Very Interesting talk, thank you. Although there were some good questions from the audience I could happily punch out one guy in particular who was adimant to show 'his' knowledge and not allow you to get to the point you were making first. You are very patient Terry. Regards mate :-)
This is why some people dont learn as much as they could....because they go to a class on antennas and then regurgitate what they think they already know. Right or wrong doesnt matter, just listen to the presentation and ask questions specific to that presentation. You also lose out on other information that may have been presented because you disrupted the flow of the speaker.
It is difficult for someone who knows more in depth about the subject than is told by presenter to keep quiet. Regurgitate unchecked information: bad. Breaking the flow because misinformation is being spread - ugly, but justified.
Terry, I watched this video again. Thanks again for this presentation. When I watch good instructional content like this I realize that I have a lot to learn! I hope when ever I get my HF station up again I can use some of the theory you explain here to build a better more efficient antenna and station install. Thanks!
Thanks for the great video. This explained my recent problems. Last year I tried cutting a 40M antenna, raised it up in the trees and discovered I had cut it about three feet too short! Rather than adding the additional length, I decided to add about 200 feet of wire to the center point of the driven side of the dipole and string it out in the trees. Using a little QRP tuner, that worked well enough for me to get WAS using QRP with FT8. However, SWR was high (about 1:3) on 15 & 80M. Last week I decided to cut that short piece of 40M driven wire from the antenna, thinking that might help get the SWR down. I was SO wrong. Cutting that piece out caused my lowest SWR to become 1:5 on all bands! UGH!!! I am now planning on just building a fan dipole and forgetting about my "random wire" antenna. LOL 73s DE KC7RAD
Found a spool of junk wire. Shot some up in the near by tree.(the core) the other end to a coil on the wire going to a tree. On the low end.(shield) Thrugh to a 300 ohm restor to ground. The darn thing covers from Maine to Florida. Then texas to Canada and have heard England. This is a receiving antenna.( And I don't care to even to measure it). Love it tks for the show. De kv4li
He mentioned that you don’t what the feed point to be at the high current point when in fact that is what you want. The the high current point on an antenna has low impedance. He should have said high voltage point.
You didn’t mention using a 9:1 unun at the feed point. I’ve heard of a “random wire” end fed that is 74 feet long if the lowest band is 75 meters, but a 9:1 unun is used at the feed point. Supposedly, it covers 75 to 10 meters without a tuner. I haven’t tried building an end fed like that yet.
The pdf for the chart doesn't appear to be posted anywhere that google can find - but this works at least for Windows.Pause video at 9:44. Then alt-PrtScr, open Paint Brush and paste.
Terry, is 148 feet your actual cut, or do you still need to consider the 0.95 VF of the wire?
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If it not a Odd Number of Wave Lengths it is a Even Number if Wave Lengths and Long as it comes out too an even Number of Wave Lengths It will Work it is the Square Root or long as you can Divide the Wave Lengths by 2 and come out with a Whole Number it will Work
Bill Loveless ....Make your wire radiator at least as long as the lowest band of use,but within the specified lengths.In other words,a wire cut for 10 meters won’t be efficient on 80 meters.
I make the length for a single band, if that is all that I want to use for that antenna. If you want to use a single antenna across all of the ham bands, use the figures in the chart.
The 6 turn coil of coax cable is to be at the input to the auto tuner, which is located at the wire antenna. The purpose of the coil is to keep stray RF energy from forming on the shield of the coax, and coming into the shack.
On lower frequencies such as 160m and 80m having a vertical antenna has a big advantage with DX, because the radiation angle of vertical antennas favor DX. . An inverted L gives you both a vertical and horizontal element for radiation and is a big favorite among a lot of people. I would recommend an inverted L using the same figures for total length, if you have the ability to have that vertical part.
AT 10:00 , you list some better wire lengths. Question: If the wire must be looped back at the ends to tie it off to the supports, do you still literally use these lengths or do you want these lengths to exclude the loops? I am building an antenna for listening only but want it to be as efficient across all bands as possible. I will be building an UnUn that is 9:1. There may be a time when I will want to get into TX, so having an antenna that may already be capable would be nice. I plan to use an insulated 16-gauge wire. The UnUn will use solid enameled copper 18-gauge. How much power would you estimate this would handle for TX? Further question on a pulley and weight. I plan to have one end attached to a tree which is about 100 feet away. If I use the 16-gauge stranded insulated wire of 84 feet, do you know how heavy the weight should be to hold it taut? Do you want the wire as straight as possible? Thanks
The loops are small in relation to the overall length of the wire. Technically the loop adds a small amount of capacitance to the circuit, but for our purposes, we will ignore that. I add enough extra wire to allow for the loop through the insulator. I measure the length from the feed point to the far end of the loop, inside the insulator. I know some will measure to the point where the wire enters the insulator. That distance is most likely a half inch difference, which in practice matters very little.
