Hi Steve,
My point about the G5RV is that as originally configured is that it yields
a reasonable match to 50 Ohm on the major ham bands that most modern day
radios can match WITHOUT AN ANTENNA TUNER. Your method of bringing in the
low loss 450 Ohm line all the way is fine and less loss but it does require
an antenna tuner (which has loss and can be a pain to keep matched as you
QSY), a device I no longer have or desire in my shack!
I recommend a T240-43 core from Amidon. With RG303 or RG141/RG142 PTFE
coax, it only requires about 6 or 8 turns to do the job!
An RG213 feed line is recommended from the balun to keep the loss low and
shouldn't be any longer than required to attach to the radio. At 100 feet,
it's only a dB of loss plus a small amount due to mismatch. No big deal
I ran up to 1000 Watts into my G5RV on 75/80 and 40 meters and never had a
problem. Likewise, AD1C does the same up to 1,500 Watts on all bands from
80 through 10 meters (except at 30 meters hi). He uses, I think, a Radio
Works or Unadillan W2DU type balun laying right on the ground!
GL and 73,
Joe, W1JR
At 12:25 PM 7/6/2002 -0700, Steve G. wrote:
>Hi Joe,
>
>Thanks for the additional info on the G5RV. It's nice to converse with
>you on the subject. As a matter of fact, I've never tried a G5RV after
>seeing one while pulling it up at a friend's house in the early
>nineties. At that time, I noted it's feed line arrangement and decided it
>wasn't for me. I've actually stuck with the ladder line feed all the way
>into each ham shack at 3 different homes now for these center fed, 100+
>feet sky-hooks.
>
>I suppose trying this feed arrangement would be in order. Based on what
>you've said, I would either live with the coaxial losses, or use a lower
>loss coax (RG 213 or better that's able to handle a mismatch) for that
>short run into the shack and tune it there. How does this arrangement
>handle high power? I suspect the RG 303 in the balun will do this quite
>easily on HF, but what of the core? You've renewed my interest, but I'm
>still such a fan of the complete ladder line feed arrangement. 73 de
>Steve, KZ9G
>
>At 07:24 AM 7/6/2002 -0400, you wrote:
>>Steve,
>>
>>With the G5RV dipole, you get reasonable VSWR on the major bands. On 80
>>meters it may get to 3:1 or so at edge of band but all my rigs with built
>>in tuners worked fine and never used an external tuner.
>>
>>There is a myth out there, perhaps started by G5RV himself (!), that
>>80-100 feet of coax is needed. If you think about that a minute, you'll
>>see that the only purpose of the long piece of coax is to lower the VSWR
>>(due to it's inherent loss).
>>
>>The easiest way to feed a G5RV antenna is to use a 1:1 current balun at
>>the end of the 450 OHm feed line (about 30-35 feet from the center of the
>>dipole). I use a W1JR type current balun, about 12-14 turns of RG142 or
>>RG303 PTFE 50 Ohm coax wound on a 2.4" diameter toroid. I also have used
>>about 50 ferrite beads like the W2DU balun. They al;l work great and many
>>are available commercially.
>>
>>My son Jim, AD1C, has a similar G5RV only up 30-35 feet and has worked
>>over 325 DXCC in the last 4 or 5 years! The G5RV is a compromise antenna
>>that does work and is not a DUMMY LOAD!
>>
>>73,
>>
>>Joe, W1JR
>>
>>At 01:08 AM 7/6/2002 -0700, Steve G. wrote:
>>>Yep... it's hard to beat these simplistic center-fed antennas that Tom
>>>has described. Just match or "tune" these low loss antenna systems
>>>(system = antenna and balanced feed line) with a capable tuner, and work
>>>the world. A combination of low and high ones like the 100' or 135'
>>>models would serve stateside and DX interests. Just take into
>>>consideration their patterns when changing bands. BTW, many articles
>>>have been written on these balanced line, center fed antennas. They
>>>show the patterns, takeoff angles, and the varying amounts of gain they
>>>have for each band, considering different heights above ground. I'm
>>>sure someone can point out the specific articles - I remember one in QST
>>>a few years back. Who needs a G5RV with it's coaxial losses if you can
>>>bring "ladder" or open wire line into your shack? With a complete
>>>balanced line run from the tuner to the antenna, these are SUPERIOR and
>>>ELEGANT. I've enjoyed them at different locations over the years...
>>>though I sure wish they were at 100+ feet like Tom's!
>>>
>>>73, Steve, KZ9G
>>>
>>>At 01:20 AM 7/6/2002 -0600, you wrote:
>>>>A *simple* solution to the 100 ft space limited antenna problem
>>>>is to just install a 100 ft center fed dipole using Ladder Line feeders
>>>>and an Antenna Tuner such as a Johnson Matchbox.
>>>>
>>>>I have 4 Ladderline fed antennas (2 - 80M dipoles, 1 - 100 ft CF,
>>>>1 - 20M dipole) which I use extensively on 80M the WARC bands.
>>>>I have worked over 320 countries on each of those 4 bands.
>>>>(OK, the 80M dipoles are at 130 ft and the 100 ft CF is at 100 ft)
>>>>
>>>>Tom N4KG
>>>>
>>>>On Sat, 06 Jul 2002 "S. Markowski Jr." <km9m-zig@attbi.com> writes:
>>>> >
>>>> >
>>>> > Van K7VS wrote:
>>>> >
>>>> > > with a g5rv, keep your antenna tuner handy as you WILL need it
>>>> > for all
>>>> > > bands. Certainly a compromise antenna but useful in some
>>>> > instances.
>>>> >
>>>> > You "CAN" work alot of DX with a G5RV and 100 watts. You will learn
>>>> > one new character trait.....
>>>> > "PATIENCE"!
>>>> > 73,
>>>> > Zig KM9M
>>>> >
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