[Lostgallifreyan]

Jeff Liebermann wrote in
:

Also, a mess of junk switcher type cell
phone chargers.


Nice catch. The noise has a pulsed interval very similar to the type of Li-
ion charger that pauses to measure voltage every second or so. It might be
one. Thing is, it is the interval that noises, not the main duration, so I
think it might be a net boz sending regular packets when idle.

[David Platt]

In article ,
Jeff Liebermann wrote:

Much depends on the device causing the problem. It's often cheaper
and easier to just buy the owner a new device instead of trying to fix
it. I've done that a few times with Chinese junk that never had a
prayer of meeting FCC Part 15 incidental radiation limits. So far,
I've replaced one ethernet switch, one 4 line phone, and 2 security
cameras in the neighborhood. Also, a mess of junk switcher type cell
phone chargers.

*rolls eyes*

A few years ago I helped chase down a noise source which was wandering
randomly through the 2-meter repeater input sub-band, and causing
prolonged noisy squelch tails on the ends of transmissions on several
different repeaters in the Silicon Valley area. It turned out to be a
(famous name) 5-port Ethernet hub, which was leaking its internal
clock-oscillator signal into all ports and back into its power supply
and was "turning the entire home wiring into a giant antenna" (as the
house-wiring-TV-antenna gimmicks used to say, decades ago).
Horrid... I could practically hear my spectrum analyzer cringe.

The owner was extremely cooperative, immediately agreed when I offered
to replace the hub with one from my own collection of spares, and the
problem went away and hasn't recurred in the years since. An unusual
failure mode, I guess (fortunately!)

[Flash]

On Fri, 25 Jul 2014 14:21:07 -0500, Lostgallifreyan wrote:

I hope to boost the incoming signal to override the ocal RF mush from nearby
flats ...

It might be wiser to see if you can identify the source(s) of the offending
"mush" instead. You would be doing yourself and others a service by doing so.
Contact your local authority and see if they will look into it. Can't hurt to
try, and the rewards may be worth it.

[Jeff Liebermann[_2_]]

On Sat, 26 Jul 2014 21:24:11 -0700, (David
Platt) wrote:

It turned out to be a
(famous name) 5-port Ethernet hub, which was leaking its internal
clock-oscillator signal into all ports and back into its power supply
and was "turning the entire home wiring into a giant antenna" (as the
house-wiring-TV-antenna gimmicks used to say, decades ago).
Horrid... I could practically hear my spectrum analyzer cringe.

Yep. I also know how to shoot myself in the foot. When I replaced
the neighbors noisy ethernet switch, he gave me the old switch for
recycling. Instead, I threw it into my pile of network boxes for a
later autopsy. After about a year, the post-it note marking it as
defective was lost. I needed a switch for the local club station, so
I grabbed the noisy switch and left. The complaints started about a
week later. Oddly, the 2.4GHz link between the repeater building and
the club station was the first to suffer interference problems. I
think just about every radio on the hill had problems, including the
county radios. On the principle of "whatever I did last was probably
wrong", I retraced my steps and eventually found the noisy switch. I
recall that it was made by Edimax, but don't recall the exact model
number.

As for "turn your house wiring into a giant TV antenna", that was my
start in electronics. I recall the ads in the back of Popular
Electronics and was intrigued by the principle. I learned that inside
the magic coupling box was a "capacitator" and that if one had an
AC-DC powered TV, it could be rather dangerous if connected
improperly. What got my attention was that it was an obvious fraud,
yet also quite successful considering that the ads were everywhere and
appeared in every electronics magazine. Instead of the traditional
policeman or fireman, I decided to become an electronics crook when I
grew up. That was heady stuff for a 9 or 10 year old. My parents
grudgingly approved if I agreed to become and engineer first, and
later a crook. That seemed reasonable and I continued on path to
success. Unfortunately, I began to reconsider when I discovered that
the owner of the company (Charles Torelli) had been busted in New York
for fraud, and served some prison time.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Michael Black[_2_]]

On Sun, 27 Jul 2014, Jeff Liebermann wrote:

On Sat, 26 Jul 2014 21:24:11 -0700, (David
Platt) wrote:

It turned out to be a
(famous name) 5-port Ethernet hub, which was leaking its internal
clock-oscillator signal into all ports and back into its power supply
and was "turning the entire home wiring into a giant antenna" (as the
house-wiring-TV-antenna gimmicks used to say, decades ago).
Horrid... I could practically hear my spectrum analyzer cringe.

