X-terminator antenna
(Scott Unit 69)
http://www.bills2way.com/equip/images/workman_sp2000.jpg
Those 2 coils on the x-terminator are only 5 turns and 9 turns which does
nothing on 27 mhz. Even a keyclown like me knows this.
Frank Gilliland
wrote:
>
>
>
>http://www.bills2way.com/equip/images/workman_sp2000.jpg
>
>Those 2 coils on the x-terminator are only 5 turns and 9 turns which does
>nothing on 27 mhz. Even a keyclown like me knows this.
>
Sure they do. You forget that the diameter of the coil makes just as much of a
difference as the number of turns. It's a perfectly legitimate loading coil, but
nothing that couldn't be done with much smaller wire.
-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
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tn...@mucks.net
wrote:
>
>
>
>http://www.bills2way.com/equip/images/workman_sp2000.jpg
>
>Those 2 coils on the x-terminator are only 5 turns and 9 turns which does
>nothing on 27 mhz. Even a keyclown like me knows this.
You are probably right on both counts......The coils and the keyclown
part.
(Scott Unit 69)
So you think the coils do nothing? Me too.
If you are not a keyclown why are you so interested in a 15,000 watt antenna?
tn...@mucks.net
>So you think the coils do nothing? Me too.
>
>If you are not a keyclown why are you so interested in a 15,000 watt antenna?
Just a curiosity.
Originally I never bought in to the belief that such a short antenna
could out do what I thought was the best antenna. I always assumed
that the full size 102"SS whip was as good as it gets.
After hearing this nonsense about these short antennas I inquired
about what this antenna was and where I could get it. I was determined
to un validate any claims that a shorter antenna could out do the 102"
SS. I was told one of these antennas was the X-Terminator. I ordered
one for testing.
After setting up a valid way of testing it I was surprised at the
results and posted them. It's to bad some can't stand the thought
that a shorter antenna can out do a longer one. It must disrupt
and totally disorganize their supposedly organized way of thinking.
lancer
How long is that antenna? (X-Terminator)
tn...@mucks.net
I think it is 5' 4''
tn...@mucks.net
Actually it's 62"..........If you can wait a second I'll give you the
entire dimensions. Maybe Mmana wants to know?
lancer
Thats what I was thinking, maybe the dimensions of the 3 sections
and coils? Give me something to do tomorrow, being Friday.
tn...@mucks.net
Starting from the base..................
9.5 inches of 1/2 inch chrome plated brass.
Then a 9 turn coil 7.5 inches long by 2.625 inches in outside
diameter.
Then 3.75 inches of 1/2 inch chrome plated brass.
Then the second coil of 5 turns, 4.5 inches long by 2.625 inches in
outside diameter.
Then 5.5 inches of 1/2 inch chrome plated brass.
Then the stinger of Stainless steel. 32 inches by 3/32 of an inch.
The coils are 5/16 inch chrome plated tubing.
Total length = 62.75 inches
lancer
Thanks, should be fun to play with.
tn...@mucks.net
>>>How long is that antenna? (X-Terminator)
>>
>> Starting from the base..................
>>
>> 9.5 inches of 1/2 inch chrome plated brass.
>>
>> Then a 9 turn coil 7.5 inches long by 2.625 inches in outside
>> diameter.
>>
>> Then 3.75 inches of 1/2 inch chrome plated brass.
>>
>> Then the second coil of 5 turns, 4.5 inches long by 2.625 inches in
>> outside diameter.
>>
>> Then 5.5 inches of 1/2 inch chrome plated brass.
>>
>> Then the stinger of Stainless steel. 32 inches by 3/32 of an inch.
>>
>> The coils are 5/16 inch chrome plated tubing.
>>
>> Total length = 62.75 inches
>
>
>the I.D. and the number of turns, not the overall length of the coil
>wire, and od.
So I don't include the length of a coil? I take it that a coil of 9
turns 5 inches long is the same as a coil of 9 turns 10 inches long?
You may want to do a little thinking before you post the next time.
Regardless I did give him the ID. If you can't figure out the ID by
the info I gave then you are the one that doesn't have a clue.
The coil gauge is also needed...........So go back to your beer.
You seem to have a better grip of that.
I could of given him the pitch of the coil but that would of totally
confused you. You seem to be confused enough.
Have a confused day
Tnom
(Scott Unit 69)
I wish someone who knew what they were talking about would tell the truth
about this antenna.There is enough BS on this group as it is without more
myths being spread.
Lancer
<bucki...@assclown.com> wrote:
>"(Scott Unit 69)" <upp...@hotmail.com> wrote in
>news:3f984f70$1...@ghostsearchers.com:
>
>
>> I wish someone who knew what they were talking about would tell the
>> truth about this antenna.There is enough BS on this group as it is
>> without more myths being spread.
>
>
>
>The funniest part this antenna is made by workman it is junk, the coils are
>low Q.
LOL
Steveo
> Give me something to do tomorrow, being Friday.
>
Steveo
Frank Gilliland
wrote:
>
I agree. If anyone has one of those beasts in my area I would be more than happy
to run some legitimate field tests that anyone is welcome to witness.
tn...@mucks.net
wrote:
I think bills two way sells them?
tn...@mucks.net
>>>>>How long is that antenna? (X-Terminator)
>>>>
>>>> Starting from the base..................
>>>>
>>>> 9.5 inches of 1/2 inch chrome plated brass.
>>>>
>>>> Then a 9 turn coil 7.5 inches long by 2.625 inches in outside
>>>> diameter.
>>>>
>>>> Then 3.75 inches of 1/2 inch chrome plated brass.
>>>>
>>>> Then the second coil of 5 turns, 4.5 inches long by 2.625 inches in
>>>> outside diameter.
>>>>
>>>> Then 5.5 inches of 1/2 inch chrome plated brass.
>>>>
>>>> Then the stinger of Stainless steel. 32 inches by 3/32 of an inch.
>>>>
>>>> The coils are 5/16 inch chrome plated tubing.
>>>>
>>>> Total length = 62.75 inches
Snip
> If you can't figure out the ID by
>> the info I gave then you are the one that doesn't have a clue.
>
>
>You didn't give the correct info face the facts. How do you figure the id
>when no wire guage is given? Either way you have no idea what the coil
>does then if your giving him it in length, plain and simple.
Snip
I'm not even going to bother responding to most of your post. You have
confirmed your confusion by the above comment. Should I spell it out
for you?
The ID is figureable by the dimensions I gave. Just as I said it was.
Given info.................OD= 2.625
Given info................The coils is made of 5/16 tubing.
ID = OD - 2 x 5/16 Duhhhhhhhhhhhh
ID = 2.625 - 10/16
ID = 2.625 - .625
ID = 2
Duhhhhhhhh again
Steveo
>> >Ok Tnom, You've peaked my interest. URL?
>
> I think bills two way sells them?
>
tn...@mucks.net
wrote:
Workman?
