Best antenna for 1mhz-50 and 1khz - 800khz

Discuss commercial and home made antennas.
Post Reply
Eagle72
Posts: 13
Joined: Thu Jan 10, 2019 2:20 pm

Best antenna for 1mhz-50 and 1khz - 800khz

Post by Eagle72 » Sat Jan 12, 2019 10:18 pm

Hi.

Im very new on this field and trys to learn how radio signals works, my question is what is the best antenna to recieve 1mhz-50 and 1khz-800khz low freqvency...

Is it possible to spot signals from distance despite the low freqvencies?

rtlsdrblog
Site Admin
Posts: 2052
Joined: Mon Nov 19, 2012 11:54 pm

Re: Best antenna for 1mhz-50 and 1khz - 800khz

Post by rtlsdrblog » Sun Jan 13, 2019 12:08 am

There is no real 'best' antenna. It all depends on your location, what space you have available, local interference, the landscape, HF conditions etc.

Generally for HF signals, bigger antennas tuned for your band of interest are better. If you have space you can set up a wire dipole for HF. Google for HF dipole antennas etc. For VLF you could try a miniwhip which reportedly works well there. Alternatively if space is an issue look into wideband magnetic loop antennas too, like Wellbrooks.

Eagle72
Posts: 13
Joined: Thu Jan 10, 2019 2:20 pm

Re: Best antenna for 1mhz-50 and 1khz - 800khz

Post by Eagle72 » Sun Jan 13, 2019 2:20 am

I see what you mean and thanks very much for your ansver, actually i thought opposite smaller antenna for low freq.. Happy to be member of this forum.. cheers

rtlsdrblog
Site Admin
Posts: 2052
Joined: Mon Nov 19, 2012 11:54 pm

Re: Best antenna for 1mhz-50 and 1khz - 800khz

Post by rtlsdrblog » Sun Jan 13, 2019 11:13 pm

Yep it's actually huge antennas for VLF/HF, and small antennas for UHF+. Optimal sizing is dependent on the wavelength which decreases as frequency goes up.

snn47
Posts: 129
Joined: Tue Dec 27, 2016 11:00 pm

Re: Best antenna for 1mhz-50 and 1khz - 800khz

Post by snn47 » Fri Jan 18, 2019 4:56 am

You might try an active antenna the cheapest form is a short whip with an associated pre-amplifier For starter from an old active car antenna could do, since it had to work for AM and FM.
or you might just put 5 or more meter of wire up. For receive you can get away with a lot and still receive signals. You can always improve with time

PS.: The disadvantage of having a very broadband antenna with preamplifier is that without filter/frequency selective antenna the receiver and or the preamplifier in the antenna may be overloaded. This means the active components cannot process all signals with the same factor, e.g. weak and stong signals by 10 dB. This is called Intermodulation or IM, which will produce additional signals that are not present at the antenna (e.g. IM 3rd order 2*f1 +f2 and 2*f2 -f1 in case you have only IM of 2 strong sigals). You can identify this if you add a 10 or 20 dB attenuator. If you have IM than all signals that were at least a bit stronger than 10 or 20 dB in signals strength are gone you have IM.

AD5NL
Posts: 34
Joined: Fri Sep 16, 2016 7:00 pm

Re: Best antenna for 1mhz-50 and 1khz - 800khz

Post by AD5NL » Thu Feb 21, 2019 7:47 pm

A few notes/thoughts:

1 MHz to 50 MHz is a very large range and having a single antenna handle all of that can be a bit tricky, but there are many commercially-available ham HF antennas that can do this.

A few options:

* An active whip (you can find these on eBay for about $20).

* A doublet fed with parallel conductor feedline. You will need an antenna tuner with a balun and an SMA to UHF pigtail for this (you can probably find a used ham antenna tuner on eBay for $30 or so). Probably about 250 feet would do, although the antenna pattern on the higher bands is going to look really weird.

* A random wire with a 9:1 balun or so.

For 1 kHZ to 800kHZ, the challenge is actually far harder.

You already have two (probably) good antennas for 1 kHZ on either side of your head. Should work up to a few kHZ depending on your age and life experience.

For VLF/LF/MF (30 kHZ and up), I would suggest perhaps some kind of loop/spiral loop antenna. There are plans for these on YouTube.

Post Reply