Hey, you asked for opinions in your first post
of the thread. If you don't like my opinions, thats
too bad. An antenna is an antenna is an antenna.
Do you think when I switch from a SWL to a ham band,
I need to switch antenna types? LOL...You guys kill me..
MK

On 12 Mar 2006 01:08:39 -0800, wrote:

Hey, you asked for opinions in your first post
of the thread. If you don't like my opinions, thats
too bad. An antenna is an antenna is an antenna.
Do you think when I switch from a SWL to a ham band,
I need to switch antenna types? LOL...You guys kill me..
MK

We're not worthy...

On 12 Mar 2006 01:08:39 -0800, wrote:

Hey, you asked for opinions in your first post
of the thread. If you don't like my opinions, thats
too bad. An antenna is an antenna is an antenna.
Do you think when I switch from a SWL to a ham band,
I need to switch antenna types? LOL...You guys kill me..
MK

Well how can your receiver work with an antenna made for transmit 8-}

In article ,
wrote:

On 12 Mar 2006 01:08:39 -0800, wrote:

Hey, you asked for opinions in your first post
of the thread. If you don't like my opinions, thats
too bad. An antenna is an antenna is an antenna.
Do you think when I switch from a SWL to a ham band,
I need to switch antenna types? LOL...You guys kill me..
MK

Well how can your receiver work with an antenna made for transmit 8-}

Basically (theoretically) an antenna made for transmit is just as
suitable for receive. This is called reciprocity.

This concept falls apart two ways in practicality:
1. The transmit situation has to handle power the receive situation does
not so for transmit the antenna elements need to be "beefier."
2. A less than full size antenna made resonant may work very well for
transmit but for receive not as well. Less than full size for receive
lowers the antenna efficiency.

--
Telamon
Ventura, California

On Sun, 12 Mar 2006 22:28:19 GMT, Telamon
wrote:

In article ,
wrote:

On 12 Mar 2006 01:08:39 -0800, wrote:

Hey, you asked for opinions in your first post
of the thread. If you don't like my opinions, thats
too bad. An antenna is an antenna is an antenna.
Do you think when I switch from a SWL to a ham band,
I need to switch antenna types? LOL...You guys kill me..
MK

Well how can your receiver work with an antenna made for transmit 8-}

Basically (theoretically) an antenna made for transmit is just as
suitable for receive. This is called reciprocity.

This concept falls apart two ways in practicality:
1. The transmit situation has to handle power the receive situation does
not so for transmit the antenna elements need to be "beefier."
2. A less than full size antenna made resonant may work very well for
transmit but for receive not as well. Less than full size for receive
lowers the antenna efficiency.

Telamon,
Thanks for the friendly answer - however, I was aware of what you
mention. My earlier response was just a case of me being flippant in
my response to MK.

Howard

In article ,
wrote:

On Sun, 12 Mar 2006 22:28:19 GMT, Telamon
wrote:

In article ,
wrote:

On 12 Mar 2006 01:08:39 -0800, wrote:

Hey, you asked for opinions in your first post of the thread. If
you don't like my opinions, thats too bad. An antenna is an
antenna is an antenna. Do you think when I switch from a SWL to a
ham band, I need to switch antenna types? LOL...You guys kill
me.. MK

Well how can your receiver work with an antenna made for transmit
8-}

Basically (theoretically) an antenna made for transmit is just as
suitable for receive. This is called reciprocity.

This concept falls apart two ways in practicality: 1. The transmit
situation has to handle power the receive situation does not so for
transmit the antenna elements need to be "beefier." 2. A less than
full size antenna made resonant may work very well for transmit but
for receive not as well. Less than full size for receive lowers the
antenna efficiency.

Telamon, Thanks for the friendly answer - however, I was aware of
what you mention. My earlier response was just a case of me being
flippant in my response to MK.

When I post whether a new thread or in this case a reply I try to be
informative as this is not like email where a reply would go directly to
you.

Hopefully other people reading the thread get a better idea of
what will work better for them. Besides there is no way for me to know
what you know or what experience you have except for what you explicitly
write and I have to guess the rest.

A level of knowledge a person has is an interesting thing in itself.
Some people are aware of the reciprocity concept and leave it at that
but you can always look at things in a deeper way that modify or even
appear to reverse a rule.

--
Telamon
Ventura, California

On Sun, 12 Mar 2006 22:28:19 GMT, Telamon
wrote:

In article ,
wrote:

On 12 Mar 2006 01:08:39 -0800, wrote:

Hey, you asked for opinions in your first post
of the thread. If you don't like my opinions, thats
too bad. An antenna is an antenna is an antenna.
Do you think when I switch from a SWL to a ham band,
I need to switch antenna types? LOL...You guys kill me..
MK

Well how can your receiver work with an antenna made for transmit 8-}

Basically (theoretically) an antenna made for transmit is just as
suitable for receive. This is called reciprocity.

This concept falls apart two ways in practicality:
1. The transmit situation has to handle power the receive situation does
not so for transmit the antenna elements need to be "beefier."

Most transmitting antennas use wire about the same size as what's
found in receiving-only antennas, 14 or 16 guage, maybe 12 guage for
full legal power.

2. A less than full size antenna made resonant may work very well for
transmit but for receive not as well. Less than full size for receive
lowers the antenna efficiency.

