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  #21   Report Post  
Old June 23rd 08, 01:01 AM posted to aus.radio.amateur.misc,rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jun 2008
Posts: 3
Default PALSTAR AT1KP Meter 1200 Watt Antenna Tuner


"Ian Jackson" wrote in message
...
In message , Albert
writes

"Ian Jackson" wrote in message
...
In message , Andy
writes

"Ian Jackson" wrote in message
...
In message , atec77
writes
Andy wrote:
"Ian Jackson" wrote in
message ...
In message , Andy
writes


"Ian Jackson" wrote in
message
...
Andy, is your endfed wire the one in your other thread of the 8th
June (ie
the 80 Meter End Fed, fed with coax at the far end)? If so,
presumably the
tuner is at the shack end. Or are you feeding it from the shack
end.


In message , Andy
writes

--

Hi Ian,

Yes its the same. The tuner is at the shack end (house) and I'm
feeding the
antenna with 50 Ohm RG-58 C/U coax at the far end of the garden.
If
I
can
get it working well I will replace it with some RG-213 that I have
here. I
put it back up yesterday and started experimenting again.

The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon
feeder. This
is all I had left spare. One side is connected to the wire antenna
and
the
other side left, not connected. The coax is connected to the 300
Ohm
at the
bottom and the braid side is now connected to the unconnected side
of
the
300 Ohm and also to the earth ground rod.
On 80 the receive is up 2-4 S points compared with the 40m coax
Centre
Fed
Dipole. I have not had chance to get any actual reports on 80 yet.
Maybe
this weekend.

73 Andy
OK, Andy. Noted.

I don't know if you will really improve things by using the 15 foot
of
300 ohm feeder. It's a sort of a zepp, but with one side of the
feeder
earthed. I would try disconnecting the earthed ('unconnected') side
from earth / coax braid. You can either leave it floating, or
connect
it to the coax inner. It will then be approximately a quarterwave
on
20m, fed in parallel with the long wire.

Don't read too much into the excellent SWR you're getting with the
tuner. That's what the TX sees, but the tuner can't affect the SWR
on
the aerial feeder. If the coax SWR is sky high (and it can be if
the
impedance at aerial feed point is high), the coax losses will be
much
more that you would get compared with when it is matched
correctly.
You only get away with it by using the lowest-loss you can find,
and
keeping the coax as short as possible.

I'm not surprised that 80m on the endfed is a bit better than the
40m
dipole. But what's 40m like on the endfed? That's when the feed
impedance (and coax SWR) will be very high, and where the RG-213
might
perform better noticeably better than the RG-58.

As I think I said before, although I am an advocate of simply using
coax (regardless), after all these years I am considering in
investing
in something like a SG230 remote tuner for the far end of the
coax.
-- Ian


Ian,
I'll have to do some experimenting with the 300 Ohm feeder and see
what
happens. The End Fed on 40m is very poor indeed. I would say
unusable
like it is.
The End Fed wire at the moment is resonate on 2. 682 MHz.
The funny thing is that when I cut the wire to bring the End Fed to
resonate on 80m, no matter how much wire I cut off it doesn't
really
move from the 2.682 MHz. I have tried this with and with out the
ribbon
feeder being in place and with coax connected direct and the braid
connected to the earth rod.
What would cause this?
I have no problem using the Analyser with my mobile and centre fed
dipoles.
73 Andy

adding a suitably cut wire counterpoise at +% for each band should
certainly assist things .

I rather think that Andy can't add counterpoises. A decent earthing
system
should work (although additional counterpoises certainly won't do any
harm).

Re the 2.682MHz resonance, this may be because the coax is completely
mismatched at lots of frequencies, and what you're seeing this is
more-or-less a spurious resonance of the coax itself. Do you still get
it
with the wire completely disconnected? Even with centre-fed dipoles,
you
often get some very unexpected resonances way off frequency
(especially
of
you are doing a wideband frequency sweep of the return loss / SWR).

