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  #31   Report Post  
Old October 21st 05, 04:04 PM
Ian White G/GM3SEK
 
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Default Messed-Up Radials Can Generate Spurious Emissions

Cecil Moore wrote:
Ian White G/GM3SEK wrote:
Thank you - and well done, Cecil, for being part of that program.


There's a fringe benefit. Some of those kids have pretty
cute grandmas. :-)


Do you teach them to spell "incorrigible"?


--
73 from Ian G/GM3SEK
  #32   Report Post  
Old October 21st 05, 05:07 PM
Frank's
 
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Default Messed-Up Radials Can Generate Spurious Emissions

I think a lot of the MW garbage I receive on 160m, etc, is
generated much the same way. I've even seen people say
that semi corroded stranded copper wire, even insulated
can cause problems like that. And...I've been seeing stronger
and stronger MW energy here every year it seems... I'm starting
to wonder if the standed wire theory may not be too far fetched,
as most all my wire is stranded, and most is getting some age
on it. I also seen to notice even the water heater or pipes seem
to generate spurious MW energy.. Been driving me crazy the last
few years, and seems to be slowly getting worse.
Not to mention all the other sources of trouble like fences, guy
wires, bad connections, etc.
I don't doubt bad radials could cause that for a minute...I've seen
things like that around here in mildew city from all kinds of bad
connections.. Once had a bad "rf in the shack" problem...Turned
out to be nothing more than corroded/rusted balun hardware at
the antenna feedpoint. Cleaned that up, bingo, all gone. MK


I had a similar problem with a W2AU balun. AM stations all over the place.
The balun "eye" bolts were severely corroded. Replacing the balun with a
stainless steel version eliminated all the AM junk. I notice that W2AU
baluns are now advertised as having all "Stainless steel" hardware.

Frank


  #33   Report Post  
Old October 21st 05, 08:04 PM
Steve Nosko
 
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Default Messed-Up Radials Can Generate Spurious Emissions

I'll only say that it is interesting that the first comments were about the
grammar not the content.

Interesting story Walt. That's what I call an ending!

Brief story 1
The apollo recovery ships had problems in the radars from high power HF
transmitters and the rusty deck railing chains.


Brief story 2...well not so brief.
To solve a problem in a 150MHz car telephone in a Caddy and one on a
motorcycle, I developed a method for finding what I dubbed "environmental
desense" of a similar nature. This amounted to the transmitter being
modulated, in its _field_ by near-by noisy joints in the car body or the
motorcycle seat springs. This produced virtual noise sidebands on the
transmitter. This "modulation" extended out to the receiver frequency. The
receiver used the same antenna, thus easily picking up this new "noise
modulation.
This is an extension of what I had called "the Screwdriver Effect" in my
early 2-way repair days. you are listening to a rather close transmitter
(or maybe not so close) and you simply rub a screwdriver across another
nearby piece of metal and you hear noise on the received signal. Same
effect - field modulation.
To explain in more detail...
1- EVERYTHING conductive is an antenna (receiving).
2- Everything has RF current in it from every transmitter (even YOU).
3- These "everythings" therefore produce small RF fields of their own,
from these currents.
4- These fields sum with the original field.
5- If two of these "everythings" come into contact, there can be a
change in current due to the new physical arrangement (current through the
new connection)
6- This change also changes the resulting fields from the "Everythings"
7- This changes the total resulting field.
8- this is just like a change in the original field and just like a
change in the transmitted signal.
9- SO... this is received just like some similar modulation on the
original transmitter. Try it, but the screwdriver part has to be near the
receive antenna and the main signal not so strong that the noise is too far
down. 2M FM may the best place to try.

Noisy screwdriver contact...noisy received signal

73, Steve, K,9.D;C'I



"Walter Maxwell" wrote in message
...
Messed Up Ground Radials Can Generate Spurious Signals

In 1948 I was the consulting engineer for the proposed first AM

broadcast
station in Mt. Pleasant, Michigan, obtaining a construction permit and

license
for WCEN, 500 watts on 1150 KHz. Using a National HRO receiver, I was

performing
a hands-on search for an available frequency for the new station, when I
encountered an interesting and unusual signal that was entirely out of

place in
the AM broadcast band-a CW Morse-code station illegally transmitting
five-letter-word code groups at 30 words per minute. The illegal signal

was S9
+40 dB on 1297.8 KHz, producing a 2200 Hz beat-note with the 1300 KHz

frequency
of WOOD, Grand Rapids, thus producing a an audible CW signal with the

receiver
BFO disabled.
The format of the coded messages appeared to be military, IDing as

NSS. We
know that NSS is the flagship station of the U.S. Navy in Annapolis, MD,

but in
the AM broadcast band? It appeared that either an NSS transmitter was

producing
a spurious emission, or a station using NSS as a fraudulent call sign was
operating clandestinely in the AM broadcast band. I deemed it important to

find
out which.
As a former FCC monitoring officer at the Allegan, Michigan

monitoring
station, the next step was to report the situation to the Allegan station.
Although Allegan was 90 airline miles away, the monitoring personnel there

could
not hear the spurious signal, even though it was S9 +40 dB at Mt.

