Yo! Harry! (or anyone else) Antenna question
 

Eisboch wrote:
"HK" wrote in message
. ..

You're kidding about the difficulty in putting a connector on properly,
aren't you? I've done it at least a dozen times over the years the old
fashioned way (never used one of the quickie "crimp" connectors).

Harry, the connector is not the issue (assuming it's done in a decent
manner).
The proper loading of any RF antenna is a complex relationship of the
designed output impedance of the radio, the characteristic impedance of the
transmission line (cable) and the impedance of the antenna.

Higher powered RF transmitters have tuning boxes between the radio output
and the transmission line/antenna arrangement that effectively changes the
length with capacitors and inductors to optimize power transfer.

I agree that at 25 watts and a on typical boat installation it isn't going
to make much difference.
To an RF engineer, it will all look and operate like trash anyway.

Eisboch



As I said, so long as I can reach the Coast Guard, I don't really care
much about VHF communication. We have really good cell coverage most
everywhere on the Bay.

Yo! Harry! (or anyone else) Antenna question
 

"HK" wrote in message
. ..
Eisboch wrote:
"HK" wrote in message
. ..

You're kidding about the difficulty in putting a connector on properly,
aren't you? I've done it at least a dozen times over the years the old
fashioned way (never used one of the quickie "crimp" connectors).

Harry, the connector is not the issue (assuming it's done in a decent
manner).
The proper loading of any RF antenna is a complex relationship of the
designed output impedance of the radio, the characteristic impedance of
the transmission line (cable) and the impedance of the antenna.

Higher powered RF transmitters have tuning boxes between the radio output
and the transmission line/antenna arrangement that effectively changes
the length with capacitors and inductors to optimize power transfer.

I agree that at 25 watts and a on typical boat installation it isn't
going to make much difference.
To an RF engineer, it will all look and operate like trash anyway.

Eisboch

As I said, so long as I can reach the Coast Guard, I don't really care
much about VHF communication. We have really good cell coverage most
everywhere on the Bay.


Until that Yamaha coughs, you drop your cell phone overboard, the wind is
picking up, water splashing over that LT, and your radio's output stage
sizzles because the SWR ratio is 4 to 1 or something. :-)


I am a nerd about this stuff and set the boat's radio systems up with SWR
meters because I can't help it. The result though is that I can
communicate easily with boats 20 miles away.

Eisboch

Yo! Harry! (or anyone else) Antenna question
 

Eisboch wrote:
"HK" wrote in message
. ..

John H. wrote:
On Tue, 25 Sep 2007 14:51:44 +0000, Larry wrote:


Another question: Most antennae seem to come with about 20 feet of wire.
Mounted on a console with the radio right there, I could get by with
about
3 feet of wire. Is all the extra wire necessary?



No. You can cut the wire to the length you need.


Not technically true, but probably doesn't matter in this application.
Performance of the radio is going to be marginal anyway. He'd be better off
coiling up the cable in a relatively large coil (not tight) for best
performance. It's length *does* affect proper antenna loading.

Eisboch




wow, I guess Horizon and my installer knew what they were talking about.

Yo! Harry! (or anyone else) Antenna question
 

On Tue, 25 Sep 2007 16:40:58 -0400, "Eisboch" wrote:


"Larry" wrote in message
.. .
John H. wrote in
:

Another question: Most antennae seem to come with about 20 feet of
wire. Mounted on a console with the radio right there, I could get by
with about 3 feet of wire. Is all the extra wire necessary?



No, it's not. If you're not a solderer, find someone who can put a new
connector on the radio end of your cable or make up a new cable. The Metz
does NOT have a cable attached to it....one of its great features. YOU
put
the cable on it so the cable can be replaced....not hard wired into the
plastic, like the little whips from Shakespeare come.

The farce of "tuning" the antenna with cable length is nonsense....

True, you don't "tune" the antenna with cable length, but you need a certain
amount of it to properly tune the antenna. My memory is rusty and I'd have
to go dig out the books, but I think you should have a 1/2 wavelength or so
in cable length. Maybe it's a 1/4 .... can't remember. Too short will
cause the antenna not to load properly (assuming it is the correct length)
and result in an excessive SWR value that reduces effective transmitted
power and, in the worst situation, cause damage to the output stage of the
radio.

If you have matching problems with the antenna and are fairly certain
that the antenna, connectors are known good and the radio is
presenting power properly, then the suspect is the length of the
feedline.

End result - you trim the feeline to bring the antenna to the correct
match. Thus you are tuning the antenna using the feedline.

That's why God invented antenna tuners. :)

Yo! Harry! (or anyone else) Antenna question
 

Eisboch wrote:
"HK" wrote in message
. ..
Eisboch wrote:
"HK" wrote in message
. ..

You're kidding about the difficulty in putting a connector on properly,
aren't you? I've done it at least a dozen times over the years the old
fashioned way (never used one of the quickie "crimp" connectors).
Harry, the connector is not the issue (assuming it's done in a decent
manner).
The proper loading of any RF antenna is a complex relationship of the
designed output impedance of the radio, the characteristic impedance of
the transmission line (cable) and the impedance of the antenna.