Steveo
$36.95 SP-5000 X-Terminator V, 1000 Watt Single Open air coil, 1/8"
square Copper wire, 70 inch overall length.
(Scott Unit 69)
Steveo <moparholic@hotmail-nospam-.com> wrote:
>tn...@mucks.net wrote:
>> On 24 Oct 2003 02:52:14 GMT, Steveo <moparholic@hotmail-nospam-.com>
>> wrote:
>>
>> >tn...@mucks.net wrote:
>> >>> >Ok Tnom, You've peaked my interest. URL?
>> >>
>> >> I think bills two way sells them?
>> >>
>> >Who makes it?
>>
>> Workman?
>>
>Is this one ok ?
>
>$36.95 SP-5000 X-Terminator V, 1000 Watt Single Open air coil, 1/8"
>square Copper wire, 70 inch overall length.
That's not the same one as Tnom is pushing.
Steveo
(Scott Unit 69)
$53.95 SP-2000 X-Terminator II, 15,000 Watt dual open air coil.
It is junk, marketed by BS. Can't wait until someone debunks it.
Steveo
If he says it talks and hears, who am I to argue?
(Scott Unit 69)
But what about what Frank said? You know Tnom's test was a sham. I just don't
like to see people get cheated.
Steveo
Frank Gilliland
wrote:
<snip>
>
>But what about what Frank said? You know Tnom's test was a sham. I just don't
>like to see people get cheated.
The X-terminator's coils work out to 1.27 uH for the 9 turn coil and 0.60 for
the 5 turn coil. The values of the coils and their positions on the shaft are
consistent with the design of a center-loaded vertical.
For those that don't already know, a loading coil is used to shorten an antenna
while still keeping it's electrical length at 1/4 wavelength. But the antenna is
necessarily less efficient because the coil radiates part of the power, and that
power is lost. Why is it lost? Using the X-terminator picture as an example, you
will see that the wire in the coil is oriented perpendicular to the antenna, so
any radiation from the coil is going to be horizontally polarized, while the
radiation from the antenna is vertically polarized. Some people might think
that's a plus because some people have horizontal antennas, but it's really
useless because it is radiated from 14 different wires (9 turns + 5 turns), and
none of them are in phase with each other. Since there is no receiver publically
available that can receive all those signals, put them back in phase with each
other and add them to the horizontal signal, the power radiated by the coil is
wasted. Nor can a receiver pick out just one signal from the fourteen. Even
worse, the coil concentrates the magnetic flux (just like any other coil) and
directs it right at the roof of the vehicle, which results in more lost power
due to eddy currents induced into the sheet metal. Any loaded antenna is a
trade-off between antenna height and efficiency.
The only difference between the X-terminator and any other center-loaded
vertical is that the former is built for kilowatts (and not very well at that,
as the conductors are chrome plated, so it's RF resistance due to skin effect is
higher than stainless steel, and much higher than bare copper or silver). There
is no way that this antenna will outperform the unloaded 102" stainless-steel
whip.
Tnom's test may or may not have been a sham -- he may have actually gotten those
numbers, but for reasons other than what he presented. Personally, I think the
only thing he tested was his imagination.
Twistedhed
>But what about what Frank said?
Irrelevant.
_
> You know Tnom's test was a sham.
_
Countered by.....Frank's claims? THAT is your claim that Tnom's
presentation is a sham?
> I just
>don't like to see people get cheated.
_
It's way beyond that on this group,,,,this is about one who prefers
Chevy, one prefers Ford, and yet another prefers Dodge. The margin of
difference when applied to the average cber will not be noticeable
between the the antennas. The actual "cheating" taking place, if indeed
such a thing is to be found among a discussion forum, are the posts of
malicious and angry origin, unprovokingly attacking one's character by
name, contacting their work, and intentional libelous content of posts.
Of course, we can always add the scumbags that post under different nics
and play both sides of the fence......
Twistedhed
>I agree with the getting cheated.
No doubt, but a claim by a person, ad or company concerning a product
they are hawking, can never be taken at face value. An educated consumer
will do their own homework, take all the claims, and make their own
informed decision.
Common sense and logic has always held that "buyer beware" is the
unwritten rule of thumb. A fudged claim isn't the same as ordering
something and not receiving such,,,,,,which is what I would refer to as
being "cheated."
scott
lancer
>
>Actually it's 62"..........If you can wait a second I'll give you the
>entire dimensions. Maybe Mmana wants to know?
Tnom;
I plugged in the values that you posted. By simulation, the
Stainless whip has just about a 1 dB edge. The S/S whip has its main
lobe at 27.9 degrees, the X-terminator at 31.2 degrees. I posted a
current plot for it in:
alt.binaries.pictures.radio
I played with the parameters for the coils, and one coil works just as
well as the 2. Guess it just doesn't look as cool?
lancer
<bucki...@assclown.com> wrote:
>"(Scott Unit 69)" <upp...@hotmail.com> wrote in
>news:3f984f70$1...@ghostsearchers.com:
>
>
>> I wish someone who knew what they were talking about would tell the
>> truth about this antenna.There is enough BS on this group as it is
>> without more myths being spread.
>
>
>
>The funniest part this antenna is made by workman it is junk, the coils are
>low Q. No way on gods green earth it beats a full 1/4 wave.
No, the coils aren't low Q
lancer
The X-terminator has its main lobe at bit higher angle than the whip
does. That may account for some of the differences.
Chrome has about the same conductivity that Stainless does, or at
least from the info I found. 3-15% for Stainless, 19% for chrome,
relative to copper.
(Scott Unit 69)
(Scott Unit 69)
I am not trying to play both sides of the fence Twist, you know me and my
CB background. But when it comes to the truth about a product there should
be no "fence" that divides us, only the truth.
tn...@mucks.net
>Tnom's test may or may not have been a sham -- he may have actually gotten those
>numbers, but for reasons other than what he presented. Personally, I think the
>only thing he tested was his imagination.
I guess picture that I posted of all the antennas I used must also be
my imagination.
tn...@mucks.net
I don't disagree with what Mmana says but, there is no antenna
simulation program that can give the definitive answer for how a
antenna will actually perform in a real installation.
In other words when a engineer plugs in his values when designing a
new product he can never just rely on the computer or that design as
the final product. If he is to give performance numbers on the product
he can never use the computed values. He must use the measured
values. The measured value is always the most direct and accurate way
to evaluate a product.
tn...@mucks.net
>The X-terminator has its main lobe at bit higher angle than the whip
>does. That may account for some of the differences.
>
>Chrome has about the same conductivity that Stainless does, or at
>least from the info I found. 3-15% for Stainless, 19% for chrome,
>relative to copper.
I'll have to go through the archives to find the numbers but chrome is
a better conductor than Stainless
tn...@mucks.net
>The only difference between the X-terminator and any other center-loaded
>vertical is that the former is built for kilowatts (and not very well at that,
>as the conductors are chrome plated, so it's RF resistance due to skin effect is
>higher than stainless steel, and much higher than bare copper or silver). There
>is no way that this antenna will outperform the unloaded 102" stainless-steel
>whip.
