<![CDATA[GBARC Forum - Antennas]]>

<![CDATA[GBARC Forum - Antennas]]> https://www.gbarc.ca/ForumBB/ Tue, 12 May 2026 01:17:26 +0000 MyBB <![CDATA[HEXBEAMS]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=1191 Wed, 24 Apr 2024 11:23:20 -0400 Dave_VE3WI]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=1191
For anyone wanting to buy one, most if not all hexbeams for sale are based on the design by Steve Hunt G3TXQ (SK), that Adam described.

Steve Hunt's website http://www.karinya.net/ is still up and has all his hexbeam info as well as a wealth of info on baluns and chokes. He did hundreds of tests of different chokes and distilled the results into a great design chart. Check it out: http://www.karinya.net/g3txq/chokes/

I don't own a hexbeam but have done a little research:

The Cadillac of hexbeams is the VHQ. It's relatively new (23 reviews on eHam.net, 5 out of 5). Also the priciest (~$2300 CDN + shipping).
https://www.vhqhex.com/

The most popular hexbeam is probably the one manufactured by K4KIO (187 reviews on eHam.net, 4.9 out of 5).
https://www.k4kio.com/

Other USA manufacturers are:

N4ARR: https://k4hex.com/

DX Engineering: https://www.dxengineering.com/search/dep...Ahexagonal

MFJ: https://mfjenterprises.com/products/mfj-1848

There are also several European manufacturers.

A complete list of all the hexbeams which have eHam reviews is at https://www.eham.net/reviews/view-category?id=11

73
Dave, VE3WI]]>
For anyone wanting to buy one, most if not all hexbeams for sale are based on the design by Steve Hunt G3TXQ (SK), that Adam described.

Steve Hunt's website http://www.karinya.net/ is still up and has all his hexbeam info as well as a wealth of info on baluns and chokes. He did hundreds of tests of different chokes and distilled the results into a great design chart. Check it out: http://www.karinya.net/g3txq/chokes/

I don't own a hexbeam but have done a little research:

The Cadillac of hexbeams is the VHQ. It's relatively new (23 reviews on eHam.net, 5 out of 5). Also the priciest (~$2300 CDN + shipping).
https://www.vhqhex.com/

The most popular hexbeam is probably the one manufactured by K4KIO (187 reviews on eHam.net, 4.9 out of 5).
https://www.k4kio.com/

Other USA manufacturers are:

N4ARR: https://k4hex.com/

DX Engineering: https://www.dxengineering.com/search/dep...Ahexagonal

MFJ: https://mfjenterprises.com/products/mfj-1848

There are also several European manufacturers.

A complete list of all the hexbeams which have eHam reviews is at https://www.eham.net/reviews/view-category?id=11

73
Dave, VE3WI]]> <![CDATA[Common mode current. Measuring effectiveness of choke]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=1158 Fri, 22 Mar 2024 15:32:13 -0400 Kevin VA3RCA]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=1158 Mark, N6MTS created this great video presentation on common mode current and how to measure the effectiveness of a choke you build.
Mark delivers a great explanation of what common mode current is and what the impacts are. He describes how to build a simple test jig to use your NanoVNA to measure the effectiveness of chokes we can build.
Using his test jig he demonstrates a number of simple common mode chokes, and graphs their impedance at frequencies across the HF spectrum!
Watch the video here:
https://youtu.be/3ReRu7Yt4Ao?si=jHpRsMWPg7kNUoe8]]> Mark, N6MTS created this great video presentation on common mode current and how to measure the effectiveness of a choke you build.
Mark delivers a great explanation of what common mode current is and what the impacts are. He describes how to build a simple test jig to use your NanoVNA to measure the effectiveness of chokes we can build.
Using his test jig he demonstrates a number of simple common mode chokes, and graphs their impedance at frequencies across the HF spectrum!
Watch the video here:
https://youtu.be/3ReRu7Yt4Ao?si=jHpRsMWPg7kNUoe8]]> <![CDATA[Antenna Information Archive]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=1099 Thu, 21 Dec 2023 10:36:42 -0500 Dave_VE3WI]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=1099
Another well-known antenna expert, Marcel ON5AU maintained an archive of Cebik's work on his website.

