It is a truism that short antennae are poor inefficient radiators, and no
amount of infantile bluster by Americanoramuses will change that.

The truth does not need the violence of abuse to force its way down
people's throats.

gareth wrote:
It is a truism that short antennae are poor inefficient radiators, and no

How short is a "short antenna"?

What is the metric for a "poor inefficient radiator"?

Without numbers all you have is arm waving.



--
Jim Pennino

On 12/11/2014 20:09, wrote:

Without numbers all you have is arm waving.

But is he holding a magnet whilst waving his arms?

On 11/12/2014 1:50 PM, gareth wrote:
It is a truism that short antennae are poor inefficient radiators, and no
amount of infantile bluster by Americanoramuses will change that.

The truth does not need the violence of abuse to force its way down
people's throats.



A perfect example is a G5RV on 75 meters. They suck. When someone joins
our group rag chew on 75, and they have a poor signal, The first thing I
ask is "Are you using a G5RV". We all have a chuckle when they answer
yes and then ask how we knew. :-)

Trying to prove with math that short antennae work as well as say a 1/2
wave dipole may give someone great sport. However, in the real world,
short antennae suck big time. I have been an American for most of my
life. Please do not paint us all with the same brush.

FBMboomer wrote:
On 11/12/2014 1:50 PM, gareth wrote:
It is a truism that short antennae are poor inefficient radiators, and no
amount of infantile bluster by Americanoramuses will change that.

The truth does not need the violence of abuse to force its way down
people's throats.



A perfect example is a G5RV on 75 meters. They suck. When someone joins
our group rag chew on 75, and they have a poor signal, The first thing I
ask is "Are you using a G5RV". We all have a chuckle when they answer
yes and then ask how we knew. :-)

Trying to prove with math that short antennae work as well as say a 1/2
wave dipole may give someone great sport. However, in the real world,
short antennae suck big time. I have been an American for most of my
life. Please do not paint us all with the same brush.

Any dipole type antenna will suck on 75M if mounted less than about
100 feet, or about .4 wavelengths. Below that you are warming clouds.


Height Gain @ Elevation
lambda

0.1 3.89 90
0.15 5.55 90
0.2 5.95 90
0.25 5.81 62
0.3 5.80 48
0.35 6.00 40
0.4 6.38 35
0.45 6.86 31
0.5 7.41 28
0.55 7.76 25
0.6 7.87 23
0.65 7.76 21


--
Jim Pennino

wrote:
FBMboomer wrote:
On 11/12/2014 1:50 PM, gareth wrote:
It is a truism that short antennae are poor inefficient radiators, and no
amount of infantile bluster by Americanoramuses will change that.

The truth does not need the violence of abuse to force its way down
people's throats.



A perfect example is a G5RV on 75 meters. They suck. When someone joins
our group rag chew on 75, and they have a poor signal, The first thing I
ask is "Are you using a G5RV". We all have a chuckle when they answer
yes and then ask how we knew. :-)

Trying to prove with math that short antennae work as well as say a 1/2
wave dipole may give someone great sport. However, in the real world,
short antennae suck big time. I have been an American for most of my
life. Please do not paint us all with the same brush.

Any dipole type antenna will suck on 75M if mounted less than about
100 feet, or about .4 wavelengths. Below that you are warming clouds.

But that is actually very useful on the low bands!

Not for working "DX", but when you want to run a roudtable in an area
it works very well, especially when not in full summer daylight.

There are several of these groups active here, and it provides a
convenient coverage area for our language area, much larger than what
you achieve on e.g. 2 meters with typical vertical omni antennas mounted
on rooftops.

Rob wrote:
wrote:
FBMboomer wrote:
On 11/12/2014 1:50 PM, gareth wrote:
It is a truism that short antennae are poor inefficient radiators, and no
amount of infantile bluster by Americanoramuses will change that.

The truth does not need the violence of abuse to force its way down
people's throats.



A perfect example is a G5RV on 75 meters. They suck. When someone joins
our group rag chew on 75, and they have a poor signal, The first thing I
ask is "Are you using a G5RV". We all have a chuckle when they answer
yes and then ask how we knew. :-)

Trying to prove with math that short antennae work as well as say a 1/2
wave dipole may give someone great sport. However, in the real world,
short antennae suck big time. I have been an American for most of my
life. Please do not paint us all with the same brush.

Any dipole type antenna will suck on 75M if mounted less than about
100 feet, or about .4 wavelengths. Below that you are warming clouds.

But that is actually very useful on the low bands!

Not for working "DX", but when you want to run a roudtable in an area
it works very well, especially when not in full summer daylight.

There are several of these groups active here, and it provides a
convenient coverage area for our language area, much larger than what
you achieve on e.g. 2 meters with typical vertical omni antennas mounted
on rooftops.

Yes, if what you want to achieve is local area coverage on HF, then
NVIS antennas work well for that.

The real problem is people throw around terms like "crappy", "sucks",
and "poor performer" without defining what it is they are trying to
achieve.



--
Jim Pennino

On 11/13/2014 6:12 PM, wrote:
FBMboomer wrote:
On 11/12/2014 1:50 PM, gareth wrote:
It is a truism that short antennae are poor inefficient radiators, and no
amount of infantile bluster by Americanoramuses will change that.

The truth does not need the violence of abuse to force its way down
people's throats.



A perfect example is a G5RV on 75 meters. They suck. When someone joins
our group rag chew on 75, and they have a poor signal, The first thing I
ask is "Are you using a G5RV". We all have a chuckle when they answer
yes and then ask how we knew. :-)


False logic. You don't know how many people with good signals are using
G5RV's, because you only ask those with poor signals.