The coils are copper with a chrome plating.................The chrome
does not cause any additional skin effect.
tn...@mucks.net
Chrome has 74.3% the conductivity of copper
Stainless Steel has 3% the conductivity of copper
tn...@mucks.net
Did you use the proper conductivity values.
Stainless = 3% of copper
Chrome = 74.3% of copper
lancer
I did notice when I was playing with the parameters on that
antenna, that a small change in the coils or element lengths made a
fairly significant change in expected gain, swr, etc. Most center
loaded, or any shortened antenna is a little more touchy about tuning,
ground and proximity to metal surfaces than a 1/4 would be.
Thanks, was a good Friday project.
Frank Gilliland
<snip>
>Chrome has about the same conductivity that Stainless does, or at
>least from the info I found. 3-15% for Stainless, 19% for chrome,
>relative to copper.
I'm not sure, I'll check it and get back on that.
Frank Gilliland
wrote:
>
And truth is Twisty's friend!!!
Frank Gilliland
<snip>
>Chrome has about the same conductivity that Stainless does, or at
>least from the info I found. 3-15% for Stainless, 19% for chrome,
>relative to copper.
For a conductor 102" long with a diameter of 0.625", the following metals have
the following AC resistance at 27 MHz:
Chromium .0194 ohms
Copper .00711 ohms
S. Steel .0451 ohms
tn...@mucks.net
<spa...@NOSPAMaimcomm.net> wrote:
>In <3f9e6668...@news.easynews.com>, lancer <lan...@lancer.web> wrote:
>
><snip>
>>Chrome has about the same conductivity that Stainless does, or at
>>least from the info I found. 3-15% for Stainless, 19% for chrome,
>>relative to copper.
>
>For a conductor 102" long with a diameter of 0.625", the following metals have
>the following AC resistance at 27 MHz:
>
>Chromium .0194 ohms
>Copper .00711 ohms
>S. Steel .0451 ohms
>
************************************************************
Chromium .0194 ohms ?
Copper .00711 ohms ?
With these figures Chrome has 36% the conductivity of copper
**************************************************************
Stainless steel is definitely more resistive than
you stated. According to your figure SS has 16%
the conductivity of copper. This is not even close.
Standard carbon steel has10% the conductivity.
Stainless is less. 18-8 is 2.5%, 13-cr is 3.5%, and
18-cr is 3%
The conductivity of the above figures on steel and
stainless steel come from the "Metals" properties table,
page 40, Ugly's electrical reference. George V. Hart
tn...@mucks.net
<spa...@NOSPAMaimcomm.net> wrote:
>In <3f9e6668...@news.easynews.com>, lancer <lan...@lancer.web> wrote:
>
><snip>
>>Chrome has about the same conductivity that Stainless does, or at
>>least from the info I found. 3-15% for Stainless, 19% for chrome,
>>relative to copper.
>
>For a conductor 102" long with a diameter of 0.625", the following metals have
>the following AC resistance at 27 MHz:
>
>Chromium .0194 ohms
>Copper .00711 ohms
>S. Steel .0451 ohms
>
http://www.amm.com/index2.htm?/ref/conduct.HTM
Chrome has 55% the conductivity of copper
Steel (all types ) 3% - 15%
tn...@mucks.net
17-7 ph stainless steel is used for most stainless antennas
Its resistivity compared to the standard (copper) can be found here
http://www.hpmetals.com/elec_resist.asp
Copper = 1.71 microohm-cm
17-7 ph = 83 microohm-cm
In other words stainless antenna stock has 2% the conductivity of
copper.
tn...@mucks.net
>>>http://www.amm.com/index2.htm?/ref/conduct.HTM
>>>
>>>Chrome has 55% the conductivity of copper
>>>
>>>Steel (all types ) 3% - 15%
>>
>> 17-7 ph stainless steel is used for most stainless antennas
>>
>> Its resistivity compared to the standard (copper) can be found here
>> http://www.hpmetals.com/elec_resist.asp
>>
>> Copper = 1.71 microohm-cm
>>
>> 17-7 ph = 83 microohm-cm
>>
>> In other words stainless antenna stock has 2% the conductivity of
>> copper.
>
>
>inches of copper or chrome material of that antenna will make little or
>no difference what so ever, you guys are nit picking about something that
>in this application is un noticeable.
Yes the whip is SS, but unlike your imagined explanation the antennas
others attributes must be making a difference. It does "make a
little difference". That was you quote by the way.
If it "makes a little difference" and does it at five feet instead of
nine then I would say it makes quit a difference.
Lancer
<bucki...@assclown.com> wrote:
>tn...@mucks.net wrote in news:k17kpv8kjaugljh2m...@4ax.com:
>What type of material is the whip of the exterminator? SS right, the few
>inches of copper or chrome material of that antenna will make little or
>no difference what so ever, you guys are nit picking about something that
>in this application is un noticeable.
The top section of that antenna is made from stainless steel. The top
section also has very little current flowing in it. The bottom
section has a majority of the current flow and does most of the
radiation. It maybe nit picking, but in theory the difference can be
seen. If you would see it in the real world is another question.
Lancer
<bucki...@assclown.com> wrote:
>lancer <lan...@lancer.web> wrote in
>news:3f9c6621...@news.easynews.com:
>Yes they are compared to a high q coil.
What do you consider high Q?
Q (Quality factor) is equal to the inductive reactance/the resistance
or loss
Capacitive coupling between the turns is part of the loss.
The coils for that antenna are large diameter tubing, less resistance.
They are spaced from eath other by at least a diameter, less
capacitive coupling.
They are "air wound", less loss due to the coil form.
The coils on that antenna have a Q of 100-300
In a typical tank circuit of a transmitter, smaller wire wound closer
together on a ceramic form, a Q of 20 is considered very good.
You make think that those coils look like they do for show, there is a
proven reason why large diameter, large gauge material is used for the
coils. And its not just for the power handling capability.
Frank Gilliland
<spa...@NOSPAMaimcomm.net> wrote:
>In <3f9e6668...@news.easynews.com>, lancer <lan...@lancer.web> wrote:
>
><snip>
>>Chrome has about the same conductivity that Stainless does, or at
>>least from the info I found. 3-15% for Stainless, 19% for chrome,
>>relative to copper.
>
>For a conductor 102" long with a diameter of 0.625", the following metals have
>the following AC resistance at 27 MHz:
>
>Chromium .0194 ohms
>Copper .00711 ohms
>S. Steel .0451 ohms
By golly, I made -another- mistake in my math, which is not such a suprise. But
when I was double-checking my work this time I ran across something that
everyone should find VERY significant. So from the beginning.....
S = Skin depth in meters = sqrt(2/(2*pi*f*u*q)), where
q = conductivity of conductor (mhos/m), and
u = 4piE07 * relative permeability of medium
This is what's interesting. Stainless steel comes in many varieties. Some of
them aren't even steel but use the term because they are used for the same
applications. Regardless, some stainless steel is ferromagnetic and some is not.
