QRP, QRPp
In Ham radio we have a term called QRP. This stems from the Morse code abbreviation for "reduce power", or QRP? - "Shall I reduce power?"
Basically - it means to operate low power! Anything under 5 watts PEP CW is considered QRP. Less than 10 watts PEP SSB is also considered QRP.
Can you guess what QRPp means? Well, if you guessed, since the last p is lower-case, that it means even lower power, that's correct! In fact, it means less than ONE (1) single watt! These power levels are measured in Milliwatts.
I have operated with QRP and QRPp levels before. I used to operate a lot of QRP at 5 watts. However, I figured out how to drop the power level down on my TS-2000 radio to QRPp levels. You do this by reducing the carrier level while the power level is set to 5 watts. You can also do it by adjusting the power level drive for 5 watts in the adjustment menu (you need the calibration software to do it).
I have routinely made QSO's running 250mw of power before. The furthest one is to Big Sandy, TX. That was a LOT of fun. I even ran through a tuner to a non-resonant dipole (I guess it wouldn't be called a dipole anymore, right?) on 40 meters (my QRP band of choice).
I measured my power output with the power level at 5 watts and the carrier level to 1 at 50 milliwatts! That's 1/20th of a watt! Does this actually lend itself to QSO's? YEP!
I just completed a QSO with W3TS in Halifax, PA running 50mw to a 40m attic dipole on 7.040 CW. Not bad! It is a little less than 300 miles between us. That's not bad at all - most hand held radios run 500mw or 1w at the lowest power output and can hardly transmit a couple miles. I made it over 200 on 50mw!!
When I'm talking power levels there is another term that comes to mind - decibels, or db. The receiver Signal, or S, meters on our radios read in units from 1-9, then +10, 20, 30, 40, 50, 60dB.
How power level, dB, and S-meter readings relate is this: for every quadruple in power you "gain" 1 S-unit (1-9) of signal strength at the receiving end - all things being equal (antenna efficiency, transmission line loss, propagation, etc).
Example: if a person running 100 watts to a dipole on 40 meters has a solid S-9 signal talking to a station in another state, or beyond, (a reasonable amount) then he can cut his power to 25 watts and still maintain an S-8 signal strength. Now, a signal strength of S-4 (depending on band conditions, sometimes higher sometimes lower) is still PLENTY readable. The transmitting station could, theoretically, drop the transmitter power level down to just 100 milliwatts (1/10th of a SINGLE watt) and still be heard.
Does that make sense? So, why do a lot of Hams run amplifiers if the FCC requires "the minimum power necessary to maintain reliable communications"? It doesn't make sense. That said, sometimes amplifiers ARE required to have reliable communications - but you shouldn't run one ALL the time. It just wastes electromagnetic spectrum and makes it so others can't enjoy the bands as much.
Basically - it means to operate low power! Anything under 5 watts PEP CW is considered QRP. Less than 10 watts PEP SSB is also considered QRP.
Can you guess what QRPp means? Well, if you guessed, since the last p is lower-case, that it means even lower power, that's correct! In fact, it means less than ONE (1) single watt! These power levels are measured in Milliwatts.
I have operated with QRP and QRPp levels before. I used to operate a lot of QRP at 5 watts. However, I figured out how to drop the power level down on my TS-2000 radio to QRPp levels. You do this by reducing the carrier level while the power level is set to 5 watts. You can also do it by adjusting the power level drive for 5 watts in the adjustment menu (you need the calibration software to do it).
I have routinely made QSO's running 250mw of power before. The furthest one is to Big Sandy, TX. That was a LOT of fun. I even ran through a tuner to a non-resonant dipole (I guess it wouldn't be called a dipole anymore, right?) on 40 meters (my QRP band of choice).
I measured my power output with the power level at 5 watts and the carrier level to 1 at 50 milliwatts! That's 1/20th of a watt! Does this actually lend itself to QSO's? YEP!
I just completed a QSO with W3TS in Halifax, PA running 50mw to a 40m attic dipole on 7.040 CW. Not bad! It is a little less than 300 miles between us. That's not bad at all - most hand held radios run 500mw or 1w at the lowest power output and can hardly transmit a couple miles. I made it over 200 on 50mw!!
When I'm talking power levels there is another term that comes to mind - decibels, or db. The receiver Signal, or S, meters on our radios read in units from 1-9, then +10, 20, 30, 40, 50, 60dB.
How power level, dB, and S-meter readings relate is this: for every quadruple in power you "gain" 1 S-unit (1-9) of signal strength at the receiving end - all things being equal (antenna efficiency, transmission line loss, propagation, etc).
Example: if a person running 100 watts to a dipole on 40 meters has a solid S-9 signal talking to a station in another state, or beyond, (a reasonable amount) then he can cut his power to 25 watts and still maintain an S-8 signal strength. Now, a signal strength of S-4 (depending on band conditions, sometimes higher sometimes lower) is still PLENTY readable. The transmitting station could, theoretically, drop the transmitter power level down to just 100 milliwatts (1/10th of a SINGLE watt) and still be heard.
Does that make sense? So, why do a lot of Hams run amplifiers if the FCC requires "the minimum power necessary to maintain reliable communications"? It doesn't make sense. That said, sometimes amplifiers ARE required to have reliable communications - but you shouldn't run one ALL the time. It just wastes electromagnetic spectrum and makes it so others can't enjoy the bands as much.
Labels: 2. Ham Radio
posted by Steve at
10:27 PM
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