Walt, W2DU, and Tiros
 

On Wed, 02 Aug 2006 15:54:26 GMT, (Rick) wrote:

On Wed, 02 Aug 2006 11:18:07 -0400, Walter Maxwell
wrote:


During the period between 1958-59 I designed the entire antenna system and
matching harness for the World's first weather satellite, TIROS 1, which was
launched April 1, 1960.


Walt,
Could you please tell me a little more about that satellite? Reason I
ask is there is a place I am sure you can enlighten us on, called Camp
Evans.
I know there is still a big dish antenna there, although the wooden
structure surrounding it is failing. Supposedly it was used for
communicating with Tiros. Is that right?

A NJ radio club had a hamfest there in April, and I was able to walk
under the antenna and they have some displays there. Supposedly Camp
Evans was also the place where the first signals were bounced off the
moon, somewhere around 1946.
Camp Evans looks like at least parts of it are being renovated.
Brookdale Comm. College has some classrooms there, very modern.
Oh yes, and on the road leading to Camp Evans (Marconi Road !!) there
is a display of the top portion of one of Marconi's towers, and a
plaque noting that there were many such towers in the area in the
early 1900s.
Quite a bit of radio history, in these parts of New Jersey, and I am
glad to know one of the pioneers frequents this newsgroup.
Not far away, in Holmdel, is where AT&T communicated with Telstar, I
believe, about the same time period. The Holmdel facility, home to
6000 Bell Labs employees as recently as1999 has been sold and is going
to be demolished.

Rick K2XT

Hi Rick,

Thanks for the response to my post.

The first eight versions of TIROS were shaped as a short 18-sided cylinder about
30 inches in diameter and about two feet tall. It contained a 1/2 inch vidicon
video camera and an infra red (IR) sensor. Direct viewing of both the camera and
IR sensor was attained whenever the spacecraft was within sighting distance of
the three ground stations, one at Ft. Monmouth, NJ, one at our RCA Space Center
at Hightstown, NJ, (where we built the spacecraft) which I operated, and one in
Australia.

There were also two tape recorders that recorded the video and IR when over
other places on Earth out of range of the ground stations, for playback when in
range.

The video and IR transmitters each delivered 5 watts, the video on 235 MHz and
the IR on 237.8 MHz. There were two beacon and telemetry transmitters, one on
108 MHz and the other on 108.03 MHz, each delivering 30 milliwatts. Beginning
with TIROS 3 and on through 8, the beacon-telemetry transmitter frequencies were
changed to 136.0 and 136.5 MHz, leaving the 108 MHz frequencies free for
aircraft communications.

The monopole antennas were sleeve type. A half-inch sleeve 1/4 wl long at 236
MHz radiated the video and IR signals, and a rod extension, along with the
sleeve, radiated the 108 MHz signals. The internal portion of the sleeve formed
a quarter-wave shorted transmission line that decoupled the rod extension at the
235 and 237.8 MHz frequencies, as part of the frequency-separation circuitry
that allowed the antenna to operate on the two frequency bands separated by
approximately an octave.

I have a number of pictures of the spacecraft in various views in JPG format
that I'll send to you as soon as I can get them together.

Now concering Camp Evans, I'm not sure that that was the location of the TIROS
dish, which was 28 feet in diameter. All I can recall after all these years is
that the dish was at Ft. Monmouth, the location of USASRDL, the Signal Corps
Development Laboratory. Camp Evans might have been on the Ft. Monmouth Army
Base, but I just can't remember.

I knew several of the engineering guys at Bell Labs Holmdel, but all I knew
there have passed on.

Hope this helps,

Walt, W2DU

Radiating Efficiency
 

Hasan,

Why don't you look for differences between BLE and NEC4?

I'm sure you'll find some.
----
Reg.

Radiating Efficiency
 

Frank,

Thank you for the above.

Can you do 36 radials from 0.6 to 8.0 metres in increments of 0.2
metres?

Must be the same input data as before :- F = 8.07 MHz, Ground =
150,16 Radial diameter = 1.64mm, Depth = 25mm.

