102" whip
 

"DrDeath" wrote:
Jack O'Neill" wrote in message
...
U-Know-Who wrote:
Is it just me, or does 55-60 MPH seem a little fast for an ice storm? I
must be getting old....


Maybe he was in K.I.T.T.?

No way, K.I.T.T. would have nagged me like a wife : )

D'OH! I know that sound!

102" whip
 

On Mon, 30 Jan 2006 15:19:26 -0500, wrote:

+
++The db calculation were computed after taking the same CB and exciting
++it with a variable power transmitter to see how the noted S-meter
++readings related to power output of the variable transmitter.
+*******
+
+Sorry I put little faith in S-meter readings. I would prefer a
+spectrum analyzer, a preamp and the test antenna to determine gain of
+the antenna.
+
+I'd prefer a Maserati
******

Your tests really do not measure gain perse of the antenna but more
the efficiency of the antennae tested. Now that can be calculated into
a dB ratio and presented as gain. In reality it is not actually the
gain of the antenna. That would reconcile the large variations of
readings between the extremes.

Radiated power(Pr) from a 1/4 antenna is

18.27* Im^2 = Pr

where Im is the magnitude of the antenna current. Gain calulations of
an antenna factor in power loss to heat and other factors(Pl). Thus
the total power into an antenna is the sum of power radiatied as a TEM
wave and those losses which are incurred. While at very small power
levels the heat loss in an antenna does apporach zero. There are other
losses besides heat. The largest of all is ground loss.

Mobile installations can be as poor as 5% efficient. That results in
only 5% of the total power input actually being radiated. A very good
mobile installation can be as good as 65% efficient. In dBs that would
be about 11dB.

Lastly,I beleive that you mentioned that the distance separating the
two antennea were about 200 feet. A better distance would be 350 feet
minimum. This will get you beyond 10 wavelengths separation. In that
distance, near field power is a nonfactor and the TEM wave off the
antenna is fully formed. The near fields from an antenna are
measurable out to about 3 wavelengths from the antenna. It is there
that the TEM wave is nearly formed and by ten wavelengths from the
antenna is its strongest.

Trust me antenna efficiency is far more important than antenna gain in
a mobile installation. HIgh ground losses, can make the best mobile
antenna look horrible.

james

102" whip
 

Your tests really do not measure gain perse of the antenna but more
the efficiency of the antennae tested. Now that can be calculated into
a dB ratio and presented as gain. In reality it is not actually the
gain of the antenna.

The db expressed was not intended to be the gain (dbd, or dbi) of the
antenna.

That would reconcile the large variations of
readings between the extremes.

Radiated power(Pr) from a 1/4 antenna is

18.27* Im^2 = Pr

where Im is the magnitude of the antenna current. Gain calulations of
an antenna factor in power loss to heat and other factors(Pl). Thus
the total power into an antenna is the sum of power radiatied as a TEM
wave and those losses which are incurred. While at very small power
levels the heat loss in an antenna does apporach zero. There are other
losses besides heat. The largest of all is ground loss.

Mobile installations can be as poor as 5% efficient. That results in
only 5% of the total power input actually being radiated. A very good
mobile installation can be as good as 65% efficient. In dBs that would
be about 11dB.

Lastly,I beleive that you mentioned that the distance separating the
two antennea were about 200 feet. A better distance would be 350 feet
minimum. This will get you beyond 10 wavelengths separation. In that
distance, near field power is a nonfactor and the TEM wave off the
antenna is fully formed. The near fields from an antenna are
measurable out to about 3 wavelengths from the antenna. It is there
that the TEM wave is nearly formed and by ten wavelengths from the
antenna is its strongest.

Trust me antenna efficiency is far more important than antenna gain in
a mobile installation. HIgh ground losses, can make the best mobile
antenna look horrible.

james

OK, so in the real world we are never effected by "antenna
efficiency", "ground loss" ect.ect.?

The test is as stated. It was never intended to be a lab test. It
was intended to show what would happen if this particular test
scenario was followed.

102" whip
 

Steveo wrote:

"DrDeath" wrote:


Jack O'Neill" wrote in message
...


U-Know-Who wrote:


Is it just me, or does 55-60 MPH seem a little fast for an ice storm? I
must be getting old....




Maybe he was in K.I.T.T.?


No way, K.I.T.T. would have nagged me like a wife : )



D'OH! I know that sound!


:-D

102" whip
 

On Tue, 31 Jan 2006 16:01:52 -0500, wrote:

+OK, so in the real world we are never effected by "antenna
+efficiency", "ground loss" ect.ect.?
+
+The test is as stated. It was never intended to be a lab test. It
+was intended to show what would happen if this particular test
+scenario was followed.
*****

In the real world ground losses in a mobile installation are real and
can be quite large. These losses affect efficiency and thus
performance.

What you did is to show that there can be marked differences between
antennae and their istallation. The more complex issue is, are these
same differences repeatable from vehicle to vehicle and area to area?
I seriously doubt that they are.

james

102" whip
 

ugly stuff for a man to allow to be splutted on his face, like you do
at petro

102" whip
 

Steveo wrote:
jim wrote:

Steveo wrote:

Vinnie S. wrote:


72 posts fot a 102" whip? WTF? ISee what happens when I leave you

incharge for a few days !

Vinnie S.


Crack that whip!


Isn't Devo from your neck of the woods hehehe


I think those whack-o's were from Akron, right next door! :)
fun to look at painful to listen to.

102" whip
 

wrote in message
...
On Mon, 30 Jan 2006 14:29:20 -0600, "DrDeath"
wrote in
:

snip
..... He stated, and I quote "If you cannot get a
cell signal you are unable to talk on 11m with 100 watts." He will try
anything to get the bull**** started.

Define "talk". Is that a keyclown term meaning 12db gain such as
the X-Terminator is purported to have over a 108" whip?
Talk, you know flapping your lips as you are doing now. As far as the
x-terminator, you got the wrong guy asshole. I don't own one and never made
that claim.

Is it like
"bird watts" which are somehow better than real watts? Or "swing"
which is considered better than PEP? And by the way, 100 watts
is illegal on CB.

What the **** are you rambling about. Did I say anything about PEP or swing
or watts?
By the way, I could care less about 100 watts being illegal you pole smoker.

102" whip
 

You could also care less about the fact that you are not heterosexual