This is a source run for an inverted L antenna for 80m that is 43 feet
vertical and 23 feet horizontal.

What would be the simplest matching network to use to produce a flat match.
My primary use would be 80m low angle work at 3.7 and 3.5 Mhz, but also want
to be able to use it (with a tuner, of course) for a local net at 3.97 megs.

While a 1.7:1 vswr at resonance is usable, I would like to get my starting
point as low as possible to maintain some sort of reasonable vswr at the
band edges, for those times when I need to check into the net.

By simple I mean no caps...they are not all that easy to find (in a hurry)
any longer. I need power handling of 500w. My two thoughts are some sort of
1/4 wave transformer (although that's a lot of coax), or a simple toroidal
transformer.

Any suggestions? Core material for the toroid (including availability),
turns ratio, etc? Or is a toroid a bad idea for this app?

TIA,

....hasan, N0AN


EZNEC ver. 3.0

Vertical over real ground 5/28/2005 6:39:29 AM

--------------- SOURCE DATA ---------------

Frequency = 3.71 MHz

Source 1 Voltage = 29.15 V. at 0.61 deg.
Current = 1 A. at 0.0 deg.
Impedance = 29.15 + J 0.308 ohms
Power = 29.15 watts
SWR (50 ohm system) = 1.715 (75 ohm system) = 2.573

Well, you can make it a little short and add a base inductor to tap to get
the high end of the band, or you can make it a little long and shorten it
with a variable cap.

W4ZCB
"hasan schiers" wrote in message
...
This is a source run for an inverted L antenna for 80m that is 43 feet
vertical and 23 feet horizontal.

What would be the simplest matching network to use to produce a flat
match.
My primary use would be 80m low angle work at 3.7 and 3.5 Mhz, but also
want
to be able to use it (with a tuner, of course) for a local net at 3.97
megs.

While a 1.7:1 vswr at resonance is usable, I would like to get my starting
point as low as possible to maintain some sort of reasonable vswr at the
band edges, for those times when I need to check into the net.

By simple I mean no caps...they are not all that easy to find (in a hurry)
any longer. I need power handling of 500w. My two thoughts are some sort
of
1/4 wave transformer (although that's a lot of coax), or a simple toroidal
transformer.

Any suggestions? Core material for the toroid (including availability),
turns ratio, etc? Or is a toroid a bad idea for this app?

TIA,

...hasan, N0AN


EZNEC ver. 3.0

Vertical over real ground 5/28/2005 6:39:29 AM

--------------- SOURCE DATA ---------------

Frequency = 3.71 MHz

Source 1 Voltage = 29.15 V. at 0.61 deg.
Current = 1 A. at 0.0 deg.
Impedance = 29.15 + J 0.308 ohms
Power = 29.15 watts
SWR (50 ohm system) = 1.715 (75 ohm system) = 2.573

Thanks Harold, but that's not what I'm trying to do. I'm not trying to
broadband the antenna...I'm trying to simply match it...so that starting out
at 1:1 instead of 1.7 : 1 will broaden the 2:1 vswr points a bit. I'm going
to use a tuner on the band edges anyway.

So the only question is:

Simplest way (without caps) to match 29 ohms to 50 ohms at the feedpoint.

....hasan, N0AN

"Harold E. Johnson" wrote in message
news:q1Zle.15771$IC6.11043@attbi_s72...
Well, you can make it a little short and add a base inductor to tap to get
the high end of the band, or you can make it a little long and shorten it
with a variable cap.

W4ZCB
"hasan schiers" wrote in message
...
This is a source run for an inverted L antenna for 80m that is 43 feet
vertical and 23 feet horizontal.

What would be the simplest matching network to use to produce a flat
match.
My primary use would be 80m low angle work at 3.7 and 3.5 Mhz, but also
want
to be able to use it (with a tuner, of course) for a local net at 3.97
megs.

While a 1.7:1 vswr at resonance is usable, I would like to get my
starting
point as low as possible to maintain some sort of reasonable vswr at the
band edges, for those times when I need to check into the net.