Trying to prove with math that short antennae work as well as say a 1/2
wave dipole may give someone great sport. However, in the real world,
short antennae suck big time. I have been an American for most of my
life. Please do not paint us all with the same brush.

Yes and no. Depending on their design, short antennas can be very
efficient. See
http://www.futurity.org/radio-wave-c...phones-801322/ for an
example.

But others are correct. The antenna itself is an efficient radiator;
it's the matching network that lowers *antenna system* efficiency.


Any dipole type antenna will suck on 75M if mounted less than about
100 feet, or about .4 wavelengths. Below that you are warming clouds.


So now it's 100 feet? It used to be 60 feet. But I have proof that is
not the case. So do a lot of other hams I know.

Your "facts" are for an idealized installation. Reality is much
different, and will never get the ideal specifications you claim.

snip

--
==================
Remove the "x" from my email address
Jerry, AI0K

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

Jerry Stuckle wrote:
On 11/13/2014 6:12 PM, wrote:
FBMboomer wrote:
On 11/12/2014 1:50 PM, gareth wrote:
It is a truism that short antennae are poor inefficient radiators, and no
amount of infantile bluster by Americanoramuses will change that.

The truth does not need the violence of abuse to force its way down
people's throats.



A perfect example is a G5RV on 75 meters. They suck. When someone joins
our group rag chew on 75, and they have a poor signal, The first thing I
ask is "Are you using a G5RV". We all have a chuckle when they answer
yes and then ask how we knew. :-)


False logic. You don't know how many people with good signals are using
G5RV's, because you only ask those with poor signals.

Trying to prove with math that short antennae work as well as say a 1/2
wave dipole may give someone great sport. However, in the real world,
short antennae suck big time. I have been an American for most of my
life. Please do not paint us all with the same brush.

Yes and no. Depending on their design, short antennas can be very
efficient. See
http://www.futurity.org/radio-wave-c...phones-801322/ for an
example.

But others are correct. The antenna itself is an efficient radiator;
it's the matching network that lowers *antenna system* efficiency.


Any dipole type antenna will suck on 75M if mounted less than about
100 feet, or about .4 wavelengths. Below that you are warming clouds.


So now it's 100 feet? It used to be 60 feet. But I have proof that is
not the case. So do a lot of other hams I know.

Your "facts" are for an idealized installation. Reality is much
different, and will never get the ideal specifications you claim.

For a dipole over average ground:

Height Gain @ Elevation
lambda

0.1 3.89 90
0.15 5.55 90
0.2 5.95 90
0.25 5.81 62
0.3 5.80 48
0.35 6.00 40
0.4 6.38 35
0.45 6.86 31
0.5 7.41 28
0.55 7.76 25
0.6 7.87 23
0.65 7.76 21
0.7 7.54 20
0.75 7.30 18
0.8 7.16 17
0.85 7.15 16
0.9 7.26 15
0.95 7.47 15
1 7.71 14

At 75M .4 lambda is about 100 feet.

Generally for DX a takeoff angle of 30 degrees or less is the rule of
thumb for best general performance.

Of course the antenna still "works" at other heights, but if DX is what
you want to achieve, then best results, on the average over average
ground, the antenna will work best for that at a height of .5 lambda
or better.

Now is you happen to be in a salt water marsh surrounded by 100 foot
tall steel blimp hangers, your results may vary.


--
Jim Pennino

wrote in message
...
But others are correct. The antenna itself is an efficient radiator;
it's the matching network that lowers *antenna system* efficiency.


Any dipole type antenna will suck on 75M if mounted less than about
100 feet, or about .4 wavelengths. Below that you are warming clouds.


So now it's 100 feet? It used to be 60 feet. But I have proof that is
not the case. So do a lot of other hams I know.

Your "facts" are for an idealized installation. Reality is much
different, and will never get the ideal specifications you claim.

For a dipole over average ground:

Height Gain @ Elevation
lambda

0.1 3.89 90
0.15 5.55 90
0.2 5.95 90
0.25 5.81 62
0.3 5.80 48
0.35 6.00 40
0.4 6.38 35
0.45 6.86 31
0.5 7.41 28
0.55 7.76 25
0.6 7.87 23
0.65 7.76 21
0.7 7.54 20
0.75 7.30 18
0.8 7.16 17
0.85 7.15 16
0.9 7.26 15
0.95 7.47 15
1 7.71 14

At 75M .4 lambda is about 100 feet.

Generally for DX a takeoff angle of 30 degrees or less is the rule of
thumb for best general performance.

Of course the antenna still "works" at other heights, but if DX is what
you want to achieve, then best results, on the average over average
ground, the antenna will work best for that at a height of .5 lambda
or better.

Now is you happen to be in a salt water marsh surrounded by 100 foot
tall steel blimp hangers, your results may vary.

At a given height wouldn't all simple horizontal antennas (halfwave dipole,
g5rv) have the same take off angle and be equal in that respect ? Say you
had a halfwave horizontal and replaced it with the g5rv at the same height
there shold not be any differance it the takeoff angle. If there is any big
differance in the signal , it would probably be the loss in the feedline
going to the 102 foot long antenna.

I have been tempted to put up a g5rv just to see what it would do. I have
an 80 meter dipole and also an OCF Carolina Windom at about the same heigth.
They are around 60 feet on the ends. There is usually not too much
differance in them except certain directions and distances. Then there can
be several S units at some directions. This is probably because they are at
right angles to each other.




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