Carl Blare

Welcoming Pleasant Gap Community Radio to this forum, recently introduced.

This statement appeared on the Introductory Entry from PGCR

Welcoming Pleasant Gap Community Radio to this forum, recently introduced.

This statement appeared on the Introductory Entry from PGCR

PGCR operates at 87.5 Mhz in compliance with the forthcoming changes to Part 15 rules, pursuant to FCC R&O/FNPRM 10-16, utilizing a Comtek BST-25 transmitter.

I don’t think we’ve head a notice posted here about the forthcoming changes. Can anyone provide this information?

In his Radio Engineering Blog for May 18

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

In his Radio Engineering Blog for May 18

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

Paul Thurst questions how radio stations plan to handle the end of the world, which will happen Saturday in Time-Zone increments.

A few members enjoyed hearing some of my “Blare OnAir” programs on part 15 topics, and I’ve just found three shows from 2007 that go into depth about the History of TV Channel 14, part of a discussion of the TV Genie, a low power UHF transmitter from years past.

Back then I called the show “Adventures in the 3rd Dementia.”

To hear them on demand select KDX3 at this link

http://kdxradio.com/demand.html

They are also available as downloadable mp3 files

http://kdxradio.com/archive.html

The program dates are Oct. 3, 4 and 6, 2007 (3 – files)

I will post the link to my working version of TalkingPixie2 V1.0 shortwave transmitter which was discussed at great length in a previous thread, during the time I got the audio to modulate.

I will post the link to my working version of TalkingPixie2 V1.0 shortwave transmitter which was discussed at great length in a previous thread, during the time I got the audio to modulate.

http://www.kdxradio.com/pixie2.html

I wish to ask opinions about one very specific portion of this circuit, namely R3 and R5.

In my first working transmitter, Qr (2N222A) was inadvertently damaged, and I replaced it with a part from the junk box, GE-20 (Phillips ECG 123A). This change of transistor caused the modulation to drop to almost nothing, but I found that making R3 = 6.8k and R5 = 10k the full modulation returned.

The question I am asking now, is, what are R3 and R5 doing which so critically matters with regard to the modulation working correctly?

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Get your Quartz Crystals, Including 13.56 MHz for Short Wave and 1.0 MHz for Medium Wave – click here for a full selection!

IT ALL BEGAN about half a hour ago when 1680 AM was turned off for the day. For awhile there was ordinary far away background noise, but suddenly, with a noticeable “on” burst I was hearing a hash noise, just like digital stream noise, with steady buzz over-laid by bursts and dips. The other day, in a different location, I reported on something similar coming on the car radio at 1680.

Thinking I could see a signal level or get an idea if the noise went up above the AM band I clicked on the Alinco communications radio, and when I got up to 1700kHz I heard a very pleasant violin recital on a frequency normally belonging to a far away sports station. Trying two other radios, I clearly heard sports on 1700kHz.

At almost 9 PM I got an idea and tried 850kHz and there was the violin music, the station there is on late during May and would sign off at 9 PM. I had been hearing their 2nd harmonic.

But it is still strange, because the other two radios could not hear the violin music, and were only able to receive the far away sports.

One last note, the 2nd harmonic from 850kHz is usually a suppressed buzz and the audio tends to be very suppressed.

Odd stuff. The computer-like noise must have stopped.

Driving to the store starts with 1680 AM (Part 15) clearly on the dashboard, until a block later it fades to background.

Driving to the store starts with 1680 AM (Part 15) clearly on the dashboard, until a block later it fades to background.

Along the way different hums and buzzes come and go at 1680, some probably from power transformers, but others sound hash-like, the way a raw digital signal would sound. After all, the phone company uses AM radio frequencies and higher for their DSL service, so it is reasonable to imagine that some of this gets radiated into the air. Of course the chunk at 1680 would only be a small bit of DSL’s total bandwidth, but interesting to contemplate.