We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissable in your locale.

Author Topic: MW/MF beacon antennas  (Read 391 times)

Offline smith

  • Newbie
  • *
  • Posts: 2
  • Karma: +0/-0
    • View Profile
MW/MF beacon antennas
« on: January 20, 2020, 0214 UTC »
Im thinking about setting up a beacon below 3 MHz, Id like to use a loaded vertical of some sort, how do I go about tuning it without a variable capacitor using just an inductor if possible, can anyone make some suggestions.
Does anyone know anything about the antennas used in the 2 mhz hifer beacons?
Thanks

Offline KaySeeks

  • DX Legend
  • ******
  • Posts: 1100
  • Karma: +3/-1
    • View Profile
Re: MW/MF beacon antennas
« Reply #1 on: January 21, 2020, 0212 UTC »
You are asking to tune the inductor instead of a capacitor. One way to do this inexpensively is to use what is called a "wandering lead". See the yellow wire with the alligator clip on the end of it in the photo I have linked to. Essentially you will tune the inductance by choosing the tap point on the inductor.

https://www.mfjenterprises.com/Downloads/MFJ-65/MFJ-65.jpg
Just somebody with a radio, a computer and a pair of headphones...

Offline Stretchyman

  • Hero Member
  • *****
  • Posts: 509
  • Karma: +21/-35
    • View Profile
Re: MW/MF beacon antennas
« Reply #2 on: January 21, 2020, 0557 UTC »
You'll need to tune out the 'reactance' so you will need a capacitor.

It's simple and called an 'L' match, real name is Conjugate Match.

Buy one of those cheapo VNAs to measure the properties of your antenna.

Oh, you'll need a Really good earth, lots of radials!

Str.
'It's better to give than receive' so why RX when you can TX!

                            Buy one from me, NOW!

Great discounts on ALL my transmitters if purchased via HFUnderground


                                              ;)