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19 notes &

First Ham lessons o’ de day

Thought I’d put down a few notes that I thought were neat as I’ll have to reference them in the future when I (hopefully) get my Technician’s License!

QTH = Where is your location?

QTH Minnesota = I am located in Minnesota

CQ = “Come in anyone” call - any station can respond.

SSTV = Slow Scan television can send pictures

APRS = Automatic Position Reporting System is hooking up GPS information with ham radio

There’s even the ability to bounce signals off the of the moon and back to the earth?!  Can you imagine:

QTH?………QTH Moon…………          …..         NASA!

Then the Ham Radio License Manual starts talking about radio signals and all of the jargon involved in understanding radio waves. I think a picture may explain this best….

So X axis is Time, Y axis is Amplitude

I have a sine wave going through as time goes on. 

Each complete up/down sequence is called a cycle (T).  This is denoted by the red line and is also known as the period of the signal.  Where you /are/ in the cycle  is called phase and is measured in degrees.  This is used to compare how different sine wave signals are aligned in relation to each other.  The way to measure this is in degrees.  So you start at 0 and by the end of the cycle, you’re at 360 degrees - and on the chart that’s denoted by the yellow dots.  If two signals are going up and down at the same time, they’re considered in phase and if one signal is going up while the other is going down, they’re considered out of phase.

In turn, the number of cycles per second is the signal’s frequency (f). You can find the frequency of the signal by getting the inverse of T or if you want to find T from the frequency, you can use T = 1/f.  Frequency is measured in “units” of hertz (Hz) and 1 T = 1 Hz. 

Ham folks are able to use more frequency ranges than say your normal radio station, whether AM or FM:

AM radios use between 550 - 1700 kHz.  FM radios cover 88-108 MHz.  And Ham folks can use from MF all the way to UHF.

Anyway, then in blue we have the wavelength of a radio wave and that’s also known as the distance that the wave travels during one cycle (T) as represented by lambda.  Er. I don’t know how to put that in the tumblr post….but it’s that funny symbol.

And with this distance of one cycle (peak to peak measurement), you can also find the frequency with a simple equation:  Lambda = c/f…..c being the speed of light and f being frequency.  And if you convert all of the numbers to MHz (as that seems to be the preferred way ham folks refer to frequencies), then you end up with an equation like the following:

Lambda = 300x10^6 / f in MHz.

Assuming you want to see the distance of a 1MHz radio wave (which is relatively low on the totem pole of the frequencies that hams use and is what AM broadcasters use), the formula looks like:

Lambda = (300 x 10^6m/sec) / (1x10^6MHz/sec)….this leads to 300 meters if you cancel out the 10^6 portions.  So to make it easier on everyone, they’ve created a simpler formula to finding frequencies.

Lambda = 300/f

So far that’s what I’ve gotten.  And that’s just the first section!


Filed under Ham radio UHF VHF amateur ham radio amplitude frequency hertz in phase lambda out of phase period phase radio wave signal wavelength tymkrs

  1. tymkrs posted this