Question about T2FDs
 

I've been reading about these and am intrigued.

These antennas are often mounted in a sloping configuration, but how
steep can the angle be? I'm sure the steepness of the angle is going to
effect the antenna's radiation pattern, but will how? Does it cause the
antenna to become highly directional as the angle increases?

How do these antennas perform in relatively noisy environments? I've
read that they're relatively slow to pick up local noise, but I'd like
to hear about some people's first hand experiences with them.

Are these antennas inevitably eyesores to those philistines who don't
appreciate the beauty of a good antenna? Is there a way to make them
less conspicuous?

Thanks,

Steve

Question about T2FDs
 

In article . com,
"Steve" wrote:

I've been reading about these and am intrigued.

These antennas are often mounted in a sloping configuration, but how
steep can the angle be? I'm sure the steepness of the angle is going
to effect the antenna's radiation pattern, but will how? Does it
cause the antenna to become highly directional as the angle
increases?

How do these antennas perform in relatively noisy environments? I've
read that they're relatively slow to pick up local noise, but I'd
like to hear about some people's first hand experiences with them.

Are these antennas inevitably eyesores to those philistines who don't
appreciate the beauty of a good antenna? Is there a way to make them
less conspicuous?

Sloping the antenna is an attempt to cause it to be more broadband.
This is not much help on reception but allows the antenna to be used
over a wider range of frequencies on transmit due to a reduction in
VSWR.

The termination resistor causes the antenna to be lossy and helps with
the VSWR aspect on transmit but is no help on reception.

The matching section is also a wast of time on receive. You are better
off using a broadband transformer.

There is nothing great about this antenna for reception. You are better
off using a folded dipole.

--
Telamon
Ventura, California

Question about T2FDs
 

On Thu, 09 Nov 2006 04:11:26 GMT, Telamon
wrote:

In article . com,
"Steve" wrote:

I've been reading about these and am intrigued.

These antennas are often mounted in a sloping configuration, but how
steep can the angle be? I'm sure the steepness of the angle is going
to effect the antenna's radiation pattern, but will how? Does it
cause the antenna to become highly directional as the angle
increases?

How do these antennas perform in relatively noisy environments? I've
read that they're relatively slow to pick up local noise, but I'd
like to hear about some people's first hand experiences with them.

Are these antennas inevitably eyesores to those philistines who don't
appreciate the beauty of a good antenna? Is there a way to make them
less conspicuous?

Sloping the antenna is an attempt to cause it to be more broadband.
This is not much help on reception but allows the antenna to be used
over a wider range of frequencies on transmit due to a reduction in
VSWR.

The termination resistor causes the antenna to be lossy and helps with
the VSWR aspect on transmit but is no help on reception.

The matching section is also a wast of time on receive. You are better
off using a broadband transformer.

There is nothing great about this antenna for reception. You are better
off using a folded dipole.

???

I would disregard everything written above. The antenna is very
quiet for receive.

Question about T2FDs
 

David wrote:

On Thu, 09 Nov 2006 04:11:26 GMT, Telamon
wrote:

In article . com,
"Steve" wrote:

I've been reading about these and am intrigued.

These antennas are often mounted in a sloping configuration, but how
steep can the angle be? I'm sure the steepness of the angle is going
to effect the antenna's radiation pattern, but will how? Does it
cause the antenna to become highly directional as the angle
increases?

How do these antennas perform in relatively noisy environments? I've
read that they're relatively slow to pick up local noise, but I'd
like to hear about some people's first hand experiences with them.

Are these antennas inevitably eyesores to those philistines who don't
appreciate the beauty of a good antenna? Is there a way to make them
less conspicuous?

Sloping the antenna is an attempt to cause it to be more broadband.
This is not much help on reception but allows the antenna to be used
over a wider range of frequencies on transmit due to a reduction in
VSWR.

The termination resistor causes the antenna to be lossy and helps with
the VSWR aspect on transmit but is no help on reception.

The matching section is also a wast of time on receive. You are better
off using a broadband transformer.

There is nothing great about this antenna for reception. You are better
off using a folded dipole.

???

I would disregard everything written above. The antenna is very
quiet for receive.

I found it to be 'quiet' because it really didn't receive very well.

