How effective is your station?

Discussion in 'Amateur Radio News' started by VK6FLAB, Feb 8, 2019.

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  1. AA5CT

    AA5CT Ham Member QRZ Page

    .
    What's rewarding is, after transmitting a few FT8 CQ frames at 30 Watts is seeing all the 'spot' flags that show up across the US on PSKReporter ... this is on 160 meters from a small city lot ...
    .
     
    KC9YGN, K0WJ and KX1MAD like this.
  2. W1VT

    W1VT Ham Member QRZ Page

    Low band conditions were good last night. Worked six continents on the low bands. Brasil PY2XB on 160; ZS6BUN South Africa, EK7DX Armenia, WB6OEE California, UR8IDX Ukraine, and KH6FHI Hawaii on 80 meters!
    I live in the suburbs on 0.3 acres 1/2 mile from a McDonalds.
     
    K8PG likes this.
  3. K4AGO

    K4AGO Ham Member QRZ Page

    Mc Donalds adds how many decibels to your signal? After all, "It's all about the decibels." Yeah, Right !!!
     
  4. PD0JBV

    PD0JBV Ham Member QRZ Page

    I think effectivity is (un)limited by our creativity. I have to deal with a HOA and have a balcony instead of a huge garden or porch like in Texas. Over the years i still worked the globe. And now i am happy with "just" 10-meters ...
     
    KF4ZKU likes this.
  5. W2CSI

    W2CSI XML Subscriber QRZ Page

    my radio: FT-450D
    Antenna: Hex beam at 20ft.
    Dipole for 6m-160m.
    I have confirmed 96 countries so far.
    I have have had tons of FUN so I am happy.
    I would like to invite all of you to join the Hex beam net every Saturday at 3pm Eastern 14.315 +/- QRM.
     
  6. HB9PJT

    HB9PJT Ham Member QRZ Page

    On the table there are points which are not ok for me:
    • That FM is more efficient than SSB is not correct. I have never heard that before and my own tests clearly show the opposite.
    • JT65 is not 25 dB better CW, but 25 dB better than SSB.
    • CW is 8-13 dB better than SSB, depending on the speech processor. But not 17 dB better.
     
    KQ6XA and WN1MB like this.
  7. AA4MB

    AA4MB XML Subscriber QRZ Page

    "-12 dB ~ To protect final transistor blow out manufacturers recommend reducing power to one-fourth normal when switching from ‘intermittent modes‘ (CW, SSB) to ‘Key-down’ modes (AM, RTTY, Digital)"

    All I can surmise from the 10 dB stronger signals than any other CW or SSB stations on any band at any given time is that the FTwhatever crowd must be using some of the best antennas on the planet at perpetually the highest efficiency elevation over ground. Either that or they must all be located 3 blocks from me. If I find out they aren't doing that, I'm going to invest in RF final transistor futures.
     
    WN1MB likes this.
  8. KG7VTO

    KG7VTO Ham Member QRZ Page

    A McDecibel w/ fries, please.
     
    KF4ZKU likes this.
  9. ZS6BV

    ZS6BV Ham Member QRZ Page

    These days noise levels, especially QRN, play a large part in the effectiveness of your station. If you cannot hear them you cannot work them. On most SOTA summits noise levels are much lower than near or in town. On some of the summits a portable rig working QRP into a 22° Inverted V has a big signal and you hear and work plenty of stations, so location has an effect, one which you cant do much about working from home.
     
    AG7JQ and WD0BCT like this.
  10. K5VOU

    K5VOU Ham Member QRZ Page

    Hi Dr. Flab,

    Let's discuss for a moment the definition of the word 'effectiveness' and just what constitutes and 'effective' signal?
    If we make an assumption (always a dangerous activity) that an effective signal is one that can be heard by the station that we want to contact then an effective signal will have a value in micro-Volts which can be stated in deciBells(dB) related to 1 micro-Volt. The deciBells by themselves are a ratio and unless they are anchored by some standard value may have little relevance to the discussion.

    A Path loss calculation determines the signal level (in dBm) that must be generated by the source (transmitter) in order to overcome all of minuses of the path. So if the noisy suburban location requires 5.0 micro-Volts (uV) of signal at the receiver input to be heard in the chosen mode on a 50 Ohm antenna, then the distant transmitter must produce sufficient power to deliver 5.0 uV to that receiver. The mode does not matter at this point because the 5.0 uV calculation has used it already. What does matter is Transmitter power out (dBm), antenna gain (+dB), transmission line loss (-dB), conversion loss from signal on the antenna to RF field strength at 28 MHz (-235 dBm?) and on HF various ionospheric and path losses like hops over water and hops over land (all -dB) until the signal gets to its destination where it is again helped by antenna gain (+dB), hampered by transmission line loss (-dB) to finally arrive at the Receiver antenna port where it must be 5.0 uV high to be heard (effective level).

    You may have noticed that some values were in power levels dBm (deciBell milliwatt), some in dB (gain or loss) and some in dbuV (dB micro-Volt) which is of course a voltage. But since we are in a 50 Ohm system a 5.0 uV signal in 50 Ohms can be converted to power and then compared to dB referenced to 1 milliwatt and found to be -93 dBm. So you add up all the pluses and minuses and determine what the pluses must be to overcome the losses and have enough left to be heard on the distant receiver and you have a 100% effective path for that QSO. The Next QSO will be different and the antenna pattern will be different and the phase of the moon will be different, etc. etc.

    So how effective is your station? 100% if you made the contact and 0% if you didn't. So all we humans can do is maximize the pluses we can control and minimize the minuses we can control and understand why sometimes it works and sometimes it doesn't.

    Tom K5VOU
     
    Last edited: Feb 11, 2019
    K0PV, AG7JQ, PD0JBV and 2 others like this.

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