On 11/14/2014 12:34 PM, wrote:
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.



You ignore the fact this is an idealized environment. That is NEVER the
case in a real installation.

I have WAS on 75 SSB (from Iowa) with an inverted Vee. The top was only
50' in the air. And late at night in the wintertime I had pretty solid
communications over much of the continental U.S. (back in the late 70's
and early 80's).

Antennas NEVER work "as predicted" - and anyone who claims they do does
not understand antenna operation.

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

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

On Friday, November 14, 2014 11:46:03 AM UTC-6,
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.

Yep, for 80m, it's usually easier to put up a good vertical for dx
than a high dipole. And even then sometimes the vertical will do the
best. W8JI talks a lot about this comparing his 160m verticals and his
high 160m dipoles. Most times, his verticals still win to long paths.
I forgot how high his dipole was, but it's pretty high vs what most
people have.
People talk about short antennas being poor radiators, but on 40m with
my appx 40 ft tall full size dipole fed with coax, my mobile antenna
would beat it most every night from Houston to Jacksonville FL.
I thought maybe it was a fluke, but I tested it a few more times, and
it almost always won. So the most efficient antenna does not always win
the race if the less efficient antenna puts more rf at the lower angles
where you want for longer paths, vs the highly efficient antenna like my
coax fed dipoles. At 40 ft on 40m, it's still shooting a lot of rf at
fairly high angles, and not so much at the low angles.
Less than my mobile antenna did.

I remember one night I was at the coast fishing, and I actually ran a wide
braid ground wire from the truck body into the ocean just to add that extra
gusto.
On longer paths, I was smoking some people using dipoles and running amps
vs my extended 14 ft tall mobile antenna sitting on the beach with 100w.
So much for small antennas always being poor radiators.. :/
Efficiency isn't always everything. But it usually is for NVIS paths,
which is why I've always preferred coax fed dipoles for my usual 75m NVIS
chatter.

On 11/14/2014 8:36 AM, 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.

snip


I strongly encourage you to use a "loaded" 1 foot long dipole on 75
meters. This will prove you are right and we can all listen to the
proof. :-)

On 11/15/2014 6:17 PM, FBMboomer wrote:
On 11/14/2014 8:36 AM, 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.

snip


I strongly encourage you to use a "loaded" 1 foot long dipole on 75
meters. This will prove you are right and we can all listen to the
proof. :-)



I suggest you stop trolling. You obviously have too much time on your
hands (and too little brains to do anything productive).

No wonder you wish to remain anonymous.

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

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

El 13-11-14 21:39, FBMboomer escribió:
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.



I agree that in many practical circumstances electrically small
antennas do not perform well. I also know that having an antanna is
better than nothing.

The smaller the antenna, the more difficulties you will experience to
get radiation out of it (heat radiation doesn't count).

In free space you can make a rather efficient antenna with say maximum
size of 0.03lambda, as long as you are a good electron tamer. If not,
electrons escape from the structure showing a nice corona, or full
breakdown occurs. Examples are tuned loops and short dipoles with
capacitive end plates and series inductors to arrive at some nice
impedance.

Tuning in the shack with lots of cable and a bad ferrite balun between
tuner and antenne mostly results in good VSWR but low efficiency (as
many people know).

In real world even a very small very efficient antenna may not perform
as expected Close to the antenna (say within 0.1 lambda), reactive
fields are very strong and they increase rapidly when reducing the
distance. This is also valid for "magnetic loops" (that Jennings HV
vacuum capacitor or thick potato cutter/slicer is for a reason). When
you put such a nice small antenna close to lossy dielectric (building
materials, ground, etc), significant part of the RF power may be
dissipated in that lossy dielectric materials.

In case of short monopoles, lots of power is mostly dissipated in the
ground/counterpoise system (saline wetlands, sea and large metallic
surfaces excepted). Of course we can solve this with lots of burried
radials, or somewhat less elevated radials, but such solutions don't
qualify for an electrically small antenna anymore.


--
Wim
PA3DJS
Please remove abc first in case of PM

But most people do not have access to tower that can get their dipole antenna 100' off the ground for 75 meters!

The
G5RV was designed to work on 20 meters.
The ladder line is the matching network.
It does not perform well on 10 or 40 meters.

That usually has something to do with a cut dipole not working well on anything that is the first harmonic.

A portion of this planet is inhabited by morons that does not know that and that picks their antenna by price rather than by performance!

My inverted V - 80M off center fed dipole antenna is only 30' off the ground in the middle and maybe 20' off the ground on the ends.
It is fed with about 60' of LMR 400 and I can converse with anyone that I can hear.

Most of the people I hear are using 600 - 1200 watt amplifiers and some other type of dipole antenna, and although their signal is louder than mine, my audio is much cleaner then theirs!

To me - amplifiers are for CB'rs that are hard of hearing and thinks that you cannot carry on a conversation unless you are 20/9!

When I become a O&O - the first thing I am going to do is send each and every one of those people a pink slip and have them explain why they use more power than necessary.

I would keep on sending them pink slips until they either get the message - that the reason for the signal report is so you can adjust your power to the minimum amount necessary to carry on the conversation, or until the ARRL / FCC gets tired of it and sends them a greetings to come and see them and explain why they can't follow the rules!

As far as these people bragging about how they pick on those that are on a G5RV - I would gladly send them pink slips also - until they reduce their power or answer for their actions in front of a FCC examiner...

I would love to see how many of these people could still pass a General Class Examination and how many of them bought their license and will let it drop - if they are asked to retest...