By simple I mean no caps...they are not all that easy to find (in a
hurry)
any longer. I need power handling of 500w. My two thoughts are some sort
of
1/4 wave transformer (although that's a lot of coax), or a simple
toroidal
transformer.

Any suggestions? Core material for the toroid (including availability),
turns ratio, etc? Or is a toroid a bad idea for this app?

TIA,

...hasan, N0AN


EZNEC ver. 3.0

Vertical over real ground 5/28/2005 6:39:29 AM

--------------- SOURCE DATA ---------------

Frequency = 3.71 MHz

Source 1 Voltage = 29.15 V. at 0.61 deg.
Current = 1 A. at 0.0 deg.
Impedance = 29.15 + J 0.308 ohms
Power = 29.15 watts
SWR (50 ohm system) = 1.715 (75 ohm system) = 2.573

"hasan schiers" wrote in message
...
Thanks Harold, but that's not what I'm trying to do. I'm not trying to
broadband the antenna...I'm trying to simply match it...so that starting
out
at 1:1 instead of 1.7 : 1 will broaden the 2:1 vswr points a bit. I'm
going
to use a tuner on the band edges anyway.

So the only question is:

Simplest way (without caps) to match 29 ohms to 50 ohms at the feedpoint.

...hasan, N0AN

"Harold E. Johnson" wrote in message
news:q1Zle.15771$IC6.11043@attbi_s72...
Well, you can make it a little short and add a base inductor to tap to
get
the high end of the band, or you can make it a little long and shorten
it
with a variable cap.

W4ZCB
"hasan schiers" wrote in message
...
This is a source run for an inverted L antenna for 80m that is 43 feet
vertical and 23 feet horizontal.

What would be the simplest matching network to use to produce a flat
match.
My primary use would be 80m low angle work at 3.7 and 3.5 Mhz, but also
want
to be able to use it (with a tuner, of course) for a local net at 3.97
megs.

While a 1.7:1 vswr at resonance is usable, I would like to get my
starting
point as low as possible to maintain some sort of reasonable vswr at
the
band edges, for those times when I need to check into the net.

By simple I mean no caps...they are not all that easy to find (in a
hurry)
any longer. I need power handling of 500w. My two thoughts are some
sort
of
1/4 wave transformer (although that's a lot of coax), or a simple
toroidal
transformer.

Any suggestions? Core material for the toroid (including availability),
turns ratio, etc? Or is a toroid a bad idea for this app?

TIA,

...hasan, N0AN


EZNEC ver. 3.0

Vertical over real ground 5/28/2005 6:39:29 AM

--------------- SOURCE DATA ---------------

Frequency = 3.71 MHz

Source 1 Voltage = 29.15 V. at 0.61 deg.
Current = 1 A. at 0.0 deg.
Impedance = 29.15 + J 0.308 ohms
Power = 29.15 watts
SWR (50 ohm system) = 1.715 (75 ohm system) = 2.573

A Twelfth-Wave transformer. QST June 1997. pp43

W4ZCB

"hasan schiers" wrote in message
...
Thanks Harold, but that's not what I'm trying to do. I'm not trying to
broadband the antenna...I'm trying to simply match it...so that starting
out
at 1:1 instead of 1.7 : 1 will broaden the 2:1 vswr points a bit. I'm
going
to use a tuner on the band edges anyway.

So the only question is:

Simplest way (without caps) to match 29 ohms to 50 ohms at the feedpoint.

...hasan, N0AN

a 2:1 balun should get you close.

"hasan schiers" wrote in message
...
Thanks Harold, but that's not what I'm trying to do. I'm not trying to
broadband the antenna...I'm trying to simply match it...so that starting
out
at 1:1 instead of 1.7 : 1 will broaden the 2:1 vswr points a bit. I'm
going
to use a tuner on the band edges anyway.

So the only question is:

Simplest way (without caps) to match 29 ohms to 50 ohms at the feedpoint.

...hasan, N0AN

"Harold E. Johnson" wrote in message
news:q1Zle.15771$IC6.11043@attbi_s72...
Well, you can make it a little short and add a base inductor to tap to
get
the high end of the band, or you can make it a little long and shorten
it
with a variable cap.

