Noisy neigborhood and HQ-129-x
 

On 05/22/2010 05:19 PM, Bill M wrote:
Bill Baka wrote:
On 05/22/2010 01:40 PM, Bill M wrote:
Bill Baka wrote:

With my scope synced to 60 Hz I can see two big spikes and lots of
little ones that take a while to settle down.
Thanks for the reply,
Bill Baka

What sort of antenna are you using? You might be able to configure
something, although I'm not exactly sure what, that can provide more
directivity and maybe escape from some of the junk noise.

I have a sort of long wire, 25 feet, and the other side is grounded to
a chain link fence. There is not enough room to put up much else
unless I run a wire to the house behind me. Yup, two rental houses on
one lot.
My stepdaughter lives in the back and I don't even know if she could
figure out the concept of radio DX noise. She is a cable TV addict and
not at all inclined to radio. I do have a radio direction finder that
I can run with a solar cell I picked up, so I can walk it around in
the sun and try to find the major noise source that way. When I scoped
it, it looked like a lot of SCR's triggering at various points so I
kind of figure it may be SCR light dimmers.

yes, with puny antennas and rental houses and chain link fences and
stepdaughters who are "cable tv addicts" to blame you really must attack
some cogent RFI initiatives from your part. That's what I was alluding
to before.

Yeah, but I have the 'longish' wire at the farthest point from any
electricity lines as is possible. If I run it back to her place then it
will be parallel to her power lines, so it might be worse. I just hope I
can find a bad connection on a power line so I can get the local
electric company to fix it. I might get blown off on that though.
Bill Baka

Noisy neigborhood and HQ-129-x
 

Bill Baka wrote:
On 05/22/2010 09:43 AM, Scott Dorsey wrote:

Welcome to the New Era. Everything has a switching supply in it. None
of them meet FCC Part 15 specs. Nobody at the FCC gives a damn. Write
your congressman and complain about the enormous arrays of CFLs, touch
lamps, and TV sets for sale at Wal-Mart which are patently illegal.

Tell me about it. Damn near everything that comes out of Walmart is
Chinese and if I buy anything it seems to fail just after any hope of
warranty. The noise seems to come from anything Chinese so I try not to
buy that stuff, but in many cases China is the only source.

Don't blame the Chinese. The Chinese make cheap crap because Americans
demand cheap crap. If Americans wanted good products, the Chinese would
make good products. But the American importers are constantly after the
Chinese factories to cut costs, not to improve quality, and so this is
what you get.

No, and I think the preamp is probably a lot of your issue, that broadband
noise is saturating it. You might want to consider a more tightly tuned
preamp, possibly one with a front end that has outrageous dynamic range and
low noise (like, say a nuvistor or even a 6X8).

It does have switch so I can bypass the preamp and just go through the
radio. The preamp only gets overloaded by an AM station here on 1,600
KHz at 5,000 or 50,000 watts, even though the station is a good 5 miles
from me. If I hit that with the preamp on, yes it will overload, but
going straight to the Hammarlund still gives excellent tuning so in
order to get

We're not talking about catastrophic overload, we're only talking about
a little nonlinearity. It doesn't take much.

You have two problems:

1. Noise that is off-channel, maybe even out of band, which either winds up
being detected due to poor selectivity, poor shielding, or because
something in the front end or early IF (or in your case the preamp) is
mixing multiple noise sources together to form a beat product on your
channel.

2. Noise that is actually on-channel, on the exact frequency you are on.

The first one can be remedied by eliminating the preamp, making sure the
receiver front end is clean (ie. the first RF stage is perfectly linear)
and possibly adding a preselector.

The second one cannot be remedied. The noise blanker is one thing people
have used; it drops the whole signal out when the signal reaches a
limiting level and it good only for impulse noise that is stronger than
the signal.

One of the DSP boxes like JPS sells can help hide on-channel noise,
sort of.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Noisy neigborhood and HQ-129-x
 

On 05/22/2010 06:30 PM, Scott Dorsey wrote:
Bill wrote:
On 05/22/2010 09:43 AM, Scott Dorsey wrote:

Welcome to the New Era. Everything has a switching supply in it. None
of them meet FCC Part 15 specs. Nobody at the FCC gives a damn. Write
your congressman and complain about the enormous arrays of CFLs, touch
lamps, and TV sets for sale at Wal-Mart which are patently illegal.

Tell me about it. Damn near everything that comes out of Walmart is
Chinese and if I buy anything it seems to fail just after any hope of
warranty. The noise seems to come from anything Chinese so I try not to
buy that stuff, but in many cases China is the only source.

Don't blame the Chinese. The Chinese make cheap crap because Americans
demand cheap crap. If Americans wanted good products, the Chinese would
make good products. But the American importers are constantly after the
Chinese factories to cut costs, not to improve quality, and so this is
what you get.