The nonferromagnetic steel will have a relative permeability close to that of
copper, or 1 for all practical purposes. OTOH, ferromagnetic steel will have a
relative permeability much higher, and the value of 500 was used in the
calculations below.
AC resistance in ohms = l / (q * S * 2 * pi * r), where
l = length of conductor (in meters)
r = radius of conductor (in meters)
Note that there are two different listings for the conductivity of chromium. The
first value is based on the information that it is 55% of the conductivity of
copper, and the second value (as well as the values for copper and stainless
steel) is based upon CRC's HC&P:
Cu Cr #1 Cr #2 S.S. S.S. (ferro)
Conductivity: 5.80E07 3.19E07 .769E07 .166E07 .166E07
Skin depth: 12.7E-06 17.1E-06 34.9E-06 75.2E-06 3.36E-06
AC resistance: .0705 ohms .0952 ohms .194 ohms .161 ohms 9.31 ohms!!!
Notice that the differences in the resistance are all insignificant except for
the ferromagnetic stainless steel. This is because of it's high relative
permeability. Now when I realized this issue I put a magnet to my whip it
doesn't stick. So I went to the shop this morning and checked a number of SS
whips of different lengths. Some were magnetic and some were not. The magnetic
whips are now all in a pile for other uses.
So even old farts like me can learn something new. From now on I'll recommend to
everyone to check an antenna with a magnet before buying it, because that's what
I intend to do myself.
Now, back to the X-terminator. Comparing the difference in radiation efficiency
with regards to length and polarization, the 102" whip has 102" that are
vertical. Everything is sent vertically polarized. Nothing is wasted in
horizontal polarization. OTOH, the X-terminator has 9.5" vertical, followed by
74" of coil, then 3.75" vertical, 41.23" of coil, 5.5" vertical, and 32" of
(gasp!) stainless steel. So you have a total of 166" of conductor, with 50.75"
of it radiating the desired vertically polarized radiation, but 115" of it
dumping horizontal hash. Let's disregard for the moment that 32" (or 63%) of the
vertical total is made of that infamous stainless steel, and forget the extra
overall resistance due to the additional length of conductor needed to wind the
coils. Let's concentrate instead on the fact that the coils consume 69% of the
total 'wire' in this antenna. Now if the current distribution was even
throughout the length of the antenna, that would mean the coils are radiating
69% of the power as multi-phasic mush. But that's not the case, as the coils are
positioned near the base of the antenna, where the antenna's current
distribution is the greatest. That means the coils are radiating -more- than if
the current was evenly distributed, and therefore -more- than 69%! And that
means the efficiency of the X-terminator is less than 31%!!!
And if that isn't bad enough, let's take a look at an el-cheapo 102" stainless
steel whip of -magnetic- persuasion. If the whip has an AC resistance of 9.31
ohms, and the input impedance is an ideal 50 ohms, that translates into a loss
of only 19%. If the input impedance is 36.5 ohms, the wire diameter is 0.25",
and accounting for power reflected back to the radio due to mismatch, loss is
still well below 30%. Both scenarios are a -hell- of a lot better than the >69%
waste caused by the X-terminator's loading coils, and we didn't even go into
absorbtion, reflection, hysteresis and eddy current losses caused from the
vehicle roof right below those coils!!!
So yes, stainless steel -is- more resistive than chromium. But the difference is
not significant. So I'll say it again -- there is no way that this antenna will
outperform an unloaded 102" whip whether it's made of fiberglass, stainless
steel OR ferromagnetic steel!
Train
Now, go buy a 7 foot SkipShooter and out talk the 102".
Train
LOL
"Frank Gilliland" <spa...@NOSPAMaimcomm.net> wrote in message
news:91clpvgbt91tg75ft...@4ax.com...
tn...@mucks.net
>Very nice job Frank..................................................
>Now, go buy a 7 foot SkipShooter and out talk the 102".
>Train
>LOL
Frank really gets into his work. Now if he could just transfer that
energy to an actual test. The paper work is interesting but does
nothing to show how a 102" SS marginally fails to beat some
shorter antennas.
Theory and formulas are fine but they will never include all the
variables. When the results are to close to call you have to go to
the end all. The actual test.
Landshark
"(Scott Unit 69)" <upp...@hotmail.com> wrote in message news:3f997d04$1...@ghostsearchers.com...
Twistedhed
handed to them on daily basis...
(Scott Unit 69)
You are wrong.
Steveo
> tn...@mucks.net wrote:
> > On 24 Oct 2003 02:52:14 GMT, Steveo <moparholic@hotmail-nospam-.com>
> > wrote:
> >
> > >tn...@mucks.net wrote:
> > >>> >Ok Tnom, You've peaked my interest. URL?
> > >>
> > >> I think bills two way sells them?
> > >>
> > >Who makes it?
> >
> > Workman?
> >
> Is this one ok ?
>
> $36.95 SP-5000 X-Terminator V, 1000 Watt Single Open air coil, 1/8"
> square Copper wire, 70 inch overall length.
>
(Scott Unit 69)
Don't buy it, Steve.
Steveo
> Steveo <moparholic@hotmail-nospam-.com> wrote:
> >> $36.95 SP-5000 X-Terminator V, 1000 Watt Single Open air coil, 1/8"
> >> square Copper wire, 70 inch overall length.
> >>
> >So anyway Tnom, is the above version ok or do have a recommendation?
>
> Don't buy it, Steve.
>
Frank Gilliland
<moparholic@hotmail-nospam-.com> wrote:
Because the reports about this antenna, and antennas like these, are classic
examples of the 'miracle miniature' syndrome that plagues antenna manufacturers
in their fierce competition. Unlike other industries, they don't have to back up
their claims of gain figures, which is why you see ads for rubber duckies with
+126 dB gain. But I'm sure you could get one for free if you post a bogus
antenna test on usenet or a web page and declare it the winner.....
Don't believe Tnom's test was valid -regardless- of the "results". It doesn't
matter which antenna scored highest because the test was done without any clue
as to how to perform such a test. For example:
- Different antenna types and lengths will give different contours when mounted
on the same vehicle; so while you might find a little gain in one direction, the
other 359 degrees suck. Same deal with radiation angle, which will directly
affect the range of the ground wave. Now I might ignore this issue if he had
tested the antennas from the top of a flying saucer....
- Probably the biggest problem with Tnom's "test" was that there was no
impedance matching from the coax to the antenna. Loaded antennas usually have a
lower feedpoint impedance, resulting in a larger mismatch (higher SWR). The
problem here is that if the radio and antenna are not properly grounded (and a
mag-mount is -not- a proper ground), the SWR meter isn't going to show that
mismatch unless the meter is connected at the antenna feedpoint, which was not
the case (and wouldn't have mattered anyway because the antenna was not properly
grounded). He might have caught the problem had he measured and compared the
forward power of all the antennas, but he didn't because he felt is was "not
needed".