I built two and chucked 'em both soon after.

dxAce
Michigan
USA

Question about T2FDs
 

"dxAce" wrote in message
...


David wrote:

On Thu, 09 Nov 2006 04:11:26 GMT, Telamon
wrote:

In article . com,
"Steve" wrote:

I've been reading about these and am intrigued.

These antennas are often mounted in a sloping configuration, but how
steep can the angle be? I'm sure the steepness of the angle is going
to effect the antenna's radiation pattern, but will how? Does it
cause the antenna to become highly directional as the angle
increases?

How do these antennas perform in relatively noisy environments? I've
read that they're relatively slow to pick up local noise, but I'd
like to hear about some people's first hand experiences with them.

Are these antennas inevitably eyesores to those philistines who don't
appreciate the beauty of a good antenna? Is there a way to make them
less conspicuous?

Sloping the antenna is an attempt to cause it to be more broadband.
This is not much help on reception but allows the antenna to be used
over a wider range of frequencies on transmit due to a reduction in
VSWR.

The termination resistor causes the antenna to be lossy and helps with
the VSWR aspect on transmit but is no help on reception.

The matching section is also a wast of time on receive. You are better
off using a broadband transformer.

There is nothing great about this antenna for reception. You are better
off using a folded dipole.

???

I would disregard everything written above. The antenna is very
quiet for receive.

I found it to be 'quiet' because it really didn't receive very well.

I built two and chucked 'em both soon after.

dxAce
Michigan
USA



Leave it to Rickets.

BH

Question about T2FDs
 

dxAce wrote:
David wrote:

On Thu, 09 Nov 2006 04:11:26 GMT, Telamon
wrote:

In article . com,
"Steve" wrote:

I've been reading about these and am intrigued.

These antennas are often mounted in a sloping configuration, but how
steep can the angle be? I'm sure the steepness of the angle is going
to effect the antenna's radiation pattern, but will how? Does it
cause the antenna to become highly directional as the angle
increases?

How do these antennas perform in relatively noisy environments? I've
read that they're relatively slow to pick up local noise, but I'd
like to hear about some people's first hand experiences with them.

Are these antennas inevitably eyesores to those philistines who don't
appreciate the beauty of a good antenna? Is there a way to make them
less conspicuous?



There is nothing great about this antenna for reception. You are better
off using a folded dipole.

???

I would disregard everything written above. The antenna is very
quiet for receive.

I found it to be 'quiet' because it really didn't receive very well.

I built two and chucked 'em both soon after.

I'm amazed at how many people I read put down the T2FD after the great
experiences I've had with it. Maybe those who knock it already have a
better low-noise antenna system in place.

I've never lived in a house where I could erect a 200 foot Doty
longwire a good distance from any noise source. My RF Systems T2FD is
probably the next best thing. My first house was in a Philly suburb,
close-in neighbors and lots of RFI around but none getting into my
receiver. Pulled in a lot of low powered, weak but clean signals from
all around the world. I'm still amazed at some of the stations I've
heard with it. My second house was much better RFI-wise but reception
was every bit as good in my first, proving to me that it was indeed the
antenna keeping the man-made noise out.

They are reputed to have low gain compared to other antennas, but the
total absence of interfering noise more than makes up for it. Try
listening to a radio in a noisy room, you need volume (gain) to
compensate for the enviornment. In a quiet room, you can turn the
volume (gain) down because its not neccessary, and also much more
relaxing and easier to listen to.

Invest in good coax, as there's no point in a low noise antenna without
a good shield coax.

My RF Systems antenna is 47 feet long, not too easy to hide but not a
monster if you have a good location to run it. One ham operator in my
town had a B&W T2FD over 90 feet long and I don't know how many times I
walked by his house before I noticed it.

The length determines the optimum frequency range. This one I have is
designed for 3.5-35 MHz. I am planning on modifying it to 35 feet long
and take off 6 inches in height to make it fit my current yard, as
right now I'm really in a tight spot! That'd put the optimum low
frequency at 4.75 MHz. They receive below the low frequency of course
but performance seems to drop off a bit.

Question about T2FDs
 

In article ,
dxAce wrote:

David wrote:

On Thu, 09 Nov 2006 04:11:26 GMT, Telamon
wrote:

In article . com,
"Steve" wrote:

I've been reading about these and am intrigued.