Reg,

Here are the results from the analysis of a 26 radial system.
All dimensions and parameters are the same as for the single
radial antenna as you defined above:

0.6 m -- Radial Z = 37.3 - j 28.1 -- Efficiency 15%
0.8 m -- Radial Z = 30.5 - j 21.0
1.0 m -- Radial Z = 26.2 - j 16.9
1.2 m -- Radial Z = 23.2 - j 14.2
1.4 m -- Radial Z = 20.9 - j 12.4
1.6 m -- Radial Z = 19.1 - j 11.1
1.8 m -- Radial Z = 17.6 - j 10.1 -- Efficiency 21.0%
2.0 m -- Radial Z = 16.2 - j 9.4
2.2 m -- Radial Z = 15.1 - j 8.8
2.4 m -- Radial Z = 14.0 - j 8.4
2.6 m -- Radial Z = 13.0 - j 8.0
2.8 m -- Radial Z = 12.1 - j 7.7
3.0 m -- Radial Z = 11.3 - j 7.4
3.2 m -- Radial Z = 10.4 - j 7.1 -- Efficiency 24.5%
3.4 m -- Radial Z = 9.7 - j 6.8
3.6 m -- Radial Z = 8.9 - j 6.5
3.8 m -- Radial Z = 8.2 - j 6.2
4.0 m -- Radial Z = 7.5 - j 5.8
4.2 m -- Radial Z = 6.9 - j 5.5
4.4 m -- Radial Z = 6.4 - j 5.1
4.6 m -- Radial Z = 5.8 - j 4.7
4.8 m -- Radial Z = 5.4 - j 4.3
5.0 m -- Radial Z = 5.0 - j 3.9 -- Efficiency 27.8%
5.2 m -- Radial Z = 4.6 - j 3.5
5.4 m -- Radial Z = 4.3 - j 3.1
5.6 m -- Radial Z = 4.0 - j 2.7
5.8 m -- Radial Z = 3.7 - j 2.3
6.0 m -- Radial Z = 3.5 - j 2.0
6.2 m -- Radial Z = 3.3 - j 1.6
6.4 m -- Radial Z = 3.1 - j 1.3
6.6 m -- Radial Z = 3.0 - j 0.9
6.8 m -- Radial Z = 2.9 - j 0.6
7.0 m -- Radial Z = 2.8 - j 0.3
7.2 m -- Radial Z = 2.7 + j 0.01
7.4 m -- Radial Z = 2.6 + j 0.3
7.6 m -- Radial Z = 2.6 + j 0.6
7.8 m -- Radial Z = 2.6 + j 0.9
8.0 m -- Radial Z = 2.5 + j 1.1 -- Efficiency 31.1%
..
..
10.0 m -- Radial Z = 3.0 + j 3.3 -- Efficiency 32.6%

Where I have shown the efficiency as sky wave power
out. The input impedance is that of all radials, so for
a single radial the input Zr must be Ztr * 26.

Frank

Radiating Efficiency
 

Reg, I meant 36 radials. The 26 is a typo.

Frank

Here are the results from the analysis of a 36 radial system.
All dimensions and parameters are the same as for the single
radial antenna as you defined above:

