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Author Topic: Part 15 AM and FM  (Read 1533 times)

Offline ThaDood

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Re: Part 15 AM and FM
« Reply #15 on: April 25, 2020, 1931 UTC »
Oh yeah??? Here's mine,    https://vk.com/realfreeradio               More bitching this weekend, than anything else. The local LPFM station digs it, since it permissibly covers where they don't. And, allows me to lazy-cast.
I can't decide upon what's worst, young and stupid, or old and chemically dumbed down.

Offline Pinole Radio

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Re: Part 15 AM and FM
« Reply #16 on: April 29, 2020, 1709 UTC »
Pinole Community Radio AM1610 on the air for 4 years 24/7 with Jazz, Blues, Vintage Country, Bluegrass, & Oldies. And of course all the important stuff that entails the city of Pinole, Ca. Our distance is pretty good. 1 1/2 miles with a Procaster.

https://www.facebook.com/pinolecommunityradio/

« Last Edit: May 02, 2020, 1939 UTC by Pinole Radio »

Offline chanito

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Re: Part 15 AM and FM
« Reply #17 on: May 02, 2020, 1915 UTC »
What is "pretty good" distance?
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Offline Dave Richards

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Re: Part 15 AM and FM
« Reply #18 on: May 02, 2020, 2016 UTC »
Pinole Community Radio AM1610 on the air for 4 years 24/7 with Jazz, Blues, Vintage Country, Bluegrass, & Oldies. And of course all the important stuff that entails the city of Pinole, Ca. Our distance is pretty good with a Procaster.

https://www.facebook.com/pinolecommunityradio/

I can testify that Pinole Community Radio has quite respectable coverage for a Part 15, and also sounds good. I drove through part of Pinole once, about a year ago, and was pleasantly surprised to be able to receive a listenable signal for the best part of a mile. The audio quality was good, the music mix very listenable, and distinctly different from everything else on the dial - either AM or FM.
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Offline chanito

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Re: Part 15 AM and FM
« Reply #19 on: May 03, 2020, 1541 UTC »
Pinole Community Radio AM1610 on the air for 4 years 24/7 with Jazz, Blues, Vintage Country, Bluegrass, & Oldies. And of course all the important stuff that entails the city of Pinole, Ca. Our distance is pretty good. 1 1/2 miles with a Procaster.

https://www.facebook.com/pinolecommunityradio/


How do you have the Procaster set up? Just curious about grounding, etc.
PCR-1000, PCR-1500, RSP1A, RSP1, VR-120D, HDT-1, Accurian HD, Royal 3000
Caras HF-315, Belar LP-1A, SuperAntenna MP-1, RatShack 20-043 discone, MLA-30, 100' wire

Offline Azimuth Coordinator

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Re: Part 15 AM and FM
« Reply #20 on: May 27, 2020, 1858 UTC »
QTH: A Clandestine location on the East Coast
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Offline chanito

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Re: Part 15 AM and FM
« Reply #21 on: July 21, 2020, 0245 UTC »
Processing is of paramount importance if the goal is to be equivalent to even classical music public or college stations in dial presence. While FM broadcast is fully capable of transmitting clean 30-15kHz "non-processed" stereo audio even when most listeners won't be listening on equipment capable of reproducing this range, Part 15 stations will be hard pressed to deliver a strong, quiet signal. High SNR makes it possible to transmit unprocessed audio with effectiveness. Hard to achieve over any considerable distance with a Part 15 transmitter. Great for around the yard. Problem is, if I'm listening on the Eton Mini, I have to turn it all the way up to hear all the music. With processing, it becomes a nice background mask to crickets, cars and airplanes.
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Offline Kingbear Radio

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Re: Part 15 AM and FM
« Reply #22 on: July 22, 2020, 0336 UTC »
Chanito, I've run across that issue myself on my lil' part 15 AM transmitter board, it doesn't sound as loud as other stations, unless I blast it hard into distortion. The sound is very good though I just don't think anyone will be able to hear it well and noise creeps in.

