Talking House and 540 kHz

[Bongwater]

This is probably a stupid question regarding the I.A.M./Talking House AM transmitter

I'm no Einstein at AM engineering, but here goes.....

Can you get a wider range broadcasting at a LOWER frequency (say 540) with one of these things?

I mean I'm sure if you could, everybody would be down there already instead of up between 1600-1700. But I notice all the stations down at that end of the dial have lower power but a VASTLY increased range.

Is it grounding? Some other issue?

 

[Tom Wells]

The 'way undersized antenna is the limiting factor, and at such dis-advantage, the highest frequency usable
is to be expected to get the most coverage.

You are right that for any given amount of power, the lower frequencies have a much greater coverage,
but that's with licensed stations with proper sized antennas.

Don't let that stop you from experimenting with a talking house on 540, sometimes there are
circumstances that make a specific situation work better or worse than expected.

 

[audioguy]

I second Tom's comments encouraging experimentation. However, in my experience with other Part 15 rigs, the improvement in ground conductivity at the low end of the dial was nullified by the decrease in antenna efficiency. On the other hand, if 540 is a quiet frequency in your area, you might get a usable signal farther away than on a higher frequency that has a lot of co-channel interference. The high end of the band, including the "spandex" band from 1600-1700, is pretty noisy at night in most parts of the country.

 

[rfry]

...I notice all the stations down at that end of the dial have lower power but a VASTLY increased range.

That is true for the radiated powers required by the FCC for licensed AM broadcast stations of various classes regardless of their assigned carrier frequency, but it is not true for Part 15 AM setups in functional compliance with Part 15.219(b).

The link below leads to a PDF of a short article published in the broadcast trade paper "Radio World Engineering Extra" of June 8, 2011 relating to this topic, as it applies to licensed operations.

However the lower groundwave propagation loss for lower transmit frequencies does not have the same direct benefit for operators in functional compliance with 15.219(b) as it does for licensed AM broadcast stations, because such Part 15 operators radiate much less r-f energy at those lower frequencies.

http://www.box.com/s/7skch6m2utgkgptspzki

RF

 

[druidhillsradio]

Fleeber on Fleeber. ;D

 

[Ermi Roos]

I didn't get the Fleeber remark, but fortunately there is Google. A 1990 film, "The Freshman," features a Professor Fleeber who uses his own work as required course material. If this is the allusion that was meant, it makes sense.

 

[rfry]

No finals in this "course", though, and no one is obliged to read that paper. I just thought it might be of interest.

It was noticed by the IEEE, who re-printed it in their Broadcast Technology Society Newsletter, Volume 19, Number 2 (Summer, 2011).

Maybe others could post their work on this subject, as some have done about Class E amplifiers?

RF

 

[Ermi Roos]

Class E, let it be.
You might as well just use class C!

 

[druidhillsradio]

I didn't get the Fleeber remark, but fortunately there is Google. A 1990 film, "The Freshman," features a Professor Fleeber who uses his own work as required course material. If this is the allusion that was meant, it makes sense.

BINGO! You win the house, the car and a trip to Las Vegas!