Carl Blare

Part of the fun of Part 15 is to design locations for locating the transmitter and the antenna. But those thoughts can become very puzzling when two many ideas collide with each other.

Part of the fun of Part 15 is to design locations for locating the transmitter and the antenna. But those thoughts can become very puzzling when two many ideas collide with each other.

One the one hand, it would be nice to have all the transmitters indoors where they’d be safe from the weather and easy to work on. But indoor antennas and grounding are not the best solution as we often talk about. And in the rare event of an FCC visit who would want them in the house?

If outdoors, on the other hand, it would be neat to have all the Part 15 facilities in one location attached to one tower or chimney, but maintenance would become a large problem with many inconveniences, and some types cannot be mounted close together, such as two AM sticks on nearby frequencies. They would need to be many meters apart. But the handiness for an inspection is an appealing facet of an outdoor system.

On the third hand, SW and FM transmitters can be connected to transmission line coax, so the transmitters could be indoors and the antennas outdoors…..

We’ve run out of hands.

As a longtime user of the Winamp Playlist method of radio programming I still do not understand what would be better about a “professional” program sequencer.

As a longtime user of the Winamp Playlist method of radio programming I still do not understand what would be better about a “professional” program sequencer.

SAM Broadcaster is being offered right now at a discount through Shoutcast, so I hope these questions have answers that can help me decide what to do.

IF a program is in progress but the clock indicates it’s time to start the next program, what if the program in progress is running late? Will SAM just cut it off?

WHAT IF a long program with built in commercials reaches a point where I want to drop in my own spots and then return to the original long program without stopping it and re-starting it at the beginning, is that possible?

TWO complex questions…..

The temperature was 107-degrees in McKinney, Texas, but The Crow was very cool on The Low Power Hour.

Listen on demand on KDX4 at

http://www.kdxradio.com/demand.html

The temperature was 107-degrees in McKinney, Texas, but The Crow was very cool on The Low Power Hour.

Listen on demand on KDX4 at

http://www.kdxradio.com/demand.html

Download the audiofile from

http://www.kdxradio.com/lph.html

The most often quoted FCC Rule for AM broadcasting is 15.219, with the familiar guidelines of “3-meter antenna, etc., and 100mW to final amp…”

The most often quoted FCC Rule for AM broadcasting is 15.219, with the familiar guidelines of “3-meter antenna, etc., and 100mW to final amp…”

But every once in awhile someone mentions “the alternate rule, based on field strength measurement.”

That alternate Rule is 15.209, with this regulation:
Frequency Band .490 to 1.705 24,000mV/F(kHz) at 30-meters (about 100-feet).

For AM transmitters located INDOORS there is an extra layer of filtering that just might allow MORE than a 3-meter antenna or MORE than 100mW to the final amp…

That extra filter is the HOUSE. The house is made from construction materials consisting of wood, bricks, plaster and some metal. Therefore the house should be part of anyone’s radiation study to see what the power will look like at the edge of the property, right around 100-feet away.

How can we build a chart showing predicted attenuation figures for different kinds of houses?

A “eureka moment” was finally reached when today I finally grasped (I hope) how INPUT TO THE FINAL STAGE is calculated.

A “eureka moment” was finally reached when today I finally grasped (I hope) how INPUT TO THE FINAL STAGE is calculated.

As everyone knows, the limit for Part 15 AM broadcast is that “No more than 100mW may be input to the Final RF Amplifier Stage.”

Here is the simple (but wrong) way I saw it.

Suppose you had a loudspeaker and some rule stated, “The input to the speaker may not exceed 10-Watts.” Well, all you would do is get a 10-Watt audio amplifier and things would be fine.

Therefore, in radio, I figured you’d get a transmitter whose 2nd-to-the-last-stage, also called “the buffer,” would have an OUTPUT power of 100mW, which would then go to the Final Stage Input. It’s so simple.

But that’s not the way it is there in reality, where everyone else lives. The actual formula is clearly explained in a July 30, 2011 posting from Radio8Z titled “POWER INPUT,” over on the Big Talker thread.

Take care because an earlier posting has the same title.

For now the KDX schedule matches my personal endurance as a listener, usually about 9-hours a day. But the radio beast tends to expand so I am considering adding more hours.

For now the KDX schedule matches my personal endurance as a listener, usually about 9-hours a day. But the radio beast tends to expand so I am considering adding more hours.

However, I worry that running the hard-drive so constantly will wear it out, and it contains tons of audio-files. Sure we try to keep everything backed up, but it seems that a non-mechanical way of streaming would be the smartest thing of all.

An SSD, solid-state-drive, would fill the bill by providing a “no moving parts” solution to streaming. But there’s a catch.

According to PC Mag the XP O.S. is not suitable to SSD performance because it lacks TRIM software, which keeps the SSD from becoming too disorganized… probably the solid state equivalent of de-fragmenting.

Economically it would probably cost more to purchase Vista and an SSD than to simply buy another hard-drive.

Good reason to be undecided.