I've tried a software compressor and it works well and know about band rack compressors but I'm thinking there should be a small box that I could plug a phone into and that into the channel combiner to the transmitter, like the ALC level controls in a tape recorder would have. Not the sound pro stations have that sounds like tape being far overdriven, just something that keeps an even keel on the sound.

I was reading on a part 15 radio board that the high compression level of pro stations shouldn't be used. Once you hit a certain level, where the sound is processed, any more and the sound just loses definition and the distortion increases. I like how clear and defined the old AM stations used to be, you could hear every word in the songs!
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Offline ThaDood

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Re: Part 15 AM and FM
« Reply #23 on: July 22, 2020, 1903 UTC »
One passing contemplation here, (Not thought, as that would hurt too much.), would be to see if your AM TX is possible of even going 100% modulation. There's some cheap kits out there that struggle to do 50%, at best. Anyway to put that to an o'scope, or an off-air AM monitor VU meter, to see what a 1kHz test tone does when you vary the audio input level? Then again, just like most modern day CB's, there maybe a limiter in your TX to on purposely keep that level low, in order to boast Part #15 FCC compliance. (OK, that was a couple of contemplations.)
I can't decide upon what's worst, young and stupid, or old and chemically dumbed down.

Offline Kingbear Radio

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Re: Part 15 AM and FM
« Reply #24 on: July 23, 2020, 1630 UTC »
My transmitter probably doesn't have full modulation, and the antenna's tuning changes the audio quality too. I have heard that some transmitters have limiters in them, to keep you in your lane, audiowise. Can the circuit in a home transmitter even get as loud as the pro's?

One thing I did was use my audio editor to make shows and use the Compression and Hard Limit on a music set or program. First run it through compression to make the sound tighter, with a second pass with hard limit for a few more DB of loudness. Done right it's hard to tell it's compressed when listening, but it's louder on the air.
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Offline secretlab

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Re: Part 15 AM and FM
« Reply #25 on: July 23, 2020, 2318 UTC »
Of the Part 15 AM transmitters I've used, the Procaster and Rangemaster can take as much modulation as the processing is able to provide, up to +125% or more (100% negative.) These can be as loud as the 'pros.' The TH 5.0 I have as a backup has an internal compressor of sorts, which apparently isn't defeatable, so in that case you get what you get.

I'm now using a Schlockwood SW-200 3 band processor with my Procaster, where it's really helped the fringe area. More is better here: AM peak envelope power (PEP) is 4x carrier power at 100% modulation, and cranking up the positive modulation with a suitable processor can increase PEP even more. You get more power on the air...legally.

I do recommend the Schlockwood, which can be both loud and pleasant sounding.
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Offline Dave Richards

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Re: Part 15 AM and FM
« Reply #26 on: July 24, 2020, 1936 UTC »
I do recommend the Schlockwood, which can be both loud and pleasant sounding.

+1 for the SW200. I've been using one with my Rangemaster continuously for over 2 years now, and it has performed flawlessly. Although the front panel controls might seem a little daunting to someone who hasn't used this type of broadcast processor before, it's pretty hard to get a bad sound from this unit - as long as you don't overmodulate the transmitter, of course.

I only had one concern when the SW200 was coming onto the market. Although, IMO, it's a good deal for genuine multi-band broadcast processing, Part 15 hobbyists tend to be budget limited. I was happy the initial production run sold out, and that sales were enough to justify a second run. I do hope the SW200 will remain on the market for quite a while. However, I am never going to give up mine, as I feel it's a classic. Same goes for my Rangemaster, and even my Behringer Eurocom SPL3220 which, for ~$100, delivers a very listenable sound. Other pieces of gear may come and go, but these ones will stay with me. If I sold them, I'd just end up trying to get them back at some point - and there are very few SW200's on the used market, as there are not that many in existence to begin with.

Great piece of kit. Buy one, and hang onto it!
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