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Because of Roel Verdult's note "If
you
found
out
better
values
than
we
describe 13.0V ,
please
drop
a
note
so
we
update
this
manual" I drop my note here.
I had at first about 13.4V but because I have not cut exactly at 19cm and 76cm so I prolonged and shortened the cable I reached at one point 25.8V for 13.56 MHz; but continued to modified and cut short a piece of the cable so now I am sticking with 21 to 23,50V
proxmark3> hw tune
Measuring antenna characteristics, please wait.........
# LF antenna: 0.00 V @ 125.00 kHz
# LF antenna: 0.00 V @ 134.00 kHz
# LF optimal: 0.00 V @ 12000.00 kHz
# HF antenna: 21.69 V @ 13.56 MHz
# Your LF antenna is unusable.
proxmark3>
thanks for the instruction "How to make..."
PS1 : the manufactured antenna bring me only 8.8V (or switch over 14.25V) Typical Newbie's mistake: Buy everything and hope you would not miss anything for the start.... should have saved that $60 ....
PS2: I could not see a place compare voltage you can achieved with self-made antenna so I put here. if that exist I will delete this one.
PS3: I post because I also found something interesting. But if someone already achieve higher voltage then that is not worth to share
Last edited by ntk (2015-06-23 00:21:53)
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Please see http://www.proxmark.org/forum/viewtopic.php?id=2269 for an explanation why you get higher voltages than reported by Roel.
PS1 : the manufactured antenna bring me only 8.8V (or switch over 14.25V) Typical Newbie's mistake: Buy everything and hope you would not miss anything for the start.... should have saved that $60 ....
Absolutely. I think that there are many issues caused by antennas which are poorly matched to the PM3 input capacitor (there are variants with either 47pF or 100pF, and it has a specified tolerance of 5%).
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thank you @piwi for the explanation but could there be also something else.
I have been away from science lesson for many years and could not remember the effect of wire length, number of winding, position of wire on inductivity, resonance, by experiment I could see there seems to be. it does not have to be exact 19cm and 76cm and 3 windings
But I have only one wire left hence I am afraid of getting worse result with accidentally shortening the wire further. At one point I had 25.8V consistent tuning using "hw tune" so better voltage than I have yet is possible.
Hence I might like to see a place where PM ask people to place the result of their HF antenna so we optimize further the technique after all the improvements in SW and HW.
Few HF antenna voltage values I saw were back from 2009, at that time lower than 20V.
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