MA5B background noise
 

Andy wrote:

I just pulled out the PL259, so just the canter pin on the PL259 on the
canter fed dipole was connected
and the noise increased with the signal and then dropped when the PL259 was
screwed back in. I had the same on the Cobwebb.

When I did this on the MA5B the 10, 12, 15 and 17 meter bands did the same ,
on 20 meters it was different. When I pulled out the PL259 so just the
center pin of the PL259 was connected the noise dropped and with the PL259
screwed in
fully the noise went up. The opposite to what I thought would happen after
trying this out on my other antennas.

Andy

Sorry, but my previous comments pertained to the MA5V (vertical).

Having just assembled a TH-3, I can only suggest that perhaps you have
an open trap or two. Did you check the electrical continuity along each
of the elements after assembling them? What is the SWR on 20?

ac6xg

MA5B background noise
 

I also forgot to mention that the noise is on all bands from 10 - 20m, only
on the MA5B.


"Andy" wrote in message
...
The noise stays the same when I turn the beam.

I will try to get a recording done this weekend if I can.

I just pulled out the PL259, so just the canter pin on the PL259 on the
canter fed dipole was connected
and the noise increased with the signal and then dropped when the PL259
was
screwed back in. I had the same on the Cobwebb.

When I did this on the MA5B the 10, 12, 15 and 17 meter bands did the same
,
on 20 meters it was different. When I pulled out the PL259 so just the
canter pin of the PL259 was connected the noise dropped and with the PL259
screwed in
fully the noise went up. The opposite to what I thought would happen after
trying this out on my other antennas.

Andy


"Jim Kelley" wrote in message
...
Andy wrote:
I've swapped the feed line over and its still the same.

When I put the antenna together I made sure all connections where good
and the analyser gave a good match on the frequencies I want to use.

I did use some conductive grease for the first time on the antenna.
Wonder if the grease is the problem or maybe this antenna just picks up
a
lot of background hiss.

Andy

The instruction manual for the antenna doesn't make it real obvious how
the feedline attaches, but it looks to me like the antenna doesn't have a
low DC resistance - like a loop would, for example. It's probably
reasonable to expect this type of antenna to be noisier than a loop. I
think Butternut attaches the feedline in a similar fashion on their HF6V,
but puts an air core choke (from memory, 15-20 turns, 14 awg, approx 1"
dia x 2.5" long) across the feedpoint. That may just be for noise
because
the antenna seems to have the same performance with, or without it.
Perhaps you could try the same with the MA5V.

I think what the OP was getting at is the noise should be a lot louder
with just the center conductor attached to the radio, and then get
quieter
when you thread the barrel on. If it doesn't do that, then there may be
a
connectivity problem somewhere.

ac6xg

MA5B background noise
 

"Jim Kelley" wrote in message
...
Andy wrote:

I just pulled out the PL259, so just the canter pin on the PL259 on the
canter fed dipole was connected
and the noise increased with the signal and then dropped when the PL259
was
screwed back in. I had the same on the Cobwebb.

When I did this on the MA5B the 10, 12, 15 and 17 meter bands did the
same ,
on 20 meters it was different. When I pulled out the PL259 so just the
center pin of the PL259 was connected the noise dropped and with the
PL259 screwed in
fully the noise went up. The opposite to what I thought would happen
after
trying this out on my other antennas.

Andy

Sorry, but my previous comments pertained to the MA5V (vertical).

Having just assembled a TH-3, I can only suggest that perhaps you have an
open trap or two. Did you check the electrical continuity along each of
the elements after assembling them? What is the SWR on 20?

ac6xg



No I didn't do a continuity test. I did put an analyser on the beam and the
SWR on all bands at the moment are,

14.225 at 1.06:
18.130 at 1.45:1
21.300 at 1.34:1
24.960 at 1.5:1
28.850 at 1.5:1

How do I check for an open trap?

Andy

MA5B background noise
 

Andy,
Just from those readings, I'd have to say the antenna seems to be
operating normally/correctly. Shaking things while doing that
continuity test is usually a fairly good idea, intermittents, although
shaking the antenna isn't going to be very easy, sort of.
Not making both connections at the antenna terminal, only the
center pin, and changing the antenna's characteristics is normal.
Sort of going from a "tuned"/resonant antenna to a random length wire
kind of thing. (Receivers just aren't as 'picky' as transmitters,
have different requirements. Not a very good way of putting it, but
you get the idea?)
Don't give up, I'm interested in what happens.
- 'Doc

MA5B background noise
 

wrote in message
...