These antennas are often mounted in a sloping configuration, but
how steep can the angle be? I'm sure the steepness of the angle
is going to effect the antenna's radiation pattern, but will
how? Does it cause the antenna to become highly directional as
the angle increases?

How do these antennas perform in relatively noisy environments?
I've read that they're relatively slow to pick up local noise,
but I'd like to hear about some people's first hand experiences
with them.

Are these antennas inevitably eyesores to those philistines who
don't appreciate the beauty of a good antenna? Is there a way to
make them less conspicuous?

Sloping the antenna is an attempt to cause it to be more
broadband. This is not much help on reception but allows the
antenna to be used over a wider range of frequencies on transmit
due to a reduction in VSWR.

The termination resistor causes the antenna to be lossy and helps
with the VSWR aspect on transmit but is no help on reception.

The matching section is also a wast of time on receive. You are
better off using a broadband transformer.

There is nothing great about this antenna for reception. You are
better off using a folded dipole.

???

I would disregard everything written above. The antenna is very
quiet for receive.

I found it to be 'quiet' because it really didn't receive very well.

I built two and chucked 'em both soon after.

I disregard everything Dave writes. If he could pay attention, which
unfortunately he can't he would recognize that the T2FD is basically a
folded dipole with modifications so it will load up on transmit. Those
modifications are a waste of time on receive and the reasons given are
the rational unlike the advice given by the short attention span guy.

As DxAce found out it will not pick up the signal levels his current
fairly long horizontal wires will with or without the T2FD
modifications.

--
Telamon
Ventura, California

Question about T2FDs
 

On Fri, 10 Nov 2006 02:56:42 GMT, Telamon
wrote:


I disregard everything Dave writes. If he could pay attention, which
unfortunately he can't he would recognize that the T2FD is basically a
folded dipole
No ''basically'' about it. It is a (relatively) wideband folded
dipole.

http://www.hard-core-dx.com/nordicdx...wire/t2fd.html

Question about T2FDs
 

"Steve" wrote:

I've been reading about these and am intrigued.

These antennas are often mounted in a sloping configuration, but how
steep can the angle be? I'm sure the steepness of the angle is going to
effect the antenna's radiation pattern, but will how? Does it cause the
antenna to become highly directional as the angle increases?

Actually, the idea behind the slope is to make it more
omnidirectional. The ideal slope is something like 30 degrees, but
there's no hard-and-fast rule on this. Set it up as best you can.


How do these antennas perform in relatively noisy environments? I've
read that they're relatively slow to pick up local noise, but I'd like
to hear about some people's first hand experiences with them.

I absolutely love mine. Or loved -- it came down and was heavily
damaged in a windstorm, so I've been stuck using an end-fed wire
instead. It seems to be far less sensitive to near-field noise than
the longwire, and yet had nearly the same signal strength from most
directions. The longwire is 400 feet long and has an extensive
grounding and radial network, so it's not exactly a slouch in the
receive department... but the T2FD was a better overall performer. I
just have to rebuild it now.


Are these antennas inevitably eyesores to those philistines who don't
appreciate the beauty of a good antenna? Is there a way to make them
less conspicuous?

Mine was quite visible, and I thought of it as an eyesore, but my
neighbors didn't even notice it. It is heavy, visible, and provides a
lot of wind loading with all the spacers it needs. I live in a *very*
high wind area and mine would always come down. I ended up with a
counterweight system to allow it to get blown out of shape by quite a
bit and then return to normal when the wind died down... but that may
not be necessary where you live.

I don't know of a good way to make them less conspicuous unless you
want to play around with using very high strength material with a dark
color for the spacers -- something that doesn't have to be too thick.
Mine used PVC spacers and was ugly, but I live in the boonies and
could get away with it.


Thanks,

Steve

Hope this is helpful,

Eric

--
Eric F. Richards

"Nature abhors a vacuum tube." -- Myron Glass,
often attributed to J. R. Pierce, Bell Labs, c. 1940

Question about T2FDs
 

Telamon wrote:


I disregard everything Dave writes. If he could pay attention, which
unfortunately he can't he would recognize that the T2FD is basically a
folded dipole with modifications so it will load up on transmit. Those
modifications are a waste of time on receive and the reasons given are
the rational unlike the advice given by the short attention span guy.

