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Originally posted by fmnotes
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Read paragraph 6 ->
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Did you know that typing your posts in capital letters is equivalent to SHOUTING?
Read paragraph 6 ->
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Originally posted by simonbaker View Post
I MEASURED HIM WITH OSCILLOGRAPH.
AND I HAD THESE RESULTS.
CH1
Vpp=1.20V
Prd=67.20us
Mean=8.00mv and -8.00mv and 0.00mv it is not constant.
freq=14.90KHz
f=17.0000KHz
CENTRAL REGULATIONS OF OSCILLOGRAPH.
ch1=200mv M25.0us CH1/16.0mv Mpos: 0.00us
THEY IS GOOD THIS RESULTS?
EXIST DOES PROBLEM?
I THANK I WAIT FOR ANSWER.Comment
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Do not write IN CAPITAL LETTERS. In forum etiquette it is like SHOUTING.Originally posted by fmnotes View Post
For example, your post above should be written as: "I didn't understand what you want to say?" not "I DIDN'T UNDERSTAND WHAT YOU WANT TO SAY?".
Now do you understand?
Comment
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Originally posted by Qiaozhi View PostDo not write IN CAPITAL LETTERS. In forum etiquette it is like SHOUTING.
For example, your post above should be written as: "I didn't understand what you want to say?" not "I DIDN'T UNDERSTAND WHAT YOU WANT TO SAY?".
Now do you understand?
Yes I understood.
But who it is the reason?
it serves this some aim?Comment
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Thank you.Originally posted by fmnotes View Post That is much better.
For a more detailed explanation of forum etiquette, please read this ->
Here is the part about not using all capital letters:
"Another violation of forum etiquette is posting in ALL CAPS. This is considered shouting and is very rude, in addition to being hard on the eyes. Something may be in caps for emphasis (e.g. I did NOT want to go!), but no post should be entirely in all caps."Comment
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Originally posted by simonbaker View Post
I measured him with oscilograph.
and i had these results
CH1
Vpp=1.20V
Prd=67.20us
Mean=8.00mv and -8.00mv and 0.00mv it is not constant.
freq=14.90KHz
f=17.0000KHz
Central regulation of oscillograph.
ch1=200mv M25.0us CH1/16.0mv Mpos: 0.00us
They is good this results?
?
I thank i wait for answer.
I THANK I WAIT FOR ANSWER.Comment
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Please tell us what exact point in the circuit you are measuring the voltage. Is it the output of the LF353 pin 7?Originally posted by fmnotes View Post
If so, the numbers seem to be good.
What is "f=17.0000KHz" ?
Regards,
-SBComment
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My big day!
My vacuumforming failed (too small oven, too thick plastic, too weak vacuum
), so I just bent it vith my hands and hot air gun.
while epoxy cures, it unbalances a coil a bit so while it is still liquid, I put some weight on windings to balance it back. its hot!!Comment
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What did you use for an oven? I have a pizza oven but am waiting until I can pick up a heat gun before trying it out.
JerryComment
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I had a few failures to start with, but now almost all my shells come out perfect. You must get the time in the oven/temp just right!! I would say that I probably wasted 5 sheets of plastic until I figured it out. Also, if your epoxy is getting hot you will have a failure for sure! It must be slow-cure potting type. You can actually melt your shell and it will certainly spoil your null if using the wrong kind! My last coil, I used very little epoxy by filling the ears first, then 2 part foam, then just a thin layer of epoxy on the bottom. It came out very rigid an light!Originally posted by habitbraker View PostMy big day!
My vacuumforming failed (too small oven, too thick plastic, too weak vacuum), so I just bent it vith my hands and hot air gun.
while epoxy cures, it unbalances a coil a bit so while it is still liquid, I put some weight on windings to balance it back. its hot!!Comment
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Jerry - Im using ordinary kichen oven with electric heating. My shell form barely fits in the oven so that I couldnt afford to make proper frame form my plastic, just about 1cm wide. Because of that, when it plastic heats up, it just drops of the frame. If not in oven, then when I sqeeze it on the wooden form it will
Dfbowers - You actually was my inspiration source. I messed up 2 sheets already.
What thichness have yours? Mines are 1.5mm.
I could heat it so hot it could vacuum form, BUT.. - see aswer for Jerry.
well it didnt melt the plastic, but surely shifted null a lot! I was readjusted the null every 10 minutes while it was still liquid.
After all my null (at LF output) is very small in A (about 200mV) , but phase from -20deg sifted to about +100deg (!!!). (relative to TX)
Despite this I can reject ferrite at middle of GB pot, discrimination is nice, and my air distance for 2cm coin is about 30cm. (really no big difference if phase is not those 20deg..) Lost about 3cm because of epoxy.
I just very anxious to get to the field
I guess I will glue next one like you suggest - one part/area of a coil at timeComment
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No they isn't measurements from this LF353 pin 7?Originally posted by simonbaker View Post
the measurements I take him from COIL RX.
That is to say disconnect COIL RX from the detector and I connect the oscillograph in the coil RX and read the measurements in the oscillograph.
f=17.0000KHz They is measurement in the oscillograph. I be believed frequency that it is.
Regards,Comment
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A good frame to support your plastic sheets surely makes things easier. I have been getting my sheets from "widgetworks" http://www.widgetworksunlimited.com/...-black-060.htmOriginally posted by habitbraker View PostJerry - Im using ordinary kichen oven with electric heating. My shell form barely fits in the oven so that I couldnt afford to make proper frame form my plastic, just about 1cm wide. Because of that, when it plastic heats up, it just drops of the frame. If not in oven, then when I sqeeze it on the wooden form it will
Dfbowers - You actually was my inspiration source. I messed up 2 sheets already.
What thichness have yours? Mines are 1.5mm.
I could heat it so hot it could vacuum form, BUT.. - see aswer for Jerry.
well it didnt melt the plastic, but surely shifted null a lot! I was readjusted the null every 10 minutes while it was still liquid.
After all my null (at LF output) is very small in A (about 200mV) , but phase from -20deg sifted to about +100deg (!!!). (relative to TX)
Despite this I can reject ferrite at middle of GB pot, discrimination is nice, and my air distance for 2cm coin is about 30cm. (really no big difference if phase is not those 20deg..) Lost about 3cm because of epoxy.
I just very anxious to get to the field
I guess I will glue next one like you suggest - one part/area of a coil at time
I have found that the correct time/temp combination is 400 degrees for 2 minutes, and that is starting with a preheated oven. I just use an ordinary shop vac. but, I typically have to "work" the plastic into sharp corners and between the ears with some sort of tool while still soft. Generally they come out very good.
Now, to keep this relavent to the TGSL thread, here is my latest 20cm coil.. 31 cm for a Euro using Eduardo's new PCB. My standard 255mm coils get a euro at 36cm but that advantage is drastically reduced in the ground. Detection depths are about the same for both in the ground..
Top pic is my standard 255mm coils, bottom pic is my latest 200mm coil..
This one has epoxy filled ears, 2 part marine foam in the middle and a layer of potting epoxy on the bottom. Very light and rigid!Comment
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