Does an external antenna for a 3G modem work, which is not connected, but simply "put on" to the modem?

Question

Antenna

I always considered all sorts of antennas for 3G modems like " canned antenna " that are connected to the modem itself in this way to be absolute absurdity and a "joke of the authors" :


But literally today I met such a kit on sale


In which the modem itself is placed in a kind of "frame", which is connected to the antenna


I am not at all strong in radio electronics, but it seems to me that the use of such an approach in microwave technology is some kind of perversion, and this method will not worsen the signal at best.

Can you please tell me if this approach can really increase the signal by a few dB? Or are such "factory" solutions nothing more than another scam to lure money?

PS My arms grow from my shoulders, I knowthe correct ways of converting modems to external antennas in the absence of adapters, and I can implement them. But I'm interested in commercial solutions. I found adapters for the most popular modems on sale, but this approach described above without reworking the modem seems to me some kind of nonsense

Answer 1

It works, but with some luck.
We tested exactly the same adapter as in the last photo. It gives about minus 15 dB. Another 5-10 meters of cable will eat up from 3-5 dB (if the cable is good) to 5-10 dB (if the cable is of average scall)
Personally, I could not get at least some stability from such an adapter.
If you do something non-contact, then in any case you still need an active amplifier.

Answer 2

I tried the method in the first picture - it does not help.
The surest way is to buy a USB extension cable and take the modem outside.

Answer 3

Theoretically, if you take a piece of iron with a strictly calculated shape, place it at a given distance from the antenna, orienting it correctly, you will get a transformer on long lines - a part used in microwave technology. Part of the signal will be transmitted to the external antenna, but not 100%, of course.
And if, like here, wind the wire anyhow or attach a piece of tin, the efficiency will be zero.