2 meter quarter wave question

[kf5qeo]

I was wondering.  I built a 2 meter quarter wave ground plane that works great.   4 ground radials and 1 stinger mounted on a so-259.  Now the question, it was made out of romex I think 12/3 wire.  The wire's hard to keep straight, and I have some metal tubes that look much like long curtain rods with green plastic covering it.  I was thinking of cutting some pieces to cover the wires, then soldering the wire to the tubes, such that the wires and tubes stay straight, in hopes that the signal would then radiate off the tubes, and perhaps give a better performance.  Reading up the higher frequency skims along the wire thinner, I'm curious to know if this will help or hurt my antenna's performance.  I'll be getting a G5RV that we'll be putting up not this saturday but next saturday, so I might take some time to try it out, but don't want to ruin a good thing.  I might also just use the tubes and a short piece of copper wire to make a 2 meter dipole from the tubes.  If I had the time and the confidence, I think I'd use the tubes to make a Yagi.  Then again, it'd be interesting figuring out which way to aim the Yagi, as I want to hit a repeater to the north and a repeater to the south.  Can't get forward gain on both directions, and I'm not going to go out there and turn the antenna every time I want to switch directions!  Especially the way I have the pole mounted on a hinge.  Buying a rotor for the 2 meter is not an option!

[Pete, WA2CWA]

Years ago I built a quarter wave 2 meter ground plane out of metal coat hangers. None of the elements were perfectly straight. Work great even after a bird tried to sit on one of the radials and bent it almost straight down. Built a 2 meter horizontal turnstile out of #36 or #38 steel drill rod. Used it for 2 meter SSB mobile back in the last century. Still have it.
Antenna materials don't have to be all that picky for things to work.

For the Yagi, to work repeaters in opposite directions; you can build a 3 element Yagi with two driven elements and a reflector in between. Feed each driven element with a quarter wave length of 75 ohm cable; terminate the far ends into a Tee connector and feed the Tee with a length of 50 ohm cable to the rig. If you want more gain, add a director in front of each driven element.

[kf5qeo]

For the Yagi, to work repeaters in opposite directions; you can build a 3 element Yagi with two driven elements and a reflector in between. Feed each driven element with a quarter wave length of 75 ohm cable; terminate the far ends into a Tee connector and feed the Tee with a length of 50 ohm cable to the rig. If you want more gain, add a director in front of each driven element.

Hmmm, sorta a Co-Phased Yagi?  I like that thought! 

[KA2DZT]

Most repeater antennas are vertical,  go with the vertical antenna.  You can make a 5/8wave antenna and get a little gain over a 1/4wave.  Try using welding rods which I think you can get in brass.  1/8" copper tubing is another thing to try.

I've made a number of VHF verticals, all from aluminum rod.

Fred

[John K5PRO]

I built a similar antenna a few years back, for slightly higher VHF frequency. The brass rods sold for hobbyist at the local Best Whatever hardware store worked perfectly, stiff and not so bendable as copper w'ore. Check that out, as they can be soldered also with enough torch.

[W3RSW]

I bolted 4 ea.#10 wires, 19 in. Long to a 4 in. Square Electrical outlet cover plate's corners. Then put three stick-on rubber feet under the plate. Use it for a base for my 5/8 wave 2 mtr. Mag mount vertical.

Didn't worry about crooked wire, can roll up a couple and it' super portable.

[wa3dsp]

I happened to notice you mentioned a G5RV in your original message. At the risk of possibly starting a another antenna discussion I would just like to say I think the G5RV is a "sucky" antenna. One of the clubs I belong to insists on using them for field day and they cause nothing but problems. The standing wave off of the antenna at the coax end is out of sight on most bands. True you can use a tuner but rig tuners often do not bring the SWR down to an acceptable level and in certain situations will not tune. If the coax run is very long the high SWR will cause additional loss on the feedline. Besides that it has a cheap ladder line matching section which is suppose to hang down at right angles to the antenna but rarely can this be achieved.

Perhaps why this antenna has become so popular is that it does match using a tuner on most bands but then a 200 foot center feed with ladder line antenna would do the same and work much better.

If I were in a situation where I wanted a wire antenna that would work all bands 80-10, and I did not have the space for a 200 foot antenna and did not want to use openwire line I would try the off center fed antennas. Buckmaster and Alpha Delta, Radiowaves make them. They are simple to homebrew. 90 feet on one side, 45 feet on the other and a 6:1 balun fed with  50 ohm coax - RG8X would be a good choice. There are variations of the ratio from side to side and if you Google "off center fed antenna" there is a lot of technical data on them including SWR curves. The claim is that you do not need a tuner on any band. That might be true for a tube rig with a pi-network but for a solid-state rig an in rig tuner would be more than adequate.

Doug

[kf5qeo]

I happened to notice you mentioned a G5RV in your original message. At the risk of possibly starting a another antenna discussion I would just like to say I think the G5RV is a "sucky" antenna. One of the clubs I belong to insists on using them for field day and they cause nothing but problems. The standing wave off of
Doug

I will definitely keep that in mind.  Though, bear in mind that the reason I am putting up the G5RV is it's the only way I can move my rig in-doors right now.  Previously, I would work stations in my truck, and I did so at limited times and it didn't work out well for digital modes which I am trying to do.  A friend is giving me a G5RV, and letting me use a power supply to move my rig in-doors.  When I sell my house in Louisiana, I plan on buying a power supply, and maybe more antennas.  Granted, my friend hates the G5RV for along the same lines as what you hate it for.  He can't get the ladder line perfectly straight down.  I originally was considering the Carolina Windom, but was told that for the difference in price (nearly $100!) the performance wasn't worth it.  I have a MFJ antenna tuner that can handle two antennas.  I may very well see about putting up another antenna perpendicular to the G5RV when I sell the house, and selecting which ever is best for the particular situation.

[Steve - K4HX]

The performance of G5RVs (yes I used the plural since there are many implementations) has been discussed more than once here and some good documentation is found elsewhere. One good link is below.

http://vk1od.net/antenna/G5RV/

[WB6NVH]

Your original question was whether thick tubing could be used.  Yes, and you might need to adjust length a bit for best VSWR.  The thicker tubing improves the bandwidth of the antenna somewhat although that isn't really an issue for ham use.