Pleasant. I
let the FCC monitors hear the signal through the telephone, but they still

heard
nothing on their receivers tuned to 1297.8 KHz. Thus the signal must be of

local
origin near Mt. Pleasant, and not from NSS. However, to be on the safe

side, FCC
notified the Navy of the spurious signals, and the NSS operators began

combing
all their transmitters for spurious signals, and found none. The situation

is
now becoming even more strange.
I then copied five minutes of the coded text and sent a copy to the

FCC,
who relayed it to NSS for comparison to their transmissions. The situation

is
now both perplexing and frustrating, because the text I copied on 1297.8

KHz
agreed exactly with a transmission that had been made by NSS. How could

that
signal have been transmitted on 1298.7 KHz if no spurious signals were

emanating
from NSS? But it's not likely to have been a fraudulent station. What

then?
A partial answer came shortly thereafter. As I resumed the search for

a
useable frequency for the new station, I proceeded downward from 1298.7

KHz,
going through 1280 KHz and hearing WFYC, Alma, 1000 watts, 15 miles away,

also
S9 +40 dB. But on continuing further downward I immediately came across

another
S9 +40 dB thumping CW signal. I switched on the BFO and discovered the CW

was
also a five-letter-word coded transmission at about 30 wpm, the same as

NSS. I
retuned to 1298.7 KHz and the NSS signal was also there, as before. So I

cranked
up a second receiver to monitor both frequencies simultaneously. Surprise!

Both
frequencies were showing identical simultaneous transmissions. I then

measured
the frequency of the lower-frequency signal-1262.2 KHz. Voila! The higher

CW
frequency was 17.8 KHz above WFYC's 1280 frequency and the lower CW

frequency
was 17.8 KHz below WFYC's frequency. A quick reference to the Berne

frequency
listing showed NSS assigned to 17.8 KHz. This situation now appeared to

indicate
something very wrong going on at WFYC. The low-frequency world-wide

ground-wave
signal from NSS was apparently somehow mixing with the signal from WFYC,

and
producing the 1297.8 and 1262.2 sum and difference frequencies. But what
non-linear device in WFYC's system could perform that mixing? Don't know,

but I
reported this new information to the FCC and that was the last I heard of

the
situation.until.
Fast forward now to 1955. I was now employed as an electrical

engineer at
the RCA Laboratories, the David Sarnoff Research Center in Princeton, NJ.

An
assignment took me to Washington, D.C. to attend the annual conference of

the
NAB, the National Association of Broadcasters. President Dwight D.

Eisenhower
gave the keynote address. However, one of the technical forums was

presented by
Jack Young, Chief Engineer of the RCA Broadcast Division. His topic was on

the
solution of mutual interference between two broadcast stations in Los

Angeles,
KFI and KNX.
It seems that in a section of the Los Angeles area it was impossible

to
hear one of these stations without hearing both simultaneously-when tuned

to 640
KHz for KFI, both KFI and KNX were heard, and when tuned to 1070 KHz for

KNX,
both KNX and KFI were heard. Young was assigned the task of determining

the
cause of the interference and eliminating it. To make a long story short,

he
discovered that there were ancient and rusty oil well derricks in the

affected
area. Currents from both KFI and KNX transmissions were being induced in

the oil
well towers, and the rusty joints were acting as mixers for the two

frequencies,
producing both the sum and difference frequencies, as well as re-radiating

both
signals on their original frequencies. When the derricks were removed the
interference stopped.
So how is this incident relevant to the NSS problem? Well, at the
conclusion of Young's presentation I had the opportunity to talk with him,

and
because of the similarity of the problems, I told him of my discovery of

the NSS
signals appearing in the AM broadcast band. Talk about coincidences! He

was
surprised and excited to learn that I had discovered the NSS problem at

WFYC,
because he was the one assigned to determine the cause of the problem. He

had
never been told how that problem originated, or how the problem had been
discovered.
He then explained that he had found the ground radial system under

the WFYC
antenna a horrible mess. Cold solder joints throughout, and far ends of

the
radials hanging loose in the water of the nearby Pine River, establishing

the
non-linear mixer condition that resulted in the sum and difference

frequencies
being generated between the NSS and WFYC signals. Cleaning up the

messed-up
radials ended the appearance of the NSS signals in the AM broadcast band,

thus
concluding an interesting journey.

Walt, W2DU



  #34   Report Post  
Old October 21st 05, 08:29 PM
Steve Nosko
 
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Default rust?Messed-Up Radials Can Generate Spurious Emissions


"ml" wrote in message
...
In article ,
Cecil Moore wrote:
hmm this kinda makes me wonder about my tvi

as my antenna is near the building master tv antenna


Mmmmm Bad sign from the beginning. This opens up a large possibility box.
IM , spurious, overload, you name it.
73, Steve, K,9.D;C'I


  #35   Report Post  
Old October 21st 05, 08:30 PM
Steve Nosko
 
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Default Messed-Up Radials Can Generate Spurious Emissions

Yous guys krack me up.
Steve

"Walter Maxwell" wrote in message
...
On Thu, 20 Oct 2005 20:26:55 GMT, Cecil Moore wrote:

Walter Maxwell wrote:
Richard, your approval of my writings is like receiving a

million-dollar jack
pot. Words cannot descibe how much your approval as an English major is
appreciated.