Really? I try to search for American products and pay a little more for
better quality, but so many companies have been killed off it is
sometimes impossible to buy American. People seem to have the attitude
"It won't cost me MY job" until it does. I bought a Kodak digital camera
hoping it would be at least 'non-Chinese' but when I got it out of the
box, sure enough, Made in China. Too bad not enough people can put cause
and effect together. I used to gripe about 'Made in Japan' 30 years ago,
but now even Japanese companies are farming things out to China.

No, and I think the preamp is probably a lot of your issue, that broadband
noise is saturating it. You might want to consider a more tightly tuned
preamp, possibly one with a front end that has outrageous dynamic range and
low noise (like, say a nuvistor or even a 6X8).

It does have switch so I can bypass the preamp and just go through the
radio. The preamp only gets overloaded by an AM station here on 1,600
KHz at 5,000 or 50,000 watts, even though the station is a good 5 miles
from me. If I hit that with the preamp on, yes it will overload, but
going straight to the Hammarlund still gives excellent tuning so in
order to get

We're not talking about catastrophic overload, we're only talking about
a little nonlinearity. It doesn't take much.

What happens is the channel is so strong the preamp gets mucked up. The
Hammarlund can still tune 1590 and it seems to be immune to a strong
station at 1600.

You have two problems:

1. Noise that is off-channel, maybe even out of band, which either winds up
being detected due to poor selectivity, poor shielding, or because
something in the front end or early IF (or in your case the preamp) is
mixing multiple noise sources together to form a beat product on your
channel.

2. Noise that is actually on-channel, on the exact frequency you are on.

The first one can be remedied by eliminating the preamp, making sure the
receiver front end is clean (ie. the first RF stage is perfectly linear)
and possibly adding a preselector.

The second one cannot be remedied. The noise blanker is one thing people
have used; it drops the whole signal out when the signal reaches a
limiting level and it good only for impulse noise that is stronger than
the signal.

One of the DSP boxes like JPS sells can help hide on-channel noise,
sort of.
--scott

Sorry, none of the above. I have my scope on the speaker leads and the
waveform indicates power line noise being fed back by SCR controlled
devices, and/or switching power supplies. Since my scope is vintage 1989
I can't freeze just one cycle to analyze. I paid over $2,200 for the
scope, brand new, for a project I was working on at the time. The
waveform looks like an SCR spike and then a gradual decay. That is the
best I can describe it for now. Nobody here has the doorbell problem
since the houses are old for about two blocks around me. I don't know if
it is one house, or many.
Detective work is needed.
Bill Baka

Noisy neigborhood and HQ-129-x
 

"Bill Baka" wrote in message
...
On 05/22/2010 01:40 PM, Bill M wrote:
What sort of antenna are you using? You might be able to configure
something, although I'm not exactly sure what, that can provide more
directivity and maybe escape from some of the junk noise.

I have a sort of long wire, 25 feet, and the other side is grounded to
a chain link fence. There is not enough room to put up much else unless
I run a wire to the house behind me. Yup, two rental houses on one lot.
My stepdaughter lives in the back and I don't even know if she could
figure out the concept of radio DX noise. She is a cable TV addict and
not at all inclined to radio. I do have a radio direction finder that I
can run with a solar cell I picked up, so I can walk it around in the
sun and try to find the major noise source that way. When I scoped it,
it looked like a lot of SCR's triggering at various points so I kind of
figure it may be SCR light dimmers.

I think I will get my RDF and go hunting tomorrow.
Thanks,
Bill Baka

To add to what Scott Dorsey said, the chain link fence may be a problem
in itself. The zinc galvanizing protects the steel below from rusting,
but it provides a nonlinear junction with any other metals touching it,
especially copper. Your radio needs a good ground with the shortest
ground lead possible. Get a good copper-clad ground rod at the home
improvement store. Locate it below the window closest the radio and run
a short, heavy gauge wire from it to the radio. Your radio should also
be grounded to the power line ground for safety.

The preamp must be very linear and have an exceptionally high dynamic
range to not cause problems. If it does not, RF interference at one
frequency will mix with all other signals to produce a cacophony of
noise. Your receiver should be more than sensitive enough on the lower
bands to not need a preamp. If you must use it on the higher bands,
consider using a high-pass filter ahead of the preamp. It will attenuate
the lower frequencies (where the noise is the strongest) yet allow the
higher frequencies to pass with little to no attenuation.

The Timewave (formerly JPS) ANC-4 and the MFJ 1026 noise cancellers work
quite well if you have a single noise source or if one noise source
dominates. With multiple sources, they do not work nearly as well. For
a homebrew version, see the article by W7XC in the July, 1994 QST. Note
that there are several subsequent corrections and additions to this
article (9/1994, 1/1995, 9/1996).