@@djterry17032 This makes me think my steel roof on my home could likewise be the counterpoise or ground plane something no-one else has admitted would work. I have a pole that I have thought about adjusting to 16 feet or so and just use the roof as the ground plane and have asked several folks with web postings and no-one seems interested in stating their opinion. The DX Commander is one I have considered putting up, but with my property being lower and surrounded by metal roofed buildings blocking any lower level take off, using a vertical on a porch roof attached to my main house roof seems the better way to get a lower level takeoff that would be just above all these metal roofs around me. My GAP Challanger was essentually disabled when I tried using it, good enough SWR but no view of the directions needed to make desired contacts. Thanks again.
Very surprised no mention of transforming the very high-end currents down to 50 ohms from as much as 2800 or more was mentioned? A very short counterpoise will work. A 49:1 transformer is commonly being used to make it work?
This presentation was built around the ICOM pole mounted auto tuner, and the lengths of wire that will work best for it. I did mention that the tuner is mounted to a house with aluminum siding that works as a RF Ground and counterpoise.
@@djterry17032 Of course an at the feed point tuner solves many issues, I guess I missed it being mentioned. Just getting aware of using transformers to broad band a halfwave wire to the higher bands, that approach has been on my mind, I have the capactors that are needed to raise an 80 meter EFHW to resonate on 75 ordered to put up a 134 foot or so wire using a 49:1 transformer to do it. Yes my brother not a ham but a Marine SSB user had a wire he used with one of the marine tuners to do exactly what you were speaking about but just the marine SSB frequencies which are also simuliar to ours harmonically. He successfully operated 4 megs to 25 megs . I am hopefull my 80 and up transformer tuned 1/2 wave at 80 can resonate on most bands no tuner necessary or just the internal from my 7300 but without actual experience only experience will tell the benefit when I get this antenna up. Facebook has a page EFHW that has 11,000 users commenting about their experience that you might find interesting. Steve Ellington has many videos of his testsing and experiences plus the theory of on TH-cam and Facebook about how this all works. One benefit is the lack of requiring the need for long counterpoises that actually turn a wire into an off- center feed dipole because both sides are necessary. We all search for an easy to install and use multiband antenna that works and I suspect Hams will be forever searching for that design? Good luck looking for yours, please share it when you find it!! Thanks 73s
If you want a single band antenna, the length of the wire is a quarter wave for that frequency. If you want it to be every ham band for HF, the chart that I projected on the screen shows, in the lower set of numbers, the usable lengths of wire to accomplish that. I do have a PDF file with that chart that will be placed on the web site w3uu.org. I will also post it on the Facebook page for Harrisburg Radio Amateurs Club.
I would have like to have listened to this, but the microphone placement where some guy's nose breathing is louder that the presenter's voice turned me off it after a few minutes. (Side note to presenter: Chimley?)
I have a Friday 9 to 100 wood that 148 feet work well with that I would appreciate a return if you would please cause I’m not sure about the Gundrum thank you
Very Interesting talk, thank you. Although there were some good questions from the audience I could happily punch out one guy in particular who was adimant to show 'his' knowledge and not allow you to get to the point you were making first. You are very patient Terry. Regards mate :-)
This is why some people dont learn as much as they could....because they go to a class on antennas and then regurgitate what they think they already know. Right or wrong doesnt matter, just listen to the presentation and ask questions specific to that presentation. You also lose out on other information that may have been presented because you disrupted the flow of the speaker.
It is difficult for someone who knows more in depth about the subject than is told by presenter to keep quiet. Regurgitate unchecked information: bad. Breaking the flow because misinformation is being spread - ugly, but justified.
Yup. Every Eric Dollard presentation disturbed by people stuck in the box
Terry, I watched this video again. Thanks again for this presentation. When I watch good instructional content like this I realize that I have a lot to learn! I hope when ever I get my HF station up again I can use some of the theory you explain here to build a better more efficient antenna and station install. Thanks!