Andy,
Just from those readings, I'd have to say the antenna seems to be
operating normally/correctly. Shaking things while doing that
continuity test is usually a fairly good idea, intermittents, although
shaking the antenna isn't going to be very easy, sort of.
Not making both connections at the antenna terminal, only the
center pin, and changing the antenna's characteristics is normal.
Sort of going from a "tuned"/resonant antenna to a random length wire
kind of thing. (Receivers just aren't as 'picky' as transmitters,
have different requirements. Not a very good way of putting it, but
you get the idea?)
Don't give up, I'm interested in what happens.
- 'Doc


I have used some conductive grease for the first time on the beam. I've
never used grease before, do you think this might be the problem?

The other thing is, that the beam is at apex roof height and mounted on the
back of the house. I have no where else to try it out to see if this is a
problem.
The centre fed dipole has the element that connects to the centre pin of the
PL259 at house end and I don't suffer any noise hiss on that like I do on
the beam and the Cobwebb is at the bottom of the garden away from the house
and that has a very quite receive on it.

Andy

MA5B background noise
 

On Sat, 26 Jul 2008 15:12:27 +0100, "Andy"
wrote:

I have used some conductive grease for the first time on the beam. I've
never used grease before, do you think this might be the problem?

Hi Andy,

It is not the problem.

The other thing is, that the beam is at apex roof height and mounted on the
back of the house. I have no where else to try it out to see if this is a
problem.

You are closer to noise in the home.

The centre fed dipole has the element that connects to the centre pin of the
PL259 at house end and I don't suffer any noise hiss on that like I do on
the beam

However close one arm of the dipole is to the house, I will bet the
feedline is far, far away from the noise source.

and the Cobwebb is at the bottom of the garden away from the house
and that has a very quite receive on it.

Even further away from the noise source.

So far, no one has asked, and you haven't offered a comprehensive
meaning to this noise.... hiss is not remarkably unique at HF. For
comprehensive you do not state what frequencies it inhabits. OK, its
on the five bands, but is it everywhere else? Is it equally
strengthed?

A portable radio is a must for noise troubleshooting. If the S-9
noise covers 5 bands, this freestanding radio should hear it all. The
noise seems to be uniquely near the house, but can you wander the
neighborhood with a transistor radio and hear it other places? Can
you bring a transistor radio near the point the antenna is mounted and
hear the noise? If you hear it there, do you hear it in the garden?

On the other hand, if you cannot hear noise on a portable; then it is
not over-the-air, it is conducted noise. Severely corroded joints
could do that, but you already state this is a new(?), greased (that
is what the grease is for) joint antenna. Is the feedpoint choked?
(This is common advice.) Does the feedline pass near noise sources?
(Use your portable along the length of the line.)

How do you ground your shack? Some folks think that ground wires
everywhere does the job - often that is the problem. Could that hiss
be a hum? Poor antenna connections would be more like a sizzle.
Descriptive terms are not often reliable symptom indicators.

You have a ground loop with your new installation.

73's
Richard Clark, KB7QHC

MA5B background noise
 

I have managed to make an mp3 up. The first 10 seconds is on the Cobwebb
followed by another 10 seconds on the MA5B beam pointed in there direction
and then back and forth every 10 seconds. The click is the antenna switch
clicking over.

It can be found here. http://www.hobby.pwp.blueyonder.co.uk/ma5b/ma5b4.mp3

If anyone needs to here a clearer one let me know, but it will be best after
the contest has finished.

Andy


"Andy" wrote in message
...
I also forgot to mention that the noise is on all bands from 10 - 20m, only
on the MA5B.


"Andy" wrote in message
...
The noise stays the same when I turn the beam.

I will try to get a recording done this weekend if I can.

I just pulled out the PL259, so just the canter pin on the PL259 on the
canter fed dipole was connected
and the noise increased with the signal and then dropped when the PL259
was
screwed back in. I had the same on the Cobwebb.

When I did this on the MA5B the 10, 12, 15 and 17 meter bands did the
same ,
on 20 meters it was different. When I pulled out the PL259 so just the
canter pin of the PL259 was connected the noise dropped and with the
PL259 screwed in
fully the noise went up. The opposite to what I thought would happen
after
trying this out on my other antennas.

Andy


"Jim Kelley" wrote in message
...
Andy wrote:
I've swapped the feed line over and its still the same.

When I put the antenna together I made sure all connections where good
and the analyser gave a good match on the frequencies I want to use.

I did use some conductive grease for the first time on the antenna.
Wonder if the grease is the problem or maybe this antenna just picks up
a
lot of background hiss.

Andy

The instruction manual for the antenna doesn't make it real obvious how
the feedline attaches, but it looks to me like the antenna doesn't have
a
low DC resistance - like a loop would, for example. It's probably
reasonable to expect this type of antenna to be noisier than a loop. I
think Butternut attaches the feedline in a similar fashion on their
HF6V,
but puts an air core choke (from memory, 15-20 turns, 14 awg, approx 1"
dia x 2.5" long) across the feedpoint. That may just be for noise
because
the antenna seems to have the same performance with, or without it.
Perhaps you could try the same with the MA5V.

