T-bone wrote:

I just don't think that discones should be dismissed as pure junk.
Within their limits, I've found them to be fine general all around signal
recievers, which is what their purpose is.

Agreed! You are absolutely right. George has been shilling Scantennas
for Antenna Warehouse for several years now. He belittles whatever else
anyone my recommend and refuses to acknowledge that another product may
suffice for another's purposes. His shamelessly partisan promotion gets
old after awhile.


--
Milepost 11.7 - UPRR Jeff City Sub - N 38°34'53", W 90°22'32", 680'
"We sleep safe in our beds because rough men stand ready in the night to
visit violence on those who would do us harm"

"Jeff" wrote in message
news:kEmDd.28049$3m6.2486@attbi_s51...

"Never anonymous Bud" wrote in message
...
Trying to steal the thunder from Arnold, "Jeff"
on Fri, 07 Jan 2005
01:27:21 GMT spoke:

Second of all there is no HUGE,, HUGE difference in db's
of attenuation between RG 6 and 9913.

Horsefeathers.

The "average" db of attenuation for 9913 per 100' from 1mhz to 1ghz is
2.17
db. The "average" atenuation for RG 6 per 100' from 1mhz. to 1ghz is
3.2 db.

MUCH more horsefeathers.

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

My I am ever so impressed with someone that has nothing
intelligent
to say and says it in such a quaint way. No I dont speak horsefeathers and
yes
the truth is out there. Try
http://www.radio-ware.com/products/t...o/coaxloss.htm
and do the math yourself, providing you know how to figure averages. The
difference IS insignificant, for runs under 100',, if you choose to not
believe
it, thats your problem.

Jeff

Averages are perhaps meaningful if the process is linear- however,
attenuation vs freq is not linear and that is why one does not speak of loss
averages- you won't find it in the literature.
2nd- 1mhz is millihertz= 0.001 Hz. You likely mean MHz.

Dale W4OP

"Dan Morisseau" wrote in message
...
T-bone wrote:

I just don't think that discones should be dismissed as pure junk.
Within their limits, I've found them to be fine general all around signal
recievers, which is what their purpose is.

Agreed! You are absolutely right. George has been shilling Scantennas for
Antenna Warehouse for several years now. He belittles whatever else anyone
my recommend and refuses to acknowledge that another product may suffice
for another's purposes. His shamelessly partisan promotion gets old after
awhile.

A discone is going to exhibit no gain, in fact probably less than unity
gain, when compared to an isotropic, but you can essentially call a discone
a 0 dB gain antenna across its entire bandwidth of operation. Using an
oversimplification, the lower frequency of the discone will be largely
determined by cone and disc element lengths (about 0.25 and 0.17
respectively), the upper frequency by the gap between the two. Although a
discone will probably only exhibit an ideal response across about a 3 to 1
range (well short of this gap limitation). A dipole will exhibit a slight
gain over the same source (isotropic), about 2.7 dB in the real world,
across its bandwidth. However, the dipole will be much more narrow banded.
The dipole has a single resonant frequency, determined mostly by physical
size. It is easy to use transmit bandwidth to define 'peak' operation.
Transmit bandwidth is defined as the band between the two frequencies at
which the SWR on the feedline has risen to stated values, it being assumed
the SWR at the band center has previously been adjusted by some means to be
1:1. However, receive bandwidth can also be defined. Receiving bandwidth
is defined as the band between the two frequencies at which receiver input
power has fallen to 1/2 the level at the band center. It is described as the
3dB bandwidth. For a Zo-matched receiver, 3dB bandwidth is 2*Fc/Q where Fc
is the center frequency and Q is the intrinsic Q of the antenna. Remember
this Q and look at where it is in the formula. For receive antenna purposes
a lower Q will mean a broader bandwidth.

The Scantenna is a modified multiple dipole antenna, on the quoted website
it calls it a '15 element clustered dipole design'. The elements that splay
out from the main element are there to broaden the bandwidth. The short
elements on the mounting boom are to cover the higher frequencies. Without
having tried the antenna myself, but having more than a little bit of
professional experience with RF, I can make a pretty good stab at what I
would expect the antenna to do in use. The longest length is about 101
inches. This is going to put the lowest usable frequency around 50 MHz.
Guestimating the length of the other elements from this 101 number it looks
like they have selected lengths that fall near certain bands, probably the
'major' scanner bands. So that the antenna will probably function quite
well in those frequency areas. If you stay in those bands you will probably
get better performance with the scantenna than you will with the discone.
However, outside those narrow bands the discone will probably perform
better.

One thing to note. At the higher frequencies the Scantenna seems to use
short boom mounted dipoles. These WILL display a directionality based on
the relationship of the received signal directions to the main set of
elements. In other words, it will look 'down' the boom better than to the
side. At those higher bands the Scantenna will probably display a better
performance ONLY when the transmitting station is along this direction.
Other than that the discone will probably appear to perform better on
average.

So, depending on your primary scan activities, the discone will probably be
the less limited choice. But, if the Scantenna fits your specific
application it may exhibit a slight performance edge, within its band
limitations.