As I said previously, persuading an approximate halfwave endfed (which
is
what you have on 40m) to work with a coax feed is certainly not ideal,
but
you can usually get it to work fairly well (with all the provisos
already
discussed). My setup here is almost twice the size of what you have,
so
the wire feed impedance will be low on 160m and I high on 80m and 40m.
80m
(corresponding to your 40m) is certainly lively enough. On 40m, the
performance does not seem to be unduly poor compared with the signal
reports swapped between others on the band.

So, Andy, I simply don't know why your 40m is so poor. Have you tried
(temporarily) reducing the length to around 33 feet, so that it is a
quarterwave on 40m? This should give a reasonable match for your coax
(at
least, nothing you can't tune out back in the shack). If this is more
lively than the 64 feet, maybe you can try two wires in parallel. This
can
be discussed later if the 33 feet shows promise. If a multiband (and
possibly compromise) aerial doesn't work well, it's a good idea to try
something simple which you know SHOULD work. The problem may lie
elsewhere.

Finally, can I ask you to follow the standard practice of bottom
posting!
Cheers...
--
Ian

I've have just connected the Analyser at the feed point on the End fed
wire.
The frequency is now at 2.898 MHz without coax being in line. I have
just
tried
to shorten the Antenna again to bring the frequency closer to the 80m
band,
but
it will not adjust from this frequency.

Ummmm...
Obviously something is wrong. It looks like your analyser is simply
telling lies. Could it have a spurious resonance at this frequency?

What's confusing me is that the End fed wire should be longer than a 1/4
wave on 80
and the frequency that it ended up on, that is now 2.898 would be
about right for the length.

A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit
on
the short side. Being only 20 feet up may pull the resonance a bit
lower,
but I doubt is could be anywhere as low as 2.898MHz.

So why won't that frequency change when I start
trimming the wire down in size?
It just isn't making any sense to me. The resonant frequency surely
should
change with the altered length.

If shortening the aerial doesn't change the frequency, I don't think
your
analyser is measuring the aerial. This is indeed a puzzle. As I
suggested
before, you could go from the sublime to the ridiculous, and try
something
like 33 feet, which should resonate at around 7MHz. If it sticks at
2.898MHz, something is seriously amiss.

--
Ian


MFJ Analyser ????

Isolate the transmission line (coax) from the antenna, ie; UGLY BALUN,
Line
Isolator

analyser may have copted a nose full of RF from the braid of feedline,
with such a mismatch

should build resonant antennas first, before inserting giant matcher, just
to see how much of your RF is dissipated in the match box. TX and RX

Unless I mis-read something, Andy says that he tried the analyser directly
on the antenna (at the antenna feedpoint) - so no coax was involved in
this particular test.

He seems to get a resonance at 2.898MHz, regardless of the length of the
antenna. Could this be because there is a strong (and permanent) RF signal
which is being picked up on the antenna, and is confusing the analyser?
--
Ian


Yes , could be a product of a Broadcast station ?
ok on the NO COAX, unless damage has been done.

tricky, will keep you off the streets, and out of the pubs Andy,
or perhaps in the pubs full as a boot if you do not get some answers soon
good luck


  #22   Report Post  
Old June 23rd 08, 01:08 AM posted to aus.radio.amateur.misc,rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jun 2008
Posts: 3
Default PALSTAR AT1KP Meter 1200 Watt Antenna Tuner

Ian Jackson wrote:
In message , Albert
writes

"Ian Jackson" wrote in message
...
In message , Andy
writes

"Ian Jackson" wrote in message
...
In message , atec77
writes
Andy wrote:
"Ian Jackson" wrote in
message ...
In message , Andy
writes


"Ian Jackson" wrote in
message
...
Andy, is your endfed wire the one in your other thread of the 8th
June (ie
the 80 Meter End Fed, fed with coax at the far end)? If so,
presumably the
tuner is at the shack end. Or are you feeding it from the shack
end.


In message , Andy
writes

--

Hi Ian,

Yes its the same. The tuner is at the shack end (house) and I'm
feeding the
antenna with 50 Ohm RG-58 C/U coax at the far end of the
garden. If
I
can
get it working well I will replace it with some RG-213 that I have
here. I
put it back up yesterday and started experimenting again.

