TX Distance question
 

Hi Folks

I have limited experience (ok almost none really) with respect to
Amateur Radio outside of the 2M band. However I just recently got my
code ticket & installed a radio on my sailboat. I am using a TS-50 with
an automatic tuner and a long copper wire to the top of the mast
(probably 50 feet or so long).

My ground plane/counterpoise consists of tying the ground to a large
aluminium area in the stern of the boat with a copper foil.

My very first contacts were established with 2 land stations on 14300 at
100W that were about 1000 miles away. They both reported that my signal
was good and that it sounded like I was "sitting right next to them". I
have no idea if this was a good distance, great, or mediocre.

I realize that propogation variables prevent anyone from giving a really
clear answer to this question, but in general, what sort of distance
should I expect to achieve? I'm trying to decide whether I need to
improve my antenna ground by adding a dynaplate (costly and requies the
boat to be taken from the water for installation) or whether the range I
am getting is decent.

Can anyone comment?

Thanks

James wrote:
I have limited experience (ok almost none really) with respect to
Amateur Radio outside of the 2M band. However I just recently got my
code ticket & installed a radio on my sailboat. I am using a TS-50 with
an automatic tuner and a long copper wire to the top of the mast
(probably 50 feet or so long).

My ground plane/counterpoise consists of tying the ground to a large
aluminium area in the stern of the boat with a copper foil.

My very first contacts were established with 2 land stations on 14300 at
100W that were about 1000 miles away. They both reported that my signal
was good and that it sounded like I was "sitting right next to them". I
have no idea if this was a good distance, great, or mediocre.

I realize that propogation variables prevent anyone from giving a really
clear answer to this question, but in general, what sort of distance
should I expect to achieve? I'm trying to decide whether I need to
improve my antenna ground by adding a dynaplate (costly and requies the
boat to be taken from the water for installation) or whether the range I
am getting is decent.

Propagation will have a HUGE effect on your distance capability. Under
good conditions your station should be able to work any point on earth.
On the other hand, when the 14MHz band "goes out" (which at this point
in the sunspot cycle will happen pretty much every night) you'll be
lucky to work 30 miles.

I think the ground you describe should be more than adequate. (many
land-based mobiles settle for something MUCH, MUCH worse!)

You'll need lower frequencies for nighttime operation. 7MHz and 3.5MHz.
The antenna *may* (or may not) be too short for effective operation on
these bands. Try it, the worst that can happen is the automatic tuner
will refuse to make a match. (I think you'll probably be OK on 7, 3.5
may be a problem)

Good luck!
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com

"James" wrote
an automatic tuner and a long copper wire to the top of the mast
(probably 50 feet or so long).

My ground plane/counterpoise consists of tying the ground to a large
aluminium area in the stern of the boat with a copper foil.

My very first contacts were established with 2 land stations on 14300 at
100W that were about 1000 miles away. They both reported that my signal
was good and that it sounded like I was "sitting right next to them". I
have no idea if this was a good distance, great, or mediocre.

I realize that propogation variables prevent anyone from giving a really
clear answer to this question, but in general, what sort of distance
should I expect to achieve? I'm trying to decide whether I need to
improve my antenna ground by adding a dynaplate (costly and requies the
boat to be taken from the water for installation) or whether the range I
am getting is decent.

James, considering you most likely have an ungrounded counterpoise instead
of a good ground commonly employed, I think that's outstanding distance from
a sailboat. In many cases during daytime operation, I have heard the Mobile
Maritime Nets have to shift around to various operators before they could
have copy as good as you describe, and from a lot less distance. If all you
intend to use the radio for is hobby work on the 40 meter band, why mess
with success? However your 50' of wire should typically also tune up on 2182
khz sufficiently for the distance commonly covered by USCG Groups and
Caribbean RCC's (about 200 miles). Canadian Coast Guard Radio stations will
often answer vessels as far as 500 miles away. Higher bands of maritime
mobile channels would be better of course. I'm sure you're aware those
require a separate station license on your vessel. Good job on installing
your station. If you come up on maritime mobile maybe we'll get to talk
someday.

Jack Painter
Oceana Radio
Virginia Beach VA

"Bill Turner" wrote in message
...
On Fri, 26 Nov 2004 10:14:46 -0500, James wrote:

I'm trying to decide whether I need to
improve my antenna ground by adding a dynaplate (costly and requies the
boat to be taken from the water for installation) or whether the range I
am getting is decent.

__________________________________________________ _______

I'd say your system is working pretty well. 50 feet is too long for a
20 meter antenna, however. Your auto tuner is correcting for it, but a
shorter length will actually work better, since the auto tuner won't
have to introduce as much correction and therefore will have lower loss
in the tuner itself.

The vertical part of a ground plane antenna (which is what you have) can
be determined by the formula Feet=234/Freq, or for 14.3 MHz, 16.4 feet
(rounded off). The exact footage depends on variables in the immediate
environment, but that should be close enough. If you have to have a 50
foot overall wire because of the height of the boat's mast, just put an
egg insulator at the 16.4 foot length to break it up. For multiple
bands, figure the length of each section and put egg insulators where
needed, and then to change bands, just connect a jumper wire across
various eggs to get the correct length. Neat, huh? :-)

Also, you can't have too much ground area, within reason. More aluminum
foil or copper is always better.

If you have access to an SWR analyzer such as the MFJ 259, so much the
better. They are highly recommended for making and troubleshooting
antennas.

--
73, Bill W6WRT

Bill,

50 foot is only too long if you are sticking with the resonant length
situation. Which is not really necessary with his setup. In fact he
probably gets better versatility with the longer length. Just an opinion.