All just a guess on my part, but defendable. For most things I would opt
for a well designed and built discone myself.

C

"Dale Parfitt" wrote in message news:rhwDd.29479$2X6.1694@trnddc07...

My I am ever so impressed with someone that has nothing
intelligent
to say and says it in such a quaint way. No I dont speak horsefeathers and
yes
the truth is out there. Try
http://www.radio-ware.com/products/t...o/coaxloss.htm
and do the math yourself, providing you know how to figure averages. The
difference IS insignificant, for runs under 100',, if you choose to not
believe
it, thats your problem.

Jeff

Averages are perhaps meaningful if the process is linear- however,
attenuation vs freq is not linear and that is why one does not speak of loss
averages- you won't find it in the literature.
2nd- 1mhz is millihertz= 0.001 Hz. You likely mean MHz.

Dale W4OP
---------------------------------------------------------------------------------------

Hi Dale,, at least its nice to read someones post that makes sense. And
yes I realize that "averages" do not directly apply to rf attenuation per coax.
My point was, no one parks there scanner on .9-1 Ghz. and leaves it there. Most
people usually listen to where 90% of the action is and that is usually between
100-500Mhz. Given worst case scenario at 1Ghz the difference between
9913 and RG 6 is -1.6db/100'. I believe the original poster said his run was
less than 50',, which would put cable loss at around -.8db between the 2.
Given the capture affect of FM transmissions a -.8db isnt going to mean the
difference of hearing or not hearing a signal. And yes I meant Mhz not mhz,
a typo. My whole point was there is "very" little if any noticeable difference
between using RG 6 and 9913 for general scanning purposes, and its a whole
lot easier to work with.


Jeff

"Colic" wrote in message
news:lZxDd.79015$k25.9878@attbi_s53...
All just a guess on my part, but defendable. For most things I would opt
for a well designed and built discone myself.

If your receiver had a front end with good dynamic range the discone might
be ok. Most scanners do not have particularly good dynamic range. The
discone will be fairly efficient in the FM broadcast band and also on some
TV channels. That may overload the scanner and result in poor performance
all around. It depends on how close the broadcast transmitters are to your
receiving antenna.

A five foot height difference can be significant if it allows the antenna to
clear nearby obstructions.

For most purposes a good grade of RG/6 like Belden 9116 performs well enough
that changing to 9113 will not result in a significant improvement. Quad
shield RG/6 has the same loss as ordinary RG/6 according to the Belden
catalog.

Has anyone had experience with both of these antennas.The 20-014 is the big
ground plane that was discontinued 5-6 years ago, it has several verticals
(three I think) and I think the radials are 14 or 15 ft wide, looks more
like a CB ground plane than a scanner antenna.
I'm trying to decide which one I want to go up with. If memory serves me
right MT gave the 20-014 a great write up. Rob Mills

Colic wrote:
For most things I would opt
for a well designed and built discone myself.

Something to consider. Anyone with basic hand tools can build their own
discone that will work just fine - and build it inexpensively, easily, and
quickly.
~~~~~~~~~~~~~~~~~~~~~
BDissident news - plus immigration, gun rights, weather, Internet Gun Show
IA HREF="http://www.alamanceind.com"ALAMANCE INDEPENDENT:
official newspaper of the Vast Right Wing Conspiracy/A/b/i

"Dirk Gently" wrote in message

I've got the "Scantenna" version in the air and it seems to work well
enough

Common since tells me that's what I should do considering that wind and ice
could destroy the 20-014 here in NE Okla. about as fast as I could get it
up. The MT review *as I recall* didn't compare the 014 to the scantenna but
declared it a clear winner over the discone. Wish I had the room to put both
up. RM~

Jeff

Averages are perhaps meaningful if the process is linear- however,
attenuation vs freq is not linear and that is why one does not speak of
loss
averages- you won't find it in the literature.
2nd- 1mhz is millihertz= 0.001 Hz. You likely mean MHz.

Dale W4OP
--------------------------------------------------------------------------
-------------

Hi Dale,, at least its nice to read someones post that makes
sense. And
yes I realize that "averages" do not directly apply to rf attenuation per
coax.
My point was, no one parks there scanner on .9-1 Ghz. and leaves it there.
Most
people usually listen to where 90% of the action is and that is usually
between
100-500Mhz. Given worst case scenario at 1Ghz the difference between
9913 and RG 6 is -1.6db/100'. I believe the original poster said his run
was
less than 50',, which would put cable loss at around -.8db between the 2.
Given the capture affect of FM transmissions a -.8db isnt going to mean
the
difference of hearing or not hearing a signal. And yes I meant Mhz not
mhz,
a typo. My whole point was there is "very" little if any noticeable
difference
between using RG 6 and 9913 for general scanning purposes, and its a whole
lot easier to work with.


Jeff

I agree Jeff,

And the difference between 75 Ohm and 50 Ohm is inconsequential given that
the scanner front end certainly does not look like 50 Ohms all across its
ranges.
There are some very good F-56 connectors out there with integral O rings
guaranteeing a nice watertight seal if also used with coax-seal or the like.

73,

Dale W4OP