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Superconducting Ant

Synchronicity said:
It seems like decades.
Has anyone made a superconducting television antenna?
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I don't think so, but I can't imagine any possible benefit (except *maybe* on high power transmitting antennae where power loss to heat might count, but then the major losses are in the feedline). Do you know of any benefits that would be worth the trouble?

When I saw the subject, I visualized small hive-dwelling arthropods in liquid nitrogen. :)

Dave
 
Re: Re: Superconducting Ant

CaveDave said:
Do you know of any benefits that would be worth the trouble?
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Well, I remember reading in pop sci or pop electronics that a golf ball
sized antenna could pick up stations 500 miles away as if they were
local, but that was alomst a decade ago. Can't find a thing on the web.
 
Re: Re: Superconducting Ant

CaveDave said:
I don't think so, but I can't imagine any possible benefit (except *maybe* on high power transmitting antennae where power loss to heat might count, but then the major losses are in the feedline). Do you know of any benefits that would be worth the trouble?

When I saw the subject, I visualized small hive-dwelling arthropods in liquid nitrogen. :)

Dave
Click to expand...

I was thinking they had discovered an ant with superconductive properties.

We need to have a rule against misleading thread titles! :)
 
I too was looking for a story about ants.

As to this topic I suspect that it is the result of some garbled understanding of the idea that some receivers have components that are cooled to reduce thermal noise.

I don't know much about this but the idea but I think it is unlikely to apply to normal antennas where all sorts of interference would swamp out any interference from the thermal noise in the receiver or the antenna.

The key to getting long range from antennas is to increase their gain, which is really a measurment of their directionality. The more gain the antenna has (meaning the more directional) the less the desired signal is affected by interference from signals not in line with the desired source signal.

MRC_Hans might have something interesting to say about this but unless he happens to have an interest in super cooled ants I suspect he's not going to read this thread.
 
Re: Re: Re: Superconducting Ant

Synchronicity said:
Well, I remember reading in pop sci or pop electronics that a golf ball
sized antenna could pick up stations 500 miles away as if they were
local, but that was alomst a decade ago. Can't find a thing on the web.
Click to expand...
I sure would like to read that if you can find it.
I've always labored under the belief that alignment of polarization and resonance of the element lengths at the frequency(s) of interrest were more important than absolute conductivity, but I'll listen to reason. :)

Dave
 
davefoc said:
I too was looking for a story about ants.

*snip*

MRC_Hans might have something interesting to say about this but unless he happens to have an interest in super cooled ants I suspect he's not going to read this thread.
Click to expand...
OH, I think insects are quite interesting. Especially if they turn out to be superconductive ;).

OK, superconducting antennas.....

Now, as already noted, conductive loss is a relatively unimportant parameter in antennas, especially for reception. Superconducting materials do offer some advantages, however.

First of all, they are free of noise. This is because the thermal noise from any conductor is a result of its resistivity. The main source of noise in a receiving system is not from the antenna, but if you are really optimizing, everything counts, of course. The reason for this is that the theoritical limit to how weak signals you can receive is not a question of amplification (you could build an amplifier with virtually unlimited gain), it is a question of noise floor. If your signal is too deep into the noise, it is unresolvable, so you will want to eliminate what noise sources you can.

Another, but related issue is tuned circuit losses. The more loss-free you can make tuned circuits, the better you can make them, and the better you can select the wanted signal within the noise. Unfortunately, this comes at the cost of bandwidth, and in fact the bandwidths used and needed in virtually all kinds of radio communication can easily be obtained using conventional methods.

So, to sum up, till such time as ambient temperature superconductors become easily and cheaply available, I doubt that superconducting antenna material is interesting except for the most exotic applications, like deep-space exploration and possibly some militaty stuff.

As for picking up signals 500 miles away, this is mainly a question of wavelength and line of sight. In the short-wave bands, we can pick up signals from all over the planet, in the VHF and higher, the line-of sight rule applies, so no antenna will change that.

Hans
 
The only thing to do with misleading threads is to reply as if you didn't read the initial post and post anyway.

So. ..

If the ant were superconductive it would act as a mirror to any magnet that was brought near it. These guys might act like tiny magnets, there magnatism being induced by the Earth's field. If that isn't enough to make them float of into space (to colonise the moon) as water is diamagnetic, they might be able to skim across the surface and conqure the world.

The only problem is that all your fellow ants would be repulsive.

Let's hope this never happens.

O.
;)
 
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