The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon
feeder. This
is all I had left spare. One side is connected to the wire antenna
and
the
other side left, not connected. The coax is connected to the
300 Ohm
at the
bottom and the braid side is now connected to the unconnected side
of
the
300 Ohm and also to the earth ground rod.
On 80 the receive is up 2-4 S points compared with the 40m coax
Centre
Fed
Dipole. I have not had chance to get any actual reports on 80 yet.
Maybe
this weekend.

73 Andy
OK, Andy. Noted.

I don't know if you will really improve things by using the 15 foot
of
300 ohm feeder. It's a sort of a zepp, but with one side of the
feeder
earthed. I would try disconnecting the earthed ('unconnected') side
from earth / coax braid. You can either leave it floating, or
connect
it to the coax inner. It will then be approximately a
quarterwave on
20m, fed in parallel with the long wire.

Don't read too much into the excellent SWR you're getting with the
tuner. That's what the TX sees, but the tuner can't affect the SWR
on
the aerial feeder. If the coax SWR is sky high (and it can be
if the
impedance at aerial feed point is high), the coax losses will be
much
more that you would get compared with when it is matched
correctly.
You only get away with it by using the lowest-loss you can
find, and
keeping the coax as short as possible.

I'm not surprised that 80m on the endfed is a bit better than
the 40m
dipole. But what's 40m like on the endfed? That's when the feed
impedance (and coax SWR) will be very high, and where the RG-213
might
perform better noticeably better than the RG-58.

As I think I said before, although I am an advocate of simply using
coax (regardless), after all these years I am considering in
investing
in something like a SG230 remote tuner for the far end of the
coax.
-- Ian


Ian,
I'll have to do some experimenting with the 300 Ohm feeder and see
what
happens. The End Fed on 40m is very poor indeed. I would say
unusable
like it is.
The End Fed wire at the moment is resonate on 2. 682 MHz.
The funny thing is that when I cut the wire to bring the End Fed to
resonate on 80m, no matter how much wire I cut off it doesn't
really
move from the 2.682 MHz. I have tried this with and with out the
ribbon
feeder being in place and with coax connected direct and the braid
connected to the earth rod.
What would cause this?
I have no problem using the Analyser with my mobile and centre fed
dipoles.
73 Andy

adding a suitably cut wire counterpoise at +% for each band should
certainly assist things .

I rather think that Andy can't add counterpoises. A decent earthing
system
should work (although additional counterpoises certainly won't do any
harm).

Re the 2.682MHz resonance, this may be because the coax is completely
mismatched at lots of frequencies, and what you're seeing this is
more-or-less a spurious resonance of the coax itself. Do you still get
it
with the wire completely disconnected? Even with centre-fed
dipoles, you
often get some very unexpected resonances way off frequency
(especially
of
you are doing a wideband frequency sweep of the return loss / SWR).

As I said previously, persuading an approximate halfwave endfed (which
is
what you have on 40m) to work with a coax feed is certainly not ideal,
but
you can usually get it to work fairly well (with all the provisos
already
discussed). My setup here is almost twice the size of what you
have, so
the wire feed impedance will be low on 160m and I high on 80m and 40m.
80m
(corresponding to your 40m) is certainly lively enough. On 40m, the
performance does not seem to be unduly poor compared with the signal
reports swapped between others on the band.

So, Andy, I simply don't know why your 40m is so poor. Have you tried
(temporarily) reducing the length to around 33 feet, so that it is a
quarterwave on 40m? This should give a reasonable match for your coax
(at
least, nothing you can't tune out back in the shack). If this is more
lively than the 64 feet, maybe you can try two wires in parallel. This
can
be discussed later if the 33 feet shows promise. If a multiband (and
possibly compromise) aerial doesn't work well, it's a good idea to try
something simple which you know SHOULD work. The problem may lie
elsewhere.

Finally, can I ask you to follow the standard practice of bottom
posting!
Cheers...
--
Ian

I've have just connected the Analyser at the feed point on the End fed
wire.
The frequency is now at 2.898 MHz without coax being in line. I have
just
tried
to shorten the Antenna again to bring the frequency closer to the 80m
band,
but
it will not adjust from this frequency.

