TallTom
Full Member
- Mar 3, 2012
- 177
- 57
- Detector(s) used
- Nokta Impact, Makro Racer, Tesoro Vaquero, Tesoro Sand Shark.
- Primary Interest:
- Metal Detecting
I posted the message below in the Tech Talk forum.
I hope it's OK to post it here, too, because other Silver uMax
users are more likely to see it here. Are any of you seeing
a problem like this?
Also, have any Compadre users run into a problem like this?
I'm thinking of buying one as a backup, especially if I can use
it when the Morse Code interference cripples my Silver uMax.
Maybe the Compadre's 12.0 kHz frequency doesn't have the problem?
Or am I all wet with my whole theory about radio interference,
and there's some other cause you can suggest?
======================================
[h=2]Interference on 10.6 kHz with Tesoro Silver uMax[/h]
I hope it's OK to post it here, too, because other Silver uMax
users are more likely to see it here. Are any of you seeing
a problem like this?
Also, have any Compadre users run into a problem like this?
I'm thinking of buying one as a backup, especially if I can use
it when the Morse Code interference cripples my Silver uMax.
Maybe the Compadre's 12.0 kHz frequency doesn't have the problem?
Or am I all wet with my whole theory about radio interference,
and there's some other cause you can suggest?
======================================
[h=2]Interference on 10.6 kHz with Tesoro Silver uMax[/h]
I recently bought a Tesoro Silver uMax metal detector.
I think I'm having a problem with radio interference from
a powerful transmitter that uses the same frequency that
my MD uses, which is 10.6 kHz, according to Tesoro's specs.
Of course, the interference might come from a transmitter
on a harmonic frequency, such as 21.2 kHz. (At least, that's
my limited understanding. I'm no radio expert.)
Here's what I encounter when I go MD-ing.
I turn on my machine and (usually) everything works fine.
I can do air tests and surface tests of coins and other
metals, both in Disc and All Metal modes, and I get the
response from the Silver uMax that I expect. I can go
to my back yard, or a nearby park, or the beach, and
I get good results. By the way, I live in the Los Angeles
area. The beach is usually Santa Monica beach.
But sometimes, I suddenly start getting weird interference
on my detector. If I leave it in Disc mode, I start getting
constant false signals. I have to turn Disc up to maximum
and Sensitivity to near minimum in order to stop most of the
false beeps. But I still get so many false beeps that detecting
becomes nearly impossible. Of course, with Disc and Sensitivity
set like that, I'm not going to detect much anyway.
This is not just true at the beach, by the way. It also happens
in my back yard and in a nearby park, both of which are about
15 miles from the beach.
But the big problem becomes more obvious when I switch to
All Metal. That gives me constant chattering that sounds
remarkably like Morse Code. I don't "speak" Morse, but I've
played with it enough over the years (Dad was a ham) that
I recognize the relative lengths of the dits and dahs, and
the spacing between characters and words. There's a little
extra beeping mixed in, but it's amazingly like Morse code,
transmitted pretty fast.
At first, I thought my detector had gone bad, maybe a loose
connection that was causing intermittent shorts when I moved
it around, causing these beeps. I finally sent it to Tesoro
to check it out. I hadn't formed my radio interference theory
at that time, so I just explained that it gave me a lot of
chattering in AM mode, and at that time I thought it might
be worse when I had made contact on the coil with moist sand
when I was at the beach. So I told them that.
Anyway, they said "Final Test Good!" and returned it to me.
It still has the same problem. I used it Friday, April 6,
and from about 5:45 PM to 6:05 PM it worked fine. Then the
"Morse Code attack" began. It continued until about 10:05 PM,
although I wasn't monitoring it the entire time. However,
it was pretty continuous from 6:05 until at least 8 PM;
at 10 PM I turned it on again and it continued, but stopped
within a few minutes after that. (All times are Pacific
Daylight Time.) I used the detector from 10:05 to 10:55 PM
or so and it was fine.
Has anyone else encountered this type of problem?
Is 10.6 kHz the only frequency that receives Morse Code?