As DxAce found out it will not pick up the signal levels his current
fairly long horizontal wires will with or without the T2FD
modifications.

Sorry, Telemon, but I disagree with you here. A stopped clock is
right twice a day, and so it is with Dave here.

Yes, the resistor is to avoid standing waves and turn it into a more
travelling wave antenna, much like such terrible receive antennas like
the Beverage and the Rhombic. (*sarcasm*)

My personal experience with wires and a T2FD is that the T2FD was
overall the better antenna with the wires having only occasional
advantages and some frequencies AND directions. The wires, BTW, have
extensive ground networks and about 20 ground radials.

For those not familiar with this antenna, this page is a good
jumping-off point for information (be sure to follow some of the
related links):

http://www.hard-core-dx.com/nordicdx...wire/t2fd.html

The late Joe Carr was an unabashed fan of this antenna, and he
certainly was a respected antenna authority for receive antennas with
a number of books under his belt, at least one of which was a
technically oriented book.

Regards,

--
Eric F. Richards

"Nature abhors a vacuum tube." -- Myron Glass,
often attributed to J. R. Pierce, Bell Labs, c. 1940

Question about T2FDs
 

In article ,
Eric F. Richards wrote:

Telamon wrote:


I disregard everything Dave writes. If he could pay attention, which
unfortunately he can't he would recognize that the T2FD is basically a
folded dipole with modifications so it will load up on transmit. Those
modifications are a waste of time on receive and the reasons given are
the rational unlike the advice given by the short attention span guy.

As DxAce found out it will not pick up the signal levels his current
fairly long horizontal wires will with or without the T2FD
modifications.

Sorry, Telemon, but I disagree with you here. A stopped clock is
right twice a day, and so it is with Dave here.

I'm going to have to disagree with you there as I used to read David's
posts and he was lucky to be right twice a month.

Yes, the resistor is to avoid standing waves and turn it into a more
travelling wave antenna, much like such terrible receive antennas like
the Beverage and the Rhombic. (*sarcasm*)

My personal experience with wires and a T2FD is that the T2FD was
overall the better antenna with the wires having only occasional
advantages and some frequencies AND directions. The wires, BTW, have
extensive ground networks and about 20 ground radials.

For those not familiar with this antenna, this page is a good
jumping-off point for information (be sure to follow some of the
related links):

http://www.hard-core-dx.com/nordicdx...wire/t2fd.html

The late Joe Carr was an unabashed fan of this antenna, and he
certainly was a respected antenna authority for receive antennas with
a number of books under his belt, at least one of which was a
technically oriented book.

I have high regard for Joe Carr and if anyone has a need they should buy
one of his books.

I'm not surprised your experience is good with a T2FD, it's a good
design.

There is a purpose behind the T2FD design and it is for transmit and
receive. For people wanting to use it only for receive the additions to
a basic folded dipole design so it will load well on transmit over a
range of frequencies are not needed and will not help on receive.

For receive only you are much better off using a BALUN of the right
transformation depending on the basic shape of the folded dipole you
construct.

--
Telamon
Ventura, California

Question about T2FDs
 

Telamon wrote:
In article ,
Eric F. Richards wrote:

Telamon wrote:


I disregard everything Dave writes. If he could pay attention, which
unfortunately he can't he would recognize that the T2FD is basically a
folded dipole with modifications so it will load up on transmit. Those
modifications are a waste of time on receive and the reasons given are
the rational unlike the advice given by the short attention span guy.

As DxAce found out it will not pick up the signal levels his current
fairly long horizontal wires will with or without the T2FD
modifications.

Sorry, Telemon, but I disagree with you here. A stopped clock is
right twice a day, and so it is with Dave here.

I'm going to have to disagree with you there as I used to read David's
posts and he was lucky to be right twice a month.

Yes, the resistor is to avoid standing waves and turn it into a more
travelling wave antenna, much like such terrible receive antennas like
the Beverage and the Rhombic. (*sarcasm*)

My personal experience with wires and a T2FD is that the T2FD was
overall the better antenna with the wires having only occasional
advantages and some frequencies AND directions. The wires, BTW, have
extensive ground networks and about 20 ground radials.

