pick an antenna, "scratch it's back" a little and it'll like you too. The first biggy is that it has to fit in the space you have available. Bending it a little won't hurt. Then you gotta get a signal to it, that's where the feed line comes in. They will want a "scratch" or two also, as in matching impedance as best you can (as practical). Then you get a transmitter to feed the whole mess. It really isn't that hard to do ... just do it.
 

graywoulf

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#40
The antenna tuner within the transceiver may not be sufficient to handle an endfed wire on all bands, but a external antenna tuner should be easy pickings at a hamfest. If you opt to get one, get one with a balanced line output. That just opens your options for the future. I prefer tuners without metering. Decent antenna tuners don't go bad. Standalone SWR meters--if needed--can always be replaced. Hope that helps.
Looking back at your recommendation on using an external tuner, I have been researching various brands and models and I found this one which has the balanced line input which is the MFJ-901B. Would this be a good choice or do you have a different recommendation?
 
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