Carl Blare

Being smart takes a long time, especially when information remains hidden for so long. Just two years ago, after 40-years in broadcasting, I finally heard about “the critical hours,” a well known AM broadcast term referring to hours before sunrise and after sunset.

Now, while reading an article on R.F.I., radio frequency interference, comes the term “the fading wall.” You probably know all about it, but I didn’t.

The fading wall is the area where the AM signal reflected from the ionosphere reaches to ground.

Of course Part 15 transmitters aren’t powerful enough to reach the ionosphere, but we are affected by fading wall syndrome coming from distant stations.

What else is there to know? I don’t have the slightest idea.

Most of the AM medium wave transmitters for Part 15 low power do not use transformer modulation, with one exception being the Ramsey AM25 which has a small hand-wound transformer. But the shortwave transmitters on the blogs titled Talking Pixie2 and Big Talker got their start with a schematic that shows a small Radio Shack transformer, 8-ohms to 1K, with no stated power handling capacity. Even though that transformer does function, I checked around and found a Triad audio transformer with a rating of 1-Watt, which seemed more in line with the circuits being used. It remains to be tested.

Right now I am only interested in your point of view about low power, Part 15, modulation transformers simply as a topic of conversation.

In the adult-sized world of power radio, making a comparison, a plate modulation transformer for a 50kW station might way a ton or more.

Down here in micro-radio, what kind of power rating should a modulation transformer have?

You may have heard that tests are determining whether 60 Hz power line accuracy will be relaxed.

http://radiomagonline.com/infrastructure/power/60hz-stability-going-away-0627/

You may have heard that tests are determining whether 60 Hz power line accuracy will be relaxed.

http://radiomagonline.com/infrastructure/power/60hz-stability-going-away-0627/

How will Part 15 operation be impacted by less accurate Power frequency?

Got a really nice power transformer but have no clue how to set the primary side for 115VAC. Here’s what I mean.

Got a really nice power transformer but have no clue how to set the primary side for 115VAC. Here’s what I mean.

The primary is capable of 115 or 230 VAC. The primary side has four solder terminals with two separate windings that are not connected together.

The box the transformer came in shows only one primary winding and a picture of a totally different transformer, so it’s no help. The website at Jameco.com at least has a correct picture of the two side-by-side primary windings, but the next line says “No data sheet available.”

I have thought of two possibilities. Either I only need to drive one of the windings with 115 VAC, or the two windings need to be wired in parallel for 115 VAC.

The secondary will be 12.6 VAC when it’s working correctly.

Just hooking it up probably won’t hurt it, but I’d rather get good advice.

KDX does not subscribe to FSN (Feature Story News) because of lacking a news budget, but this morning I decided to sample the news to see how FSN was doing. The headlines or bulletin or whatever I had told of “the worst tornados in North Carolina history.” Wow, I thought. And an hour later I was telling the butheress at Save-So-Much about the bad storms in N.C.

But now I think that news was months old and the “update” I downloaded was beyond its shelf-life.

If FSN is still in business, why would they have an old newscast still posted?

I’m thinking maybe someone here is a subscriber and knows the inside deal.

Low Power Hour No. 10 is now in a dispatch mode

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

Endorsed by default by anyone who has not checked the box to un-endorse.