| Author |
Message |
    
Spacemann
New member
Username: Spacemann
Post Number: 7
Registered: 3-2015
| | Posted on Wednesday, January 06, 2016 - 11:57 pm: | 
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Anyone know the length of each side offhand? Thanks!! |
Dale
Senior Member
Username: Dale
Post Number: 2261
Registered: 12-2002
| | Posted on Saturday, January 09, 2016 - 9:33 am: |
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just guessing but id try 18 feet each side. will probaly need to trim 3 or 4 inches off each side
dale/a.k.a.hotrod
cef426
cvc#64
454 [dx numbers]
38lsb
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Tech237
Moderator
Username: Tech237
Post Number: 1847
Registered: 4-2004
| | Posted on Saturday, January 09, 2016 - 4:51 pm: |
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Actually around 9ft each side. Dipoles are a halfwave total length.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Press_man
Advanced Member
Username: Press_man
Post Number: 904
Registered: 5-2008
| | Posted on Saturday, January 09, 2016 - 5:50 pm: |
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The length for 1/2 wave CB is less than 9ft per side.
http://www.hamuniverse.com/kl7jrdipoleTmount.html
You can get the materials from Copper except the bracket, it's available at Lowe's or Home depot. Copper carries a 1/2 wave dipole in the antenna section.
73 Pressman
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Tech237
Moderator
Username: Tech237
Post Number: 1848
Registered: 4-2004
| | Posted on Sunday, January 10, 2016 - 5:43 pm: |
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Pressman it will vary somewhat depending on surroundings. Always better to start a little longer and trim down. Officially at 27.195MHz it would be 8ft 6inches, but I'd rather have the extra 6 inches to play with.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Press_man
Advanced Member
Username: Press_man
Post Number: 906
Registered: 5-2008
| | Posted on Monday, January 11, 2016 - 5:36 pm: |
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Me too!
The little antenna listed is two 1/4 wave whips. Stainless works and a couple of fiberglass whips work nice to. I built several of the ones from Ham U and every one of them came out different especially mounted in an attic but they were mounted in the V configuration to best use the attic space. It's just a neat antenna for the first time hobbyist that wants that, I did it, feeling.
73 Pressman
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Charliebrown
Intermediate Member
Username: Charliebrown
Post Number: 474
Registered: 10-2002
| | Posted on Monday, January 11, 2016 - 7:51 pm: |
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I agree with 237 But I would suggest you get a line isolator. This will help with any problem of current coming back through the line to the radio. There are more benefit's but to much to get into. Check it out. You could also get an MFJ tuner to help. I am sure other's can add to this to help you. |
Wire_saber
Junior Member
Username: Wire_saber
Post Number: 48
Registered: 4-2015
| | Posted on Thursday, March 16, 2017 - 8:21 am: |
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I have a few 10' copper pipes from an old project. Has someone ever used rigid copper pipe for a dipole? I'd like to know if any advantages (bandwidth?) may be achieved. If it's a worthwhile experiment, I will start looking for an isolating plate. I'm aware that maintaining rigidity will be a challenge. |
Tech833
Moderator
Username: Tech833
Post Number: 2376
Registered: 8-2002
| | Posted on Thursday, March 23, 2017 - 1:43 am: |
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Unless the diameter gets up close to 5% of the wavelength, there won't be any major difference in bandwidth on a dipole.
Now, that being said, assuming you compared a copper pipe dipole to a wire dipole made from 30 ga. transformer wire, then yes, you would notice an improvement in bandwidth.
Diameter mostly gains you some power handling capability.
Then again, if you are talking about coils, then a whole new mathematical equation comes into play.
Your radio 'Mythbuster' since 1998
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Raya
Junior Member
Username: Raya
Post Number: 12
Registered: 6-2017
| | Posted on Sunday, June 23, 2019 - 3:19 am: |
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The general formula for the length on each side of a dipole is 234 divided by the desired operation frequency in Mhz.
Keep in mind that this is only a general length. SWER will depend on the height of the antenna above ground and the physical structures around said dipole. You may have to add a bit to the length or trim a little bit of wire.
Be flexible. |