Yep. I also know how to shoot myself in the foot. When I replaced
the neighbors noisy ethernet switch, he gave me the old switch for
recycling. Instead, I threw it into my pile of network boxes for a
later autopsy. After about a year, the post-it note marking it as
defective was lost. I needed a switch for the local club station, so
I grabbed the noisy switch and left. The complaints started about a
week later. Oddly, the 2.4GHz link between the repeater building and
the club station was the first to suffer interference problems. I
think just about every radio on the hill had problems, including the
county radios. On the principle of "whatever I did last was probably
wrong", I retraced my steps and eventually found the noisy switch. I
recall that it was made by Edimax, but don't recall the exact model
number.

Masking tape is a better choice, it stays on for much longer.


As for "turn your house wiring into a giant TV antenna", that was my
start in electronics. I recall the ads in the back of Popular
Electronics and was intrigued by the principle. I learned that inside
the magic coupling box was a "capacitator" and that if one had an
AC-DC powered TV, it could be rather dangerous if connected
improperly. What got my attention was that it was an obvious fraud,
yet also quite successful considering that the ads were everywhere and
appeared in every electronics magazine. Instead of the traditional
policeman or fireman, I decided to become an electronics crook when I
grew up. That was heady stuff for a 9 or 10 year old. My parents
grudgingly approved if I agreed to become and engineer first, and
later a crook. That seemed reasonable and I continued on path to
success. Unfortunately, I began to reconsider when I discovered that
the owner of the company (Charles Torelli) had been busted in New York
for fraud, and served some prison time.

My sister bought one of those phone line antenna things about five years
ago. It was new, and obviously junk. I felt so bad that she'd thought it
would help.


Michael

[amdx[_3_]]

On 7/26/2014 10:51 PM, Lostgallifreyan wrote:
amdx wrote in :

I've* calculated a 6 inch loop made with a #12 or #14 wire will
resonate the FM band with a cap between 6.5pf and 10pf. Roughly!
Now, I'll see if I can generate the gumption in the next couple
of days to build it to see if it has any positive effect.
I hope someone beats me to it.
With an AM loop and radio the signal couples to the internal loop very
well, I don't know how well you can couple a signal into an FM radio.
Mikek

* actually I used a couple of online calculators.

http://www.deephaven.co.uk/lc.html

http://www.daycounter.com/Calculator...lculator.phtml


This is nice because it beats the issue with two ways to be selective. Even
so, I have to have one last shot at the broadband notion: could a 6dB boost
with one of those MAR6-based antenna amps be worth a shot? Driving a local
diple, taped to a doorframe perhaps, in the centre of the flat? Given the
tiny size of those IC's I doubt the amount of power getting out of the flat
will be a nuisance, especially given its reluctance to allow RF in (except
through the celing, and a dipole taped vertically to a doorframe isn't going
to send a lot upwards either.. To some extent the business may be eased by
the fact that the two frequencies I'm most keen to get, 91.5MHz and 93.7MHz,
aren't far apart. If there is ANY chance this can be solved with no
modification or encumbrance to the tiny radio I intend to carry from room to
room, that's the way I want to do it.

I made a 6 inch loop with a 2pf to 10pf cap, I could see a peak in
the loop where I adjusted it to, but it was very low Q and when I
started dangling it around my radio I couldn't hear any change.
It may take a slightly smaller loop, I had my cap set at minimum
to get it to tune the low end of the band.
In my mind the experiment failed.
I have had loads of fun with AM band loops with high Q and obvious
effect on reception.
Mikek

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[Lostgallifreyan]

Michael Black wrote in
news:alpine.LNX.2.02.1407271422560.23911@darkstar. example.org:

Masking tape is a better choice, it stays on for much longer.


No, no, the stuff dries up, goes yellow, and flakes off like dry paint.
And electrical tape's got seepage, big time... What realyl soes stick around
is the double-sided adhesive foam tape sold for sticking stuff on car
dashboards (and HeNe tubes into place, it stands the heat very well), but
finding labels that use the same glue is a thing I never solved. I want to,
because the stuff would stay put for decades without seepage even if it gets
warm or humid.

[Lostgallifreyan]

amdx wrote in :

I made a 6 inch loop with a 2pf to 10pf cap, I could see a peak in
the loop where I adjusted it to, but it was very low Q and when I
started dangling it around my radio I couldn't hear any change.
It may take a slightly smaller loop, I had my cap set at minimum
to get it to tune the low end of the band.
In my mind the experiment failed.
I have had loads of fun with AM band loops with high Q and obvious
effect on reception.


