I've been using a G5RV as a temporary antenna, not very high and have been
getting out adequately with the barefoot Omni 6; its real merit is the
ability to work all the HF bands with a single wire. The tuner is an
absolute must, of course - except for parts of 20 it's far from an
acceptable impedance, though my preference is to have a decent tuner in line
no matter what is overhead. My impression is it's definitely inferior to
properly-sized dipoles on 40 and 80, and since I plan to leave it in place
when the 40 and 80 straight wires get back up I'll have a basis for
comparison. But it's certainly much better than nothing. I have no
problem busting pileups on CW, but the real weak ones that others seem to
work with no great difficulty just don't seem to hear me - that tells me
everything. K3TX
----- Original Message -----
From: "Bob McGraw - K4TAX" <RMcGraw@Blomand.net>
To: <wb2vuf@arrl.net>; "Discussion of Ten-Tec Equipment"
<tentec@contesting.com>
Sent: Friday, January 30, 2009 12:07 PM
Subject: Re: [TenTec] bill orr article
> Bob is correct on this and I fully agree. The G5RV works well for a wire
> antenna on 20M. As to other bands, it is compromised to a very
> compromised
> antenna. I know lots of hams have used one and think it is a very good
> antenna. Perhaps it is due to space limitations not being able to put up
> 135 ft of wire to operate 80M - 10M or the desire to have a "all band"
> antenna without using a tuner. My experience indicates that a tuner is
> still really needed with the G5RV for most applications. The high SWR at
> the balanced to unbalanced transition through the balun and the loss in
> the
> coax make the antenna appear to have a low SWR at the radio.
>
> One good approach to an antenna is put up what ever length of wire you can
> support, feed it in the center with a balanced feed system, connect it to
> the tuner that one used for the G5RV, but use the balanced output, and
> enjoy
> a new world of ham radio. Balanced wire feed is really not that difficult
> to install and use. Just keep it about 6" to 10" away from parallel runs
> of
> metal towers, masts, downspouts and such and it works just fine. As to
> getting it through the window, walls or floor or ceiling, no Herculean
> effort is required. Actually MFJ makes a panel to do just that. As to
> lightning protection, The Wireman make a static discharge device to use
> outside of the house that addresses that concern. It makes no difference
> if
> you use the true open wire line, although a bit more of a challenge to
> handle or if you use the covered web type line. I would comment that the
> covered web type line is more prone change tuning with rain, snow and ice,
> but the tuner takes care of that nicely. As to using 300 ohm line, 450 ohm
> line or 600 ohm line, take your choice. I have a beautiful folded dipole
> for 75M made totally out of the 300 ohm web type line. Works great and
> stayed up through 2 Winters of snow and ice.
>
> As to concerns of RFI or TVI, if you have these problems then you have an
> installation problem. It is not a fault of the balance feed-line, so
> don't
> blame that. I use a balanced feed on my 256 ft center fed wire, bring the
> balanced feed from the top of the tower on 12" PVC stand-offs that I made,
> then through the wooden attic eve vent, under the roof rafters and it
> drops
> down through the ceiling via a 1" slot direct behind the tuner. The TV
> antenna and its coax is on the same tower along with the DSS antenna and
> there is NO RFI or TVI issues at legal limit power, any band, any mode.
> Oh,
> the only ground for the station is via 3rd pin safety ground supplied via
> dedicated 230 volt 20 amp service direct from the breaker panel to the
> operating position. I'm on the 2nd floor and in the middle of a wood
> frame
> house so any ground is 50 or so ft away. My lightening protection system
> is
> mounted on the tower at the point the balanced feed enters the house. The
> tower has driven grounds at its base and it is BONDED back to the main AC
> ground, all outside of the house.
>
> 73
> Bob, K4TAX
>
>
>
>
> ----- Original Message -----
> From: "Bwana Bob" <wb2vuf@gti.net>
> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
> Sent: Friday, January 30, 2009 10:11 AM
> Subject: Re: [TenTec] bill orr article
>
>
>> Yes, The G5RV is optimized only for 20 meters, where it is a 3/2
>> wavelength. The 30 feet of twin lead is a matching section cut for 20
>> meters. At the end of the twin lead on all other bands the swr will be
>> high. Th secret to the wide bandwidth and low swr on all bands that
>> some claim is the fact that most G5RV designs specify 70 feet of coax
>> connected to the twin lead. The resulting high losses in the coax due to
>> normal loss plus high swr has the effect of smoothing out the swr.
>>
>> Years ago I used a G5RV rigged as an inverted V (not the best
>> configuration, but the only way it would fit in the back yard). It
>> worked OK on 80, 40 and 20, but was terrible on 15 and 10. On 10
>> meters, a dipole in the attic out performed it. I took it down when I
>> discovered that a simple 1/4 wave inverted L was better on 80.
>>
>> Check out Walt Maxwell's (W2DU) site. It has a good discussion of the
>> G5RV vs the merits of a dipole with twin lead, window line, or ladder
>> line running to the shack.
>>
>>
>> 73,
>>
>> Bob WB2VUF
>>
>> Bob McGraw - K4TAX wrote:
>>> Do a Google search for G5RV. You'll find a bountiful amount of info.
>>> Lots
>>> of test data, construction techniques and design information.
>>>
>>>>From my use of a G5RV some years ago, I'd say if that's the only antenna
>>>>one
>>> can put up, it's better than no antenna at all, but not much. There are
>>> much better antenna configurations, antennas that are more efficient,
>>> more
>>> reliable and work quite well. All much simpler and easier to build.
>>> Try
>>> the 135 ft center fed wire fed with a balanced feed system. And oh yes,
>>> the
>>> balanced feed system is much much easier to install and keep in the air
>>> than
>>> 90% of the hams understand. It will always have lower loss than any
>>> coax
>>> fed antenna too.
>>>
>>> 73
>>> Bob, K4TAX
>>>
>>>
>>> ----- Original Message -----
>>> From: "Verne Smith" <vernew7grn@cascadeaccess.com>
>>> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
>>> Sent: Thursday, January 29, 2009 8:10 PM
>>> Subject: [TenTec] bill orr article
>>>
>>>
>>>> bill orr has a book on antennas in which he covered g5rv i believe it
>>>> is
>>>> available from arrl
>>>>
>>>> verne
>>>> w7grn
>>>> _______________________________________________
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>>>>
>>>
>>>
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>>>
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>
>
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