| Author |
Message |
    
Capt_hook
Intermediate Member
Username: Capt_hook
Post Number: 119
Registered: 6-2004
| | Posted on Saturday, January 29, 2005 - 5:23 am: | 
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let me see if iam saying this right is it called a G5RV or GR5V its a dipole inverted with 300ohm feed wire to a coax to radio ?hooks to tower and slopes downward. Ron |
Tech808
Moderator
Username: Tech808
Post Number: 4668
Registered: 8-2002
| | Posted on Saturday, January 29, 2005 - 6:55 am: |
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Capt_hook,
Sorry I have never used one but the Link below has Plenty of information on it for you.
http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=9752
Hope this helps,
Lon
Tech808
CEF808
N9OSN
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The ELCO guy (Unregistered Guest)
Unregistered guest
| | Posted on Saturday, January 29, 2005 - 11:18 am: |
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Re CH
The name of the antenna is a G5RV antnna. It got its name from the Amateur Call Sign of the amateur who first designed it.
The original antenna design is a center fed length of wire 102 feet long. It can be configured in a horizontal or V format. It is fed with 34 feet of 75 ohm twinlead which in turn is usually fed with 50 ohm coax. The antenna is disigned to work best on 20 meters ham band but will work in theory from 3.5 to 30 mhz--which includes the CB Band.
Do not expect a low SWR with this antenna. IF YOU DO see a low SWR without a tuner in use suspect very bad loss in your coax used to feed the 75 ohm twinlead.
You will in all probability WILL NEED an antenna tuner to use this antenna. There is no particularly strong gain to the antenna as it is just a big dipole. BUT if you are a ham guy and has room for only ONE antenna and you want to work multiple ham bands off of the one anetnna then you can get by with the G5RV.
You might also try an OCF Antenna. The Off Center Fed antenna is also a multiband antenna that also works harmonics. Unlike the dipole/G5RV (which is fed in the center) the OCF antenna is a half wave antenna that is cut to the lowest frequency you intend to operate on and fed 1/3 of the distance from one end with a 4:1 Balun or a 6:1 balun using regular 50 ohm coax for the feedline.
Both the G5RV and the OCF Antennas will probably require an antenna tuner.
Might I suggest that you to to the ARRL Web Page at
www.arrl.org
Check out their selection of ham anenna books. They have a large selection of books on antenna design and theory. While they will be largly for the ham bands the 10 meter antennas can be scaled a tad bit longer for use in the CB Band.
Later
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Tech833
Moderator
Username: Tech833
Post Number: 976
Registered: 8-2002
| | Posted on Saturday, January 29, 2005 - 12:03 pm: |
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The G5RV (that was the inventors callsign) is a balanced dipole with a critical length of twinlead feeding it from a coax balun. They work O.K., but keep the twinlead away from everything!
Oh, and be dang sure to use a Polyphaser. |
Capt_hook
Intermediate Member
Username: Capt_hook
Post Number: 120
Registered: 6-2004
| | Posted on Saturday, January 29, 2005 - 4:27 pm: |
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polyphaser?????is that anything like the coal miners steak.LOL |
Tech808
Moderator
Username: Tech808
Post Number: 4675
Registered: 8-2002
| | Posted on Saturday, January 29, 2005 - 4:52 pm: |
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Capt_hook,
Guess you have not read the Review on the Poly Phasers yet or looked at the Pictures I posted in the Article (RADIO EQUIPMENT & GROUNDING) that I posted. 
