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Post by mark on Oct 22, 2016 16:36:56 GMT
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Post by thelegacy on Oct 25, 2016 21:50:27 GMT
It was very interesting when it was posted on part15(dot)us as it made me think of the moral issues of an Album Rock station transmitting in Mono to get more range. However AM would be mono for most folks unless they are in a GM car with a Radio that has AM Stereo.
If it made the difference between getting to the Deltaville market parking lot when you turn to it (with the experimental license) or not I'd probably go for it. I know however it takes quite a bit of power to do this indoors even near a window.
We know it takes 832,000 uV/M at 3 meters to get that mile or two range on FM. That being said we know that the Stereo generator does create some noise. I suppose we'll have to find out one day.
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Post by Druid Hills Radio on Dec 14, 2016 14:24:29 GMT
Thanks for this post Mark. Our LPFM (WLSL-LP) is broadcasting in stereo. Most of the material is in stereo particularly music. When one is in the 60 dBuV contour the separation is easily detectable. Admittedly the talk content is mono so there is no advantage of transmitting in stereo when these programs are aired. I think during the break here at work I might experiment transmitting in mono to see what benefits if any exist. Anyone else have any experiences to share? |
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Post by Deleted on Dec 14, 2016 16:17:44 GMT
Something to Share
During the 1980s I was involved with a 12,500 Watt FM which had never upgraded to stereo, and this was financially good because the equalized 5-mile telephone line was expensive enough each month.
Our engineering team and I agreed that the audio fidelity was noticeably better then our stereo neighbors in the high frequency audio range where tinkling bells, cymbals and whatnot sounded more present. Also, our far distant listeners seemed to indicate that the station's range was virtually equal to the 100,000 Watt stations.
Stereo FM rolls off the audio about 15 kHz so it will not cut into the 19 kHz pilot-tone, and we suspect that the roll-off kills upper audio harmonics which ears seemingly detect.
The experience is admittedly subjective and anecdotal.
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Post by Druid Hills Radio on Dec 15, 2016 13:36:02 GMT
Something to ShareDuring the 1980s I was involved with a 12,500 Watt FM which had never upgraded to stereo, and this was financially good because the equalized 5-mile telephone line was expensive enough each month. Our engineering team and I agreed that the audio fidelity was noticeably better then our stereo neighbors in the high frequency audio range where tinkling bells, cymbals and whatnot sounded more present. Also, our far distant listeners seemed to indicate that the station's range was virtually equal to the 100,000 Watt stations. Stereo FM rolls off the audio about 15 kHz so it will not cut into the 19 kHz pilot-tone, and we suspect that the roll-off kills upper audio harmonics which ears seemingly detect. The experience is admittedly subjective and anecdotal. Thanks Carl. With regard to the 15 kHz brick wall filter, that's probably going to still be in place even when in mono. I will have to look at the transmitter schematic to verify. We are using a Nicom NT 250 transmitter. |
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Post by mighty1650 on Dec 16, 2016 15:35:25 GMT
My experience puts FM Mono ahead of FM Stereo as far as range goes, Stereo kicks up the noise floor. The FM Translator at the Full-Power runs in mono and easily has double the coverage compared to other stereo translators in the area.
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Post by Deleted on Dec 16, 2016 19:49:26 GMT
Which Reminds Me
Some low power FM transmitters provide no way to turn-off the stereo circuitry, and this is a disappointment.
Both the C.Crane FM 1 & 2 are stereo only with no choice.
Our Wholehouse 2.0 does have a stereo selector with no description of what actually switches off... the stereo generator? The pilot tone? The brick-wall filter? Also, although certified, the model spits out a lot of spurious signals.
Ramsey's FM25B and FM30B have stereo defeat but unknown is how much of it gets bypassed.
Good area for further study.
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Post by mighty1650 on Dec 16, 2016 21:10:03 GMT
As long as you kill the pilot the radio will decode in Mono.
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Post by Deleted on Dec 16, 2016 22:54:42 GMT
Mono FM With Power Cranked Up
As long as I was driving on the street I set the Ramsey FM30b for Max Power in Mono with its 30" telescopic antenna located in the center of our indoors.
It was rock solid to about 800' then got decent but spotty to 1,000'.
The area covered is so insignificant I am declaring it to be nothing important.
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Post by mighty1650 on Dec 18, 2016 20:26:23 GMT
Something to note, a car FM radio will automatically blend to mono as the signal geats weaker. You might not notice a difference between mono and stereo operation.
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Post by mark on Dec 18, 2016 23:46:52 GMT
One thing to remember is any receiver/radio is way more sensitive in mono than stereo and the receiver sensitivity is just as much important to range as the transmitter power.
Mark
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