ON5AU recently passed away, so Lonney K1LH picked up the torch and created a great website preserving Cebik's work and making it available for all of us.

https://www.antenna2.net/cebik/

73
Dave, VE3WI]]>
Another well-known antenna expert, Marcel ON5AU maintained an archive of Cebik's work on his website.

ON5AU recently passed away, so Lonney K1LH picked up the torch and created a great website preserving Cebik's work and making it available for all of us.

https://www.antenna2.net/cebik/

73
Dave, VE3WI]]> <![CDATA[Tower, Beam, and rotor available but must be taken down]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=1067 Fri, 27 Oct 2023 19:22:48 -0400 Bernie ve3bqm]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=1067
If you would like a tri band 10-15-20 beam , 3 section of tower and Hy-Gain rotor and control box.
The widow of a past VE3TTV Henry would like to have it gone.
Its located near Kelso Beach Owen Sound.
If interested a 50/50 split donation to the club and widow would be appreciated.

Other Equipment may be available.

Please contact Bernie VE3BQM via Text at 519.270.1330.

Thank

20231026_122309.jpg Size: 63.9 KB Downloads: 33

]]>
If you would like a tri band 10-15-20 beam , 3 section of tower and Hy-Gain rotor and control box.
The widow of a past VE3TTV Henry would like to have it gone.
Its located near Kelso Beach Owen Sound.
If interested a 50/50 split donation to the club and widow would be appreciated.

Other Equipment may be available.

Please contact Bernie VE3BQM via Text at 519.270.1330.

Thank

20231026_122309.jpg Size: 63.9 KB Downloads: 33

]]> <![CDATA[LIGHTNING DETECTION]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=1014 Fri, 14 Jul 2023 12:02:05 -0400 Dave_VE3WI]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=1014 "A very large amount of lightning was approaching my area so I disconnected my 80 meter dipole and inserted a large blue LED in the connector".

https://www.youtube.com/watch?v=HQ4Gxye8Sn4&t=73s

Think about all those pulses lighting up that LED, lighting up your rig instead. And the storm was still miles away.

73
Dave, VE3WI]]> "A very large amount of lightning was approaching my area so I disconnected my 80 meter dipole and inserted a large blue LED in the connector".

https://www.youtube.com/watch?v=HQ4Gxye8Sn4&t=73s

Think about all those pulses lighting up that LED, lighting up your rig instead. And the storm was still miles away.

73
Dave, VE3WI]]> <![CDATA[New Antenna Tower]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=996 Sat, 24 Jun 2023 14:05:51 -0400 ryan_va3ryc]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=996
I am Ryan, VA3RYC. I am new to the group, and new to the area. I just purchased a home in Flesherton, and I'm looking to put up a tower for Starlink and Amateur antennas. This will be my first tower, and I was going to see if anyone in the area had some experience to share.

I talked to the municipality, and I have it in writing that I do not need a building permit, and I plan to stay under 15m so I fall under ISED and not the land use authority. So I am close to ready for a tower.

My ideal location is right next to the house, so that brings up a few questions. First off, does anyone feel strongly about concrete vs house-attached. Second, does that affect how I ground the tower (I normally would cadweld a new ground rod around and bond the tower with a clamp, but I am unsure being close to the house if I would need to tie it to the house ground too?).

I also know that if I use concrete I probably need to deal with the leverage effect and make it the same depth as the foundation (which would be obnoxious and heavy) or I need to make a flex joint (which I have not done with concrete before).

I'm also planning a hinge base, possibly a Wade: https://wadeantenna.com/product/golden-n...e-up-base/ because I can get a good deal on it.

Any advice would be appreciated!

73 VA3RYC]]>
I am Ryan, VA3RYC. I am new to the group, and new to the area. I just purchased a home in Flesherton, and I'm looking to put up a tower for Starlink and Amateur antennas. This will be my first tower, and I was going to see if anyone in the area had some experience to share.

