Carl Blare

It’s chilly out there, and dark, but I went out to study the antenna system mounted on my auto. There is a whip antenna 28″ in length which cannot be telescoped to any other length, mounted at the front center of the roof right at the front windshield and laying back at about a 33-degree angle.

Right at the foot of the antenna, embedded in the windshield, is a fine mesh about 1.5′ wide X 2.5″ vertical, which I assume is part of an embedded antenna.

The rear window has horizontal wires embedded in the window about 1.5″ apart, which I assume are heating elements.

What do you know about embedded (surface mount) antennas?

IMPORTANT EXPLANATION – Now that I think about it ALL antennas are “surface mounted,” so let me explain what I am talking about here…… a “flat” mount antenna that lays flat on the surface and does not protrude; an antenna that in essence IS the surface, or is part of the surface.

Think PZM microphone. “Pressure Zone.”

EDITOR FOUND SOMETHING: I did a quick search and found reference to Fresnel Zone Antennas. Look at this interesting clue from the Wikipedia item:

An offset Fresnel zoneplate can be flush mounted to the wall or roof of a building, printed on a window, or made conformal to the body of a vehicle.

The transmission line or lead-in wire for a 3-meter antenna is part of the measurement. That always needs to be said as a kind of “pledge of allegiance” to the rules. Having established that fact, what approach is best for a lead-in or transmission line…. an open wire or a shielded line ?

In the first tests comparing our AMT3000 with the new AMT5000 we discovered that the AMT5000 out performs the AMT3000, but we also recognized that our methods needed better organization. These are the New Formal Tests.

Test Date / Time / Temp: Monday October 17, 2011 Between 11 AM and 12 Noon, Farenheit Lower 50s;

AMT3000 received with grade A signal to a point 435 feet from transmitter;

AMT5000 received with grade A signal to a point 643 feet from transmitter;

The auto radio followed a straight line street in front of neighborhood housing;

The same antenna was used for both transmitters, located in the rear of the house, therefore the received signals came from back behind the buildings, not line of sight;

The transmitters were located indoors on an extended window sill 21″ above the floor, grounded to a single long heavy gauge copper wire that exits the house at ground level and is buried in a southerly direction going uphill;

The RF output of the transmitters are attached to a 4.5′ aluminum window frame with indoor attached vertical wire from window to baseboard and outdoor vertical wire from top of window to overhang. Total antenna length 10′;

The AMT3000 was attached directly to the antenna array;

The AMT5000 was attached to the antenna array with a 20 pF ceramic capacitor to compensate for capacitance;

The AMT5000 was set for output to final of 99 mW.

ANECDOTAL COMMENTS: In a previous test the AMT5000 had been set to 113 mW for one trial, and to 105 mW for another, and the differences in distance were noticeable in feet.

By reasonable estimates the achievable distance would increase substantially with a well installed outdoor antenna.

CONCLUSION: The AMT5000 lives up to its Specifications and is a Professional Class Transmitter.

Another thing that is driving at my heels is a corporate business deadline coming up in a few days. I keep avoiding it because working with the new AMT5000 is much more fun, and I am pursuing happiness like I thought it was a true liberty.

But the pursuit of happiness isn’t in the Constitution. It’s only in the Declaration of Independence, which is a letter to the Kingdom of England declaring war. It’s not even addressed to us.

It’s very likely I’ll order a second AMT5000 because it is wonderful having the control over the signal it provides. Tonight I’ve reduced power at 1550 kHz to 50 mW during a program with indelicate language. Nobody can complain if they can’t get it, but I can still receive it.

The FCC language rule allowing indecent words after 10 PM but totally banning obscenity is beyond my comprehension. When I hear the more ribald personalities utter vile words, I have no clue whether the words are indecent or obscene. The notion of “community standards” is so stupid I shouldn’t have to explain why. If you call a community meeting the resultant mob will bend overboard trying to appear much holier than they really are and find the word “darn” to be offensive because it’s a stand-in for a worse word. But listen to them at a hockey game.

I feel much better now that I’ve brought my grudges to the Part 15 community. It’s one community you can trust.

This site has entertained several mentions of the Slinky Toy, a copyright of Poof Slinky, Inc., Plymouth, Michigan. The metallic Slinky has been put forward as a potential helical antenna, as a clever way to dodge a high expense.
Today I entered a dollar type store, where everything costs $5, but their slinky was plastic. Yet the young woman who helped me find it went way out of her way to serve me, while her boss was screaming for help at the register.

Second stop was K-Mart where I encountered a shopping couple in the toy aisle and asked if they’d seen a Slinky, and they allowed that they hadn’t seen one in years. The second person I came to I asked to please report to me if she saw a Slinky and she said, “I know where they are!” That’s why now I own a metallic slinky, and look forward to tinkering with it antenna wise.

If life makes sense in any way at all, it is with regard to Part 15 activity.

Last week here at Part15.us we made the suggestion that low power radio might solve the ban on bull-horns imposed over on Wall Street. Someone else had the same idea, and now Wall Street has a voice at 107.1 mHz.

I read about this on Paul Thurst’s blog, and he got the story from John Anderson’s DIY Media site.

Scroll down about two stories and read about it

http://www.engineeringradio.us/blog/