- Tnom used a radio modified for 'swang' and modulated it with a tone. The test
should have been done without -any- modulation because any change in modulation
will change the signal strength from a radio so modified, and unless the
modulation comes from a source of constant amplitude (an audio signal
generator), the readings are worthless. Notice that he never did disclose the
source of his "constant tone" (someone whistling in the mic?).
- Bandwidth was never measured. The coils on that antenna should have a very
high Q, which means a very narrow bandwidth. If the test showed that the antenna
actually has a wide bandwidth, then there is some power being dumped somewhere
as heat and not RF, probably from a resistor hidden somewhere in the shaft, and
most likely the shaft inside the coil, shunting the coil and lowering it's Q.
- Field strength was not measured from a field strength meter, but from a
commercial receiver, almost all of which incorporate some variation of AGC
(Automatic Gain Control). IOW, the receiver's gain changes according to the
strength of the signal. So for that reason alone the readings are not accurate.
- Tnom did two tests. The first test used two receivers. If the variables of the
test were constant, the readings should have been identical if not proportional.
They were neither. In his second test he eliminated the second receiver because
it was "not needed". In fact, they -are- needed because it's an empirical method
of double-checking your work.
- The concept of center-loading an antenna has been around for a very long time.
If it were at all possible to shorten a 1/4 wave vertical and get better
performance, the design would have been implemented into AM broadcast towers
decades ago. Drive around and look at some of the towers in your area. How many
of them look like the X-terminator? None.
- The antenna is ugly.
Now if you still want to buy the antenna, it's your money to waste. But who
knows... it might have some collector value in a hundred years or so, just like
all those quack medical devices.
tn...@mucks.net
snip
>- Tnom used a radio modified for 'swang' and modulated it with a tone.
Just a example of how you are making these statements up now. That's
why you are an oxyMORON like I said earlier.
tn...@mucks.net
begin quotes
*****************************************
tnom : All tested with a constant tone, constant power transmitter
oxyMORON :Using....? An audio signal generator and a TRC-453?
What was the radio modded? What was the modulation
percentage?
tnom: A transmitter with no alc set for a constant low power
carrier was used.
*****************************************
end quotes
The test was done on SSB. A constant tone on SSB is what?
tn...@mucks.net
>- Tnom did two tests. The first test used two receivers. If the variables of the
>test were constant, the readings should have been identical if not proportional.
>They were neither. In his second test he eliminated the second receiver because
>it was "not needed". In fact, they -are- needed because it's an empirical method
>of double-checking your work.
Frank you are not only a oxyMORON but now you are a liar also.
tn...@mucks.net
>- Field strength was not measured from a field strength meter, but from a
>commercial receiver, almost all of which incorporate some variation of AGC
>(Automatic Gain Control). IOW, the receiver's gain changes according to the
>strength of the signal. So for that reason alone the readings are not accurate.
>
S-meters are not accurate and I never stated they were. The are very
accurate in giving relative readings.
tn...@mucks.net
>- Different antenna types and lengths will give different contours when mounted
>on the same vehicle; so while you might find a little gain in one direction, the
>other 359 degrees suck. Same deal with radiation angle, which will directly
>affect the range of the ground wave. Now I might ignore this issue if he had
>tested the antennas from the top of a flying saucer....
And in my setup the X-Terminator outperformed the 102"SS
I never said it would outperform in any other setup because I never
ran any other setup.
>- Probably the biggest problem with Tnom's "test" was that there was no
>impedance matching from the coax to the antenna. Loaded antennas usually have a
>lower feedpoint impedance, resulting in a larger mismatch (higher SWR). The
>problem here is that if the radio and antenna are not properly grounded (and a
>mag-mount is -not- a proper ground), the SWR meter isn't going to show that
>mismatch unless the meter is connected at the antenna feedpoint, which was not
>the case (and wouldn't have mattered anyway because the antenna was not properly
>grounded). He might have caught the problem had he measured and compared the
>forward power of all the antennas, but he didn't because he felt is was "not
>needed".
>
And my setup was typical for a magnet mount. I never said it was
anything different. Being a typical setup you would expect typical
results. A typical result is the most accurate result for a typical
setup.
tn...@mucks.net
>- The antenna is ugly.
Congrats.......You got something right.
tn...@mucks.net
>> $36.95 SP-5000 X-Terminator V, 1000 Watt Single Open air coil, 1/8"
>> square Copper wire, 70 inch overall length.
>>
>So anyway Tnom, is the above version ok or do have a recommendation?
http://www.wep4hams.com/mobile_cb_antennas.htm
http://www.geocities.com/mgo171/moviles.htm
http://www6.mailordercentral.com/hyelectronics/products.asp?dept=41
http://www.bills2way.com/equip/antennas.html
I don't know if the 5000 is a performer or not.
Steveo
Landshark
>
> You are wrong.
>
> "Landshark" <S3B...@jgkdls.com> wrote:
> > Forge
> >
> >"(Scott Unit 69)" <upp...@hotmail.com> wrote in message
news:3f997d04$1...@ghostsearchers.com...
> >>
Nope, you're not Scott. Try all you want,
but you are forging his name, posting from
AOL through put, using Ghostsearchers website.
Landshark
--
Hard things are put in our way,
not to stop us, but to call out our
courage and strength.
Dave VanHorn
> Because the reports about this antenna, and antennas like these, are
classic
> examples of the 'miracle miniature' syndrome that plagues antenna
manufacturers
> in their fierce competition. Unlike other industries, they don't have to
back up
> their claims of gain figures, which is why you see ads for rubber duckies
with
> +126 dB gain.
Entirely reasonable, provided they tell you what the reference is.
A claim of "5 dB gain" is meaningless. In ham circles, when I see this, I
automatically assume they mean dBi, but given the level of snake oil in CB
circles, I think in terms of dBdummyload.
An interesting test would be to measure two of the same antenna, against
each other, on the same vehicle, then measure the first one again. Of
course the readings should be identical, but differences would indicate
problems in mounting most likely, or variations in local conditions, like
reflected signal from vehicles and people moving around. It would give a
good idea of the size of the inherent error in the measurements made.
In order to truly show what's going on, you also need to pattern the
antenna, measuring the signal at regular points around the compass. While an
onmi antenna mounted on a vehicle may show gain in one direction, there will
be a corresponding notch somewhere else. The pattern, when mounted on a
vehicle, can be surprisingly "lumpy".
In order to do a reasonably accurate test, you'll need a nice RF quiet area
to test in, and a whole lot of open space. Ideally, you'd put the vehicle
on a turntable, but that's normally not practical.
I'd settle for very slowly driving in as tight a circle as possible, to
minimize effects from the antenna waving around.
> - Probably the biggest problem with Tnom's "test" was that there was no
> impedance matching from the coax to the antenna. Loaded antennas usually
have a
> lower feedpoint impedance, resulting in a larger mismatch (higher SWR).
Another variable to consider, is wether they were tuned at all, and if so,
were they tuned for resonance, or lowest SWR. I tune for resonance, and
match for SWR.