Dan/W4NTI

....Keep the 50 feet, use a tuner. Quit wasting good
'worry' on tuner losses, they don't amount to enough
to worry about. The 'additional' length (and that
tuner) gives you access to other bands. Will it be the
'best' possible antenna? Of course not, but it'll
certainly be adequate...
'Doc

'Doc wrote:
...Keep the 50 feet, use a tuner. Quit wasting good
'worry' on tuner losses, they don't amount to enough
to worry about. The 'additional' length (and that
tuner) gives you access to other bands. Will it be the
'best' possible antenna? Of course not, but it'll
certainly be adequate...
'Doc


Thanks for the feedback folks. Doc is on the right track. THe tuner
works really well (way to go SGC, nice product!) and the antenna length
doesn't seem to be impeding transmission distance.

Furthermore, the length, although not electrically correct for all
frequencies, is convenient physically for a sail boat.

Glad to hear that the 1000 mile distance I attained was acceptable
performance. My actual planned use is for keeping in touch with other
vessels (friends) that are within a couple of thousand miles tops.
Hopefully it will do the trick.

Thanks for the feedback folks. Muuch appreciated.

Jimmy

"Bill Turner" wrote in message
...
On Fri, 26 Nov 2004 10:14:46 -0500, James wrote:

I'm trying to decide whether I need to
improve my antenna ground by adding a dynaplate (costly and requies the
boat to be taken from the water for installation) or whether the range I
am getting is decent.

__________________________________________________ _______

I'd say your system is working pretty well. 50 feet is too long for a
20 meter antenna, however. Your auto tuner is correcting for it, but a
shorter length will actually work better, since the auto tuner won't
have to introduce as much correction and therefore will have lower loss
in the tuner itself.

The vertical part of a ground plane antenna (which is what you have) can
be determined by the formula Feet=234/Freq, or for 14.3 MHz, 16.4 feet
(rounded off). The exact footage depends on variables in the immediate
environment, but that should be close enough. If you have to have a 50
foot overall wire because of the height of the boat's mast, just put an
egg insulator at the 16.4 foot length to break it up. For multiple
bands, figure the length of each section and put egg insulators where
needed, and then to change bands, just connect a jumper wire across
various eggs to get the correct length. Neat, huh? :-)

Exactly what I was going to suggest. This will be easy to do if you have a
pully on the top end so you can easily drop the wire to change the shorting
straps. With the 50 foot wire, I would be concerned about getting high angle
radiation on 10/15/20 metters. Dog bone insulators might put less capacitive
loading on the top of the disconnected section.

Tam/WB2TT

Also, you can't have too much ground area, within reason. More aluminum
foil or copper is always better.

If you have access to an SWR analyzer such as the MFJ 259, so much the
better. They are highly recommended for making and troubleshooting
antennas.

--
73, Bill W6WRT

Bill Turner wrote:
On Sat, 27 Nov 2004 06:35:49 GMT, 'Doc wrote:


Will it be the
'best' possible antenna? Of course not, but it'll
certainly be adequate...
'Doc


__________________________________________________ _______

More cost, less performance. Amazes me what some people think is
"adequate".

I'd lose the tuner and spend the money on more goodies for the boat.

Oh, well.

--
Bill W6WRT


How about adequate performance and convenience?

Ever been aboard an ocean going sail boat when the waves hit 5 meters
and the wind is howling like a freight train? If not you can't imagine
the fury. I've been there. It's exhilirating but not easy to endure. In
fact it's damned hard work. That is NOT the time to be playing with
knobs and switches trying to tune for a particular band. Believe me, I
will have more imporant things to do. But I do want to know that I can
tranmsit immediately if something terrible happens by just keying the
mic. No fuss.

No offence but I've always been intrigued watching amateur enthusiasts
wiggling knobs and waggling switches. Reminds me of a scene from the
wizard of oz for some reason. Seems so unnecessary in this day and age.

CONVENIENCE is a VERY good a reason as any to use a tuner. And they're
not all that costly either. A few hundred bucks at best.

Just my 2 cents worth.

Jimmy

In article ,
Bill Turner wrote:

If you're a purist, a simple L-network at the base will
transform whatever impedance you have to exactly 50 ohms. L-networks of
this type are quite broadbanded and one setting will usually cover the
whole band.

Tuners, begone! :-)

--
Bill W6WRT

In what world does an "L network" not equal exactly what a tuner does
for a wire antenna? An autotuner is nothing more than a binary
incremented L Network with autofeedback of directional power, and phase.
You suggestion is the same thing with no feedback or incremental changes.


Me

In article ,
James wrote:

Thanks for the feedback folks. Doc is on the right track. THe tuner
works really well (way to go SGC, nice product!) and the antenna length
doesn't seem to be impeding transmission distance.

Furthermore, the length, although not electrically correct for all
frequencies, is convenient physically for a sail boat.

Glad to hear that the 1000 mile distance I attained was acceptable
performance. My actual planned use is for keeping in touch with other
vessels (friends) that are within a couple of thousand miles tops.
Hopefully it will do the trick.

Thanks for the feedback folks. Muuch appreciated.

Jimmy

With a 50' antenna length and an adiquate RF Ground, one could
consider that a respectable Marine Radio Installation.

One thing that needs to be understood is that ALL Autotuners
have a REALLY BIG difficency that is inherent in their design.
They can NOT tune wires at the Half Wavelength point and 50Khz on each
side. At this point antenna impedance becomes Infinite and can't be
tuned. so a boater must make sure that he never intends to transmit
on the frequency that is at the electrical Half Wavelength of the
antenna. He may need to lengthen ot shorten the wire to adjust
for this condition.


Bruce in alaska
--
add a 2 before @