I just constructed a homebrew G5RV, 51' on each leg, 32' 9" for the
ladder line matching section.Then there's about 10 turns of RG8X in a
6" dia. coil for a RF choke. It's in an inverted V configuration. It
seems to work well enough on 80 and 40 meters, but the SWR on 20
meters seems a bit high. It's 3:1 at 14.001 and seems to climb
somewhat higher at 14.349. I made the matching section 32' 9" should I
trim some off of the matching section, say down to 32' even or leave
well enough alone ? I can tune it to 1:1 with my manual tuner, though
the best the autotuner can do with it is about 1:6 to 1. I would like
to have it resonant on 20 just because that was the band it was
designed for IIRC.

73 Gary

Gary wrote:
I just constructed a homebrew G5RV, 51' on each leg, 32' 9" for the
ladder line matching section.Then there's about 10 turns of RG8X in a
6" dia. coil for a RF choke. It's in an inverted V configuration. It
seems to work well enough on 80 and 40 meters, but the SWR on 20
meters seems a bit high. It's 3:1 at 14.001 and seems to climb
somewhat higher at 14.349. I made the matching section 32' 9" should I
trim some off of the matching section, say down to 32' even or leave
well enough alone ? I can tune it to 1:1 with my manual tuner, though
the best the autotuner can do with it is about 1:6 to 1. I would like
to have it resonant on 20 just because that was the band it was
designed for IIRC.

If the SWR climbs from 14 to 14.35, then the matching section
is too long and resonates the antenna system below 14 MHz. My
matching section is 29 feet on 14.2 MHz using "450" ohm ladder-
line (closer to Z0=388 ohms). But don't expect the get the
SWR much lower than 2:1 on 20m where the antenna is 1.5
wavelengths long.
--
73, Cecil http://www.qsl.net/w5dxp

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On Mon, 30 May 2005 23:20:27 -0500, Cecil Moore
wrote:

Gary wrote:
I just constructed a homebrew G5RV, 51' on each leg, 32' 9" for the
ladder line matching section.Then there's about 10 turns of RG8X in a
6" dia. coil for a RF choke. It's in an inverted V configuration. It
seems to work well enough on 80 and 40 meters, but the SWR on 20
meters seems a bit high. It's 3:1 at 14.001 and seems to climb
somewhat higher at 14.349. I made the matching section 32' 9" should I
trim some off of the matching section, say down to 32' even or leave
well enough alone ? I can tune it to 1:1 with my manual tuner, though
the best the autotuner can do with it is about 1:6 to 1. I would like
to have it resonant on 20 just because that was the band it was
designed for IIRC.

If the SWR climbs from 14 to 14.35, then the matching section
is too long and resonates the antenna system below 14 MHz. My
matching section is 29 feet on 14.2 MHz using "450" ohm ladder-
line (closer to Z0=388 ohms). But don't expect the get the
SWR much lower than 2:1 on 20m where the antenna is 1.5
wavelengths long.

Ok, thanks Cecil. I suspected the matching section was too long
because as you said the SWR rose the higher I went in frequency. I'll
trim a foot or so off of it. Its not important but I don't know why
the autotuner can only tune it to 1:6 to 1 as I mistakenly tuned 80
into my 20 meter dipole with not much problem. Maybe the letters MFJ
have something to do with it

73 Gary K8IQ

On Mon, 30 May 2005 23:53:25 -0400, Gary wrote:

I just constructed a homebrew G5RV, 51' on each leg, 32' 9" for the
ladder line matching section.Then there's about 10 turns of RG8X in a
6" dia. coil for a RF choke. It's in an inverted V configuration. It
seems to work well enough on 80 and 40 meters, but the SWR on 20
meters seems a bit high. It's 3:1 at 14.001 and seems to climb
somewhat higher at 14.349. I made the matching section 32' 9" should I
trim some off of the matching section, say down to 32' even or leave
well enough alone ? I can tune it to 1:1 with my manual tuner, though
the best the autotuner can do with it is about 1:6 to 1. I would like
to have it resonant on 20 just because that was the band it was
designed for IIRC.