>The problem here is that if the radio and antenna are not properly grounded
(and a
> mag-mount is -not- a proper ground), the SWR meter isn't going to show
that
> mismatch unless the meter is connected at the antenna feedpoint, which was
not
> the case (and wouldn't have mattered anyway because the antenna was not
properly
> grounded). He might have caught the problem had he measured and compared
the
> forward power of all the antennas, but he didn't because he felt is was
"not
> needed".
A 1 wavelength feedline, of something reasonably efficient like FSJ1-50
would suffice.
The reactive component will be roated back around to the same point, and
it's way more convenient than measuring at the base of the antenna.
> - Bandwidth was never measured. The coils on that antenna should have a
very
> high Q, which means a very narrow bandwidth. If the test showed that the
antenna
> actually has a wide bandwidth, then there is some power being dumped
somewhere
> as heat and not RF, probably from a resistor hidden somewhere in the
shaft, and
> most likely the shaft inside the coil, shunting the coil and lowering it's
Q.
Important, and easy to do. Impedance measurements at Ch1 and CH40 would
tell the story.
> - The concept of center-loading an antenna has been around for a very long
time.
> If it were at all possible to shorten a 1/4 wave vertical and get better
> performance, the design would have been implemented into AM broadcast
towers
> decades ago. Drive around and look at some of the towers in your area. How
many
> of them look like the X-terminator? None.
To be fair, fabricating the coils for such an antenna would be an
interesting challenge.
I run a cobra 6000, which seems a reasonable design. It's mounted in the
center of the roof of my Expedition, and just slightly taller than the
Diamond SG-7900 in front of it. Overall height is somewhat of a concern.
It tunes to resonance nicely, and ends up at a 2/1 SWR, which isn't far
enough off to bother matching.. If I had a 2-1 un-un handy, I'd probably use
it. I'm not too surprised at the high impedance (100 ohms) at resonance, I
think they are designed to be used in a co-phased arraingement on trucks.
There's another typical sight, a pair of antennas, often not the same type,
running "co-phased" on a very small car, placed much too close together,
like 2' separation. The resulting pattern is rather amusing.
I run into the same BS on the other end of the spectrum.
I recently had to look into antennas for a bluetooth transciever, and was
rather dissapointed to find the equivalent of "rubber ducks" at 2.4 GHz,
selling for $12. (in production quantities!) These are so called "chip
antennas" that are roughly the size of this letter "W" on your screen, being
marketed as "high gain" antennas. When I finally was able to get a plot out
of them, it turned out that the highest gain was -10dBi, and as low
as -20dBi...
High gain compared to a 50 ohm resistor the same size, I suppose.
We ended up using a simple monopole, just a track on the PCB. Cost,
essentially zero.
Gain, roughly 1-2dBi. I didn't bother patterning, simple emperical tests
show it's overkill for our intended application. It's giving measurably
less operating distance than a reference dipole, but the dipole is
inconveniently large.
> Now if you still want to buy the antenna, it's your money to waste. But
who
> knows... it might have some collector value in a hundred years or so, just
like
> all those quack medical devices.
My favorite CB gimmick was the "zing ring". You were supposed to clamp this
little halo around the bottom of your antenna to improve the ground. The
thing had a radius of about 6 inches or so.
It wouldn't even have had that effect up on VHF, where it's dimensions
become a significant fraction of a wavelength. Lately the Zing Ring is
gone, replaced with three little stubby wound whips that connect to the base
of the antenna electrically.. The new version looks better anyway.. I'm
sure it's just as effective as the old one.
You have to laugh at the concept of a "15,000 Watt" antenna, on a mag-mount,
fed with cheap RG-58 sized coax.
These antenna gimmicks are all 100% effective in meeting their design goals.
They look good enough to separate suckers and their money.
Any benefit to your radiation efficiency or pattern is totally coincidental.
Frank Gilliland
wrote:
>
>> Because the reports about this antenna, and antennas like these, are
>classic
>> examples of the 'miracle miniature' syndrome that plagues antenna
>manufacturers
>> in their fierce competition. Unlike other industries, they don't have to
>back up
>> their claims of gain figures, which is why you see ads for rubber duckies
>with
>> +126 dB gain.
>
>Entirely reasonable, provided they tell you what the reference is.
>A claim of "5 dB gain" is meaningless. In ham circles, when I see this, I
>automatically assume they mean dBi, but given the level of snake oil in CB
>circles, I think in terms of dBdummyload.
....or dB over the transmission line.
>An interesting test would be to measure two of the same antenna, against
>each other, on the same vehicle, then measure the first one again. Of
>course the readings should be identical, but differences would indicate
>problems in mounting most likely, or variations in local conditions, like
>reflected signal from vehicles and people moving around. It would give a
>good idea of the size of the inherent error in the measurements made.
I agree. In order to exclude such confounds the control or reference antenna
should be measured several times and any variation noted, even any variation
during a single transmission.
>In order to truly show what's going on, you also need to pattern the
>antenna, measuring the signal at regular points around the compass. While an
>onmi antenna mounted on a vehicle may show gain in one direction, there will
>be a corresponding notch somewhere else. The pattern, when mounted on a
>vehicle, can be surprisingly "lumpy".
That's called "mapping the contour". It's not difficult to do, and is a basic
procedure for any antenna testing. In fact, it's a procedure that is required
before any broadcast station can get it's license, as the map is used to
calculate the ERP of the transmitter.
>In order to do a reasonably accurate test, you'll need a nice RF quiet area
>to test in, and a whole lot of open space. Ideally, you'd put the vehicle
>on a turntable, but that's normally not practical.
>I'd settle for very slowly driving in as tight a circle as possible, to
>minimize effects from the antenna waving around.
The salt flats in Utah come to mind, but we have some pretty flat desert areas
just west of here.
>> - Probably the biggest problem with Tnom's "test" was that there was no
>> impedance matching from the coax to the antenna. Loaded antennas usually
>have a
>> lower feedpoint impedance, resulting in a larger mismatch (higher SWR).
>
>Another variable to consider, is wether they were tuned at all, and if so,
>were they tuned for resonance, or lowest SWR. I tune for resonance, and
>match for SWR.
That's fine and practical for one antenna, but when comparing several where
different input impedances will be encountered, the method of tuning should be
independant of input Z. About the only way to do that is with an FSM. After all,
a 50 ohm dummy load will show a 1:1 SWR.....
>>The problem here is that if the radio and antenna are not properly grounded
>(and a
>> mag-mount is -not- a proper ground), the SWR meter isn't going to show
>that
>> mismatch unless the meter is connected at the antenna feedpoint, which was
>not
>> the case (and wouldn't have mattered anyway because the antenna was not
>properly
>> grounded). He might have caught the problem had he measured and compared
>the
>> forward power of all the antennas, but he didn't because he felt is was
>"not
>> needed".
>
>A 1 wavelength feedline, of something reasonably efficient like FSJ1-50
>would suffice.
