Am sure that a GNSS antenna can pick up other frequencies than GNSS ones, so is there anyone who tested that theory?

  • $\begingroup$ Hello and welcome! What is "gnss antenna"? There are thousands of products that meet that description, from the 10 cm piece of scrap wire that I often use, to a $20k beast from Leica. Can you provide a link to the datasheet? $\endgroup$
    – tomnexus
    Commented Dec 10, 2023 at 20:19
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    $\begingroup$ @tomnexus any antenna wich is meant for (GPS,GLONASS,BEIDOU,......) $\endgroup$
    – user25171
    Commented Dec 10, 2023 at 21:13
  • $\begingroup$ It depends on the antenna You have selection to one, two or three frequencies (and which). And usually one select the minimum for own device (to reduce noises). $\endgroup$ Commented Dec 11, 2023 at 14:53
  • $\begingroup$ @GiacomoCatenazzi i think you also misunderstood my question. Let me put it that way; can a gnss antenna ment for (gps, glonass, ...) pick up FM and AM signals? $\endgroup$
    – user25171
    Commented Dec 11, 2023 at 17:59
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    $\begingroup$ and I didn't say "AM&FM" , I sad "for the usual AM and FM bands"; it would help if you really read the comments and answers precisely before reacting negatively! You have now multiple people that address exactly the things you ask, and are in the video, and explain to you that antennas do not generally work the way you claim. You are still doing the thing were you act as if we all must be misunderstanding you, because we're don't agree with you: that is not the case. We are telling you that you are making assumptions about GNSS antennas that are wrong, exactly because we understand!… $\endgroup$ Commented Dec 13, 2023 at 11:56

2 Answers 2


It of course is very important for a GNSS antenna to reject out-of-band radiation (because the signal you want to detect is very weak, you will be utterly deafened if signals from adjacent bands are present at the output of your receive antenna).

So, as a prior:

Am sure that gnss antenna can pick up other frequencies than gnss ones,

that's true for any antenna to a lesser or larger extent; there's no perfectl band-limiting of any system in this universe. But: GNSS antennas will be among the more narrow ones you will meet in the wild.

So, your certainty expressed by "sure" sounds a bit overconfident here!

is there anyone who tested that theory?

Yes, the people building that antenna. Any reasonable antenna you can buy has a datasheet with data that will show its efficiency for a range of frequencies. There's little guesswork involved for electronics systems manufacturers – you just wouldn't build anything involving an antenna that doesn't state over which frequencies it works well.

Now, for GNSS antennas, things are usually a bit more extreme: SNR in GNSS reception is very low – in fact, usually, GNSS is weaker than the thermal noise in your receiver.

To not lose the remaining signal quality to cable losses, it makes sense to have an amplifier close to the actual antenna (see: Friis noise formula). Such antenna-amplifier combinations are often called active antenna.

The thing with amplifiers is that you want them to behave linearly to avoid harmonics and unwanted intermodulation products with other signals; you can only achieve that through very high power consumption and expensive parts, or by filtering to remove all the frequencies you don't want from your amplifier in- and output. So, another front where the assumption that GNSS antennas will be good for much but GNSS bands seems to be built on treacherous grounds.

TL;DR: no, to the extent that you mean, commercial GNSS antennas will be pretty restricted to GNSS bands.

  • $\begingroup$ Thank müller for the long detailed answer, here what i know about the antennas the bigger antenna the lower the frequency (but this can pick up higher one s too) the smalest antenna the higher the frequency (this one can only pick up higher and higher frequencies) so that mean the GNSS antenna wich is small one will act in some sort as a filter to low frequencies, you mentioned in your answer that datasheets mention the frequency span of the antenna am sure it gonna not be only about GNSS for exampl LNB operate at 30GHz it maybe be picked up. $\endgroup$
    – user25171
    Commented Dec 10, 2023 at 21:11
  • $\begingroup$ No, that's not quite how that works. $\endgroup$ Commented Dec 11, 2023 at 2:00
  • $\begingroup$ To be specific: what you think you know about antennas is wrong; a large antenna is not working at all higher frequencies, that's just not how that works! This is a pretty fundamental misunderstanding, and it might be interesting from where you got it. But it really doesn't change the fact that if you buy something that was designed to be a GNSS antenna, then it was designed to work well in the GNSS bands – and to work bad on other frequencies, because you definitely don't want to pick up interferer when you're amplifiying signals at or below noise floor. So, my answer stands! $\endgroup$ Commented Dec 11, 2023 at 8:14
  • $\begingroup$ Müller "large antenna is not working at all higher frequencies" i said the opposit, a question can a GPS antenna pick up FM & AM frequencies? $\endgroup$
    – user25171
    Commented Dec 11, 2023 at 9:44
  • $\begingroup$ @Tintin no. As I said multiple times in my answer and my comments! It's not clear why you think that would be the case, because what you claim in your first comment is just physically wrong! $\endgroup$ Commented Dec 11, 2023 at 9:48

Your question seems to display a fundamental misapprehension of a core aspect of antenna theory: resonance.

Antennas operate most efficiently at their designed frequency of resonance, which is largely (but not only) a function of their physical size. As a signal's frequency deviates (higher OR lower) from the antenna's design frequency, the efficiency of the signal capture (for lack of a better term) decreases.

For any particular antenna, you can define it's effective bandwidth by 1) first defining minimum acceptable efficiency in transferring power from the antenna to the feed-line or radio and then 2) understanding how the antenna's performance aligns with that requirement.

I think you'll find that the answer at Calculating bandwidth of antenna? may get you pointed on the right track, and give you some additional terms to read up on.

The short answer to your original question is technically yes but effectively no. Other frequencies outside of the design of your GNSS antenna will impart non-zero energy, but most everything will be on the same order (or LESS) as the same excitation of the local noise floor; meaning that any signal possibly delivered from, say a broadcast FM radio station or a 30GHz source will be substantially less than that of background static and undetectable as a result.

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    $\begingroup$ Oh! Very nice, and good reference! I think the reference might be a bit too math-y for OP, though, to be completely honest. But I think it works to illustrate the point: antennas have a bandwidth, and it's not like any antenna would work for all frequencies below or above a specific cutoff frequency. $\endgroup$ Commented Dec 12, 2023 at 10:41
  • $\begingroup$ @webmarc "and give you some additional terms to read up on." That show you are a mature and a professional person i like it, this video illustrate what i was asking for, i a span from 1MHz to 7.5GHz the guy test an antenna that is meant for wifi and bleutooth at 0:54 (time) we can see that the top frequency is 650 MHz. $\endgroup$
    – user25171
    Commented Dec 13, 2023 at 0:59
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    $\begingroup$ @Tintin yes, but a GPS antenna is not a simple monopole or dipole like the antenna shown; exactly as we've all been telling you, it's not that simple. $\endgroup$ Commented Dec 13, 2023 at 11:59
  • $\begingroup$ @webmarc "you’re misinterpreting that video" how is that? "Frequency measurement inducator" that what i was asking for sorry for the lack of termology 😔. $\endgroup$
    – user25171
    Commented Dec 13, 2023 at 14:00
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    $\begingroup$ @Tintin it sometimes useful to challenge assumptions. For ex: since GNSS antennas aren't currently used outside of GNSS applications, why do you suppose this to be so, especially since they are so compact? Or perhaps you have a particular application in mind that is not stated in your original question and we can address that? $\endgroup$
    – webmarc
    Commented Dec 13, 2023 at 19:44

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