Dipoles and the "inverted V" placement

[FPR1981]

I've run dipoles through the years with considerable success. When I was younger, I polarized them horizontally. They worked and I talked all over town very well. It wasn't until 1996 that a ham friend suggested I go vertical, high up in the 90-year-old oak tree. We shot it up there with a sling shot, about 50 feet, tied it off and BAM.

The reaction from locals was immediate:

"Wow, when did you get such a loud radio?!"

"Wow, what are you playing on? You're wall to wall."

At 13, I had a Teaberry T-Command that a local CB shop "adjusted." It was my first base station. That dipole went up when I was 16. I felt so privileged, and couldn't fathom how that antenna could outperform even an old aluminum Ringo ground plane I had on the roof that I eventually stopped using because the SWR climbed and would never come back down again.

I've read about polarizing the dipole as an inverted V shape. I know that's frequently suggested as an alternative to an exposed antenna, with attic placement. Who has experience with the inverted V, either in the attic or elsewhere, and what was performance like?

 

[KEWB-N1EXA]

Like This ?
Works Fine...

Peter N1EXA

 

[FPR1981]

Like This ?
Works Fine...

Peter N1EXA

Yes sir, that's it.

Review?

 

[KEWB-N1EXA]

Yes sir, that's it.

Review?

lIke a mentioned in your low power 4 watt cb forum... A Lowels special ... Electrical pipe and U clamps a plastic board. 75 feet of RG6 and a Folgers coffee container...Use some Romex for the wire and weed whacker string to hold the V shape.
Talk to a guy 12 miles north of me on CB SSB ...Go on the local 10 meter Net they hear me too.

Peter N1EXA

 

[FPR1981]

lIke a mentioned in your low power 4 watt cb forum... A Lowels special ... Electrical pipe and U clamps a plastic board. 75 feet of RG6 and a Folgers coffee container...Use some Romex for the wire and weed whacker string to hold the V shape.
Talk to a guy 12 miles north of me on CB SSB ...Go on the local 10 meter Net they hear me too.

Peter N1EXA

What is the purpose of the coffee can?

I see that the weed wacker string goes between the Y, but do you also "trace" the wires with it too, so it's a "skeleton"?

And the Romex, is it 3 wires per side, total? You're using all of them?

Sorry for the questions, but I want to make sure I understand, because I have a roll of unused Romex and I'm building one of these, LOL.

 

[prcguy]

An inverted V shape will reduce your signal level by about 3dB when talking to a local with a vertical antenna. For skip it doesn't matter as the polarity there is random. Even with the 3dB or so degradation an inverted V will work better than a lot of other small base antennas.

First time I used on on CB was around 1978 when I traveled to visit a family member and they lived in a condo with no way to put an antenna outside. The condo was all wood and I made an inverted V and hung it on a wall. It worked surprisingly well indoors and got me a good 5mi range from ground level.

 

[FPR1981]

An inverted V shape will reduce your signal level by about 3dB when talking to a local with a vertical antenna. For skip it doesn't matter as the polarity there is random. Even with the 3dB or so degradation an inverted V will work better than a lot of other small base antennas.

First time I used on on CB was around 1978 when I traveled to visit a family member and they lived in a condo with no way to put an antenna outside. The condo was all wood and I made an inverted V and hung it on a wall. It worked surprisingly well indoors and got me a good 5mi range from ground level.

I am going to install an inverted V in someone's attic later in the week. They don't want an antenna on the outside of the house. I'll keep everyone posted on how it works.

Meanwhile, I used dual 18 gauge speaker wire and built a dipole for a buddy. He was using a Tram 300 magnet mount, magnetized to a metal roof. He's about 1.5 miles away with terrain and slight altitude change in between and was hitting me with 7db, but some static in there. I took him the dipole and it was too snowy to install outside, so he ran it across his radio room. His previous 7db signal became a solid 9 swinging 10db and no more static.

I wonder what would perform better, horizontal across an upstairs bedroom as a radio room, or inverted V in the attic.

Opinions?

 

[KEWB-N1EXA]

What is the purpose of the coffee can?

I see that the weed wacker string goes between the Y, but do you also "trace" the wires with it too, so it's a "skeleton"?

And the Romex, is it 3 wires per side, total? You're using all of them?

Sorry for the questions, but I want to make sure I understand, because I have a roll of unused Romex and I'm building one of these, LOL.

The coffee can has 20-21 feet of RG-6 coiled around it to make an RF Choke which stops the RF travelling down the shield and back to the radio and it cuts down getting into everything else around the house too... Its a easy out instead of buying a 1:1 Balun. You can look it up on Google on many versions of this Choke !

Cut the Romex and use only one piece of wire inside each pipe...234/frequency x 12 = total inches for each side. All the weed wacker string
does is keep the V shape and the Impedance...If the antenna sags the antenna will have a different impedance... You can cut or add to the
wire to find a sweet (swr) spot...

