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eBay - (bazooka) Atsali

Posted: Mon May 11, 2015 7:53 pm
by MerchManDan

Re: eBay - (bazooka) Atsali

Posted: Tue May 12, 2015 8:56 am
by Catawampus
Is there some sort of a meaning behind wearing a shirt with the name of a musical instrument or rocket launcher on it?

And does that make it an anti-tank top? If so, perhaps Castela ought to be wearing a junior version thereof.

Re: eBay - (bazooka) Atsali

Posted: Tue May 12, 2015 11:05 am
by Dave
The "double bazooka" is a type of radio antenna, of a somewhat controversial nature.

Clearly, since Atsali can generate all sorts of Siren moxie power, she needs someway to radiate it! :mrgreen:

Re: eBay - (bazooka) Atsali

Posted: Tue May 12, 2015 12:33 pm
by GlytchMeister
Dave wrote:The "double bazooka" is a type of radio antenna, of a somewhat controversial nature.

Clearly, since Atsali can generate all sorts of Siren moxie power, she needs someway to radiate it! :mrgreen:
Google failed to explain why double bazooka antennae are controversial... What's up with them? How can an antenna type even be controversial?

Re: eBay - (bazooka) Atsali

Posted: Tue May 12, 2015 2:56 pm
by Leak
GlytchMeister wrote:
Dave wrote:The "double bazooka" is a type of radio antenna, of a somewhat controversial nature.

Clearly, since Atsali can generate all sorts of Siren moxie power, she needs someway to radiate it! :mrgreen:
Google failed to explain why double bazooka antennae are controversial... What's up with them? How can an antenna type even be controversial?
Think less antennae and more, uh, radiating domes...

Re: eBay - (bazooka) Atsali

Posted: Tue May 12, 2015 4:34 pm
by jwhouk
I'm old. I immediately questioned why Pablo didn't add her blowing a bubble.

Re: eBay - (bazooka) Atsali

Posted: Tue May 12, 2015 7:43 pm
by Dave
GlytchMeister wrote:
Dave wrote:The "double bazooka" is a type of radio antenna, of a somewhat controversial nature.

Clearly, since Atsali can generate all sorts of Siren moxie power, she needs someway to radiate it! :mrgreen:
Google failed to explain why double bazooka antennae are controversial... What's up with them? How can an antenna type even be controversial?
The controversy is "How well does it actually work, and why?"

Some hams like the double bazooka very much, especially for operating on the lower-frequency HF bands e.g. 3.5 - 4 MHz ("75/80 meter") and 7.0-7.3 Mhz ("40 meter"). It's not easy to find an antenna which "works well" on bands that are this "wide" (upper and lower frequencies differing by more than a few percent). Most common antennas work well over a fairly narrow frequency range - but outside that range, they become "reactive" (their electrical impedance gets wonky), and transmitters have difficulty delivering signal into them. If you use an antenna too far from its preferred "resonant" frequency, your transmitter can overheat, or start arcing... making what VW owners used to call "expensive noises".

The double bazooka antenna had/has a reputation for maintaining an "easy to drive" impedance (with a "low standing wave ratio") over an unusually broad range of frequencies. There were lots of ideas as to why, but they didn't seem to match up with electrical theory or modeling. People thought of it as somewhat of a "magic" antenna.

Some years back, somebody figured out what was really going on. With a more complete model of the antenna design, it was shown that the antenna actually has significant electrical "loss" within the antenna itself... the high currents and high voltages in the coaxial sections end up "heating up" the antenna itself. In effect, the antenna is acting as a big resistor... and these losses block some of the reactivity and make the standing wave ratio look better than it would, otherwise.

So, it turns out to be not-as-good, and not-as-magic as a lot of people had proclaimed for years. Some folks still swear by it as the best single-band antenna around, others consider it an "expensive dummy load". There's probably an element of truth to both of these attitudes. The "terminated folded dipole" antenna is popular (and scorned) for much the same reasons.

If you want to see a really controversial antenna, look up the "E/H" or "crossed-field" antenna, and the Isotron antennas.

Re: eBay - (bazooka) Atsali

Posted: Wed May 13, 2015 2:54 am
by Jabberwonky
Paul beat me to it with Bubbleicious...

But this is what I saw when I saw 'Bazooka'...
Image

A bigger and more satisfying version here...