I seriously doubt you could hear the difference between a full size
antenna at frequency, and one slightly shorter for space
considerations.

bob
k5qwg

In article ,
Bob Miller wrote:

On Sun, 12 Mar 2006 22:28:19 GMT, Telamon
wrote:

In article ,
wrote:

On 12 Mar 2006 01:08:39 -0800, wrote:

Hey, you asked for opinions in your first post
of the thread. If you don't like my opinions, thats
too bad. An antenna is an antenna is an antenna.
Do you think when I switch from a SWL to a ham band,
I need to switch antenna types? LOL...You guys kill me..
MK

Well how can your receiver work with an antenna made for transmit 8-}

Basically (theoretically) an antenna made for transmit is just as
suitable for receive. This is called reciprocity.

This concept falls apart two ways in practicality:
1. The transmit situation has to handle power the receive situation does
not so for transmit the antenna elements need to be "beefier."

Most transmitting antennas use wire about the same size as what's
found in receiving-only antennas, 14 or 16 guage, maybe 12 guage for
full legal power.

Ever calculate antenna resistance at HF for those gauges? What is the
expected loss for some band you worked on?

What is legal power for hams on HF? 1500 watts? And is that continuous
power or PEP?

2. A less than full size antenna made resonant may work very well for
transmit but for receive not as well. Less than full size for receive
lowers the antenna efficiency.

I seriously doubt you could hear the difference between a full size
antenna at frequency, and one slightly shorter for space
considerations.

On receive the antenna efficiency is related to is size by means of
radiation resistance. Antenna efficiency is directly dependent on the
combination of radiation and antenna element resistance (DC+AC).

This affects the received signal power just like it does for transmit
but like I said on transmit you can use materials with higher dielectric
constants and reactive components to launch an EM wave efficiently.
However, on receive you can't affect the environment around the antenna
in the same fashion as the antenna itself therefor what I stated stands
unless you can refute it.

The key here in the non-reciprocity of antenna performance is the fact
that "you can't affect the environment around the antenna in the same
fashion as the antenna itself." The environment around the antenna has
an impedance value not affected by the antenna but antenna size directly
correlates to radiation resistance.

Think about it. If you were right then everyone would be using a whip
antenna. Why bother to build full size antennas?

--
Telamon
Ventura, California

On Mon, 13 Mar 2006 04:10:24 GMT, Telamon
wrote:

In article ,
Bob Miller wrote:

On Sun, 12 Mar 2006 22:28:19 GMT, Telamon
wrote:

In article ,
wrote:

On 12 Mar 2006 01:08:39 -0800, wrote:

Hey, you asked for opinions in your first post
of the thread. If you don't like my opinions, thats
too bad. An antenna is an antenna is an antenna.
Do you think when I switch from a SWL to a ham band,
I need to switch antenna types? LOL...You guys kill me..
MK

Well how can your receiver work with an antenna made for transmit 8-}

Basically (theoretically) an antenna made for transmit is just as
suitable for receive. This is called reciprocity.

This concept falls apart two ways in practicality:
1. The transmit situation has to handle power the receive situation does
not so for transmit the antenna elements need to be "beefier."

Most transmitting antennas use wire about the same size as what's
found in receiving-only antennas, 14 or 16 guage, maybe 12 guage for
full legal power.

Ever calculate antenna resistance at HF for those gauges? What is the
expected loss for some band you worked on?

Well, I could have built my 80 meter dipole out of copper pipe, but
the neighbors might have objected -- I used 18 guage stranded, which
is fine for my 100 watts, and would probably handle legal power, too.

For my 20 meter inverted L, I used #26 stranded. It's hooked to a
mightly 3.5 watt qrp rig.

What is legal power for hams on HF? 1500 watts?

1500, and I believe it's continuous, but you can check the FCC site if
you wish.

And is that continuous
power or PEP?

2. A less than full size antenna made resonant may work very well for
transmit but for receive not as well. Less than full size for receive
lowers the antenna efficiency.

I seriously doubt you could hear the difference between a full size
antenna at frequency, and one slightly shorter for space
considerations.

On receive the antenna efficiency is related to is size by means of
radiation resistance. Antenna efficiency is directly dependent on the
combination of radiation and antenna element resistance (DC+AC).

This affects the received signal power just like it does for transmit
but like I said on transmit you can use materials with higher dielectric
constants and reactive components to launch an EM wave efficiently.
However, on receive you can't affect the environment around the antenna
in the same fashion as the antenna itself therefor what I stated stands
unless you can refute it.

The key here in the non-reciprocity of antenna performance is the fact
that "you can't affect the environment around the antenna in the same
fashion as the antenna itself." The environment around the antenna has
an impedance value not affected by the antenna but antenna size directly
correlates to radiation resistance.

Think about it. If you were right then everyone would be using a whip
antenna. Why bother to build full size antennas?

Well, they're more broad-banded, for one thing.

Once again, less-than-half-wave antennas, properly tweaked, are as
loud to my ears as half-wave antennas. I know I'm right because I'm
talking about what I hear.

As far as whip antennas go, actully, a lot of hams do pretty good on
75 meters with highly tweaked 6- or 8-foot whips on their cars.

bob
k5qwg

In article . com,
wrote:

Hey, you asked for opinions in your first post
of the thread. If you don't like my opinions, thats
too bad. An antenna is an antenna is an antenna.
Do you think when I switch from a SWL to a ham band,
I need to switch antenna types? LOL...You guys kill me..

I did not ask to get bagged on by an amateur. Learn to post without
being offensive.

--
Telamon
Ventura, California