Telamon,
Starting-Off Today with Only
Heinz 57 to go +1 ) ~ RHF
[ It's About : N U M B 3 R S ]

The Number "57" has Mystical Significance
http://www.straightdope.com/classics/a1_195

In article ,
switcher wrote:

That's what I did, 10nF added to the loop- var cap setup, and now I see
that RMC INfo on 216 comes in with sig 9... (without loop: about 1).

Strange thing is that with var cap + 10nF the loop only tunes between
say 207 and 225 khz, while on AM (without the 10nF), it tunes 1 MHz wide
..

Of course, now I can add more turns to the loop.

The loop is 2 x 3 meter of PVC tube, bended in a circle.
There are now 3 turns. Guess ... how many turns to have the LW
153-279khz ???

picture of a previous version , large (2 m) and small 83 cm hulahoop

http://users.fulladsl.be/spb13810/oc/IMAG0015.JPG

The way I construct the hulahoop now, so that it "keeps head up":
http://users.fulladsl.be/spb13810/amloop/loopbottom.jpg
http://users.fulladsl.be/spb13810/amloop/loop83cm.jpg
http://users.fulladsl.be/spb13810/am...oopbottom2.jpg
(when the box is closed, you can put a radio on it, nicely positioned
inside the loop)


these formumla's say:
http://www.mindspring.com/~loop_ante...r_emc_calc.htm

some 15 turns... on a 2m diam loop ...

I know about the computer flat cable trick...

(I put the first formula in cm (100 cm = 1 meter) on
http://users.fulladsl.be/spb13810/amloop.htm
)

--
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switcher wrote:

The loop is 2 x 3 meter of PVC tube, bended in a circle.
There are now 3 turns. Guess ... how many turns to have the LW
153-279khz ???

If 3 turns resonated with about 11000 pF (your 10 nF plus about 1 nF
from the tuning capacitor) produces a resonance within that band, then
raising the turns to about 9 (3 times as much for about 3^2 times as
much inductance) would resonate at the same frequency with about 1/9th
as much capacitance (same L*C product). Of course, those extra turns
will also add quite a bit of stray capacitance between turns, so you
may not be able to reach the top of the band at minimum tuning
capacitance.

What kind of insulation is on the wire in the big loop? Its thickness
and dielectric constant have a big effect on the total stray
capacitance each turn will add.

In article ,
John Popelish wrote:

switcher wrote:

The loop is 2 x 3 meter of PVC tube, bended in a circle.
There are now 3 turns. Guess ... how many turns to have the LW
153-279khz ???

If 3 turns resonated with about 11000 pF (your 10 nF plus about 1 nF
from the tuning capacitor) produces a resonance within that band, then
raising the turns to about 9 (3 times as much for about 3^2 times as
much inductance) would resonate at the same frequency with about 1/9th
as much capacitance (same L*C product). Of course, those extra turns
will also add quite a bit of stray capacitance between turns, so you
may not be able to reach the top of the band at minimum tuning
capacitance.

What kind of insulation is on the wire in the big loop? Its thickness
and dielectric constant have a big effect on the total stray
capacitance each turn will add.

I guess copper 0.7 mm, insulation soft plastic .25 mm

--
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http://users.fulladsl.be/spb13810/bwnl.htm
Breng je iMac G5 terug (ik wil binnen 2 jaar geen defecte 2de hands Apple kopen)
http://www.apple.com/nl/support/imac...ensionprogram/

switcher wrote:
In article ,
John Popelish wrote:
(snip)
What kind of insulation is on the wire in the big loop? Its thickness
and dielectric constant have a big effect on the total stray
capacitance each turn will add.


I guess copper 0.7 mm, insulation soft plastic .25 mm

Sounds like ordinary PVC insulated hook up wire. The PVC is a little
lossy, but not too bad at this low frequency. You would have a lot
more trouble with high capacitance if you were using enameled (magnet)
wire. My favorite for such things is Teflon or Tefzel insulated wire
(low loss and low dielectric constant), but it is expensive and hard
to find. Another good, but hard to find insulation is polyethylene.
It is sometimes used in low capacitance, data grade cables, but
stripping out enough for this project would be a career.

Do you think it is practical to pull 6 more turns through your pipe?

In article ,
John Popelish wrote:

switcher wrote:
In article ,
John Popelish wrote:
(snip)
What kind of insulation is on the wire in the big loop? Its thickness
and dielectric constant have a big effect on the total stray
capacitance each turn will add.


I guess copper 0.7 mm, insulation soft plastic .25 mm

Sounds like ordinary PVC insulated hook up wire. The PVC is a little
lossy, but not too bad at this low frequency. You would have a lot
more trouble with high capacitance if you were using enameled (magnet)
wire. My favorite for such things is Teflon or Tefzel insulated wire
(low loss and low dielectric constant), but it is expensive and hard
to find. Another good, but hard to find insulation is polyethylene.
It is sometimes used in low capacitance, data grade cables, but
stripping out enough for this project would be a career.

Do you think it is practical to pull 6 more turns through your pipe?

It is possible .... I'll look for some time ...
I have the right tools ..

--
een appeltje te schillen met http://applefaulty.be
http://users.fulladsl.be/spb13810/bwnl.htm
Breng je iMac G5 terug (ik wil binnen 2 jaar geen defecte 2de hands Apple kopen)
http://www.apple.com/nl/support/imac...ensionprogram/