0.6 m -- Radial Z = 37.3 - j 28.1 -- Efficiency 15%
0.8 m -- Radial Z = 30.5 - j 21.0
1.0 m -- Radial Z = 26.2 - j 16.9
1.2 m -- Radial Z = 23.2 - j 14.2
1.4 m -- Radial Z = 20.9 - j 12.4
1.6 m -- Radial Z = 19.1 - j 11.1
1.8 m -- Radial Z = 17.6 - j 10.1 -- Efficiency 21.0%
2.0 m -- Radial Z = 16.2 - j 9.4
2.2 m -- Radial Z = 15.1 - j 8.8
2.4 m -- Radial Z = 14.0 - j 8.4
2.6 m -- Radial Z = 13.0 - j 8.0
2.8 m -- Radial Z = 12.1 - j 7.7
3.0 m -- Radial Z = 11.3 - j 7.4
3.2 m -- Radial Z = 10.4 - j 7.1 -- Efficiency 24.5%
3.4 m -- Radial Z = 9.7 - j 6.8
3.6 m -- Radial Z = 8.9 - j 6.5
3.8 m -- Radial Z = 8.2 - j 6.2
4.0 m -- Radial Z = 7.5 - j 5.8
4.2 m -- Radial Z = 6.9 - j 5.5
4.4 m -- Radial Z = 6.4 - j 5.1
4.6 m -- Radial Z = 5.8 - j 4.7
4.8 m -- Radial Z = 5.4 - j 4.3
5.0 m -- Radial Z = 5.0 - j 3.9 -- Efficiency 27.8%
5.2 m -- Radial Z = 4.6 - j 3.5
5.4 m -- Radial Z = 4.3 - j 3.1
5.6 m -- Radial Z = 4.0 - j 2.7
5.8 m -- Radial Z = 3.7 - j 2.3
6.0 m -- Radial Z = 3.5 - j 2.0
6.2 m -- Radial Z = 3.3 - j 1.6
6.4 m -- Radial Z = 3.1 - j 1.3
6.6 m -- Radial Z = 3.0 - j 0.9
6.8 m -- Radial Z = 2.9 - j 0.6
7.0 m -- Radial Z = 2.8 - j 0.3
7.2 m -- Radial Z = 2.7 + j 0.01
7.4 m -- Radial Z = 2.6 + j 0.3
7.6 m -- Radial Z = 2.6 + j 0.6
7.8 m -- Radial Z = 2.6 + j 0.9
8.0 m -- Radial Z = 2.5 + j 1.1 -- Efficiency 31.1%
.
.
10.0 m -- Radial Z = 3.0 + j 3.3 -- Efficiency 32.6%

Where I have shown the efficiency as sky wave power
out. The input impedance is that of all radials, so for
a single radial the input Zr must be Ztr * 36.

Frank

Radiating Efficiency
 

Here are the results from the analysis of a 26 radial system.

0.6 m -- Radial Z = 37.3 - j 28.1 -- Efficiency 15%
0.8 m -- Radial Z = 30.5 - j 21.0
1.0 m -- Radial Z = 26.2 - j 16.9
1.2 m -- Radial Z = 23.2 - j 14.2
1.4 m -- Radial Z = 20.9 - j 12.4
1.6 m -- Radial Z = 19.1 - j 11.1
1.8 m -- Radial Z = 17.6 - j 10.1 -- Efficiency 21.0%
2.0 m -- Radial Z = 16.2 - j 9.4
2.2 m -- Radial Z = 15.1 - j 8.8
2.4 m -- Radial Z = 14.0 - j 8.4
2.6 m -- Radial Z = 13.0 - j 8.0
2.8 m -- Radial Z = 12.1 - j 7.7
3.0 m -- Radial Z = 11.3 - j 7.4
3.2 m -- Radial Z = 10.4 - j 7.1 -- Efficiency 24.5%
3.4 m -- Radial Z = 9.7 - j 6.8
3.6 m -- Radial Z = 8.9 - j 6.5
3.8 m -- Radial Z = 8.2 - j 6.2
4.0 m -- Radial Z = 7.5 - j 5.8
4.2 m -- Radial Z = 6.9 - j 5.5
4.4 m -- Radial Z = 6.4 - j 5.1
4.6 m -- Radial Z = 5.8 - j 4.7
4.8 m -- Radial Z = 5.4 - j 4.3
5.0 m -- Radial Z = 5.0 - j 3.9 -- Efficiency 27.8%
5.2 m -- Radial Z = 4.6 - j 3.5
5.4 m -- Radial Z = 4.3 - j 3.1
5.6 m -- Radial Z = 4.0 - j 2.7
5.8 m -- Radial Z = 3.7 - j 2.3
6.0 m -- Radial Z = 3.5 - j 2.0
6.2 m -- Radial Z = 3.3 - j 1.6
6.4 m -- Radial Z = 3.1 - j 1.3
6.6 m -- Radial Z = 3.0 - j 0.9
6.8 m -- Radial Z = 2.9 - j 0.6
7.0 m -- Radial Z = 2.8 - j 0.3
7.2 m -- Radial Z = 2.7 + j 0.01
7.4 m -- Radial Z = 2.6 + j 0.3
7.6 m -- Radial Z = 2.6 + j 0.6
7.8 m -- Radial Z = 2.6 + j 0.9
8.0 m -- Radial Z = 2.5 + j 1.1 -- Efficiency 31.1%
.
.
10.0 m -- Radial Z = 3.0 + j 3.3 -- Efficiency 32.6%

Where I have shown the efficiency as sky wave power
out. The input impedance is that of all radials, so for
a single radial the input Zr must be Ztr * 26.