73 Gary

Good Morning Gary,

You do not say what type of line you are using for the matching section.
you have to figure the Volocity Factor of the Line into your caculations..
So it should mostlikey be a bit shorter than 31 feet or so. Mine her with
homebrew 525 ohm line is 31 feet 2" , Why 525 ohm line because that was
about the same a Varney's original So his figures will change depending
upon the Line. Cebik has a good write up on the G5RV. at
http://www.cebik.com/wire/g5rv2.html
Have a good day 73 Dave



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Gary, the G5RV needs a tuner. If you wanted to operate on 14.3, trimming the
match section to 25.7 feet would give you the best match. However it would
affect all other bands and by definition no longer be a G5RV.

The above assumes you are using 450 Ohm Ladder line.

"Gary" wrote in message
...
I just constructed a homebrew G5RV, 51' on each leg, 32' 9" for the
ladder line matching section.Then there's about 10 turns of RG8X in a
6" dia. coil for a RF choke. It's in an inverted V configuration. It
seems to work well enough on 80 and 40 meters, but the SWR on 20
meters seems a bit high. It's 3:1 at 14.001 and seems to climb
somewhat higher at 14.349. I made the matching section 32' 9" should I
trim some off of the matching section, say down to 32' even or leave
well enough alone ? I can tune it to 1:1 with my manual tuner, though
the best the autotuner can do with it is about 1:6 to 1. I would like
to have it resonant on 20 just because that was the band it was
designed for IIRC.

73 Gary

On Tue, 31 May 2005 06:52:31 -0400, KC1DI wrote:

On Mon, 30 May 2005 23:53:25 -0400, Gary wrote:

I just constructed a homebrew G5RV, 51' on each leg, 32' 9" for the
ladder line matching section.Then there's about 10 turns of RG8X in a
6" dia. coil for a RF choke. It's in an inverted V configuration. It
seems to work well enough on 80 and 40 meters, but the SWR on 20
meters seems a bit high. It's 3:1 at 14.001 and seems to climb
somewhat higher at 14.349. I made the matching section 32' 9" should I
trim some off of the matching section, say down to 32' even or leave
well enough alone ? I can tune it to 1:1 with my manual tuner, though
the best the autotuner can do with it is about 1:6 to 1. I would like
to have it resonant on 20 just because that was the band it was
designed for IIRC.

73 Gary

Good Morning Gary,

You do not say what type of line you are using for the matching section.
you have to figure the Volocity Factor of the Line into your caculations..
So it should mostlikey be a bit shorter than 31 feet or so. Mine her with
homebrew 525 ohm line is 31 feet 2" , Why 525 ohm line because that was
about the same a Varney's original So his figures will change depending
upon the Line. Cebik has a good write up on the G5RV. at
http://www.cebik.com/wire/g5rv2.html
Have a good day 73 Dave

Thanks Dave, I'm using 450 ohm ladder line and some triming brought
the SWR down to about 1:8 to 1.

73 Gary.

Thanks for the information. I am using 450 ohm ladder line. Some
trimming as Cecil recommended brought it down to about 1:8 to one.

73 Gary

On Tue, 31 May 2005 11:33:46 -0400, "Fred W4JLE"
wrote:

Gary, the G5RV needs a tuner. If you wanted to operate on 14.3, trimming the
match section to 25.7 feet would give you the best match. However it would
affect all other bands and by definition no longer be a G5RV.

The above assumes you are using 450 Ohm Ladder line.

"Gary" wrote in message
.. .
I just constructed a homebrew G5RV, 51' on each leg, 32' 9" for the
ladder line matching section.Then there's about 10 turns of RG8X in a
6" dia. coil for a RF choke. It's in an inverted V configuration. It
seems to work well enough on 80 and 40 meters, but the SWR on 20
meters seems a bit high. It's 3:1 at 14.001 and seems to climb
somewhat higher at 14.349. I made the matching section 32' 9" should I
trim some off of the matching section, say down to 32' even or leave
well enough alone ? I can tune it to 1:1 with my manual tuner, though
the best the autotuner can do with it is about 1:6 to 1. I would like
to have it resonant on 20 just because that was the band it was
designed for IIRC.

73 Gary