Ummmm...
Obviously something is wrong. It looks like your analyser is simply
telling lies. Could it have a spurious resonance at this frequency?

What's confusing me is that the End fed wire should be longer than a
1/4
wave on 80
and the frequency that it ended up on, that is now 2.898 would be
about right for the length.

A quarterwave on 80m is around 66 feet. Your 63 feet is actually a
bit on
the short side. Being only 20 feet up may pull the resonance a bit
lower,
but I doubt is could be anywhere as low as 2.898MHz.

So why won't that frequency change when I start
trimming the wire down in size?
It just isn't making any sense to me. The resonant frequency surely
should
change with the altered length.

If shortening the aerial doesn't change the frequency, I don't think
your
analyser is measuring the aerial. This is indeed a puzzle. As I
suggested
before, you could go from the sublime to the ridiculous, and try
something
like 33 feet, which should resonate at around 7MHz. If it sticks at
2.898MHz, something is seriously amiss.

--
Ian


MFJ Analyser ????

Isolate the transmission line (coax) from the antenna, ie; UGLY BALUN,
Line
Isolator

analyser may have copted a nose full of RF from the braid of feedline,
with such a mismatch

should build resonant antennas first, before inserting giant matcher,
just
to see how much of your RF is dissipated in the match box. TX and RX

Unless I mis-read something, Andy says that he tried the analyser
directly on the antenna (at the antenna feedpoint) - so no coax was
involved in this particular test.

He seems to get a resonance at 2.898MHz, regardless of the length of the
antenna. Could this be because there is a strong (and permanent) RF
signal which is being picked up on the antenna, and is confusing the
analyser?

or a faulty fitting , time to check things with a multimeter to
eliminate a short
  #23   Report Post  
Old June 23rd 08, 11:43 AM posted to aus.radio.amateur.misc,rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Apr 2008
Posts: 71
Default PALSTAR AT1KP Meter 1200 Watt Antenna Tuner


"Ian Jackson" wrote in message
...
In message , Andy
writes
"Ian Jackson" wrote in message
...
In message , Andy
writes

"Ian Jackson" wrote in message
...
In message , atec77
writes
Andy wrote:
"Ian Jackson" wrote in
message ...
In message , Andy
writes


"Ian Jackson" wrote in
message
...
Andy, is your endfed wire the one in your other thread of the 8th
June (ie
the 80 Meter End Fed, fed with coax at the far end)? If so,
presumably the
tuner is at the shack end. Or are you feeding it from the shack
end.


In message , Andy
writes

--

Hi Ian,

Yes its the same. The tuner is at the shack end (house) and I'm
feeding the
antenna with 50 Ohm RG-58 C/U coax at the far end of the garden.
If
I
can
get it working well I will replace it with some RG-213 that I have
here. I
put it back up yesterday and started experimenting again.

The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon
feeder. This
is all I had left spare. One side is connected to the wire antenna
and
the
other side left, not connected. The coax is connected to the 300
Ohm
at the
bottom and the braid side is now connected to the unconnected side
of
the
300 Ohm and also to the earth ground rod.
On 80 the receive is up 2-4 S points compared with the 40m coax
Centre
Fed
Dipole. I have not had chance to get any actual reports on 80 yet.
Maybe
this weekend.

73 Andy
OK, Andy. Noted.

I don't know if you will really improve things by using the 15 foot
of
300 ohm feeder. It's a sort of a zepp, but with one side of the
feeder
earthed. I would try disconnecting the earthed ('unconnected') side
from earth / coax braid. You can either leave it floating, or
connect
it to the coax inner. It will then be approximately a quarterwave
on
20m, fed in parallel with the long wire.

Don't read too much into the excellent SWR you're getting with the
tuner. That's what the TX sees, but the tuner can't affect the SWR
on
the aerial feeder. If the coax SWR is sky high (and it can be if
the
impedance at aerial feed point is high), the coax losses will be
much
more that you would get compared with when it is matched
correctly.
You only get away with it by using the lowest-loss you can find,
and
keeping the coax as short as possible.