Awesome sound and video guy. Keep up the good work (Elmer)Terry. WB3BKN
Thanks for the great video. This explained my recent problems. Last year I tried cutting a 40M antenna, raised it up in the trees and discovered I had cut it about three feet too short! Rather than adding the additional length, I decided to add about 200 feet of wire to the center point of the driven side of the dipole and string it out in the trees. Using a little QRP tuner, that worked well enough for me to get WAS using QRP with FT8. However, SWR was high (about 1:3) on 15 & 80M. Last week I decided to cut that short piece of 40M driven wire from the antenna, thinking that might help get the SWR down. I was SO wrong. Cutting that piece out caused my lowest SWR to become 1:5 on all bands! UGH!!!
I am now planning on just building a fan dipole and forgetting about my "random wire" antenna. LOL
73s
DE KC7RAD
i like seeing him coming in, carrying the HT like a beer.
Found a spool of junk wire. Shot some up in the near by tree.(the core) the other end to a coil on the wire going to a tree. On the low end.(shield) Thrugh to a 300 ohm restor to ground. The darn thing covers from Maine to Florida. Then texas to Canada and have heard England. This is a receiving antenna.( And I don't care to even to measure it). Love it tks for the show. De kv4li
Resistor working as a weak diode on your ground, just in case of a lightning strike?
Thank you Terry, very informative and a big, big help!
Thank you, I am happy that it helped
10:00 Best lengths.
He mentioned that you don’t what the feed point to be at the high current point when in fact that is what you want. The the high current point on an antenna has low impedance. He should have said high voltage point.
You are correct.
You didn’t mention using a 9:1 unun at the feed point. I’ve heard of a “random wire” end fed that is 74 feet long if the lowest band is 75 meters, but a 9:1 unun is used at the feed point. Supposedly, it covers 75 to 10 meters without a tuner. I haven’t tried building an end fed like that yet.
The pdf for the chart doesn't appear to be posted anywhere that google can find - but this works at least for Windows.Pause video at 9:44. Then alt-PrtScr, open Paint Brush and paste.
Just made one with 52.1 m (171 ft) of wire, a 9:1 balun and a tuner, of course. Seems to work well in all bands from 160 m to 6 m.
Seems you made a 1/4 wave for 160m, with harmonics on the lower ham wavelengths. 'Random' seems a misnomer.
@@joeshmoe7899 Seems you don't master arithmetic.
Terry, is 148 feet your actual cut, or do you still need to consider the 0.95 VF of the wire?
If it not a Odd Number of Wave Lengths it is a Even Number if Wave Lengths and Long as it comes out too an even Number of Wave Lengths It will Work it is the Square Root or long as you can Divide the Wave Lengths by 2 and come out with a Whole Number it will Work
Why not an end fed?
So, if I understand this video, creating a random length antenna, I make the length for the band I'm using?
Thanks
Bill Loveless ....Make your wire radiator at least as long as the lowest band of use,but within the specified lengths.In other words,a wire cut for 10 meters won’t be efficient on 80 meters.
I make the length for a single band, if that is all that I want to use for that antenna. If you want to use a single antenna across all of the ham bands, use the figures in the chart.
8:00 always some stooge that wants the attention. Thank you for the lecture.
Is the 6 plus turns of wire to form a choke part of the 148feet or additional to it?
The 6 turn coil of coax cable is to be at the input to the auto tuner, which is located at the wire antenna. The purpose of the coil is to keep stray RF energy from forming on the shield of the coax, and coming into the shack.
How does a random wire (configured in horizontal only) compare to an endfed (configured as inverted L)
On lower frequencies such as 160m and 80m having a vertical antenna has a big advantage with DX, because the radiation angle of vertical antennas favor DX. . An inverted L gives you both a vertical and horizontal element for radiation and is a big favorite among a lot of people. I would recommend an inverted L using the same figures for total length, if you have the ability to have that vertical part.
AT 10:00 , you list some better wire lengths. Question: If the wire must be looped back at the ends to tie it off to the supports, do you still literally use these lengths or do you want these lengths to exclude the loops?
I am building an antenna for listening only but want it to be as efficient across all bands as possible. I will be building an UnUn that is 9:1. There may be a time when I will want to get into TX, so having an antenna that may already be capable would be nice. I plan to use an insulated 16-gauge wire. The UnUn will use solid enameled copper 18-gauge. How much power would you estimate this would handle for TX?