Be persistent with the power company but do not get your hopes up. I
once called the power company and they sent a crew out. They listened
with their truck two-way radio and said they could not hear any noise.
Of course, the truck radio was FM! :-(

73, Barry WA4VZQ

Noisy neigborhood and HQ-129-x
 

On 05/23/2010 07:05 PM, WA4VZQ wrote:
"Bill wrote in message
...
On 05/22/2010 01:40 PM, Bill M wrote:
What sort of antenna are you using? You might be able to configure
something, although I'm not exactly sure what, that can provide more
directivity and maybe escape from some of the junk noise.

I have a sort of long wire, 25 feet, and the other side is grounded to
a chain link fence. There is not enough room to put up much else unless
I run a wire to the house behind me. Yup, two rental houses on one lot.
My stepdaughter lives in the back and I don't even know if she could
figure out the concept of radio DX noise. She is a cable TV addict and
not at all inclined to radio. I do have a radio direction finder that I
can run with a solar cell I picked up, so I can walk it around in the
sun and try to find the major noise source that way. When I scoped it,
it looked like a lot of SCR's triggering at various points so I kind of
figure it may be SCR light dimmers.

I think I will get my RDF and go hunting tomorrow.
Thanks,
Bill Baka

To add to what Scott Dorsey said, the chain link fence may be a problem
in itself. The zinc galvanizing protects the steel below from rusting,
but it provides a nonlinear junction with any other metals touching it,
especially copper. Your radio needs a good ground with the shortest
ground lead possible. Get a good copper-clad ground rod at the home
improvement store. Locate it below the window closest the radio and run
a short, heavy gauge wire from it to the radio. Your radio should also
be grounded to the power line ground for safety.

Good advice but this house is old and does not have a third wire ground
line. There is one at the junction box, but only two lead wire feeding
the house. It may be time to sink a ground rod under my window.

The preamp must be very linear and have an exceptionally high dynamic
range to not cause problems. If it does not, RF interference at one
frequency will mix with all other signals to produce a cacophony of
noise. Your receiver should be more than sensitive enough on the lower
bands to not need a preamp. If you must use it on the higher bands,
consider using a high-pass filter ahead of the preamp. It will attenuate
the lower frequencies (where the noise is the strongest) yet allow the
higher frequencies to pass with little to no attenuation.

I try to DX on anything from 540KHz to 31 MHZ, so it is a mixed bag. The
noise waveform on the scope is the same with and without the preamp in
the loop. If it is power line I could always hook a scope probe to the
high (hot) side of the 110 VAC and take a look. I can easily build a
simple filter to take out the 60 Hz power line and just look for spikes.

The Timewave (formerly JPS) ANC-4 and the MFJ 1026 noise cancellers work
quite well if you have a single noise source or if one noise source
dominates. With multiple sources, they do not work nearly as well. For
a homebrew version, see the article by W7XC in the July, 1994 QST. Note
that there are several subsequent corrections and additions to this
article (9/1994, 1/1995, 9/1996).

I'm thinking that one of these or something I design would be synced to
the power line and just take out a piece at a time. A one shot for the
delay to the biggest noise pulse (variable by me) and another one shot
with variable width to cover the width of the noise pulse. A double
section one shot and a digital switch like a DG411 could take out the
worst pulse. Depending on my ambition I could make another few for the
next biggest pulses, but at some point all the chopping of the signal
might make the actual signal un-listenable.


Be persistent with the power company but do not get your hopes up. I
once called the power company and they sent a crew out. They listened
with their truck two-way radio and said they could not hear any noise.
Of course, the truck radio was FM! :-(

73, Barry WA4VZQ



The only thing I have ever gotten out of the power company was an extra
transformer due to overload from one transformer feeding about ten
houses, all with A/C going. They finally gave in and put in another so
that only 5 houses per transformer was the end game. I tried the noise
thing a while back and they just asked if I had power, and I said yes,
then they said 'NO'. With so few of us non-internet addicts around these
days they could care less about radio reception.
About ten years ago I located a noisy pole and told them but they did
nothing until it arced over and burned off the top of the pole. Only
then did they respond, and it was way more expensive than fixing it in
the first place would have been.
Thanks,
Bill Baka

Noisy neigborhood and HQ-129-x
 

On May 22, 7:03*pm, Bill Baka wrote:
On 05/22/2010 04:44 PM, petev wrote:

I can vouch for the MFJ noise cancelling antenna. However, you have to
keep re-adjusting
* it as you change frequency. Not by much, but it requires re-tweaking.
It makes the noise
practically dissapear, without the artifacts of a noise limiter.
Perhaps you can find one on ebay,
Or appeal to a ham club or two for a loaner or a donation.

