FBCS-Series, A Lighter Touch--Zero Input Power

[retrod]

I am wondering if maybe, just maybe the 1.43mhz wave you are seeing could be a local AM broadcast station (1430khz = 1.43mhz). Have you tried to demodulate the signal by attaching an audio amp to listen, or checked your local spectrum with a radio?
Just a thought,

RD

[Spherenot]

That?s the velocity in free space though.(it will be to long)
You want to compensate for velocity running through wire,,

Try Google search for ?antenna calculator?
And don?t be surprised that different  calculators give different numbers.

I should have looked into this before I built pancake number two last night,? and this morning.

Yes I did it. All 172 feet of it using 30 gauge enamel-coated magnet wire.

I fixed a broom to the garage wall and a large C-clamp to the workbench last night at a measured distance of 21 feet 7.5 inches apart.  I looped the wire around the broom and the clamp 8 times, for a total of 173 feet.  (I wanted an extra foot to give me more options in cleaning-up the final connections.)  I cut this in half as I wound each half on it's own spool.

I fixed the spools on a axle overhead.  It did not feel right; the wires would be pulling up.  So, I fixed the spools to my right instead.  Much better.  (But, as I learned later, they were too far away.  The wires coiled off the spools and acted like springs.  They would pull the freshly laid wires up over the pancake-coil before the super-glue had time to dry.)

I carefully arranged and taped my central lead wires on the back, (with hub ridge,) of a clear CD, through the hole.  I flip over the disk, uncrossing the wires that lead to each spool, as planned, and pat myself on the back.

I took a deep breath before starting to wind and noticed how much wire was on them spools.  I looked at the CD.  I looked at the spools again.  Hmm, I never did calculate how much radius I would need for this trick.  I was assuming that skinny-ass 30 gauge wire would fit.  Calculation showed?

I needed another 5.7 mm radius on the CD.  Whew!  I was sure glad I ran that calculation before I cracked open that glue.

My Easter-egg hunt for a replacement yielded only paper plates.  (There goes my naming convention.)  I found the center and drilled thru four plates.  I epoxied a laminate of two plates with weights to maintain flatness and rigidity.  I used the other two plates underneath for extra support during assembly.

I threw together a quick fixture with six-too many screws I thought I would need for 'hold down wires' crisscrossing over the growing pancake.  I ended up not trying this feature fearing the glue would stick to these wires.  But, three of the screws came in handy for other fixturing methods later on.

Two screws were reused as spool posts when I moved the spools to the fixture to reduce that annoying spring action I was getting while winding.  This worked.

I fixed a magnet and two washers to a third screw to guide the wires from the spools, which were further away, to the edge of the plate surface.  Later, I used one wire between screws to hold the wire closer to the plate surface.  Blah, blah, blah about the fixture.  (Photos included.)

Anyway, I went to bed this morning at 4:30 AM.  Pancake half wound.  Up again at 9:00 AM winding.  Finished.  Seven hours just winding with a chopstick and superglue.

My right eye is blurry.  It may have received too many super-clue vapors.  Yes, this makes typing difficult.  My body hurts.

"Uncle,"? for now.

[Spherenot]

I am wondering if maybe, just maybe the 1.43mhz wave you are seeing could be a local AM broadcast station (1430khz = 1.43mhz). Have you tried to demodulate the signal by attaching an audio amp to listen, or checked your local spectrum with a radio?
Just a thought,

RD

1460 kHz and 1480 kHz are strong stations around here.  Do you think that one or both of these is the source of the sine wave?

When I tune to 1430 kHz I hear a faint blending of many stations.

How do I demodulate the signal by attaching an audio amp to listen?

I just got my scope.  Maybe all I did was make an antenna.

Can someone please show us how to do just that; make a simple antenna for an oscilloscope so we can "see" an AM radio broadcast?

[retrod]

 Attached is a schematic of a simple crystal radio. The diode is a 1N34. Lets say you don't need the cap or external antenna because you are making a coil tuned to the precise frequency. The speaker shown is normally a high impedance crystal earphone.  As you can see the simple set needs no other energy to operate, it comes from the stations transmitter. I think you can attach an audio amp in place of the crystal earphone as a test to hear the signal. I have heard of crystal sets being built with large inductors that can actually light an LED when tuned to a carrier, I have not seen this in person or know of a schematic on-line. It would be a neat trick if it could be accomplished.

RD

[MeggerMan]

Hi Spherenot,
Very impressive winding that many turns onto the back of a paper plate!

Try your scope on some of the lower frequency settings.
I think it may have been 1ms/div.
I saw what looked like a train of square blocks of two different sizes.

I think you could use some ordinary CDs as the variable capacitor, just slide them in and out across the windings to increase/decrease the capacitance.
Or make and air spaced variable capacitor from some sheets of 0.4 - 1mm aluminium, bolts + washers or spacers.
Even some copper clad board would work.

Then you need a signal diode as shown in the diagram.

Using a set of PC speakers with a built in amp should work to amplify the output enough, certainly my Logitech speakers give off a loud mains hum if you unplug then from the sound card and touch the 3.5mm jack plug.

You may need to check you have any wifi kit turned off too.

Regards
Rob