I talked to the municipality, and I have it in writing that I do not need a building permit, and I plan to stay under 15m so I fall under ISED and not the land use authority. So I am close to ready for a tower.

My ideal location is right next to the house, so that brings up a few questions. First off, does anyone feel strongly about concrete vs house-attached. Second, does that affect how I ground the tower (I normally would cadweld a new ground rod around and bond the tower with a clamp, but I am unsure being close to the house if I would need to tie it to the house ground too?).

I also know that if I use concrete I probably need to deal with the leverage effect and make it the same depth as the foundation (which would be obnoxious and heavy) or I need to make a flex joint (which I have not done with concrete before).

I'm also planning a hinge base, possibly a Wade: https://wadeantenna.com/product/golden-n...e-up-base/ because I can get a good deal on it.

Any advice would be appreciated!

73 VA3RYC]]> <![CDATA[UHF Quick Disconnect - Who Knew?]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=964 Thu, 27 Apr 2023 10:38:51 -0400 Dave_VE3WI]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=964
If you're not familiar with The Wireman, have a look at their website. They have a big selection of antenna-related wire, cable & accessories for the ham market.

https://thewireman.com/

73
Dave, VE3WI

quickconnect.pdf Size: 71.75 KB Downloads: 7

]]>
If you're not familiar with The Wireman, have a look at their website. They have a big selection of antenna-related wire, cable & accessories for the ham market.

https://thewireman.com/

73
Dave, VE3WI

quickconnect.pdf Size: 71.75 KB Downloads: 7

]]> <![CDATA[Hardline splicing]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=908 Sun, 22 Jan 2023 20:54:04 -0500 Rob_Walker]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=908
I didn't get my Yagi up this past summer so my 1/2" Heliax sits in two pieces. I have an Andrews connector specifically for splicing hardline, and I also have a collection of "N" connectors with bulkhead connectors for joining them.

I was particularly interested in the newsletter article using copper tubing. I'm curious what one would use for a dielectric after the centre conductor was joined but before the 1/2" copper tubing was installed on the outside jacket?

What I like about this method is it would minimize the weak spot where the hardline might want to kink. Open to suggestions.

73 Rob]]>
I didn't get my Yagi up this past summer so my 1/2" Heliax sits in two pieces. I have an Andrews connector specifically for splicing hardline, and I also have a collection of "N" connectors with bulkhead connectors for joining them.

I was particularly interested in the newsletter article using copper tubing. I'm curious what one would use for a dielectric after the centre conductor was joined but before the 1/2" copper tubing was installed on the outside jacket?

What I like about this method is it would minimize the weak spot where the hardline might want to kink. Open to suggestions.

73 Rob]]> <![CDATA[Another tower project, 40m Yagi]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=837 Mon, 10 Oct 2022 16:35:37 -0400 Rob_Walker]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=837
The tower is a light duty Wade but the boom for the Yagi is 15' and the elements are 46' long. I am anchoring the tower with guy lines at the 30' and 40' mark. I needed some headroom for the guy lines so the support for the lines protrude 5' out of the ground. I used 1.7" Schedule 40 pipe with 1/4" walls and sank this 5' into the ground with lots of contrete. Inside the 1.7" pipe is another 1-1/2" Schedule 40 pipe with 1/4" walls so the supports are very rigid.

[Image: IMG_5088.JPG]

Even though the tower is not free standing, I still used just over 1 cu. yd. of concrete and 8" of stone for drainage. The concrete had to be hand-bombed from the street to the back of my yard.

[Image: IMG_5090.JPG]

This afternoon I started fabricating two torque arms out of 2" x 2" angle iron. My guy lines will attach at the torque arms and prevent the tower from twisting in on itself. The upper guy wires will be 40' which would require me to break the guy lines up so they don't couple with the antenna.