I'm not surprised that 80m on the endfed is a bit better than the
40m
dipole. But what's 40m like on the endfed? That's when the feed
impedance (and coax SWR) will be very high, and where the RG-213
might
perform better noticeably better than the RG-58.

As I think I said before, although I am an advocate of simply using
coax (regardless), after all these years I am considering in
investing
in something like a SG230 remote tuner for the far end of the
coax.
-- Ian


Ian,
I'll have to do some experimenting with the 300 Ohm feeder and see
what
happens. The End Fed on 40m is very poor indeed. I would say
unusable
like it is.
The End Fed wire at the moment is resonate on 2. 682 MHz.
The funny thing is that when I cut the wire to bring the End Fed to
resonate on 80m, no matter how much wire I cut off it doesn't
really
move from the 2.682 MHz. I have tried this with and with out the
ribbon
feeder being in place and with coax connected direct and the braid
connected to the earth rod.
What would cause this?
I have no problem using the Analyser with my mobile and centre fed
dipoles.
73 Andy

adding a suitably cut wire counterpoise at +% for each band should
certainly assist things .

I rather think that Andy can't add counterpoises. A decent earthing
system
should work (although additional counterpoises certainly won't do any
harm).

Re the 2.682MHz resonance, this may be because the coax is completely
mismatched at lots of frequencies, and what you're seeing this is
more-or-less a spurious resonance of the coax itself. Do you still get
it
with the wire completely disconnected? Even with centre-fed dipoles,
you
often get some very unexpected resonances way off frequency
(especially
of
you are doing a wideband frequency sweep of the return loss / SWR).

As I said previously, persuading an approximate halfwave endfed (which
is
what you have on 40m) to work with a coax feed is certainly not ideal,
but
you can usually get it to work fairly well (with all the provisos
already
discussed). My setup here is almost twice the size of what you have,
so
the wire feed impedance will be low on 160m and I high on 80m and 40m.
80m
(corresponding to your 40m) is certainly lively enough. On 40m, the
performance does not seem to be unduly poor compared with the signal
reports swapped between others on the band.

So, Andy, I simply don't know why your 40m is so poor. Have you tried
(temporarily) reducing the length to around 33 feet, so that it is a
quarterwave on 40m? This should give a reasonable match for your coax
(at
least, nothing you can't tune out back in the shack). If this is more
lively than the 64 feet, maybe you can try two wires in parallel. This
can
be discussed later if the 33 feet shows promise. If a multiband (and
possibly compromise) aerial doesn't work well, it's a good idea to try
something simple which you know SHOULD work. The problem may lie
elsewhere.

Finally, can I ask you to follow the standard practice of bottom
posting!
Cheers...
--
Ian

I've have just connected the Analyser at the feed point on the End fed
wire.
The frequency is now at 2.898 MHz without coax being in line. I have
just
tried
to shorten the Antenna again to bring the frequency closer to the 80m
band,
but
it will not adjust from this frequency.

Ummmm...
Obviously something is wrong. It looks like your analyser is simply
telling lies. Could it have a spurious resonance at this frequency?

What's confusing me is that the End fed wire should be longer than a 1/4
wave on 80
and the frequency that it ended up on, that is now 2.898 would be
about right for the length.

A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit
on
the short side. Being only 20 feet up may pull the resonance a bit
lower,
but I doubt is could be anywhere as low as 2.898MHz.

So why won't that frequency change when I start
trimming the wire down in size?
It just isn't making any sense to me. The resonant frequency surely
should
change with the altered length.

If shortening the aerial doesn't change the frequency, I don't think
your
analyser is measuring the aerial. This is indeed a puzzle. As I
suggested
before, you could go from the sublime to the ridiculous, and try
something
like 33 feet, which should resonate at around 7MHz. If it sticks at
2.898MHz, something is seriously amiss.