For those not familiar with this antenna, this page is a good
jumping-off point for information (be sure to follow some of the
related links):

http://www.hard-core-dx.com/nordicdx...wire/t2fd.html

The late Joe Carr was an unabashed fan of this antenna, and he
certainly was a respected antenna authority for receive antennas with
a number of books under his belt, at least one of which was a
technically oriented book.

I have high regard for Joe Carr and if anyone has a need they should buy
one of his books.

I'm not surprised your experience is good with a T2FD, it's a good
design.

There is a purpose behind the T2FD design and it is for transmit and
receive. For people wanting to use it only for receive the additions to
a basic folded dipole design so it will load well on transmit over a
range of frequencies are not needed and will not help on receive.

For receive only you are much better off using a BALUN of the right
transformation depending on the basic shape of the folded dipole you
construct.

--
Telamon
Ventura, California

My TTFD works well only above 7mc because of the size. It isn't as
quiet as I would like, or thought it would be, because it is in the
attic. I mostly use my 160m dipole for swl. I am sticking up a 200'
long wire next week at the back corner of my property across the river.
I'll probably stick a 2m 1/4 wave in the attic and scrap the TTFD. It
was a worthwhile experiment and would probably do very well if it were
bigger, tilted more, and away from the house.

73
NEO

Question about T2FDs
 

On Nov 9, 10:02 pm, Eric F. Richards wrote:
"Steve" wrote:
I've been reading about these and am intrigued.

These antennas are often mounted in a sloping configuration, but how
steep can the angle be? I'm sure the steepness of the angle is going to
effect the antenna's radiation pattern, but will how? Does it cause the
antenna to become highly directional as the angle increases?

- Actually, the idea behind the slope is to make it more
omnidirectional.

That is one of the the reasons often cited for Sloping the Wire
Antenna Element : The Inverted "V" being another example.

- The ideal slope is something like 30 degrees,
- but there's no hard-and-fast rule on this.

Yes 30 Degrees works well for most Sloping Receiving Antennas.
Horizontal (Flat) Wire = 100% Horizontal Dimension Area of Radiation.
Vertcal (Upright) Wire = 100% Vertical Dimension Area of Radiation.
45 Degree Sloping Wire = 50% Horizontal and 50% Vertical
Dimension Area of Radiation.
30 Degree Sloping Wire = 87% Horizontal Dimension and
50% Vertical Dimension Areas of Radiation.
- - - Roughly speaking.
The 30 Degree Sloping Wire Antenna Element to some
degree can be though of as the same space equalent as
an Inverted "L" Antenna which would make up the other
Two Sides of a Triangle created by the Sloping Side.
* 30 Ft Sloper Antenna would take up the same space as
a 15 Ft Vertical by 26 Ft Horizontal Inverted "L" Antenna.
Note - This Inverted "L" would be 41 Ft long (+11 Ft) and
have 37% more Wire-in-the-Air.
* 52 Ft Sloper Antenna would take up the same space as
a 26 Ft Vertical by 45 Ft Horizontal Inverted "L" Antenna
Note - This Inverted "L" would be 71 Ft long (+19 Ft) and
have 37% more Wire-in-the-Air.

- - - For some it simply comes down to the fact that the
Sloping Wire Antenna may be eaiser to Rig then the
Inverted "L" Wire Antenna.

numb3rs ~ RHF

Question about T2FDs
 

Telamon wrote:

Sorry, Telemon, but I disagree with you here. A stopped clock is
right twice a day, and so it is with Dave here.

I'm going to have to disagree with you there as I used to read David's
posts and he was lucky to be right twice a month.

True enough, but it's the same idea, different scale.

I have high regard for Joe Carr and if anyone has a need they should buy
one of his books.

I'm not surprised your experience is good with a T2FD, it's a good
design.

There is a purpose behind the T2FD design and it is for transmit and
receive. For people wanting to use it only for receive the additions to
a basic folded dipole design so it will load well on transmit over a
range of frequencies are not needed and will not help on receive.

I'm not so sure I'm convinced by that, simply because of the amount of
material I've read on the T2FD. Yes, it was designed as a transmit
antenna, and yes, the resistor is vital to that role, but like in a
rhombic or Beverage, it still plays an important role in reception.