[Image: IMG_5086.JPG]

I found I could make neat and precise work of my angle iron cuts using a 10" Dewalt mitre saw, an 80 tooth metal cutting blade and a cheap speed controller to keep the saw around 1800 rpm.

[Image: IMG_5087.JPG]

]]>
The tower is a light duty Wade but the boom for the Yagi is 15' and the elements are 46' long. I am anchoring the tower with guy lines at the 30' and 40' mark. I needed some headroom for the guy lines so the support for the lines protrude 5' out of the ground. I used 1.7" Schedule 40 pipe with 1/4" walls and sank this 5' into the ground with lots of contrete. Inside the 1.7" pipe is another 1-1/2" Schedule 40 pipe with 1/4" walls so the supports are very rigid.

[Image: IMG_5088.JPG]

]]> <![CDATA[nanoVNAs]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=783 Fri, 08 Jul 2022 09:55:26 -0400 Dave_VE3WI]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=783
"Messen ist Wissen, aber messen ohne Wissen ist kein Wissen" ("measurement is knowledge, but measurement without knowledge is not knowledge")

73
Dave, VE3WI]]>
"Messen ist Wissen, aber messen ohne Wissen ist kein Wissen" ("measurement is knowledge, but measurement without knowledge is not knowledge")

73
Dave, VE3WI]]> <![CDATA[Antenna Tuner Tips]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=719 Thu, 07 Apr 2022 11:05:38 -0400 Tom VA3TS]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=719 1. Never center feed a half-wave multi-band antenna with a high impedance feedline that is close to an odd multiple of a quarter-wave long.
2. Never center feed a full-wave antenna with any feedline close to a multiple of a half-wave long.
3. If a tuner will not tune a multi-band antenna, add or subtract 1/8 wave of feedline (for the band that won't tune) and try again.
4. Never try to load a G5RV or cente fed dipole on a band below the half-wave design frequency. If you want to operate an 80 meter antenna on 160 meters, feed either or both conductors as a longwire against the station ground.

To avoid problems matching or feeding any dipole antenna with high impedance lines, keep the lines around these lengths
[ The worst possible line lengths are shown in brackets ]:
160 meter dipole:
35-60, 170-195 or 210-235 feet.
[ Avoid 130, 260 ft]
80 meter dipole:
34-40, 90-102 or 160-172 feet.
[ Avoid 66, 135, 190 ft ]
40 meter dipole:
42-52, 73-83, 112-123 or 145-155 feet.
[ Avoid 32, 64, 96, 128 ft ]
NOTE:
Some trimming or adding of line may be necessary to accommodate higher bands.
WARNING:
To avoid problems, a dipole antenna should be a full half-wave on the lowest band.
On 160 meters, an 80 or 40 meter antenna fed the normal way will be extremely reactive with only
a few ohms of feedpoint resistance. Trying to load an 80 meter (or higher frequency) antenna on
160 meters can be a disaster for both your signal and the tuner. The best way to operate 160 with
an 80 or 40 meter antenna is to load either or both feedline wires (in parallel) as a longwire. The
antenna will act like a "T" antenna worked against the station ground

Taking the antenna tuner approach is not a good idea when you are using coaxial cable under high (greater than 3:1) SWR conditions. The tuner may provide the 50 ohm match to your radio, but the mismatch and high SWR still exists between the antenna tuner and the antenna! This translates to high losses in the coaxial cable.

autoxfrmr.jpg Size: 382.66 KB Downloads: 14

]]> 1. Never center feed a half-wave multi-band antenna with a high impedance feedline that is close to an odd multiple of a quarter-wave long.
2. Never center feed a full-wave antenna with any feedline close to a multiple of a half-wave long.
3. If a tuner will not tune a multi-band antenna, add or subtract 1/8 wave of feedline (for the band that won't tune) and try again.
4. Never try to load a G5RV or cente fed dipole on a band below the half-wave design frequency. If you want to operate an 80 meter antenna on 160 meters, feed either or both conductors as a longwire against the station ground.

