Author Topic: Which radio frequency do you like? AM or FM?  (Read 23080 times)
Cole D.
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Re: Which radio frequency do you like? AM or FM? « Reply #45 on: July 02, 2018, 10:25:51 PM » Author: Cole D.
It did on my car radio on FM once, when I was driving in a parking lot near Taco Bell. The strikes did seem to be really close by.
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lightinglover8902
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Re: Which radio frequency do you like? AM or FM? « Reply #46 on: July 03, 2018, 03:43:58 PM » Author: lightinglover8902
It did on my car radio on FM once, when I was driving in a parking lot near Taco Bell. The strikes did seem to be really close by.

Did you have the FM radio on static? Also theres going to be storms in my area in the evening, so I might try it. ;)
« Last Edit: July 03, 2018, 03:45:46 PM by lightinglover8902 » Logged

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Cole D.
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Re: Which radio frequency do you like? AM or FM? « Reply #47 on: July 04, 2018, 07:57:51 AM » Author: Cole D.
I was actually tuned to a strong station when I heard it.
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lightinglover8902
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Re: Which radio frequency do you like? AM or FM? « Reply #48 on: July 04, 2018, 11:25:43 PM » Author: lightinglover8902
Hmm, yeah so basically it disrupts the signal when a lightning bolt hits near by. But seriously, I might try it but, it has to be a very close lightning bolt.
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Medved
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Re: Which radio frequency do you like? AM or FM? « Reply #49 on: July 05, 2018, 10:16:47 AM » Author: Medved
Hmm, yeah so basically it disrupts the signal when a lightning bolt hits near by. But seriously, I might try it but, it has to be a very close lightning bolt.

I don't think it really disrupts the signal, the lightning does not reach that high in the frequencies, plus the FM being inherently strong against disturbance (the in-band disturbance would have to be higher than signal-10dB in order to cause just marginal effect).
But it may quite easily overload the radio input stage by its strong out-of-band energy (many FM sets are designed really poorly when it comes to robustness against strong interferers in the 1..30MHz range overloading the input), so the radio becomes "deaf" for some time (for the disturbance duration, so some 10's us, enough to cause a hearable crack).
The most common error is the antenna input being just capacitively coupled to the input transistor, so more than ~30mV on any out of band frequency causes first many stations becoming mirrored across the whole FM dial range and then with higher voltages the normal stations disappear.
Adding a band-pass (the simple double LC available in the form of a thick film compact filter like GFWB3, aka one parallel LC as a shunt plus one series LC as a series element towards the amplifier) may seem as some extra losses with no apparent selectivity benefit, but its main role is just preventing the input stage overload by all the out of the FM band mess the antenna may pick up.
Some radios are better with this, some are worse (it uses to be the weakest point of the many modern DSP-chip based designs - the digital filtering may seem to do miracles, but an overloaded input mixer is just in no way to be recovered by the processing "magic" afterwards), it could even be one badly designed receiver converting the low frequency high power signals into the FM band and disturbing all reception around.
A real experience with a HAM supposedly disturbing the TV reception (keying a SW transmitter caused severe TV distortion all around, but all the transmitting equipment was tested and found perfectly OK):
The culprit was found to be a clamp of pair of antiparallel diodes in one TV-set (some block away from the transmitter), which acted as a frequency multiplier, so absorbed some 3.5/7M/14Hz from the HAM transmission coming via the TV antenna coax (outer coax surface acting as a "long wire" SW antenna, carrying that current into the TVs) and radiated it as a disturbance in the VHF TV band; first clipping those diodes off fixed all the disturbance problems (before that he ensured with the TV service documentation the front end is robust enough against damage just by itself).
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Medved
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Re: Which radio frequency do you like? AM or FM? « Reply #50 on: July 17, 2018, 11:59:59 AM » Author: Medved
The problem with HF (so LW/MW/SW aka all AM, experimental DRM) vs VHF (FM or DAB) bands and commercial broadcasters in Europe is, their technical range could be very long, but the commercially interesting range for such businesses is quite small, because of the very high number of small nations in Europe.
The problem is, the music industry is charging fees according to the technical range (how many people live in the technical range of the transmitters), but the commercial pays are according to the given nation and/or range with quality reception.
With VHF both technical range, as well as quality reception range are the same and quite easy to limit them (by adjusting the antenna shape and output power), so the music industry bills about the same coverage as you get from commercials income.
but in HF, mainly using AM (the digital DRM haven't started yet except few experiments) you need rather high power to overcome the local industrial noise, but then in the quieter surrounding the reach could easily become 100km, so the music industry is charging per 100km range. But the commercial income is just based on the about 20km range the signal is still of reasonable quality and where the people still speak the same language (it is the distance, where the commercials are really effective).
This makes the financial situation of an AM or any inherently long reaching technology broadcaster way more difficult, hence the lack of interrest into such areas...
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tolivac
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Re: Which radio frequency do you like? AM or FM? « Reply #51 on: July 18, 2018, 02:51:27 AM » Author: tolivac
In the US-AM is slowly dying.Broadcast equipment suppliers no longer stock replacement AM transmitters.Some stations are going off air because the revenue is going.
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hannahs lights
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Re: Which radio frequency do you like? AM or FM? « Reply #52 on: July 19, 2018, 02:21:02 PM » Author: hannahs lights
When I was a young girl all the decent stations were on mediumwave stations like radio 1  on 202 275 and 285 meters the pop music network in the UK also radio Monte Carlo 206 meters and radio Luxembourg  208 meters with was then the most powerful commercial radio station in the world according to them anyway all these stations had a very full nice sounding audio I think they used lots of compression but it sounded great in later years a station called BIG L 214 meters international had the same big full sounding audio FM by comparison  always sounded thin and just really weedy and horrible FM seemed to be where all the rubbish stations were
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Mandolin Girl
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Re: Which radio frequency do you like? AM or FM? « Reply #53 on: July 19, 2018, 02:57:09 PM » Author: Mandolin Girl
When I was a young girl all the decent stations were on mediumwave stations like radio 1  on 202 275 and 285 meters the pop music network in the UK also radio Monte Carlo 206 meters and radio Luxembourg  208 meters with was then the most powerful commercial radio station in the world according to them anyway all these stations had a very full nice sounding audio I think they used lots of compression but it sounded great in later years a station called BIG L 214 meters international had the same big full sounding audio FM by comparison  always sounded thin and just really weedy and horrible FM seemed to be where all the rubbish stations were
Meters are for measuring electricity and gas with, don't you mean metres..?  :P :D
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Mandolin Girl
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Re: Which radio frequency do you like? AM or FM? « Reply #54 on: July 29, 2018, 08:16:41 PM » Author: Mandolin Girl
When I was a young girl all the decent stations were on mediumwave stations like radio 1  on 202 275 and 285 meters the pop music network in the UK also radio Monte Carlo 206 meters and radio Luxembourg  208 meters with was then the most powerful commercial radio station in the world according to them anyway all these stations had a very full nice sounding audio I think they used lots of compression but it sounded great in later years a station called BIG L 214 meters international had the same big full sounding audio FM by comparison  always sounded thin and just really weedy and horrible FM seemed to be where all the rubbish stations were
You're showing your age there...  ;)
Oops I did as well by saying that.  :D
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lightinglover8902
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Re: Which radio frequency do you like? AM or FM? « Reply #55 on: July 31, 2018, 04:23:19 PM » Author: lightinglover8902
Well the funny thing about AM radios in vehicles, once you start driving after a stop sign or a traffic signal, (if you have your AM radio on static) you hear the alternator running once you start putting the accelerator on the car.
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Medved
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Re: Which radio frequency do you like? AM or FM? « Reply #56 on: August 01, 2018, 07:25:51 AM » Author: Medved
Well the funny thing about AM radios in vehicles, once you start driving after a stop sign or a traffic signal, (if you have your AM radio on static) you hear the alternator running once you start putting the accelerator on the car.