For receive only you are much better off using a BALUN of the right
transformation depending on the basic shape of the folded dipole you
construct.

Unfortunately, I've no experience modelling the antenna, or I would do
so to see if that's correct. Do you have a model to back up this
assertion? I'm interested in seeing this result.

Regards,

--
Eric F. Richards

"Nature abhors a vacuum tube." -- Myron Glass,
often attributed to J. R. Pierce, Bell Labs, c. 1940

Question about T2FDs
 

On Sat, 11 Nov 2006 09:51:16 -0700, Eric F. Richards
wrote:

Telamon wrote:

Sorry, Telemon, but I disagree with you here. A stopped clock is
right twice a day, and so it is with Dave here.

I'm going to have to disagree with you there as I used to read David's
posts and he was lucky to be right twice a month.

True enough, but it's the same idea, different scale.

I have high regard for Joe Carr and if anyone has a need they should buy
one of his books.

I'm not surprised your experience is good with a T2FD, it's a good
design.

There is a purpose behind the T2FD design and it is for transmit and
receive. For people wanting to use it only for receive the additions to
a basic folded dipole design so it will load well on transmit over a
range of frequencies are not needed and will not help on receive.

I'm not so sure I'm convinced by that, simply because of the amount of
material I've read on the T2FD. Yes, it was designed as a transmit
antenna, and yes, the resistor is vital to that role, but like in a
rhombic or Beverage, it still plays an important role in reception.


For receive only you are much better off using a BALUN of the right
transformation depending on the basic shape of the folded dipole you
construct.

Unfortunately, I've no experience modelling the antenna, or I would do
so to see if that's correct. Do you have a model to back up this
assertion? I'm interested in seeing this result.

Regards,

Cebic has some interesting feedpoint info on the terminated folded
dipole at http://www.cebik.com/gup/groundup.html

Also, I'm guessing the signal loss he mentions might be why some find
the antenna to be "quiet."

bob
k5qwg

Question about T2FDs
 

i cant vouch for the T2FD at shortwave frequencies but i built one cut
for vhf and it was a rocket! it was red hot when compared to all of my
other scanner antennas, including a fairly expensive name brand ground
plane antenna (whose name escapes me at this moment). as far as one
persons statement goes that for receive a simple unterminated dipole is
the same or superior to the terminated one, if that is true then it
would simplify the antenna considerably. it does seem logical that the
terminating resistor would attenuate or reduce at least some received
signal. however at rf frequencies some strange factors arise that are
unknown to me and logic doesnt always serve well when it comes to
antennas. for instance as a teenager i had one of those antique all
metal box springs for my bed. it didnt calculate out that the springs
would load up at all but they were the best hf receive antenna that i
have ever had in my life. the bottom line is this, T2FD is a GREAT
antenna! maybe plain TFD is as good? TRY ONE! (tilt is for omni pattern,
sometimes this is good, sometimes not so good!) you will find
circumstances that arise where the one antenna receives when the other
hears nothing. there is no perfect antenna, several variations to choose
from and compare between is the swl ideal. BUILD THAT DAMN ANTENNA! and
the others too! and most of all, post your results!

Question about T2FDs
 

Bob Miller wrote:

Cebic has some interesting feedpoint info on the terminated folded
dipole at http://www.cebik.com/gup/groundup.html

Thanks, I'm going to be looking at it soon.

Also, I'm guessing the signal loss he mentions might be why some find
the antenna to be "quiet."

When I compare it against my 400 foot wire with a ground, matching
network, radials, etc., I find that the S/N ratio is far better on the
T2FD. In fact, usually, the signal level is indistinguishable on
receivers with accurate S meters.

There are exceptions, of course -- the T2FD doesn't do as well below 2
MHz, but then it wasn't designed to. Above there, the T2FD is the
better all 'round player. If I had to have only one of my two
antennas, there simply would be no competition.

--
Eric F. Richards

"Nature abhors a vacuum tube." -- Myron Glass,
often attributed to J. R. Pierce, Bell Labs, c. 1940

Question about T2FDs
 

On Sat, 11 Nov 2006 22:33:28 -0700, Eric F. Richards
wrote:

Bob Miller wrote:

Cebic has some interesting feedpoint info on the terminated folded
dipole at http://www.cebik.com/gup/groundup.html

Thanks, I'm going to be looking at it soon.