I've checked the usage of the radio spectrum and it shows no
usage for 10.6 kHz. (See http://www.vlf.it/trond2/10-15khz.html )
And finally, it there anything I can do about this? Should I
ask Tesoro if they can modify my Silver uMax to use a different
frequency? And if so, what is better?
By the way, there are interesting explanations about VLF and its
uses in Wikipedia at:
http://en.wikipedia.org/wiki/Very_low_frequency
and
http://en.wikipedia.org/wiki/Lualualei_VLF_transmitter
The big Lualualei transmitter uses 21.4 kHz to transmit. That's close
enough to 21.2 (twice my 10.6) that I wonder if it's the cause of
my problem. Radio transmissions to submarines!
Thanks in advance for any info you can provide that might help me
figure out the cause of this problem and what to do about it.
I think I'm having a problem with radio interference from
a powerful transmitter that uses the same frequency that
my MD uses, which is 10.6 kHz, according to Tesoro's specs.
Of course, the interference might come from a transmitter
on a harmonic frequency, such as 21.2 kHz. (At least, that's
my limited understanding. I'm no radio expert.)
Here's what I encounter when I go MD-ing.
I turn on my machine and (usually) everything works fine.
I can do air tests and surface tests of coins and other
metals, both in Disc and All Metal modes, and I get the
response from the Silver uMax that I expect. I can go
to my back yard, or a nearby park, or the beach, and
I get good results. By the way, I live in the Los Angeles
area. The beach is usually Santa Monica beach.
But sometimes, I suddenly start getting weird interference
on my detector. If I leave it in Disc mode, I start getting
constant false signals. I have to turn Disc up to maximum
and Sensitivity to near minimum in order to stop most of the
false beeps. But I still get so many false beeps that detecting
becomes nearly impossible. Of course, with Disc and Sensitivity
set like that, I'm not going to detect much anyway.
This is not just true at the beach, by the way. It also happens
in my back yard and in a nearby park, both of which are about
15 miles from the beach.
But the big problem becomes more obvious when I switch to
All Metal. That gives me constant chattering that sounds
remarkably like Morse Code. I don't "speak" Morse, but I've
played with it enough over the years (Dad was a ham) that
I recognize the relative lengths of the dits and dahs, and
the spacing between characters and words. There's a little
extra beeping mixed in, but it's amazingly like Morse code,
transmitted pretty fast.
At first, I thought my detector had gone bad, maybe a loose
connection that was causing intermittent shorts when I moved
it around, causing these beeps. I finally sent it to Tesoro
to check it out. I hadn't formed my radio interference theory
at that time, so I just explained that it gave me a lot of
chattering in AM mode, and at that time I thought it might
be worse when I had made contact on the coil with moist sand
when I was at the beach. So I told them that.
Anyway, they said "Final Test Good!" and returned it to me.
It still has the same problem. I used it Friday, April 6,
and from about 5:45 PM to 6:05 PM it worked fine. Then the
"Morse Code attack" began. It continued until about 10:05 PM,
although I wasn't monitoring it the entire time. However,
it was pretty continuous from 6:05 until at least 8 PM;
at 10 PM I turned it on again and it continued, but stopped
within a few minutes after that. (All times are Pacific
Daylight Time.) I used the detector from 10:05 to 10:55 PM
or so and it was fine.
Has anyone else encountered this type of problem?
Is 10.6 kHz the only frequency that receives Morse Code?
I've checked the usage of the radio spectrum and it shows no
usage for 10.6 kHz. (See http://www.vlf.it/trond2/10-15khz.html )
And finally, it there anything I can do about this? Should I
ask Tesoro if they can modify my Silver uMax to use a different
frequency? And if so, what is better?
By the way, there are interesting explanations about VLF and its
uses in Wikipedia at:
http://en.wikipedia.org/wiki/Very_low_frequency
and
http://en.wikipedia.org/wiki/Lualualei_VLF_transmitter
The big Lualualei transmitter uses 21.4 kHz to transmit. That's close
enough to 21.2 (twice my 10.6) that I wonder if it's the cause of
my problem. Radio transmissions to submarines!
Thanks in advance for any info you can provide that might help me
figure out the cause of this problem and what to do about it.