Further question on a pulley and weight. I plan to have one end attached to a tree which is about 100 feet away. If I use the 16-gauge stranded insulated wire of 84 feet, do you know how heavy the weight should be to hold it taut? Do you want the wire as straight as possible?
Thanks
The loops are small in relation to the overall length of the wire. Technically the loop adds a small amount of capacitance to the circuit, but for our purposes, we will ignore that. I add enough extra wire to allow for the loop through the insulator. I measure the length from the feed point to the far end of the loop, inside the insulator. I know some will measure to the point where the wire enters the insulator. That distance is most likely a half inch difference, which in practice matters very little.
Do you have to have a counterpoise on your random wire antenna if you are just receiving?
Yes, there is always a counterpoise. On my home station the counterpoise is the aluminum siding on my house.
@@djterry17032 This makes me think my steel roof on my home could likewise be the counterpoise or ground plane something no-one else has admitted would work. I have a pole that I have thought about adjusting to 16 feet or so and just use the roof as the ground plane and have asked several folks with web postings and no-one seems interested in stating their opinion. The DX Commander is one I have considered putting up, but with my property being lower and surrounded by metal roofed buildings blocking any lower level take off, using a vertical on a porch roof attached to my main house roof seems the better way to get a lower level takeoff that would be just above all these metal roofs around me. My GAP Challanger was essentually disabled when I tried using it, good enough SWR but no view of the directions needed to make desired contacts. Thanks again.
well been working on home made G - 5 r v all day.
Very surprised no mention of transforming the very high-end currents down to 50 ohms from as much as 2800 or more was mentioned? A very short counterpoise will work. A 49:1 transformer is commonly being used to make it work?
This presentation was built around the ICOM pole mounted auto tuner, and the lengths of wire that will work best for it. I did mention that the tuner is mounted to a house with aluminum siding that works as a RF Ground and counterpoise.
@@djterry17032 Of course an at the feed point tuner solves many issues, I guess I missed it being mentioned. Just getting aware of using transformers to broad band a halfwave wire to the higher bands, that approach has been on my mind, I have the capactors that are needed to raise an 80 meter EFHW to resonate on 75 ordered to put up a 134 foot or so wire using a 49:1 transformer to do it. Yes my brother not a ham but a Marine SSB user had a wire he used with one of the marine tuners to do exactly what you were speaking about but just the marine SSB frequencies which are also simuliar to ours harmonically. He successfully operated 4 megs to 25 megs . I am hopefull my 80 and up transformer tuned 1/2 wave at 80 can resonate on most bands no tuner necessary or just the internal from my 7300 but without actual experience only experience will tell the benefit when I get this antenna up. Facebook has a page EFHW that has 11,000 users commenting about their experience that you might find interesting. Steve Ellington has many videos of his testsing and experiences plus the theory of on TH-cam and Facebook about how this all works. One benefit is the lack of requiring the need for long counterpoises that actually turn a wire into an off- center feed dipole because both sides are necessary. We all search for an easy to install and use multiband antenna that works and I suspect Hams will be forever searching for that design? Good luck looking for yours, please share it when you find it!! Thanks 73s
Ps I do use a pixie2 my pet. And do switch to that when xmit ing.
If you want a single band antenna, the length of the wire is a quarter wave for that frequency. If you want it to be every ham band for HF, the chart that I projected on the screen shows, in the lower set of numbers, the usable lengths of wire to accomplish that. I do have a PDF file with that chart that will be placed on the web site w3uu.org. I will also post it on the Facebook page for Harrisburg Radio Amateurs Club.
Terry,
Do you have a link to the PDF? Looked on the Facebook page and w3uu.org and found nothing. 73 WB3BJU
I would have like to have listened to this, but the microphone placement where some guy's nose breathing is louder that the presenter's voice turned me off it after a few minutes.
(Side note to presenter: Chimley?)
Chimley is a local joke. For some reason many of the older locals say that when they mean chimney.
One lenght is short the other lenght is open
I have a I have 49 to 100 Andra will that 148 feet of wire work well with that my call is K1emw Thank you
Simply put - the wire needs to be a NON-RESONANT length.
A tuner does not absorb all your power, please read Walt Maxwells book reflections
We Really need too Stop using the Term Random Wire Antennas and Start using something like End Fed or Long Wire or just Wire Antenna
I have a Friday 9 to 100 wood that 148 feet work well with that I would appreciate a return if you would please cause I’m not sure about the Gundrum thank you
Why doesn’t the guy who knows everything just QRU?? Gave up and left the channel!!