NOAA APT 137MHz DIY antenna only with 75Ohm coax

[AlarmedFelix]

Hi guys i need help i want to build myself antenna for 137MHz circular polarization but i dont have 50Ohm cable so can somebody tell me is it possible to create antenna for NOAA without 50 Ohm coaxial cable and dipole i already have.




I KNOW 50OHM CABLE COST FEW DOLLARS BUT I DONT WANT RIDE TO THE CITY.

[rtlsdrblog]

Yes 75 Ohm cable will work fine.

[AlarmedFelix]

OK thanks. I am asking because i saw 75 Ohm and 50 Ohm cables combined for some antenna (Turnstile, Cross Dipole etc.)

[snn47]

OK thanks. I am asking because i saw 75 Ohm and 50 Ohm cables combined for some antenna (Turnstile, Cross Dipole etc.)

The 70 Ohm cable is normally used only for phasing purposes when combining the two dipoles, while the feeding cable is 50 Ohm. Check HAM Radio literature, e.g. ARRL antenna handbook for more information for building antennas.

You can also check out for QFH antennas.

[AlarmedFelix]

snn47 I am trying QHF antenna right now iam waiting for next pass of some NOAA satellites but i like METEOR sat. more.

[Username]

How about other Antenna Design?
I will build an Antenna to. There are some Helix Antenna who look nice does the have an besser Gain?

[rtlsdrblog]

Helix antennas are emuch more directional. Only really useful if you have a tracking mount set up to follow the satellite as it passes over.

[Username]

I found some HowTo. But which one is the best? My Problem is if I want get the best result the Antenna must be place on the Roof who I cant get there and the Antenna could only replace in Summer when the Roof is dry.
https://www.motherearthnews.com/nature- ... az93onztak
https://www.dxzone.com/dx30769/double-c ... tenna.html
https://www.aeronetworks.ca/2017/12/
http://tinhatranch.com/how-to-build-a-q ... atellites/

[Username]

So I got some thick and stiff Copper Wire (its for an Ground Connection) on a 20m Coil and I am ready to get my finger dirty.
So what is the best design for the Weather Sat? An well known Helix Antenna?