I do have an Old Antenna Specialist Mag mount in the attic stuck to a eletrical box plate with aluminfoil radials 5% more than 1/4 wave
and that works too but not as good the V dipole.

It works really good..Sure beats spending big buck for the Sirio Dipole antenna or the Boomerang.
Questions ...Just ask !

Peter N1EXA

 

[FPR1981]

Is that pipe PVC or metal?

 

[KEWB-N1EXA]

Is that pipe PVC or metal?

PVC Plastic - Just the Gray $3 each stuff from Lowels... there10 feet each cut down to 105 inches or so.

The pipes holding the antenna up is a piece 1 and 1-1/4 inch metal eletrical pipe with a hose clamp...Trying to keep is small and Light weight.

I guess you could use steel pipe for the V antenna but is would become a weapon in the wind.

 

[prcguy]

The best place in your case is the highest spot you can get the antenna with the least amount of metal around it like house wiring in the walls, metal A/C ducting in the attic, possible foil backed insulation, etc.

Do not put much faith in a coil of coax as a choke balun. In most cases its a waste of coax and does little to nothing. With the right amount of coax, and its critical, you might have a choke that will REFLECT RF (VSWR) on the outside of the coax back towards the antenna a bit where a good choke balun made with ferrite will ABSORB RF on the outside of the coax. Just get a single FT-240-61 ferrite core and wrap 12 turns of your coax through it and you will have an extremely good RF choke at 27MHz that is at least 10X better than some coax coiled up.

I am going to install an inverted V in someone's attic later in the week. They don't want an antenna on the outside of the house. I'll keep everyone posted on how it works.

Meanwhile, I used dual 18 gauge speaker wire and built a dipole for a buddy. He was using a Tram 300 magnet mount, magnetized to a metal roof. He's about 1.5 miles away with terrain and slight altitude change in between and was hitting me with 7db, but some static in there. I took him the dipole and it was too snowy to install outside, so he ran it across his radio room. His previous 7db signal became a solid 9 swinging 10db and no more static.

I wonder what would perform better, horizontal across an upstairs bedroom as a radio room, or inverted V in the attic.

Opinions?

 

[jwt873]

Like This ?
Works Fine...
Peter N1EXA

It's a V but it appears to be a complete triangle, (wire on three sides). If that's the case, it's technically a delta loop and not an inverted vee.

 

[KEWB-N1EXA]

It's a V but it appears to be a complete triangle, (wire on three sides). If that's the case, it's technically a delta loop and not an inverted vee.

No the top is Weed Whacker line !
Its to keep the V form !
Well most of the time - Its a little loaded down with ice today~!

 

[KANE4109]

I am curious about the radiation pattern on that one.
Normally called the "inverted V" means that normally the V is pointy end up, with the elements draped downward. That has the effect of making the radiation pattern more omni-directional but still "upward and outward".

It would seem that in this V configuration it would be firing downward toward the ground.

Of course,that said, I have never had one of these up in the air either!!!! Just what I have read about them...

Does this really radiate outward enough to do good?

 

[prcguy]

The upward radiation pattern should be similar if its elements are pointing up or down. There will probably be more effect from the height above ground than elements pointing up or down. The worst would be the feedpoint and first third or so of the elements about 1/4 wave off the ground were that would put most power into the sky and less at the horizon. Placing the feedpoint at 1/2 wavelength above ground or multiples of 1/2 wavelength will place the main lobe closer to the horizon with higher 1/2 wave increments being better.

The inverted V puts out plenty of signal off the broad sides compared to either side of the V. If you make the inverted V out of wire its most likely going to have elements pointed down. If you make it from rigid material then you have a choice of pointing the elements up and gaining a little more height.

I am curious about the radiation pattern on that one.
Normally called the "inverted V" means that normally the V is pointy end up, with the elements draped downward. That has the effect of making the radiation pattern more omni-directional but still "upward and outward".

It would seem that in this V configuration it would be firing downward toward the ground.

Of course,that said, I have never had one of these up in the air either!!!! Just what I have read about them...

Does this really radiate outward enough to do good?

 

[jwt873]

No the top is Weed Whacker line !

Got it... So it's an un-inverted vee Good job..

Well most of the time - Its a little loaded down with ice today~!

Had the ice here a few weeks ago. My wire antennas looked like they were made with white 1/2 inch nylon rope.

 

[KEWB-N1EXA]

I am curious about the radiation pattern on that one.
Normally called the "inverted V" means that normally the V is pointy end up, with the elements draped downward. That has the effect of making the radiation pattern more omni-directional but still "upward and outward".

It would seem that in this V configuration it would be firing downward toward the ground.

Of course,that said, I have never had one of these up in the air either!!!! Just what I have read about them...

Does this really radiate outward enough to do good?

Did you read the comment about the ice today? This is not how it normally looks