>The reactive component will be roated back around to the same point, and
>it's way more convenient than measuring at the base of the antenna.
The problem there is that the feedline may be radiating when there is a mismatch
at the antenna. Regardless, he never indicated the length of the coax -or- if
the coax was tested for RF on the shield.
>> - Bandwidth was never measured. The coils on that antenna should have a
>very
>> high Q, which means a very narrow bandwidth. If the test showed that the
>antenna
>> actually has a wide bandwidth, then there is some power being dumped
>somewhere
>> as heat and not RF, probably from a resistor hidden somewhere in the
>shaft, and
>> most likely the shaft inside the coil, shunting the coil and lowering it's
>Q.
>
>Important, and easy to do. Impedance measurements at Ch1 and CH40 would
>tell the story.
Three points (freqs) would be better, as it will verify that the frequency
response is curved and not flat (resistive).
>> - The concept of center-loading an antenna has been around for a very long
>time.
>> If it were at all possible to shorten a 1/4 wave vertical and get better
>> performance, the design would have been implemented into AM broadcast
>towers
>> decades ago. Drive around and look at some of the towers in your area. How
>many
>> of them look like the X-terminator? None.
>
>To be fair, fabricating the coils for such an antenna would be an
>interesting challenge.
True. But in broadcasting, efficiency is everything. If that antenna design
worked better than the basic tower, the justification would be the long-term
power savings to the station. And with all the stations that are operating these
days, don't you think at least one station would have built such an antenna?
>I run a cobra 6000, which seems a reasonable design. It's mounted in the
>center of the roof of my Expedition, and just slightly taller than the
>Diamond SG-7900 in front of it. Overall height is somewhat of a concern.
>It tunes to resonance nicely, and ends up at a 2/1 SWR, which isn't far
>enough off to bother matching.. If I had a 2-1 un-un handy, I'd probably use
>it. I'm not too surprised at the high impedance (100 ohms) at resonance, I
>think they are designed to be used in a co-phased arraingement on trucks.
You may be getting reflection from the other antenna. Try tuning without the
other stick.
>There's another typical sight, a pair of antennas, often not the same type,
>running "co-phased" on a very small car, placed much too close together,
>like 2' separation. The resulting pattern is rather amusing.
I saw a Penetrator on a Geo once.....
>I run into the same BS on the other end of the spectrum.
>
>I recently had to look into antennas for a bluetooth transciever, and was
>rather dissapointed to find the equivalent of "rubber ducks" at 2.4 GHz,
>selling for $12. (in production quantities!) These are so called "chip
>antennas" that are roughly the size of this letter "W" on your screen, being
>marketed as "high gain" antennas. When I finally was able to get a plot out
>of them, it turned out that the highest gain was -10dBi, and as low
>as -20dBi...
>High gain compared to a 50 ohm resistor the same size, I suppose.
Didn't someone come out with some sort of quack antenna for cell phones? I
thought I saw that on a TV commercial or something....
>We ended up using a simple monopole, just a track on the PCB. Cost,
>essentially zero.
>Gain, roughly 1-2dBi. I didn't bother patterning, simple emperical tests
>show it's overkill for our intended application. It's giving measurably
>less operating distance than a reference dipole, but the dipole is
>inconveniently large.
>
>> Now if you still want to buy the antenna, it's your money to waste. But
>who
>> knows... it might have some collector value in a hundred years or so, just
>like
>> all those quack medical devices.
>
>My favorite CB gimmick was the "zing ring". You were supposed to clamp this
>little halo around the bottom of your antenna to improve the ground. The
>thing had a radius of about 6 inches or so.
>It wouldn't even have had that effect up on VHF, where it's dimensions
>become a significant fraction of a wavelength. Lately the Zing Ring is
>gone, replaced with three little stubby wound whips that connect to the base
>of the antenna electrically.. The new version looks better anyway.. I'm
>sure it's just as effective as the old one.
Sounds like these "tuning rings" on some current antennas.
>You have to laugh at the concept of a "15,000 Watt" antenna, on a mag-mount,
>fed with cheap RG-58 sized coax.
>
>These antenna gimmicks are all 100% effective in meeting their design goals.
>They look good enough to separate suckers and their money.
>Any benefit to your radiation efficiency or pattern is totally coincidental.
The thought of 15 KW on a vehicle makes me shudder -- knowing that the vehicle
itself is carrying the same voltage and current as the antenna, but terminated
with a gas tank!!!!
Lancer
> In <20031028012156.286$x...@newsreader.com>, Steveo
> <moparholic@hotmail-nospam-.com> wrote:
>
> - Bandwidth was never measured. The coils on that antenna should have a
> very high Q, which means a very narrow bandwidth. If the test showed that
> the antenna actually has a wide bandwidth, then there is some power being
> dumped somewhere as heat and not RF, probably from a resistor hidden
> somewhere in the shaft, and most likely the shaft inside the coil,
> shunting the coil and lowering it's Q.
>
Frank;
Sorry for snipping a bunch of your post out;
If the coils had a Q 0f 300, they should show a bandwidth of 306 Khz
with an SWR of <1.5-1.
You make valid points on testing antennas, It would be great to have
actual tests that were run with all variables being accounted for. Looking
at the way he did his tests, is more real world. That is, the way a
typical person would do when the purchased an antenna and put it on their
vehicle. His tests show which one worked best for the testing he was
doing. Which would probably have different results on someone elses
installation.
Dave VanHorn
> >Entirely reasonable, provided they tell you what the reference is.
> >A claim of "5 dB gain" is meaningless. In ham circles, when I see this,
I
> >automatically assume they mean dBi, but given the level of snake oil in
CB
> >circles, I think in terms of dBdummyload.
>
> ....or dB over the transmission line.
dBradiax? :)
> The problem there is that the feedline may be radiating when there is a
mismatch
> at the antenna. Regardless, he never indicated the length of the coax -or-
if
> the coax was tested for RF on the shield.
This is why I pay $2000/Day to my FCC testing guys. It's not as simple as
it looks!
> You may be getting reflection from the other antenna. Try tuning without
the other stick.
That's my primary radio. I use the CB for road conditions, but if one of
them has to compromise..
> Didn't someone come out with some sort of quack antenna for cell phones? I
> thought I saw that on a TV commercial or something....
Yeah, the "patch" to get your yangtenna up.
I got one free in a parts order once. It's worth at least twice what I paid
for it.
I did give it a fair trial. No noticable effect one way or the other.
> Sounds like these "tuning rings" on some current antennas.
The tuning ring on an Astron 99 or similar at least does something.
I use one of those as my HF vertical.
The zing ring was the "cell phone antenna sticker" of it's day.
> The thought of 15 KW on a vehicle makes me shudder
Figuring a generous 60% efficiency at the amp, that's 1800A from your
battery, more or less.
You know, I've always known that power dosen't count for much on these
bands, and as I was driving back from Georgia again this weekend, I remarked
to the wife that listening to the truckers fade in and out going the other
direction, I can't tell much difference between the guy that claims he's
running the 150W or 500W amplifier, and the ones that claim not to be..
