Understanding my antennas

Having satisfied myself that my Nissei RS-40 SWP/Power Meter is working pretty accurately, I decided it would be nice to really understand my UHF/VHF antennas and how they performed without the aid of an ATU or anything. So it was with much anticipation that I accepted Wallace’s (VK4CBW) offer of an antenna analyser.

I had never used one before so was eagerly looking forward to (firstly) working out how to use one, and secondly, comparing the results with those I obtained with the Nissei RS-40.

This is what I found:

DX-60 vertical 2m/70cm antenna:

144.60 – 147.00 MHz: 1.8:1

148.00 MHz: 1.9:1

433.00 MHz: 2.4:1

435.00 MHz: 2.1:1

438 MHz: 1.3:1

440.00 MHz: 1.0:1

With the Nissei RS-40 I an SWR of 1.5:1 for the 2m frequencies, so I guess the meter is close enough, especially as it is an analogue meter.

Frequencies in the 70cm band showed SWR readings of between 1.8:1 and 1.3:1 on the RS-40. So I am happy.

 

 

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2 thoughts on “Understanding my antennas

  1. I have a Diamond base antenna for 6 M, 2M and 70CM. It is about 9 feet tall and has
    three radials that screw into the base when it is assembled. There is one radial that
    has a coil built into it, and it is supposed to be matched to a small notch on the
    bottom of the antenna, with the other two radials being in the other two screw
    holes. Once I failed to remember the notch when I was moving the antenna and
    put odd radial in the wrong hole. When I checked the SWR, I found that the
    antenna covered the whole 6M band, even the CW parts, but the 70CM band
    no longer had perfect SWR. The antenna is supposed to be for the FM portions
    of the three bands only. It was interesting to work some 6M DX (Indiana to Colorado)
    on that antenna with SSB before climbing up on the roof and changing it. The notch
    is very difficult to see. Mine was bought about 2006.

    • It’s so easy to just assume the antenna is performing fine, Roy. Glad you were able to take advantage of your situation and work some 6m DX. Fascinating hobby, this. Now I need to calibrate my MFJ-860 SWP/Power meter so it can monitor my 6m transmissions through my Cushcraft 6m Ringo vertical antenna.

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