===========================================
Frank,

The input impedance of 26 radials is NOT equal to all 26 connected in
parallel. There is a non-linear relationship between the number N and
input impedance because they share the same volume of soil at least
when they are short.

For 26 radials the resonant effects have disappeared which I cannot
explain. Yet attenuation is the same, Zo converges on Zin at
approximately 8 or 10 metres as before.

You appear to have automated the results. Can you do a large number
of radials, say around 100, from 0.4 to 8.0 metres?

And can you do a small number of radials such as 6 or 8, from 0.4 to
8.0 metres?

Radiating Efficiency
 

Frank,

The input impedance of 26 radials is NOT equal to all 26 connected in
parallel. There is a non-linear relationship between the number N and
input impedance because they share the same volume of soil at least
when they are short.

For 26 radials the resonant effects have disappeared which I cannot
explain. Yet attenuation is the same, Zo converges on Zin at
approximately 8 or 10 metres as before.

You appear to have automated the results. Can you do a large number
of radials, say around 100, from 0.4 to 8.0 metres?

And can you do a small number of radials such as 6 or 8, from 0.4 to
8.0 metres?

Reg,

I suspected as much concerning the input impedance of a number or
radials. Note that my model was 36 radials, not 26. 26 was simply a
typo.

Believe me there is no automation involved in running NEC, although
the work is trivial. The 36 radial model was taking 13 minutes per
run as I approached 8 m length radials. I can certainly model the
small number of radials, which should not take too long.

As for 100 radials; this exceeds the maximum number of junctions
limit in NEC. This does not mean it cannot be done, there are
work-arounds. Due to excessive computer time I will have to
develop a model with a more realistic run time. I am interested
in doing this for my own benefit, but it will take some time. I
will be very busy for the next few weeks, but will be able
to squeeze some time in occasionally.

Frank

Radiating Efficiency
 

The input impedance of 26 radials is NOT equal to all 26 connected in
parallel. There is a non-linear relationship between the number N and
input impedance because they share the same volume of soil at least
when they are short.

For 26 radials the resonant effects have disappeared which I cannot
explain. Yet attenuation is the same, Zo converges on Zin at
approximately 8 or 10 metres as before.

You appear to have automated the results. Can you do a large number
of radials, say around 100, from 0.4 to 8.0 metres?

And can you do a small number of radials such as 6 or 8, from 0.4 to
8.0 metres?


Reg,

Here is the analysis of an 8 radial system. All other parameters
the same:

0.4 m -- Radial Z = 65.4 - j 58.1 -- Efficiency 11.2%
0.6 m -- Radial Z = 48.7 - j 55.4
0.8 m -- Radial Z = 39.8 - j 29.6
1.0 m -- Radial Z = 34.2 - j 23.5
1.2 m -- Radial Z = 30.2 - j 19.2
1.4 m -- Radial Z = 27.2 - j 16.1
1.6 m -- Radial Z = 24.9 - j 13.7
1.8 m -- Radial Z = 23.0 - j 11.7 -- Efficiency 19.4%
2.0 m -- Radial Z = 21.3 - j 10.0
2.2 m -- Radial Z = 19.9 - j 8.5
2.4 m -- Radial Z = 18.7 - j 7.1
2.6 m -- Radial Z = 17.7 - j 5.9
2.8 m -- Radial Z = 16.7 - j 4.6
3.0 m -- Radial Z = 15.9 - j 3.5
3.2 m -- Radial Z = 15.2 - j 2.3 -- Efficiency 22.4%
3.4 m -- Radial Z = 14.7 - j 1.1
3.6 m -- Radial Z = 14.3 + j 0
3.8 m -- Radial Z = 14.0 + j 1.1
4.0 m -- Radial Z = 13.9 + j 2.2 -- Efficiency 23.2%
4.2 m -- Radial Z = 13.9 + j 3.2
4.4 m -- Radial Z = 14.1 + j 4.2
4.6 m -- Radial Z = 14.4 + j 5.0
4.8 m -- Radial Z = 14.7 + j 5.7
5.0 m -- Radial Z = 15.2 + j 6.3 -- Efficiency 23.0%
5.2 m -- Radial Z = 15.6 + j 6.7
5.4 m -- Radial Z = 16.1 + j 7.1
5.6 m -- Radial Z = 16.5 + j 7.3
5.8 m -- Radial Z = 16.9 + j 7.4
6.0 m -- Radial Z = 17.2 + j 7.5
6.2 m -- Radial Z = 17.5 + j 7.5 -- Efficiency 22.5%
6.4 m -- Radial Z = 17.8 + j 7.5
6.6 m -- Radial Z = 18.0 + j 7.4
6.8 m -- Radial Z = 18.1 + j 7.4
7.0 m -- Radial Z = 18.3 + j 7.4
7.2 m -- Radial Z = 18.4 + j 7.3
7.4 m -- Radial Z = 18.4 + j 7.3
7.6 m -- Radial Z = 18.5 + j 7.2
7.8 m -- Radial Z = 18.6 + j 7.2
8.0 m -- Radial Z = 18.6 + j 7.2 -- Efficiency 22.4%

Note that after 4 m the antenna efficiency starts to drop,
which is not the case for large numbers of radials.

Now I have to figure out the best way to model a 100
radial system.

Frank

Radiating Efficiency
 

Reg,

Here is the analysis of an 8 radial system. All other parameters
the same:

0.4 m -- Radial Z = 65.4 - j 58.1 -- Efficiency 11.2%
0.6 m -- Radial Z = 48.7 - j 55.4
0.8 m -- Radial Z = 39.8 - j 29.6
1.0 m -- Radial Z = 34.2 - j 23.5
1.2 m -- Radial Z = 30.2 - j 19.2
1.4 m -- Radial Z = 27.2 - j 16.1
1.6 m -- Radial Z = 24.9 - j 13.7
1.8 m -- Radial Z = 23.0 - j 11.7 -- Efficiency 19.4%
2.0 m -- Radial Z = 21.3 - j 10.0
2.2 m -- Radial Z = 19.9 - j 8.5
2.4 m -- Radial Z = 18.7 - j 7.1
2.6 m -- Radial Z = 17.7 - j 5.9
2.8 m -- Radial Z = 16.7 - j 4.6
3.0 m -- Radial Z = 15.9 - j 3.5
3.2 m -- Radial Z = 15.2 - j 2.3 -- Efficiency 22.4%
3.4 m -- Radial Z = 14.7 - j 1.1
3.6 m -- Radial Z = 14.3 + j 0
3.8 m -- Radial Z = 14.0 + j 1.1
4.0 m -- Radial Z = 13.9 + j 2.2 -- Efficiency 23.2%
4.2 m -- Radial Z = 13.9 + j 3.2
4.4 m -- Radial Z = 14.1 + j 4.2
4.6 m -- Radial Z = 14.4 + j 5.0
4.8 m -- Radial Z = 14.7 + j 5.7
5.0 m -- Radial Z = 15.2 + j 6.3 -- Efficiency 23.0%
5.2 m -- Radial Z = 15.6 + j 6.7
5.4 m -- Radial Z = 16.1 + j 7.1
5.6 m -- Radial Z = 16.5 + j 7.3
5.8 m -- Radial Z = 16.9 + j 7.4
6.0 m -- Radial Z = 17.2 + j 7.5
6.2 m -- Radial Z = 17.5 + j 7.5 -- Efficiency 22.5%
6.4 m -- Radial Z = 17.8 + j 7.5
6.6 m -- Radial Z = 18.0 + j 7.4
6.8 m -- Radial Z = 18.1 + j 7.4
7.0 m -- Radial Z = 18.3 + j 7.4
7.2 m -- Radial Z = 18.4 + j 7.3
7.4 m -- Radial Z = 18.4 + j 7.3
7.6 m -- Radial Z = 18.5 + j 7.2
7.8 m -- Radial Z = 18.6 + j 7.2
8.0 m -- Radial Z = 18.6 + j 7.2 -- Efficiency 22.4%

Note that after 4 m the antenna efficiency starts to drop,
which is not the case for large numbers of radials.

