general hardware questions

[thrival57]

Hi,

I'm new to this Ham Radio Forum and not experienced with ham radio yet, I hope I don't offend any old-timers
who no doubt have their hardware preferences. So here's my impertinent question: Has anyone
to date come up with a HAM radio sound card or software that I could simply install to convert
my desktop PC or laptop into a transmitter/receiver station? It seems simple enough in theory,
most computers have sufficient frequency capability, I've found frequency generator software
that could conceivably work for tuning. And power supply output would seem more than adequate.
Just adding a card or downloading a program would make HAM accessable to a lot more people by
lowering the learning curve. And it could even open up the idea of a truly gate-keeper free
internet.

Of course antennaes are another issue, again I'm speaking from ignorance here, but Tesla claimed
that his coils emitted a non-hertzian wave (which for sake of simplicity I'll just call electro-
static) that he said, have the potential for an unlimited number of discreet, private frequencies;
in other words a radio station transmitting from a tesla coil / antennae. Has anyone done experiments
in that direction?

 

[Ham4CW]

Hi thrival,

Has anyone to date come up with a HAM radio sound card or software that I could simply install to convert
my desktop PC or laptop into a transmitter/receiver station?

Yes and no. Most sound cards only run up to about 22khz, some really high-end ones go to maybe 44khz or so, but neither of these will have an output frequency that would be of any use directly.

They can be used for monitoring naturally occurring VLF phenomena such as 'tweeks', 'shrieks', and 'whistlers' etc, here's a website to get you going: http://www.auroralchorus.com/bbb4rx3.htm

There are some kits available that allow the output from the sound card to be converted up to more usable radio frequencies made by SoftRock SDR. An eham review can be found here: http://www.eham.net/reviews/detail/7134

Just adding a card or downloading a program would make HAM accessible to a lot more people by
lowering the learning curve.

These days it couldn't be simpler. Just hand over your cash and walk away with a full-blown all band all mode transceiver. The exams are minimal (for the novice grades anyhow). Any less learning and it would be called Citizens Band Radio

And it could even open up the idea of a truly gate-keeper free
internet.

Not too sure what you mean by that comment?

Of course antennaes are another issue, again I'm speaking from ignorance here, but Tesla claimed
that his coils emitted a non-hertzian wave (which for sake of simplicity I'll just call electro-
static) that he said, have the potential for an unlimited number of discreet, private frequencies;
in other words a radio station transmitting from a tesla coil / antennae. Has anyone done experiments
in that direction?

A number of experimenters have worked on electrostatic systems over the years, and they do work, but only over a limited range. The electrostatic field decays with the cube of the distance (as does the magnetic field from induction systems), whereas electromagnetic waves obey the inverse square law. In a nutshell you can go a whole lot further with electromagnetic systems than you can with either electrostatic or inductive transmission systems.

You mention that Tesla said that his system has "the potential for an unlimited number of discreet, private frequencies". In modern language we call that tuning.

A number of Radio Hams have fooled around with what they call 'Tesla antennas', which at first site appear to be totally alien to the average amateurs' eyes, but upon closer inspection (and with a little re-drawing of fanciful diagrams), we find that they are little more than a lumped inductance with a large top loading capacity hat. No magic, just easily explainable physics.

73, Mark.