To avoid problems matching or feeding any dipole antenna with high impedance lines, keep the lines around these lengths
[ The worst possible line lengths are shown in brackets ]:
160 meter dipole:
35-60, 170-195 or 210-235 feet.
[ Avoid 130, 260 ft]
80 meter dipole:
34-40, 90-102 or 160-172 feet.
[ Avoid 66, 135, 190 ft ]
40 meter dipole:
42-52, 73-83, 112-123 or 145-155 feet.
[ Avoid 32, 64, 96, 128 ft ]
NOTE:
Some trimming or adding of line may be necessary to accommodate higher bands.
WARNING:
To avoid problems, a dipole antenna should be a full half-wave on the lowest band.
On 160 meters, an 80 or 40 meter antenna fed the normal way will be extremely reactive with only
a few ohms of feedpoint resistance. Trying to load an 80 meter (or higher frequency) antenna on
160 meters can be a disaster for both your signal and the tuner. The best way to operate 160 with
an 80 or 40 meter antenna is to load either or both feedline wires (in parallel) as a longwire. The
antenna will act like a "T" antenna worked against the station ground

Taking the antenna tuner approach is not a good idea when you are using coaxial cable under high (greater than 3:1) SWR conditions. The tuner may provide the 50 ohm match to your radio, but the mismatch and high SWR still exists between the antenna tuner and the antenna! This translates to high losses in the coaxial cable.

autoxfrmr.jpg Size: 382.66 KB Downloads: 14

]]> <![CDATA[EZNEC Antenna Modelling]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=663 Sat, 01 Jan 2022 14:38:33 -0500 VA3KOT John]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=663
It is a Windows program but it runs nicely under Wine on my Linux Mint PC. One big advantage of the Pro version is the restriction of only 20 segments is removed so more complicated antennas can be modeled.

It's worth a look for anybody who wants to evaluate their antennas. I use it principally to determine the radiation pattern of my antennas.]]>
It is a Windows program but it runs nicely under Wine on my Linux Mint PC. One big advantage of the Pro version is the restriction of only 20 segments is removed so more complicated antennas can be modeled.

It's worth a look for anybody who wants to evaluate their antennas. I use it principally to determine the radiation pattern of my antennas.]]> <![CDATA[A better PL-259?]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=652 Thu, 16 Dec 2021 20:51:33 -0500 Dave_VE3WI]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=652
For those of you who still use the solder type, there is a better (but pricey) variation that is new to me. The Amphenol Connex #182120, is mostly identical to any PL-259, but as you can see below, instead of 4 tiny holes where you solder the shield braid, it has 2 larger slots. This makes soldering easier and more secure.

I found them at Digi-Key.ca for $13 each (ouch!). RF Connection down in Maryland has them for $8.00 CDN each, (still ouch!).

A cheaper way to accomplish much the same thing might be to open up the holes in a standard PL-259 with a Dremel.

I'll stick to crimp connectors, but these are an interesting alternative.

73
Dave, VE3WI

]]>
For those of you who still use the solder type, there is a better (but pricey) variation that is new to me. The Amphenol Connex #182120, is mostly identical to any PL-259, but as you can see below, instead of 4 tiny holes where you solder the shield braid, it has 2 larger slots. This makes soldering easier and more secure.

I found them at Digi-Key.ca for $13 each (ouch!). RF Connection down in Maryland has them for $8.00 CDN each, (still ouch!).

A cheaper way to accomplish much the same thing might be to open up the holes in a standard PL-259 with a Dremel.

I'll stick to crimp connectors, but these are an interesting alternative.

73
Dave, VE3WI

]]> <![CDATA[A Spiral Counterpoise]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=573 Tue, 07 Sep 2021 11:13:20 -0400 VA3KOT John]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=573 A ground-mounted vertical antenna needs a lot of radials to make it efficient, but if the antenna feed point is raised above ground fewer radials are required to obtain the same efficiency.

Operating out in the field makes it very difficult to deploy a lot of radials so a single raised counterpoise is often used. The counterpoise must be one quarter of a wavelength long. The vertical element is also one quarter of a wavelength long so the combination is similar to a half-wave dipole that is bent at 90 degrees at the feed point. It works very well; I have made many contacts with such an arrangement.