Now I have to figure out the best way to model a 100
radial system.

Frank
================================================== ===

Frank,

Thank you very much for the results on 8 radials.

As expected, it seems that for small numbers of radials the resonance
effects are begining to appear again.

I have ideas as to why this should happen. It's to do with the
geometry of the system and the fact that the ends of the radials are
not terminated with true open-circuits when calculating input
impedance. ( As is assumed by program Radial3.)

I look forward to receiving results for 100 or more radials which may
allow me to improve, in the mathematical model, the function of N
which describes the system's input impedance in terms of the number N
of radials.

----------------------------------------------------------------------
-----------------------

But, let's face it, a good understanding of what's going on under the
soil surface, without investigating input impedance at say 25 MHs, and
without investigating input imedance at soil resistivities of say 2000
ohm-metres, will be known only crudely.

Is it all worth the trouble?

After all, we already know enough quite enough about radial systems at
HF to design one which will work good enough, performance-wise, to
keep anybody happy. ( BL&E's work, as good as it may be, does not
apply at HF.)

Just lay one or two dozen radials, in ordinary soils, with lengths
equal to about half antenna height. Which is a good enough
rule-of-thumb for anybody who doesn't expect to win contests because
he has the advantage of 0.05 S-units.

And extremely few people know what their local soil resistivity is
within +/- 40 percent. It's largely guesswork!

But please keep up the good work with NEC4 in which I have great
confidence.
----
Reg, G4FGQ

Radiating Efficiency
 

On Sat, 5 Aug 2006 19:11:17 +0100, "Reg Edwards"
wrote:

Thank you very much for the results on 8 radials.

As expected, it seems that for small numbers of radials the resonance
effects are begining to appear again.

I have ideas as to why this should happen.

Hi Reggie,

You "should" if you had read Brown, Lewis, and Epstein. They
discussed this nearly 70 years ago. Radial3 appears to miss that mark
by various amounts ranging from 6 to 60dB.

It's to do with the geometry of the system

Duh. And the problem you injected in that you abstract one wire to
many.

and the fact that the ends of the radials are
not terminated with true open-circuits when calculating input
impedance. ( As is assumed by program Radial3.)

Given Hassan's and other's reports of the outrageous departures
between Radial3 and BLE/NEC4 (with your concurrence):
But please keep up the good work with NEC4 in which I have great
confidence.
there are at least two of us who find your contradictions would
warrant another fling of chalk off your noggin from Lord Kelvin.

73's
Richard Clark, KB7QHC

Radiating Efficiency
 

On Sat, 5 Aug 2006 19:11:17 +0100, "Reg Edwards"
wrote:


After all, we already know enough quite enough about radial systems at
HF to design one which will work good enough, performance-wise, to
keep anybody happy. ( BL&E's work, as good as it may be, does not
apply at HF.)

Just lay one or two dozen radials, in ordinary soils, with lengths
equal to about half antenna height. Which is a good enough
rule-of-thumb for anybody who doesn't expect to win contests because
he has the advantage of 0.05 S-units.

And extremely few people know what their local soil resistivity is
within +/- 40 percent. It's largely guesswork!

Reg, G4FGQ

Hi Reg,

You're saying that BL&E's work doesn't apply at HF. I believe that's an
overstatement.

They've shown that with about 100 radials of 0.4 lamba length the result is
almost perfect ground, regardless of the ground conditions beneath the radials.

I contend that using the radial setup as described above will always result in a
near-perfect ground at any HF frequency, with close to 100 percent efficiency.

Would you not agree?

Walt, W2DU