One of my friends refers to MFJ as Mighty Fine Junk. How good is it?
Bill Baka

Some of MFJ's products are indeed questionable (like their RTTY
reader)
but the noise cancelling antenna actually works as advertised. It is
very
tweak intensive, however, and precludes casual band surfing, as the
phase
relationship between the noise and signal antennas changes as you
change frequency.

Noisy neigborhood and HQ-129-x
 

On 06/07/2010 07:14 PM, petev wrote:
On May 22, 7:03 pm, Bill wrote:
On 05/22/2010 04:44 PM, petev wrote:

I can vouch for the MFJ noise cancelling antenna. However, you have to
keep re-adjusting
it as you change frequency. Not by much, but it requires re-tweaking.
It makes the noise
practically dissapear, without the artifacts of a noise limiter.
Perhaps you can find one on ebay,
Or appeal to a ham club or two for a loaner or a donation.

One of my friends refers to MFJ as Mighty Fine Junk. How good is it?
Bill Baka

Some of MFJ's products are indeed questionable (like their RTTY
reader)
but the noise cancelling antenna actually works as advertised. It is
very
tweak intensive, however, and precludes casual band surfing, as the
phase
relationship between the noise and signal antennas changes as you
change frequency.

Sounds almost like work. The noise is worst at the lower frequencies but
still wreaks havoc with me even getting WWV at 10 MHz. There is one
permanent spike at the peaks of the power line, so it is something that
is being rectified, and the rest just seem random in nature. I thought
it might have been SCR noise but it doesn't follow any kind of logical
pattern. The Hammarlund's noise limiter chops the main spike but thinks
the rest is a legitimate signal.
Bill Baka

Noisy neigborhood and HQ-129-x
 

Bill Baka wrote:
Sounds almost like work. The noise is worst at the lower frequencies but
still wreaks havoc with me even getting WWV at 10 MHz. There is one
permanent spike at the peaks of the power line, so it is something that
is being rectified, and the rest just seem random in nature. I thought
it might have been SCR noise but it doesn't follow any kind of logical
pattern. The Hammarlund's noise limiter chops the main spike but thinks
the rest is a legitimate signal.

This can be just about anything, including SCRs, switching supplies, and
arcing.

All you can do, once you have established that it isn't your house, is to
get a handheld AM radio and use the loopstick to try and DF it. The problem
is that the junk gets into power lines and then radiates from there, so
it can seem to be coming from everywhere at times.

It's amazing how much trash one touch lamp can put out.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Noisy neigborhood and HQ-129-x
 

On 06/08/2010 07:10 AM, Scott Dorsey wrote:
Bill wrote:
Sounds almost like work. The noise is worst at the lower frequencies but
still wreaks havoc with me even getting WWV at 10 MHz. There is one
permanent spike at the peaks of the power line, so it is something that
is being rectified, and the rest just seem random in nature. I thought
it might have been SCR noise but it doesn't follow any kind of logical
pattern. The Hammarlund's noise limiter chops the main spike but thinks
the rest is a legitimate signal.

This can be just about anything, including SCRs, switching supplies, and
arcing.

All you can do, once you have established that it isn't your house, is to
get a handheld AM radio and use the loopstick to try and DF it. The problem
is that the junk gets into power lines and then radiates from there, so
it can seem to be coming from everywhere at times.

It's amazing how much trash one touch lamp can put out.
--scott

Well,
I do have a marine RDF, but I can't find it under my piles of stuff,
radios, car parts, more 'stuff'.
When I find it I will be out looking around.
Bill

Noisy neigborhood and HQ-129-x
 

"Bill Baka" wrote in message
...
On 06/08/2010 07:10 AM, Scott Dorsey wrote:
Bill wrote:
Sounds almost like work. The noise is worst at the lower
frequencies but
still wreaks havoc with me even getting WWV at 10 MHz.
There is one
permanent spike at the peaks of the power line, so it is
something that
is being rectified, and the rest just seem random in
nature. I thought
it might have been SCR noise but it doesn't follow any
kind of logical
pattern. The Hammarlund's noise limiter chops the main
spike but thinks
the rest is a legitimate signal.

This can be just about anything, including SCRs,
switching supplies, and
arcing.

All you can do, once you have established that it isn't
your house, is to
get a handheld AM radio and use the loopstick to try and
DF it. The problem
is that the junk gets into power lines and then radiates
from there, so
it can seem to be coming from everywhere at times.

It's amazing how much trash one touch lamp can put out.
--scott

Well,
I do have a marine RDF, but I can't find it under my piles
of stuff, radios, car parts, more 'stuff'.
When I find it I will be out looking around.
Bill

Its salutary for collectors of stuff to read about the
Collyer brothers. A good account can be found at:

http://en.wikipedia.org/wiki/Collyer_brothers

Electrical noise is a PITA in spades, doubled.



--
Richard Knoppow
Los Angeles
WB6KBL