There is a problem though. The physical footprint of a vertical antenna is very small, but when we add a raised counterpoise - which for the 40m band is 33 feet long - we need a lot more space. But there is a solution - a spiral counterpoise.

A spiral counterpoise is loosely based on the Petlowany coil antenna. It is a disc holding a well-spaced coil of wire, one quarter wavelength long, in a horizontal plane. My spiral counterpoise holds 33 feet of wire in a disc with a diameter of just two feet, mounted at the base of the vertical element.

I used a sheet of 1/8 inch thick MDF drilled with lots of holes through which the wire is threaded in basket-weave fashion. It is lightweight, yet rigid enough to keep the wire turns in place.

A spiral counterpoise works because there is very little inductance or capacitance in the coil. The radio can't see the shape of the counterpoise; it only sees Resistance, Inductive Reactance and Capacitive Reactance. My antenna tunes up nicely on 20m and 40m without further adjustment and I have made QSOs with it. The pictures below show it deployed in my back yard.

]]> A ground-mounted vertical antenna needs a lot of radials to make it efficient, but if the antenna feed point is raised above ground fewer radials are required to obtain the same efficiency.

Operating out in the field makes it very difficult to deploy a lot of radials so a single raised counterpoise is often used. The counterpoise must be one quarter of a wavelength long. The vertical element is also one quarter of a wavelength long so the combination is similar to a half-wave dipole that is bent at 90 degrees at the feed point. It works very well; I have made many contacts with such an arrangement.

There is a problem though. The physical footprint of a vertical antenna is very small, but when we add a raised counterpoise - which for the 40m band is 33 feet long - we need a lot more space. But there is a solution - a spiral counterpoise.

A spiral counterpoise is loosely based on the Petlowany coil antenna. It is a disc holding a well-spaced coil of wire, one quarter wavelength long, in a horizontal plane. My spiral counterpoise holds 33 feet of wire in a disc with a diameter of just two feet, mounted at the base of the vertical element.

I used a sheet of 1/8 inch thick MDF drilled with lots of holes through which the wire is threaded in basket-weave fashion. It is lightweight, yet rigid enough to keep the wire turns in place.

A spiral counterpoise works because there is very little inductance or capacitance in the coil. The radio can't see the shape of the counterpoise; it only sees Resistance, Inductive Reactance and Capacitive Reactance. My antenna tunes up nicely on 20m and 40m without further adjustment and I have made QSOs with it. The pictures below show it deployed in my back yard.

]]> <![CDATA[ELECTRICAL SAFETY]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=518 Wed, 23 Jun 2021 11:13:37 -0400 Dave_VE3WI]]> https://www.gbarc.ca/ForumBB/showthread.php?tid=518
In summer we're installing towers & antennas, fixing antennas, taking down antennas & towers, etc. Two big hazards: gravity and electricity.

There are lots of electrical safety videos out there but I think this one is the best. It's from Dominion Energy in Virginia.

https://www.youtube.com/watch?v=2Xoyb9M5-EA

Enjoy & learn, and please be careful if there are power lines near your antenna project.

73
Dave, VE3WI

PS: They're energizing the 7 kV demo line by backfeeding through a 240V pole transformer. Good demonstration of why you must isolate the grid from your home wiring when running your generator during an outage.]]>
In summer we're installing towers & antennas, fixing antennas, taking down antennas & towers, etc. Two big hazards: gravity and electricity.

There are lots of electrical safety videos out there but I think this one is the best. It's from Dominion Energy in Virginia.

https://www.youtube.com/watch?v=2Xoyb9M5-EA

Enjoy & learn, and please be careful if there are power lines near your antenna project.

73
Dave, VE3WI

PS: They're energizing the 7 kV demo line by backfeeding through a 240V pole transformer. Good demonstration of why you must isolate the grid from your home wiring when running your generator during an outage.]]>