Thanks for trying though, it's good info. One reason I imagined staying with
a dipole is it's close to what already works as standard. A loop for VHF is a
niuce idea for the selectivity of tuning and of orientation, but most radios
couple VHF to what amounts to a wire, not a magnetic coupling, so my
suspicion is that aiming for magnetic coupling won't work so well as a
dipole.

[John S]

On 7/27/2014 3:16 PM, amdx wrote:
On 7/26/2014 10:51 PM, Lostgallifreyan wrote:
amdx wrote in :

I've* calculated a 6 inch loop made with a #12 or #14 wire will
resonate the FM band with a cap between 6.5pf and 10pf. Roughly!
Now, I'll see if I can generate the gumption in the next couple
of days to build it to see if it has any positive effect.
I hope someone beats me to it.
With an AM loop and radio the signal couples to the internal loop
very
well, I don't know how well you can couple a signal into an FM radio.
Mikek

* actually I used a couple of online calculators.

http://www.deephaven.co.uk/lc.html

http://www.daycounter.com/Calculator...lculator.phtml


This is nice because it beats the issue with two ways to be selective.
Even
so, I have to have one last shot at the broadband notion: could a 6dB
boost
with one of those MAR6-based antenna amps be worth a shot? Driving a
local
diple, taped to a doorframe perhaps, in the centre of the flat? Given the
tiny size of those IC's I doubt the amount of power getting out of the
flat
will be a nuisance, especially given its reluctance to allow RF in
(except
through the celing, and a dipole taped vertically to a doorframe isn't
going
to send a lot upwards either.. To some extent the business may be
eased by
the fact that the two frequencies I'm most keen to get, 91.5MHz and
93.7MHz,
aren't far apart. If there is ANY chance this can be solved with no
modification or encumbrance to the tiny radio I intend to carry from
room to
room, that's the way I want to do it.

I made a 6 inch loop with a 2pf to 10pf cap, I could see a peak in
the loop where I adjusted it to, but it was very low Q and when I
started dangling it around my radio I couldn't hear any change.
It may take a slightly smaller loop, I had my cap set at minimum
to get it to tune the low end of the band.
In my mind the experiment failed.
I have had loads of fun with AM band loops with high Q and obvious
effect on reception.
Mikek

Hi, Mike - 6 inch circumference, 6 inch diameter, or 6 inch radius. Just
clarifying...

John

[amdx[_3_]]

On 7/27/2014 4:35 PM, John S wrote:
On 7/27/2014 3:16 PM, amdx wrote:
On 7/26/2014 10:51 PM, Lostgallifreyan wrote:
amdx wrote in :

I've* calculated a 6 inch loop made with a #12 or #14 wire will
resonate the FM band with a cap between 6.5pf and 10pf. Roughly!
Now, I'll see if I can generate the gumption in the next couple
of days to build it to see if it has any positive effect.
I hope someone beats me to it.
With an AM loop and radio the signal couples to the internal loop
very
well, I don't know how well you can couple a signal into an FM radio.
Mikek

* actually I used a couple of online calculators.

http://www.deephaven.co.uk/lc.html

http://www.daycounter.com/Calculator...lculator.phtml



This is nice because it beats the issue with two ways to be selective.
Even
so, I have to have one last shot at the broadband notion: could a 6dB
boost
with one of those MAR6-based antenna amps be worth a shot? Driving a
local
diple, taped to a doorframe perhaps, in the centre of the flat? Given
the
tiny size of those IC's I doubt the amount of power getting out of the
flat
will be a nuisance, especially given its reluctance to allow RF in
(except
through the celing, and a dipole taped vertically to a doorframe isn't
going
to send a lot upwards either.. To some extent the business may be
eased by
the fact that the two frequencies I'm most keen to get, 91.5MHz and
93.7MHz,
aren't far apart. If there is ANY chance this can be solved with no
modification or encumbrance to the tiny radio I intend to carry from
room to
room, that's the way I want to do it.

I made a 6 inch loop with a 2pf to 10pf cap, I could see a peak in
the loop where I adjusted it to, but it was very low Q and when I
started dangling it around my radio I couldn't hear any change.
It may take a slightly smaller loop, I had my cap set at minimum
to get it to tune the low end of the band.
In my mind the experiment failed.
I have had loads of fun with AM band loops with high Q and obvious
effect on reception.
Mikek

Hi, Mike - 6 inch circumference, 6 inch diameter, or 6 inch radius. Just
clarifying...

John

Diameter.

Five minutes with these calculators and you can pick your own dimensions.


http://www.deephaven.co.uk/lc.html

http://www.daycounter.com/Calculator...lculator.phtml

Mikek

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