I think what the OP was getting at is the noise should be a lot louder
with just the center conductor attached to the radio, and then get
quieter
when you thread the barrel on. If it doesn't do that, then there may be
a
connectivity problem somewhere.

ac6xg

MA5B background noise
 

Andy wrote:
I have managed to make an mp3 up. The first 10 seconds is on the Cobwebb
followed by another 10 seconds on the MA5B beam pointed in there direction
and then back and forth every 10 seconds. The click is the antenna switch
clicking over.

It can be found here. http://www.hobby.pwp.blueyonder.co.uk/ma5b/ma5b4.mp3

If anyone needs to here a clearer one let me know, but it will be best after
the contest has finished.

Andy

This sounds to me as if the MA5B has a very high angle lobe which the
Cobwebb may not. More galactic noise in proportion to the wanted signal?

John

MA5B background noise
 

"Andy" wrote in message
...
I have managed to make an mp3 up. The first 10 seconds is on the Cobwebb
followed by another 10 seconds on the MA5B beam pointed in there direction
and then back and forth every 10 seconds. The click is the antenna switch
clicking over.

It can be found here. http://www.hobby.pwp.blueyonder.co.uk/ma5b/ma5b4.mp3

If anyone needs to here a clearer one let me know, but it will be best
after the contest has finished.

Andy


"Andy" wrote in message
...
I also forgot to mention that the noise is on all bands from 10 - 20m,
only on the MA5B.


"Andy" wrote in message
...
The noise stays the same when I turn the beam.

I will try to get a recording done this weekend if I can.

I just pulled out the PL259, so just the canter pin on the PL259 on the
canter fed dipole was connected
and the noise increased with the signal and then dropped when the PL259
was
screwed back in. I had the same on the Cobwebb.

When I did this on the MA5B the 10, 12, 15 and 17 meter bands did the
same ,
on 20 meters it was different. When I pulled out the PL259 so just the
canter pin of the PL259 was connected the noise dropped and with the
PL259 screwed in
fully the noise went up. The opposite to what I thought would happen
after
trying this out on my other antennas.

Andy


"Jim Kelley" wrote in message
...
Andy wrote:
I've swapped the feed line over and its still the same.

When I put the antenna together I made sure all connections where good
and the analyser gave a good match on the frequencies I want to use.

I did use some conductive grease for the first time on the antenna.
Wonder if the grease is the problem or maybe this antenna just picks
up a
lot of background hiss.

Andy

The instruction manual for the antenna doesn't make it real obvious how
the feedline attaches, but it looks to me like the antenna doesn't have
a
low DC resistance - like a loop would, for example. It's probably
reasonable to expect this type of antenna to be noisier than a loop. I
think Butternut attaches the feedline in a similar fashion on their
HF6V,
but puts an air core choke (from memory, 15-20 turns, 14 awg, approx 1"
dia x 2.5" long) across the feedpoint. That may just be for noise
because
the antenna seems to have the same performance with, or without it.
Perhaps you could try the same with the MA5V.

I think what the OP was getting at is the noise should be a lot louder
with just the center conductor attached to the radio, and then get
quieter
when you thread the barrel on. If it doesn't do that, then there may
be a
connectivity problem somewhere.

ac6xg














I forgot to mention before that the Cobwebb is 3 meters lower than the MA5B
beam.
Here are some more recordings, as before 10 seconds from the Cobwebb
followed by 10 seconds from the beam followed by the Cobwebb and then by the
beam again and so on till the end of the recording. All recordings will be
like this to save me explaining over each time. The beam is pointed in there
direction. The noise and signal increases every time when switching to the
beam.

http://www.hobby.pwp.blueyonder.co.uk/ma5b/ma5b5.mp3

http://www.hobby.pwp.blueyonder.co.uk/ma5b/ma5b6.mp3

MA5B background noise
 

"John Livingston" wrote in message
...
Andy wrote:
I have managed to make an mp3 up. The first 10 seconds is on the Cobwebb
followed by another 10 seconds on the MA5B beam pointed in there
direction and then back and forth every 10 seconds. The click is the
antenna switch clicking over.

It can be found here.
http://www.hobby.pwp.blueyonder.co.uk/ma5b/ma5b4.mp3

If anyone needs to here a clearer one let me know, but it will be best
after the contest has finished.

Andy

This sounds to me as if the MA5B has a very high angle lobe which the
Cobwebb may not. More galactic noise in proportion to the wanted signal?

John



Do you think the 2m/70cm collinear above the beam could cause this?

Andy