Also, I'm guessing the signal loss he mentions might be why some find
the antenna to be "quiet."

When I compare it against my 400 foot wire with a ground, matching
network, radials, etc., I find that the S/N ratio is far better on the
T2FD. In fact, usually, the signal level is indistinguishable on
receivers with accurate S meters.

There are exceptions, of course -- the T2FD doesn't do as well below 2
MHz, but then it wasn't designed to. Above there, the T2FD is the
better all 'round player. If I had to have only one of my two
antennas, there simply would be no competition.

I'd wonder how it would compare to an ordinary non-folded,
non-terminated dipole, although that might not be a valid comparison,
since a dipole is typically designed for a single frequency. Oh,
well...

bob
k5qwg

Question about T2FDs
 

On Sun, 12 Nov 2006 14:23:44 GMT, Bob Miller
wrote:



I'd wonder how it would compare to an ordinary non-folded,
non-terminated dipole, although that might not be a valid comparison,
since a dipole is typically designed for a single frequency. Oh,
well...

A dipole, as used by most SWLs, is unbalanced and has no CMR.

Question about T2FDs
 

But what about them purples?
cuhuln
.................................................. .............
went upstairs,went to bed,stepped over the pee pot over my head,,,,
couldn't swim,couldn't float,a little green turd went down my throat.
.................................................. ............

Question about T2FDs
 

In article ,
Eric F. Richards wrote:

Telamon wrote:

Sorry, Telemon, but I disagree with you here. A stopped clock is
right twice a day, and so it is with Dave here.

I'm going to have to disagree with you there as I used to read David's
posts and he was lucky to be right twice a month.

True enough, but it's the same idea, different scale.

I have high regard for Joe Carr and if anyone has a need they should buy
one of his books.

I'm not surprised your experience is good with a T2FD, it's a good
design.

There is a purpose behind the T2FD design and it is for transmit and
receive. For people wanting to use it only for receive the additions to
a basic folded dipole design so it will load well on transmit over a
range of frequencies are not needed and will not help on receive.

I'm not so sure I'm convinced by that, simply because of the amount of
material I've read on the T2FD. Yes, it was designed as a transmit
antenna, and yes, the resistor is vital to that role, but like in a
rhombic or Beverage, it still plays an important role in reception.


For receive only you are much better off using a BALUN of the right
transformation depending on the basic shape of the folded dipole you
construct.

Unfortunately, I've no experience modelling the antenna, or I would do
so to see if that's correct. Do you have a model to back up this
assertion? I'm interested in seeing this result.

I don't model antennas because as don't see the need. A folded dipole is
well understood.

--
Telamon
Ventura, California

Question about T2FDs
 

Telamon wrote:

I don't model antennas because as don't see the need. A folded dipole is
well understood.

But it's not a simple folded dipole.

Somewhere I may have modelling data on the T2FD, but I have more
pressing things to do today.

But whatever -- I don't know why you feel the need to beat on the
thing so much. The bottom line, for /me/, is that it works and works
well. In /my/ situation, it far outperforms a well-designed end-fed
wire.

So my advice to the original poster is, go ahead and try it. For that
matter, try slinky-dipoles, end-fed wires, whatever. See what works
for you, and give it a run.

The original poster can play games like using the resistor, opening
that end of the dipole, shorting that end of the dipole, whatever.
Let him decide what works best for him.

--
Eric F. Richards

"Nature abhors a vacuum tube." -- Myron Glass,
often attributed to J. R. Pierce, Bell Labs, c. 1940

Question about T2FDs
 

On Nov 12, 9:56 am, David wrote:
On Sun, 12 Nov 2006 14:23:44 GMT, Bob Miller
wrote:



I'd wonder how it would compare to an ordinary non-folded,
non-terminated dipole, although that might not be a valid comparison,
since a dipole is typically designed for a single frequency. Oh,
well...

- A dipole, as used by most SWLs, is unbalanced
- and has no CMR.

David can you expand on this comment ?

* Dipole is Un-Balanced {As used by most SWLs}

* Has no CMR.