I certainly don't hear them 20-50 miles away..
>-- knowing that the vehicle
> itself is carrying the same voltage and current as the antenna, but
terminated
> with a gas tank!!!!
Back an August, I was sitting at a gas station fueling up the Expedition,
which does take a while..
I was sitting there, with my 50W aprs transmitter running periodically (on
the glassmount antenna right above the gas tank), the other two VHF
transcievers were shut down. I was making a call on my cell phone, when I
noticed that the truck parked in the next bay was idling, and dripping
something that was spattering on the concrete... The truck was labeled
"liquid oxygen", and "no smoking within 50 feet".. As the cold liquid
oxygen vapor mixed with the gasoline vapor hugging the ground, I was
thinking "and they are worried about my cell phone?"
Dave VanHorn
> You make valid points on testing antennas, It would be great to have
> actual tests that were run with all variables being accounted for.
Looking
> at the way he did his tests, is more real world. That is, the way a
> typical person would do when the purchased an antenna and put it on their
> vehicle. His tests show which one worked best for the testing he was
> doing. Which would probably have different results on someone elses
> installation.
The trick is to get a feel for the magnitude of the variables that are hard
to control, and take that into account when evaluating any measured or
perceived differences.
The audiophile guys are buying $7500 AC line cords because they think that
it makes a difference in how the sound comes out. (ignoring the same old 50'
of crappy 12 ga wire in the wall back to the box, and the rest of how the
power gets to the house)
(Scott Unit 69)
"Landshark" <S3b...@Georgesobsession.com> wrote:
>
>"(Scott Unit 69)" <upp...@hotmail.com> wrote in message
>news:3f9d6f7e$1...@ghostsearchers.com...
>>
>> You are wrong.
>>
>> "Landshark" <S3B...@jgkdls.com> wrote:
>> > Forge
>> >
>> >"(Scott Unit 69)" <upp...@hotmail.com> wrote in message
>news:3f997d04$1...@ghostsearchers.com...
>> >>
>
> Nope, you're not Scott. Try all you want,
>but you are forging his name, posting from
>AOL through put, using Ghostsearchers website.
>
> Landshark
Well I am sorry but you are wrong. Since I got my ham license I use Ghostsearchers
on Usenet so I don't crap up my regular ISP with spam and trash from rrcb.
Frank Gilliland
>Frank Gilliland wrote:
>
>> In <20031028012156.286$x...@newsreader.com>, Steveo
>> <moparholic@hotmail-nospam-.com> wrote:
>>
>> - Bandwidth was never measured. The coils on that antenna should have a
>> very high Q, which means a very narrow bandwidth. If the test showed that
>> the antenna actually has a wide bandwidth, then there is some power being
>> dumped somewhere as heat and not RF, probably from a resistor hidden
>> somewhere in the shaft, and most likely the shaft inside the coil,
>> shunting the coil and lowering it's Q.
>>
>
>Frank;
> Sorry for snipping a bunch of your post out;
That's Twisty's issue, not mine.
> If the coils had a Q 0f 300, they should show a bandwidth of 306 Khz
>with an SWR of <1.5-1.
Not disputing your figures, but how did you get there?
> You make valid points on testing antennas, It would be great to have
>actual tests that were run with all variables being accounted for. Looking
>at the way he did his tests, is more real world. That is, the way a
>typical person would do when the purchased an antenna and put it on their
>vehicle. His tests show which one worked best for the testing he was
>doing. Which would probably have different results on someone elses
>installation.
I think the only thing proven with his experiment is that a good antenna can
work just as crappy as a crappy antenna -- the only difference is in the
installation. Radio requires attention to several factors, such as knowing the
difference between an RF ground and a DC ground, how SWR and field-strength
meters really work and how to use them, using the right equipment for the right
job, location of the antenna on the vehicle, etc, etc. And BTW, these are things
that should be learned and put into practice by anyone serious about the hobby.
Dave VanHorn
> I think the only thing proven with his experiment is that a good antenna
can
> work just as crappy as a crappy antenna -- the only difference is in the
> installation. Radio requires attention to several factors, such as knowing
the
> difference between an RF ground and a DC ground, how SWR and
field-strength
> meters really work and how to use them, using the right equipment for the
right
> job, location of the antenna on the vehicle, etc, etc. And BTW, these are
things
> that should be learned and put into practice by anyone serious about the
hobby.
You wouldn't believe (maybe you would, at that) how many hams I know, that
think a 6' wire to a ground stake is an RF ground for their VHF/UHF
station..
Lancer
I believe quite a few would believe that on HF, but VHF/UHF. What do
you think would make a good RF ground for VHF/UHF?
Lancer
<spa...@NOSPAMaimcomm.net> wrote:
>In <1072218.7...@posting.lancer.com>, Lancer <lan...@lancer.web> wrote:
>
>>Frank Gilliland wrote:
>>
>>> In <20031028012156.286$x...@newsreader.com>, Steveo
>>> <moparholic@hotmail-nospam-.com> wrote:
>>>
>>> - Bandwidth was never measured. The coils on that antenna should have a
>>> very high Q, which means a very narrow bandwidth. If the test showed that
>>> the antenna actually has a wide bandwidth, then there is some power being
>>> dumped somewhere as heat and not RF, probably from a resistor hidden
>>> somewhere in the shaft, and most likely the shaft inside the coil,
>>> shunting the coil and lowering it's Q.
>>>
>>
>>Frank;
>> Sorry for snipping a bunch of your post out;
>
>That's Twisty's issue, not mine.
>
>> If the coils had a Q 0f 300, they should show a bandwidth of 306 Khz
>>with an SWR of <1.5-1.
>
>Not disputing your figures, but how did you get there?
That was from a simulation. I have a modified cut down mast and a
modified hustler RM-75 (6') that I use for CB, it has about the same
bandwidth.
>
>> You make valid points on testing antennas, It would be great to have
>>actual tests that were run with all variables being accounted for. Looking
>>at the way he did his tests, is more real world. That is, the way a
>>typical person would do when the purchased an antenna and put it on their
>>vehicle. His tests show which one worked best for the testing he was
>>doing. Which would probably have different results on someone elses
>>installation.
>
>I think the only thing proven with his experiment is that a good antenna can
>work just as crappy as a crappy antenna -- the only difference is in the
>installation. Radio requires attention to several factors, such as knowing the
>difference between an RF ground and a DC ground, how SWR and field-strength
>meters really work and how to use them, using the right equipment for the right
>job, location of the antenna on the vehicle, etc, etc. And BTW, these are things
>that should be learned and put into practice by anyone serious about the hobby.
>
as with all aspects of radio as a hobby these days, its turned into an
appliance hobby, much like buying a TV set.
Dave VanHorn
> I believe quite a few would believe that on HF, but VHF/UHF. What do
> you think would make a good RF ground for VHF/UHF?
A tub of mercury? :)
Nothing really.
I ground my antennas to a stake, but only for lightning protection.