Y'all shudda did ah reright in Suthurn so us Texians kud unnerrstan.


Cecil, shud I huv writ my last 3 emales ta ya in Suthurn so ya kud of

unnerrstud
em sufeeciently ta reeplie?

Waalltre





  #36   Report Post  
Old October 21st 05, 08:35 PM
Steve Nosko
 
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Default Messed-Up Radials Can Generate Spurious Emissions

The singular (implied plural) was well accepted.

100 kc

Go up 3 kc, please


"Allodoxaphobia" wrote in message
...
On Thu, 20 Oct 2005 21:05:31 -0400, Hal Rosser wrote:

I noticed also you referred to frequencies in KHZ. But shouldn't that

have
been "KC" or for historic accuracy.
;-)


Well, it should've been "kc/s".
More 'short-handedly': "kcs".
A Hertz is a "cycle per second".

Jonesy W3DHJ



  #37   Report Post  
Old October 21st 05, 08:38 PM
Walter Maxwell
 
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Default Messed-Up Radials Can Generate Spurious Emissions

On 21 Oct 2005 14:23:49 GMT, Allodoxaphobia wrote:

On Thu, 20 Oct 2005 23:00:49 -0400, Walter Maxwell wrote:
On 21 Oct 2005 02:50:10 GMT, Allodoxaphobia wrote:
On Thu, 20 Oct 2005 21:05:31 -0400, Hal Rosser wrote:

I noticed also you referred to frequencies in KHZ. But shouldn't that have
been "KC" or for historic accuracy.
;-)

Well, it should've been "kc/s".
More 'short-handedly': "kcs".
A Hertz is a "cycle per second".

Jonesy W3DHJ


Then I should have said KHz/s, or KHzs, right?


_That_ would be doubly redundant. :-)
It would be the equivalent to saying "kilo-cycles per second per second".
Some sort of "FM propagation", I suppose.

Jonesy


As I see it, Jonesy, kc = kilocycles, but we think of it as kilocycles per sec.
kc/s = kilocycles/sec, which accurately specifies it as such, so it is not
redundant.

Therefore, KHz is also proper, but KHz/s more accurately specifies it, and is
also not redundant.

But aren't we being a little picky picky?

Walt
  #38   Report Post  
Old October 21st 05, 08:39 PM
Steve Nosko
 
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Default Messed-Up Radials Can Generate Spurious Emissions


"K7JEB" wrote in message
news:1J66f.3561$i%.2682@fed1read07...
Hi Walt,

Enjoyed reading the story. Thanks!

...a bad splice in the
wires on my 80/40-meter dipole through the appearance
of mixing products from the broadcasters all up and
down both bands. ....


How many mixer diodes do you know about that can
handle half a kilowatt.

73,
Jim, K7JEB



Probably all the ones that are on about 20% of all the ham antennas in the
world... (:-)
73, Steve, K,9.D;C'I


  #39   Report Post  
Old October 21st 05, 08:47 PM
Bob Spooner
 
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Default Messed-Up Radials Can Generate Spurious Emissions

"Walter Maxwell" wrote in message
...
On 21 Oct 2005 14:23:49 GMT, Allodoxaphobia wrote:

As I see it, Jonesy, kc = kilocycles, but we think of it as kilocycles per

sec.
kc/s = kilocycles/sec, which accurately specifies it as such, so it is not
redundant.

Therefore, KHz is also proper, but KHz/s more accurately specifies it, and

is
also not redundant.

But aren't we being a little picky picky?

Walt


Actually, the Hertz is is defined as a unit of frequency equal to one cycle
per second. That would mean the KHz/s is redundant. But you're right - it is
picky unless the meaning isn't clear from the context.

Bob


  #40   Report Post  
Old October 21st 05, 09:17 PM
Jim Kelley
 
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Default Messed-Up Radials Can Generate Spurious Emissions



Bob Spooner wrote:

"Walter Maxwell" wrote in message
...

On 21 Oct 2005 14:23:49 GMT, Allodoxaphobia wrote:

As I see it, Jonesy, kc = kilocycles, but we think of it as kilocycles per


sec.

kc/s = kilocycles/sec, which accurately specifies it as such, so it is not
redundant.

Therefore, KHz is also proper, but KHz/s more accurately specifies it, and


is

also not redundant.

But aren't we being a little picky picky?

Walt



Actually, the Hertz is is defined as a unit of frequency equal to one cycle
per second. That would mean the KHz/s is redundant.


KHz/s is a sweep rate.

ac6xg


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