David what is CMR ?

i want to know - iane ~ RHF

Question about T2FDs
 

On 14 Nov 2006 23:56:14 -0800, "RHF"
wrote:



On Nov 12, 9:56 am, David wrote:
On Sun, 12 Nov 2006 14:23:44 GMT, Bob Miller
wrote:



I'd wonder how it would compare to an ordinary non-folded,
non-terminated dipole, although that might not be a valid comparison,
since a dipole is typically designed for a single frequency. Oh,
well...

- A dipole, as used by most SWLs, is unbalanced
- and has no CMR.

David can you expand on this comment ?

* Dipole is Un-Balanced {As used by most SWLs}

* Has no CMR.

David what is CMR ?

i want to know - iane ~ RHF
.
.
. .
http://www.w8ji.com/common-mode_noise.htm

Question about T2FDs
 

On Nov 15, 5:41 am, David wrote:
On 14 Nov 2006 23:56:14 -0800, "RHF"
wrote:







On Nov 12, 9:56 am, David wrote:
On Sun, 12 Nov 2006 14:23:44 GMT, Bob Miller
wrote:

I'd wonder how it would compare to an ordinary non-folded,
non-terminated dipole, although that might not be a valid comparison,
since a dipole is typically designed for a single frequency. Oh,
well...

- A dipole, as used by most SWLs, is unbalanced
- and has no CMR.

David can you expand on this comment ?

* Dipole is Un-Balanced {As used by most SWLs}

* Has no CMR.

David what is CMR ?

i want to know - iane ~ RHF
.
.
. .http://www.w8ji.com/common-mode_noise.htm- Hide quoted text -- Show quoted text -
David - Thank you ~ RHF
That explains "CMN" Common Mode Noise
? Was CMR a typo ?

Question about T2FDs
 

On 15 Nov 2006 22:05:20 -0800, "RHF"
wrote:



On Nov 15, 5:41 am, David wrote:
On 14 Nov 2006 23:56:14 -0800, "RHF"
wrote:







On Nov 12, 9:56 am, David wrote:
On Sun, 12 Nov 2006 14:23:44 GMT, Bob Miller
wrote:

I'd wonder how it would compare to an ordinary non-folded,
non-terminated dipole, although that might not be a valid comparison,
since a dipole is typically designed for a single frequency. Oh,
well...

- A dipole, as used by most SWLs, is unbalanced
- and has no CMR.

David can you expand on this comment ?

* Dipole is Un-Balanced {As used by most SWLs}

* Has no CMR.

David what is CMR ?

i want to know - iane ~ RHF
.
.
. .http://www.w8ji.com/common-mode_noise.htm- Hide quoted text -- Show quoted text -
David - Thank you ~ RHF
That explains "CMN" Common Mode Noise
? Was CMR a typo ?
.
CMR is the ability of the system to balance out local (near field?)
noise.

Question about T2FDs
 

On Nov 16, 6:27 pm, David wrote:
On 15 Nov 2006 22:05:20 -0800, "RHF"
wrote:







On Nov 15, 5:41 am, David wrote:
On 14 Nov 2006 23:56:14 -0800, "RHF"
wrote:

On Nov 12, 9:56 am, David wrote:
On Sun, 12 Nov 2006 14:23:44 GMT, Bob Miller
wrote:

I'd wonder how it would compare to an ordinary non-folded,
non-terminated dipole, although that might not be a valid comparison,
since a dipole is typically designed for a single frequency. Oh,
well...

- A dipole, as used by most SWLs, is unbalanced
- and has no CMR.

David can you expand on this comment ?

* Dipole is Un-Balanced {As used by most SWLs}

* Has no CMR.

David what is CMR ?

i want to know - iane ~ RHF
.
.
. .http://www.w8ji.com/common-mode_noise.htm-Hide quoted text -- Show quoted text -
David - Thank you ~ RHF
That explains "CMN" Common Mode Noise
? Was CMR a typo ?
.CMR is the ability of the system to balance out local (near field?)
noise.- Hide quoted text -- Show quoted text -

David -?- "CMR" = Common Mode Rejection ~ RHF
http://acronyms.thefreedictionary.co...Mode+Rejection
http://www.edn.com/index.asp?layout=...850&ref=n bra

http://www.benchmarkmedia.com/caig/html/caig04.html
http://www.maxim-ic.com/appnotes.cfm...e_number/2045/