Our resident 11 meter dipole expert

[SpugEddy]

Who here in the forum is our 11 meter home dipole antenna expert? I have a question about
a nice (looking) dipole antenna that I just finished building. I'm going to try uploading links
to the images of the build. My question is: why is my antenna 96" on each side to get my
SWR down low? In most cases, almost all of the homemade 11 meter dipole antennas get
trimmed at just around 102" each side. Mine is 96" each side in order to get my SWR down
to 1.2:1. Is the size going to make a difference in how much I receive and how far I get out?

If the images go through, image #1 is sort of an exploded view of the build with plenty of notes
and measurements. image #2 is the overall view of the antenna (what you see from the outside)

Image #1

Image #2

 

[Voyager]

Where are you measuring from? The end of the PVC box or the feedpoint?

The diagram looks like it's not taking the length of the feedpoint to endcap into account.

 

[SpugEddy]

Measuring from the end of the PVC box. I'm going to post some actual
pictures or maybe even a short video in a bit, so you guys all have a much
better idea of exactly what I have

 

[kf5bti]

When measuring a dipole you should measure the entire antenna (tip to tip) as everything from the feed-point also radiates.

 

[SpugEddy]

Here are some much better pix

 

[SpugEddy]

Interesting. I was under the assumption that I was to measure only
that which was exposed. Hmmmmm. (so much for misinformation)
Thank you

 

[SpugEddy]

With a little bit more testing and tweaking today, It seems as though
I have receive. In fact, my receive is not bad at all. I picked up quite a
few stations from UK, Norway, etc on 38 LSB. I just wasnt able to make
any contacts. I switched radios and I made a few DX contacts, but unable
to do it on the dipole. (I also have a magnum S-9 on a Solarcon A99)
The radio on the dipole is a very stock President HR2510.
So, at this point, it sees like receive is better than transmit. Still tweaking,
testing, learning, and looking for any suggestions.

Thank you guys

 

[majoco]

Where is the matching Balun? A dipole is a balanced antenna - both sides are the same. You should have a Balun to match to the unbalanced coaxial cable to your rig. (Balun transformer - BALanced-to-UNbalanced.)

 

[SpugEddy]

I have no answer because I have no balun. Next project, 1:1 balun.... Gonna be a fun night in the shop

update 8:46pm balun almost finished

 

[prcguy]

If the dipole has a very good match and is stable, meaning running your hand up and down the coax doesn't change anything, then a balun is not really necessary. The pattern might be a little closer to texbook with a balun, but you probably will not notice any difference.

On a Yagi with certain kinds of feeds where there is common mode currents on the feedline, a 1:1 balun will clean up the pattern by keeping the coax from radiating and there are other antennas that will benefit from a balun, but its not always required.
prcguy

Where is the matching Balun? A dipole is a balanced antenna - both sides are the same. You should have a Balun to match to the unbalanced coaxial cable to your rig. (Balun transformer - BALanced-to-UNbalanced.)

 

[SpugEddy]

Quite possible prcguy. I finished the "Folger" balun. I used 21' of RG 58 coax and an empty plastic Folger's coffee container (hence the name)
The antenna feed point is still the same spot and I soldered an SO 239 connector inside the can. My very first SWR readings were
1.5:1 on 40 and 1.6:1 on 1. The SWR has definitely dropped but now it says the antenna is too short. So, lots of testing tomorrow.

I appreciate everybody's help here. Obviously, I'm new to the forum but not new to the hobby nor electronics.
I've been an electronics / security systems engineer for over 20 years. The RF stuff is a little bit out of my field, but I know enough to be dangerous.

 

[prcguy]

A coil of coax type choke balun is a very specific size and inductance for a particular frequency and you may have too many turns. Check out this site where the author tests various types of ferrite core and air core RF chokes. He shows about 5 turns of RG-58 with a 4.25" id as an optimum size for CB/10 frequencies.

Common-mode chokes

Many "ugly baluns" are sold as 1.6 to 30MHz but they are really only good for maybe one ham band at best. You can get better choking and much wider frequency range with a ferrite loaded choke.
prcguy

Quite possible prcguy. I finished the "Folger" balun. I used 21' of RG 58 coax and an empty plastic Folger's coffee container (hence the name)
The antenna feed point is still the same spot and I soldered an SO 239 connector inside the can. My very first SWR readings were
1.5:1 on 40 and 1.6:1 on 1. The SWR has definitely dropped but now it says the antenna is too short. So, lots of testing tomorrow.

I appreciate everybody's help here. Obviously, I'm new to the forum but not new to the hobby nor electronics.
I've been an electronics / security systems engineer for over 20 years. The RF stuff is a little bit out of my field, but I know enough to be dangerous.

 

[prcguy]

Duplicate post - removed.

 

[SpugEddy]

I got the length from Dave Teasdale (you tube antenna building kind-of-guy) and some other website. They said its good for 10 meter all the way to 60 meter( I think?) Haven't had a chance to make any adjustments and test it yet today. As soon as I'm finished, I'll post results for anybody who is interested. Thanks

 

[SpugEddy]

Here is the actual page that I followed

BUILD AN AIR WOUND 1:1 CHOKE BALUN FOR HF - THE UGLY BALUN!

 

[majoco]

prcguys link shows that you only need 5 turns of RG213 on a 4.25inch former for 10metres.

 

[nd5y]

Everybody is forgetting something that should be obvious.

The reason his antenna appears to be too short is because the length of the brown wires that appear to be at least several inches long. What they are connect to is not in the pictures so we don't know how long.

The antenna starts at the point where the coax sheild and center conductor split. If the brown wires are connected to the coax or a connector then they are part of the antenna.

 

[prcguy]

The link states "18 to 21 feet should cover all of 160 through 10 meters" which is complete BS, they are not one size fits all. Since your dipole is only one band you could optimize an ugly balun for it.
prcguy

Here is the actual page that I followed

BUILD AN AIR WOUND 1:1 CHOKE BALUN FOR HF - THE UGLY BALUN!

 

[SpugEddy]

Sorry nd5y. The brown wires WERE about 5" long and they were soldered
to the SO 239 connector. The brown wires have been removed and now the
coax from the balun are in their place.

As I said, I used 21' of RG58. Apparently the site that I got the information from
says 160 - 10 meter.

Here are a few pix of the "Folger Balun"

 

[SpugEddy]

Hey prcguy, I've since read a couple of different sites where people
said that 21' is absolutely ridiculous. The problem I'm finding is; 20
people have 20 different opinions and recipes. One site says that the
amount of turns doesn't matter, it's the total length. Another says it's all
about how many turns in a given length and diameter of the form.
Somebody please help me, my head is literally spinning in circles now.

I guess the good thing is that since Im 21' I can always shorten it.