--
Ian


I haven't had time to try a 33" End fed to see if it would tune on 40m
.But
I did have time to connect a temp 60 feet of wire from the top of the
ribbon
feeder on the braid side to make a close 63 feet centre fed dipole fed
with
300 Ohm feeder and the antenna resonates at 3.780 MHz with a 1.1:1 and the
AT1KP backs this reading up. I haven't tried to lengthen or shorten the
antenna yet. To see if it changes resonance, but I will do tomorrow.

It can't stay like that unfortunately.

So either my Analyser doesn't like to read End Fed antennas or there
something else causing the funny readings. If the Analyser senses the
change
in frequency tomorrow when I start lengthening the antenna then it must be
working OK or there is a fault with it and it can't read End Fed wires
correctly. Is this even possible considering its reading everything else
correct.

What do you think?

73 Andy

Andy, you've gone back to top posting, and this makes it very difficult to
follow the discussion. In newsgroups (unlike emails), you should really
post at the bottom. This is the established convention.

Anyway, it's interesting what you have found out with the dipole
configuration. Presumably, you still have the coax braid and one side of
300 ohm feeder earthed. If so, I would not have expected there to be quite
such a dramatic change of resonance. However, if your earth rods are
totally ineffective (or you have disconnected the earth), you might expect
things to change a lot when you add 'the other half of the dipole'. If you
actually have room to put up an appx 60 foot + 60 foot dipole, why not
consider a G5RV (which, I believe, you have already tried) or a W3DZZ trap
dipole? This would get rid of your earthing problems.
--
Ian



How I got the extra 60 feet + up was to bring it back on itself towards the
house in a shape of the letter V. The wire is very low to the floor and in
every ones way. I have no idea how it radiates in this shape. It can only be
like this as a temp solution.
I really need to understand why the End Fed wire is behaving the way it
does. I think the Analyser is working OK or it wouldn't be able to tune a
Centre Fed Dipole. I hope

When the earth rod was connected to the End Fed wire as a ground, there was
a definite 2 S points up on received signal compared to it being
disconnected. So it must be doing something.

I had a listen around 2 - 3.5 MHz for any strong signals and I can't find
any that might cause me problems.

I would have expected the frequency to change when altering the length of
the wire.

73 Andy.


  #24   Report Post  
Old June 23rd 08, 02:56 PM posted to aus.radio.amateur.misc,rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Nov 2007
Posts: 568
Default PALSTAR AT1KP Meter 1200 Watt Antenna Tuner

In message , Andy
writes

"Ian Jackson" wrote in message
...


Anyway, it's interesting what you have found out with the dipole
configuration. Presumably, you still have the coax braid and one side of
300 ohm feeder earthed. If so, I would not have expected there to be quite
such a dramatic change of resonance. However, if your earth rods are
totally ineffective (or you have disconnected the earth), you might expect
things to change a lot when you add 'the other half of the dipole'. If you
actually have room to put up an appx 60 foot + 60 foot dipole, why not
consider a G5RV (which, I believe, you have already tried) or a W3DZZ trap
dipole? This would get rid of your earthing problems.
--
Ian



How I got the extra 60 feet + up was to bring it back on itself towards the
house in a shape of the letter V. The wire is very low to the floor and in
every ones way. I have no idea how it radiates in this shape. It can only be
like this as a temp solution.
I really need to understand why the End Fed wire is behaving the way it
does. I think the Analyser is working OK or it wouldn't be able to tune a
Centre Fed Dipole. I hope

When the earth rod was connected to the End Fed wire as a ground, there was
a definite 2 S points up on received signal compared to it being
disconnected. So it must be doing something.


True.

I had a listen around 2 - 3.5 MHz for any strong signals and I can't find
any that might cause me problems.


Noted.

I would have expected the frequency to change when altering the length of
the wire.

73 Andy.

What you have done is essentially to add a counterpoise / radial which
is appx a quarterwave long. This is really the other half of the dipole.
The higher it is up in the air, the more it will radiate. Note that, as
it is at the top end of the 15 feet of 300 ohm feeder, the feeder will
act like a transformer, and couple RF into 'counterpoise'. The
'counterpoise' will be more lively than if it were connected to the
braid at the far end of the coax.

