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AM vs FM


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Correct me if I'm wrong, but didn't German AFV's use FM radios and the Allies use AM on their vehicles? This could make considerable difference on LOS issues for command control with tank platoons.

Anyone know whether this is true or not?

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<BLOCKQUOTE>quote:</font><HR>Originally posted by Cueball:

Correct me if I'm wrong, but didn't German AFV's use FM radios and the Allies use AM on their vehicles? This could make considerable difference on LOS issues for command control with tank platoons.

<HR></BLOCKQUOTE>

Yes, the Germans were often distracted

because they got such better music on

their radios.

--Rett

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Guest Babra

<BLOCKQUOTE>quote:</font><HR>Originally posted by CMplayer:

What do you mean by LOS problems with

a radio?

<HR></BLOCKQUOTE>

Signals modulate by their amplitude can be "clipped" by obstructions. Park under a bridge and tune in an AM station if you can. The signal will be very fuzzy since much of it has been shorn off.

A signal modulated by frequency has a constant amplitude -- even if the amplitude is clipped by obstructions, the signal remains undistorted since the message is carred in the modulated frequency.

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First, most WWII German tactical radios were AM, not FM. In fact, most tactical military radios in WWII were AM. FM was a relatively new technology and more expensive to produce.

Here is more than you probably want to know:

Army Radio

In modern entertainment radio, the AM band is at a much lower frequency than the FM band. The frequency range (or band) is more important to signal propagation than the modulation technology.

Low frequency signals tend to bounce and skip, and can use the atmosphere itself to achieve great range.

Higher frequency signals have more penetrating ability of LOS obstructions, up to a point, but less propensity to skip. In the VHF range, they are more or less limited to the horizon.

If your guy is on the other side of a hill, you have a better chance of reaching with low-frequency signals, as the signal will be reflected to him (hopefully) from multiple directions.

FM will usually have a clearer signal until it is gone, and then it is completely gone. AM will tend to degrade as the signal weakens, and may flicker in and out as the signal reaches the limits of its power, as described by Babra.

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