Then get fixed your car (when the ignition causes the noise - worn out spark plugs, dying components of the ignition system) and/or the radio (drying electrolytes, when the alternator is whining, because that is just noise in the audio frequencies; or the car wiring is deteriorating - bad isolation, so current leakage between some power and loudspeaker wires due to humidity,...).
The EMC regulations (all vehicles have to comply for quite a long time) allow all radiation to be way below the natural noise in the bands, so the car should never make any noise on its radio.

Very often the disturbance may come from very unexpected way, like "engine causing disturbance of an aircraft radio", while all the ignition was found OK. It was only later found out, the main culprit was the corona discharge on the propeller tips because of static buildup on the aircraft body when flying. Few corona dissipation needles (usually on the wings) and few carbon paint stripes along the propeller and "miracle", the radio had way greater range...
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MissRiaElaine
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Re: Which radio frequency do you like? AM or FM? « Reply #57 on: August 01, 2018, 08:59:00 AM » Author: MissRiaElaine
Well the funny thing about AM radios in vehicles, once you start driving after a stop sign or a traffic signal, (if you have your AM radio on static) you hear the alternator running once you start putting the accelerator on the car.
Why would you have your radio on static.  ???
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Mandolin Girl
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Re: Which radio frequency do you like? AM or FM? « Reply #58 on: August 01, 2018, 09:03:16 AM » Author: Mandolin Girl
I don't remember if I've said this before, but putting my pedant's hat on (it's the only one I've got that fits :P) AM and FM are modes of modulation, not frequencies. I've been known to transmit on AM on bands which are usually used for FM and vice versa. I'm a bit revolutionary like that sometimes  ;D :D
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Mandolin Girl
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Re: Which radio frequency do you like? AM or FM? « Reply #59 on: August 01, 2018, 10:27:31 AM » Author: Mandolin Girl
I've been known to transmit on AM on bands which are usually used for FM and vice versa. I'm a bit revolutionary like that sometimes  ;D :D
You always have been a bit of a rebel...  :P
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