As the 'counterpoise' is coming back under the actual aerial wire
(albeit at an angle) the radiation will tend to oppose that from the
aerial. This will reduce the overall radiation, so the greater the
separation, the better.

[Of course, if the counterpoise can be run in the opposite direction
from the aerial wire, the radiation doesn't cancel, and you might as
well erect the counterpoise as high as possible. What you will have, of
course, is a 'normal' dipole.]

I still think all of this points to the fact that your earth rods are
making very poor contact with the ground. If you have a fantastic earth
connection, counterpoises and radials have little effect. With an
absolutely lousy ground contact (and poor ground conductivity), they can
make a great difference. With the single wire (and no counterpoise), the
analyser will need a good earth connection. Without it, it's going to
read rubbish, which may explain why a change of wire length makes no
difference.

I think I would concentrate on improving the ground connection a bit
more (more earth rods, or maybe some wires buried in the ground?). My
inverted-L aerial feed is at the fence at the end of my back garden. The
earthing system (at the fence) consists of three old bits of galvanized
water pipe (about 6 foot long), and each about 6 feet apart. In addition
to that, the wooden fence posts are mounted into 'Metposts'
http://www.metpost.co.uk/
each of which is about around 2.5 foot long, with only about 6 inches
above the ground. The length of the fence is 70 feet, so there about
Metposts. Most of these are also connected to my earthing system. I did
once try adding a counterpoise for 80m, but it had no effect. [My soil,
by the way, is mainly clay and flints. That which is not, is old
bricks.]

When you've done as much as is reasonable with you earth system, all you
can do is to add counterpoises etc.

If you really cannot get an efficient earth/counterpoise system, you
will probably be better concentrating your efforts on dipoles (even if
you have to use bent or compressed versions). At least you know where
you are with a dipole.
--
Ian
  #25   Report Post  
Old June 25th 08, 03:00 PM posted to aus.radio.amateur.misc,rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jun 2008
Posts: 1
Default PALSTAR AT1KP Meter 1200 Watt Antenna Tuner

It may once have been an established convention to bottom post - these days
many people don't bother unless there is a specific need to reference
particular comments in multiple parts of a posting. May be irritating for
some, but build a bridge and get over it.
A more serious PITA is people not trimming the unnecessary parts from their
responses when there is no requirement to include it. If people really want
to have a look at how the discussion plays out, then they can go back and
look through it, post by post. Much more of a PITA to have people include a
couple of hundred lines of text - or more - and then reply with a couple of
words......
As to the actual topic of the post, yes, the analyser might be picking up a
strong local transmission that is confusing it - having said that, at my
current QTH, I am pretty close to a number of MW broadcast sites with high
TX levels and I have not experienced any of the problems or issues as
outlined by Andy.


me

"Ian Jackson" wrote in message
...
Andy, you've gone back to top posting, and this makes it very difficult to
follow the discussion. In newsgroups (unlike emails), you should really
post at the bottom. This is the established convention.

Anyway, it's interesting what you have found out with the dipole
configuration. Presumably, you still have the coax braid and one side of
300 ohm feeder earthed. If so, I would not have expected there to be quite
such a dramatic change of resonance. However, if your earth rods are
totally ineffective (or you have disconnected the earth), you might expect
things to change a lot when you add 'the other half of the dipole'. If you
actually have room to put up an appx 60 foot + 60 foot dipole, why not
consider a G5RV (which, I believe, you have already tried) or a W3DZZ trap
dipole? This would get rid of your earthing problems.
--
Ian





  #26   Report Post  
Old June 26th 08, 01:01 AM posted to aus.radio.amateur.misc,rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Jun 2008
Posts: 3
Default PALSTAR AT1KP Meter 1200 Watt Antenna Tuner

On Jun 26, 12:09*am, Walt Davidson wrote:
On Thu, 26 Jun 2008 00:00:39 +1000, "wazzzzup"
wrote:

[drivel snipped]

Kill-filed for top-posting.

73 de G3NYY

--
Walt Davidson * * * * * * * * * * * * * * * Email: g3nyy @despammed.com


Kill-filed for being a ******.

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