Higher powered RF transmitters have tuning boxes between the radio output
and the transmission line/antenna arrangement that effectively changes
the length with capacitors and inductors to optimize power transfer.

I agree that at 25 watts and a on typical boat installation it isn't
going to make much difference.
To an RF engineer, it will all look and operate like trash anyway.

Eisboch
As I said, so long as I can reach the Coast Guard, I don't really care
much about VHF communication. We have really good cell coverage most
everywhere on the Bay.


Until that Yamaha coughs, you drop your cell phone overboard, the wind is
picking up, water splashing over that LT, and your radio's output stage
sizzles because the SWR ratio is 4 to 1 or something. :-)


I am a nerd about this stuff and set the boat's radio systems up with SWR
meters because I can't help it. The result though is that I can
communicate easily with boats 20 miles away.

Eisboch




I've listened to the usual channels on VHF for hours at a time and
hardly ever hear much conversation. I can call the CG on my VHF, and
maybe with all the breaks some other boater within range will come by
for a look see. But unless you are in one of the higher boater density
areas, you're mostly all along out there. Where I fish for flounder, I
can go half the day without seeing another boat.

Frankly, I think we need something a lot better than VHF, some variant
of marine cell (not satellite) for in shore and near shore. The bigger
offshore boats that sink, well, we need more fishing reefs anyway, right?

Yo! Harry! (or anyone else) Antenna question
 

On Tue, 25 Sep 2007 16:44:13 -0400, HK wrote:

VHF is just a clunky way to communicate when you have cell
phones and friends out in boats with cell phones.

Tell me, just out of curiosity, what is your understanding of how cell
phones work?

Yo! Harry! (or anyone else) Antenna question
 

Short Wave Sportfishing wrote:
On Tue, 25 Sep 2007 16:44:13 -0400, HK wrote:

VHF is just a clunky way to communicate when you have cell
phones and friends out in boats with cell phones.

Tell me, just out of curiosity, what is your understanding of how cell
phones work?


Let's see. I dial a phone number on my cell, I hear ringing, and either
the person I am calling answers, or I get his voice mail. The Bay
shoreline is peppered with cell towers; the only dead spot I have
encountered in years here is in the marina.

Do I need to know more about how cell phones work? Do I need a SWR meter
for my built in cell antenna? Directions in pushing the number keys?

Yo! Harry! (or anyone else) Antenna question
 

On Tue, 25 Sep 2007 16:58:32 -0400, "Eisboch" wrote:

I am a nerd about this stuff and set the boat's radio systems up with SWR
meters because I can't help it.

Amen brother - amen.

I have an antenna tuner under the console so if I need to retune to
get the best match, I can.

Now that's obcessive. :)

Yo! Harry! (or anyone else) Antenna question
 

Short Wave Sportfishing wrote:
On Tue, 25 Sep 2007 16:58:32 -0400, "Eisboch" wrote:

I am a nerd about this stuff and set the boat's radio systems up with SWR
meters because I can't help it.

Amen brother - amen.

I have an antenna tuner under the console so if I need to retune to
get the best match, I can.

Now that's obcessive. :)


So, what's the VHF reception like on that little lake you frequent?
Better question: is anyone listening? :}

Yo! Harry! (or anyone else) Antenna question
 

Short Wave Sportfishing wrote:
On Tue, 25 Sep 2007 16:40:58 -0400, "Eisboch" wrote:

"Larry" wrote in message
...
John H. wrote in
:

Another question: Most antennae seem to come with about 20 feet of
wire. Mounted on a console with the radio right there, I could get by
with about 3 feet of wire. Is all the extra wire necessary?


No, it's not. If you're not a solderer, find someone who can put a new
connector on the radio end of your cable or make up a new cable. The Metz
does NOT have a cable attached to it....one of its great features. YOU
put
the cable on it so the cable can be replaced....not hard wired into the
plastic, like the little whips from Shakespeare come.

The farce of "tuning" the antenna with cable length is nonsense....
True, you don't "tune" the antenna with cable length, but you need a certain
amount of it to properly tune the antenna. My memory is rusty and I'd have
to go dig out the books, but I think you should have a 1/2 wavelength or so
in cable length. Maybe it's a 1/4 .... can't remember. Too short will
cause the antenna not to load properly (assuming it is the correct length)
and result in an excessive SWR value that reduces effective transmitted
power and, in the worst situation, cause damage to the output stage of the
radio.

If you have matching problems with the antenna and are fairly certain
that the antenna, connectors are known good and the radio is
presenting power properly, then the suspect is the length of the
feedline.

End result - you trim the feeline to bring the antenna to the correct
match. Thus you are tuning the antenna using the feedline.

That's why God invented antenna tuners. :)

That is the beauty of rec.boats, even when you think every possible
boating discussion has been beat to death, a new informative topic will
arise, that we can learn from.

Of course, we will beat this one to death.