W4ZCB
"hasan schiers" wrote in message
...
This is a source run for an inverted L antenna for 80m that is 43 feet
vertical and 23 feet horizontal.

What would be the simplest matching network to use to produce a flat
match.
My primary use would be 80m low angle work at 3.7 and 3.5 Mhz, but also
want
to be able to use it (with a tuner, of course) for a local net at 3.97
megs.

While a 1.7:1 vswr at resonance is usable, I would like to get my
starting
point as low as possible to maintain some sort of reasonable vswr at
the
band edges, for those times when I need to check into the net.

By simple I mean no caps...they are not all that easy to find (in a
hurry)
any longer. I need power handling of 500w. My two thoughts are some
sort
of
1/4 wave transformer (although that's a lot of coax), or a simple
toroidal
transformer.

Any suggestions? Core material for the toroid (including availability),
turns ratio, etc? Or is a toroid a bad idea for this app?

TIA,

...hasan, N0AN


EZNEC ver. 3.0

Vertical over real ground 5/28/2005 6:39:29 AM

--------------- SOURCE DATA ---------------

Frequency = 3.71 MHz

Source 1 Voltage = 29.15 V. at 0.61 deg.
Current = 1 A. at 0.0 deg.
Impedance = 29.15 + J 0.308 ohms
Power = 29.15 watts
SWR (50 ohm system) = 1.715 (75 ohm system) = 2.573

I'm sorta surprised you would need to match it, if it's a
1/4 wave...I think your match in the real world, would
be better than on paper...I've never had to "match" a
1/4 wave here, L or straight.... But.....if I did, I would
just slap the tuner inline...On that band, any mismatch
would have to be large to give a high line loss. That
won't be the case for you just going from one part of
the band to another...Also, you should be able to get
a better match than 1.7:1, just by tweaking the wire
length.
MK

hasan schiers wrote:
Any suggestions?

For single-band operation, an autotransformer comes to mind.
Wind a coil with about 12 microhenries of inductance. Transmitter
output goes to the top of the coil. Ground goes to the bottom.
Tap down from the top on the coil for the antenna feedpoint.
The transformation ratio is roughly equal to the square of the
turns ratio.
--
73, Cecil http://www.qsl.net/w5dxp


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For single-band operation, an autotransformer comes to mind.
Wind a coil with about 12 microhenries of inductance. Transmitter
output goes to the top of the coil. Ground goes to the bottom.
Tap down from the top on the coil for the antenna feedpoint.
The transformation ratio is roughly equal to the square of the
turns ratio.
--
73, Cecil http://www.qsl.net/w5dxp

===============================

Cec, it seldom works. You forgot to mention the most important
parameter is the input impedance to the antenna.

For an analysis of an inverted-L or vertical antenna, plus tuner L and
C component values, download in a few seconds program ENDFEED from
website below. No unzipping inconveniences. Run immediately. Easy to
use.
----
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........

Perfecto, Reg!

This is exactly what I was looking for ...but I had forgotten you had
written this little jewel.

I am a bit surprised at the small effect on losses in the number of radials
once one gets above 8 radials of 20m length.

I need to play more with wire size (confounded mm!)

Thanks again for your contribution of this program. 73

....hasan, N0AN
"Reg Edwards" wrote in message
...

For single-band operation, an autotransformer comes to mind.
Wind a coil with about 12 microhenries of inductance. Transmitter
output goes to the top of the coil. Ground goes to the bottom.
Tap down from the top on the coil for the antenna feedpoint.
The transformation ratio is roughly equal to the square of the
turns ratio.
--
73, Cecil http://www.qsl.net/w5dxp

===============================

Cec, it seldom works. You forgot to mention the most important
parameter is the input impedance to the antenna.

For an analysis of an inverted-L or vertical antenna, plus tuner L and
C component values, download in a few seconds program ENDFEED from
website below. No unzipping inconveniences. Run immediately. Easy to
use.
----
.................................................. .........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. .........