On Thursday, November 13, 2014 10:13:02 PM UTC-6, Channel Jumper wrote:
But most people do not have access to tower that can get their dipole
antenna 100' off the ground for 75 meters!

I actually want my 80 meter antennas to shoot straight up. I'm
working NVIS paths 98 percent of the time. Only the DX'ers need
a high dipole. Or a good vertical, which generally is better.


When I become a O&O - the first thing I am going to do is send each and
every one of those people a pink slip and have them explain why they use
more power than necessary.

Knock yourself out. You will only succeed in looking like a jackass,
and the FCC could care less as long as they don't exceed the legal
limit or cause splatter due to an underloaded amp, etc.

On 11/13/2014 9:21 PM, Channel Jumper wrote:
But most people do not have access to tower that can get their dipole
antenna 100' off the ground for 75 meters!

The
G5RV was designed to work on 20 meters.
The ladder line is the matching network.
It does not perform well on 10 or 40 meters.

That usually has something to do with a cut dipole not working well on
anything that is the first harmonic.

A portion of this planet is inhabited by morons that does not know that
and that picks their antenna by price rather than by performance!

My inverted V - 80M off center fed dipole antenna is only 30' off the
ground in the middle and maybe 20' off the ground on the ends.
It is fed with about 60' of LMR 400 and I can converse with anyone that
I can hear.

Most of the people I hear are using 600 - 1200 watt amplifiers and some
other type of dipole antenna, and although their signal is louder than
mine, my audio is much cleaner then theirs!

To me - amplifiers are for CB'rs that are hard of hearing and thinks
that you cannot carry on a conversation unless you are 20/9!

When I become a O&O - the first thing I am going to do is send each and
every one of those people a pink slip and have them explain why they use
more power than necessary.

I would keep on sending them pink slips until they either get the
message - that the reason for the signal report is so you can adjust
your power to the minimum amount necessary to carry on the conversation,
or until the ARRL / FCC gets tired of it and sends them a greetings to
come and see them and explain why they can't follow the rules!

As far as these people bragging about how they pick on those that are on
a G5RV - I would gladly send them pink slips also - until they reduce
their power or answer for their actions in front of a FCC examiner...

I would love to see how many of these people could still pass a General
Class Examination and how many of them bought their license and will let
it drop - if they are asked to retest...




OH Channel Jumper, you will be so powerful as an O&O. Your pink slips
will surely intimidate everyone. They will just operate they way you
want them to operate. Just think of the satisfaction you will get
sending that pink slip. Never mind that it is an exercise in impotency.
Did it ever occur to you that running the power necessary to communicate
is not quantifiable by any standard but your own. How little S/N ratio
are you willing to hear. If you like noise instead of audio then by all
means demand that your contact reduce power.

On 11/13/2014 7:06 PM, Wimpie wrote:
El 13-11-14 21:39, FBMboomer escribió:
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.



I agree that in many practical circumstances electrically small antennas
do not perform well. I also know that having an antanna is better than
nothing.

The smaller the antenna, the more difficulties you will experience to
get radiation out of it (heat radiation doesn't count).

In free space you can make a rather efficient antenna with say maximum
size of 0.03lambda, as long as you are a good electron tamer. If not,
electrons escape from the structure showing a nice corona, or full
breakdown occurs. Examples are tuned loops and short dipoles with
capacitive end plates and series inductors to arrive at some nice
impedance.

Tuning in the shack with lots of cable and a bad ferrite balun between
tuner and antenne mostly results in good VSWR but low efficiency (as
many people know).

In real world even a very small very efficient antenna may not perform
as expected Close to the antenna (say within 0.1 lambda), reactive
fields are very strong and they increase rapidly when reducing the
distance. This is also valid for "magnetic loops" (that Jennings HV
vacuum capacitor or thick potato cutter/slicer is for a reason). When
you put such a nice small antenna close to lossy dielectric (building
materials, ground, etc), significant part of the RF power may be
dissipated in that lossy dielectric materials.

In case of short monopoles, lots of power is mostly dissipated in the
ground/counterpoise system (saline wetlands, sea and large metallic
surfaces excepted). Of course we can solve this with lots of burried
radials, or somewhat less elevated radials, but such solutions don't
qualify for an electrically small antenna anymore.


Wimpie,

Let them use short antennas. Do not discourage them. It makes more room
on 75 for those of us using full size antennas and power. They can talk
around the block about how great there antenna is, and not bother anyone
else. I hope the biggest antenna they ever use is a G5RV.

On Thursday, November 13, 2014 2:38:40 PM UTC-6, 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.

But again, as everyone has pointed out, it's not the radiator, it's
the feed system that provides the losses.
The *usual* G5RV is generally lousy compared to a coax fed 1/2 dipole
because of the funky poorly designed feed system, not the radiator.
IE: coax to a choke balun to twin lead to the radiator. That's a joke..

The feed system is the culprit, not the slightly shortened radiator.
Which BTW, is not really all that short, as far as short antennas go.
It's more like a reduced size radiator, rather than actually short like
say a short mobile antenna, or a very small dipole.

If you can feed a 102 ft dipole with nothing but twin lead, the
antenna system is quite efficient. Say if you use Cecil Moore's
method of feeding a G5RV with ladder line.

You are blaming the wrong culprit, same as Gareth continues to do.
You have to consider the whole antenna *system*, not just the radiator.
Only the *very* short radiators suffer from ohmic losses. The 102 ft
dipole used with a G5RV does not qualify in that regard. Most all
the loss is in the feed system, not the radiator itself. And that can
be corrected to be pretty much a non issue.