Subscriber (Preview)
» Product Reviews
» Polyphaser - Lightning Arrestor
» Review
Ask The Tech
» Installations
» General
» RADIO EQUIPMENT & GROUNDING
Lon
Tech808
CEF808
N9OSN |
Bluegrass
Intermediate Member
Username: Bluegrass
Post Number: 112
Registered: 12-2004
| | Posted on Saturday, January 29, 2005 - 5:43 pm: |
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To build a dipole for cb use the 468 equation.take 468 then divide it by the freq in mhz.so a dipole for cb is about 18 feet long but add an extra 3 feet for attaching it to the insulators and tuning.so get 10 or 18 guage insulated copper wire and cut off a 21 foot length of it then cut the 21 foot section right in the middle then strip off 6 inches of insulation from one end of each section then strip off 18 inches of insulation from the other end of each section.attach the 6 inch striped ends to the center insulator by just twisting it back on it self and wraping the exposed wire in electrical tape then attach the 18 inch striped ends to the end insulators in a simaler matter but don't wrap it in tape until you have checked the swr.you can tune the antenna by attaching a 50 ohm coax and hoisting the antenna (using a non-conductive rope)up to a proper hight and using an swr meter then adjust the swr by lengthening or shorting the wire at the end insulators.once you have tuned it wrap the bare wire in tape and hoist it back up and your done.The insulators i'm talking about are HF insulators you can get at any ham radio supply store.well i hope this helps. |
Capt_hook
Intermediate Member
Username: Capt_hook
Post Number: 121
Registered: 6-2004
| | Posted on Sunday, January 30, 2005 - 8:56 am: |
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thanks lon on here one tends to be careful .(coal miners steak,inverted twist ,tooth strecher,finagin pin,and so fourth .) i will check it out .capt hook |
Don123 (Unregistered Guest)
Unregistered guest
| | Posted on Sunday, January 30, 2005 - 9:46 am: |
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Hi Ron,
Others here already gave you a link and some good info on the G5RV antenna. One thing to keep in mind this is a multiband wire antenna that Hams would use to enable them to use just one antenna on multiple bands (80meters thru 10meters) but also used WITH a tuner. I have used a number of G5RV antennas and they work modest on the Ham bands (51 feet of wire for each side/leg of the antenna mounted inverted 'V' or 'H'orz then a 31 foot or so vertical leg of ladder line (300 or 450 ohm) to balun or coax then 70ft or so of coax to the tuner/rig, also note that many folks stir away from ladder line but don't as it is a good feedline for lower loss to the antenna and as long as it is away from metal objects a few inches works well). Because this is the CB forum section I would assume you want to use this for one band being the CB band (27mhz) so I would recommend a simple dipole cut to the exact band of operation mounted horz or vert....if you are looking for wire antennas with some more gain you might try a delta loop or wire beam antenna for cb or 27mhz. Have fun and believe me wires work well.
de kb9umt Don
http://www.HamRadioHelp.com |
Capt_hook
Intermediate Member
Username: Capt_hook
Post Number: 122
Registered: 6-2004
| | Posted on Sunday, January 30, 2005 - 11:32 am: |
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thank you gentlemen this is just another thing i wanted to try it seems interesting i have made other antennas j-pole out of copper pipe,wire coat hanger and old tv antennas.called fun i think .thanks again Ron Capt Hook |
Lowpowerhal
Intermediate Member
Username: Lowpowerhal
Post Number: 386
Registered: 7-2003
| | Posted on Sunday, January 30, 2005 - 2:13 pm: |
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Yes the g5rv is a good dipole for 80 to 10 meter band , it works great but you need a tuner in line also. I had 300 ohm tv twin line running into a heathkit balun b-1 . but had lighting hit the dipole and fried the 300 ohm line, ( had the polyphaser in line) saved a bunch of equipment!!!
also have a Van Gordon 1 to 1 dipole up also.
Dipoles work great for multiband operation. but you have dead spots. nother words if you hear them you can talk to them.
They dont have gain like a beam dose, but they work real good if conditions are just right.
hope this helps!
lowpowerhal
73 |
Capt_hook
Intermediate Member
Username: Capt_hook
Post Number: 123
Registered: 6-2004
| | Posted on Monday, January 31, 2005 - 12:43 pm: |
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what is a good lenth for this 51'wire and 300ohmwire 29'6" to a so239 connector ? |
