Experimenting with the vmh3cs transmitter

[6666]

What was the black material in the jar ?

[6666]

With the little white coil you were useing, was it shielded ? were did you connect the shield ? thanks

[Altra]

Great work Altra, well done.

Thanks!

[Altra]

With the little white coil you were useing, was it shielded ? were did you connect the shield ? thanks

Yes the coil (8in) is shielded. The bare coil is held with polypropylene spiral wrap and then shielded with Scotch 3m #24 tape. The coil shield wire is connected to the RG-58 shield. This method I learned from BBsailors article and some of Eric's posts. see photo of a similar winding.


The bottle is full black sand, it came from a Florida beach after a storm exposed the layer. Not sure of it's composition, but causes problems for beach hunters. It is probably weak compared to real black sand found in gold deposits?

[Orbit]

Yes the coil (8in) is shielded. The bare coil is held with polypropylene spiral wrap and then shielded with Scotch 3m #24 tape. The coil shield wire is connected to the RG-58 shield. This method I learned from BBsailors article and some of Eric's posts. see photo of a similar winding.


The bottle is full black sand, it came from a Florida beach after a storm exposed the layer. Not sure of it's composition, but causes problems for beach hunters. It is probably weak compared to real black sand found in gold deposits?

[Ferric Toes]

Yes the coil (8in) is shielded. The bare coil is held with polypropylene spiral wrap and then shielded with Scotch 3m #24 tape. The coil shield wire is connected to the RG-58 shield. This method I learned from BBsailors article and some of Eric's posts. see photo of a similar winding.


The bottle is full black sand, it came from a Florida beach after a storm exposed the layer. Not sure of it's composition, but causes problems for beach hunters. It is probably weak compared to real black sand found in gold deposits?

I have about 5lbs of black sand from California. It is composed of Magnetite grains. It has very strong magnetic susceptibility, but weak viscosity. Rather like the 'soft' ferrites that can be used as a core for PI probes. Australian ironstone is rather different as it contains a mineral called Maghemite that has both high susceptibility and high viscosity. Volcanic lavas often have high viscosity, as do soils derived from such rocks. Such a soils can be found at Red Hill, Virginia. I have some here that I use for testing ground balance as well as the Oz ironstone. Try a red fired house brick as these often exhibit strong viscosity as the heat of firing converts the magnetite to hematite. It is strange that there is black sand in Florida as I thought it is mainly coral sand.

Great videos on YouTube. Also great to see that when interest is focused on development, tidying up is not an option. I will have to show my wife who often chides me about my workshop. The cover on this book alway made me feel good.



Eric.

[KingJL]

... I will have to show my wife who often chides me about my workshop...

... and, in my case, the kitchen table and center island!

[Altra]

I have about 5lbs of black sand from California. It is composed of Magnetite grains. It has very strong magnetic susceptibility, but weak viscosity. Rather like the 'soft' ferrites that can be used as a core for PI probes. Australian ironstone is rather different as it contains a mineral called Maghemite that has both high susceptibility and high viscosity. Volcanic lavas often have high viscosity, as do soils derived from such rocks. Such a soils can be found at Red Hill, Virginia. I have some here that I use for testing ground balance as well as the Oz ironstone. Try a red fired house brick as these often exhibit strong viscosity as the heat of firing converts the magnetite to hematite. It is strange that there is black sand in Florida as I thought it is mainly coral sand.

Great videos on YouTube. Also great to see that when interest is focused on development, tidying up is not an option. I will have to show my wife who often chides me about my workshop. The cover on this book alway made me feel good.

[ATTACH]48690[/ATTACH]

Eric.

Hi Eric,

Guilty of a messy workbench. I use to receive a news letter from National Semi years ago. One of my favorite parts of that news letter was called "Pease Porridge" a column written by Bob Pease. When Bob passed away someone posted a picture of his main bench it was three layers deep. It made me feel normal.

Florida is a limestone coral formation. I looked into the iron oxide layer in the past. One theory I recall and will try to find again claimed African dust. Every summer Sahara dust storms carry across the Atlantic and settle over the Carribian and Florida. Over 10s of thousand of years it accumulates and settles to the hardpan. South Florida well water in places has iron problems. I will try to track down the history. Here is a news article highlighting the well problem.

https://www.sun-sentinel.com/news/fl...706-story.html

Add: What do think about this as a test material?

https://www.ebay.com/itm/10-lb-Red-I...5.c10#viTabs_0

[6666]

Yes the coil (8in) is shielded.

Hi Altra thanks for that info there is another small question but my internet is about to drop out, cheers.

[ivconic]

Explore the space Eric!
If there is any comfort in this:

[ivconic]

BTW great job Altra!
Although i would agree with Davor.
It creeps me out when see such transformers.
Trauma from radio days!
Great way to protect your work from copying btw!

[eclipse]

My thought as well for the transformers. There must be a better way of achieving this with discrete mosfet drivers, has anyone looked into that?

[dbanner]

I can suggest a push pull topology to drive the mosfet. Winding toroids ain't my idea of a fun Sunday.

[ivconic]

I can suggest a push pull topology to drive the mosfet. Winding toroids ain't my idea of a fun Sunday.

Winding is the easiest part of a story.
Question is in proper type of toroids and wire.
Various toroids are having various permeability.
Also the most closest wire specs to one used by initial author.
That has been always the headache.

[dbanner]

Winding is the easiest part of a story.
Question is in proper type of toroids and wire.
Various toroids are having various permeability.
Also the most closest wire specs to one used by initial author.
That has been always the headache.

Sure, so many parameters to be considered, requiring hours upon hours of tests. But once it is gotten right, then it will be great.
Problem is that this method is not easily transferrable to another DIY'er, because another man must source correct toroid, correct wire size and correct spacings of windings and then scratch his head when inductances and performance don't match the other guy's toroid.

This is what is known as "one man's toroid is another man's hell!"