[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Sheflug] Odd router frequencies

A dipole (one of the most basic antenna you can get) would need to be
3.908cm in length, each section 1.954cm.

It would have to be very accurate length to tune correctly. I tried to
build a SlimJim for 70cm band (430mhz) and that wasn't accurate enough to
have a good SWR.

I've done a SlimJim for 2m (144mhz) it's got a SWR of about 1.5, which is a
little high, but acceptable.

A local amateur radio club may be able to help. I'm a member of Mexborough
club. https://www.facebook.com/profile.php?id=61552239524110

HTH

Johnathan

On Sun, 7 Apr 2024, 10:17 John Southern, <linuxtarragon@xxxxxxxxx> wrote:

> Yesterday at the ShefLUG meeting it was mentioned that a router supplied by
> BT had a hidden frequency in the 3GHz range.
>
> There is a 3.65GHz range (802.11y) but it is only licensed in the USA (the
> range is under the old CB radio band). The USA designated this band for
> licensed transmitting stations only as they have to avoid areas which have
> satellite earth stations
>
> The problem with detecting it is the antenna would need a completely
> different length.
>
> A 2.4GHz antenna would be approximately 61.44mm (or division of such as the
> common 30.7mm) for the dipole which could also be used for the 5GHz range
> (1/2, 1/4 wavelength  etc). To get a 3.65GHz would need a unique antenna to
> detect.
>
> What am I missing and how would I know that the frequency was there? Would
> I need to make an antenna 81.633mm (300/3.675Ghz = 81.633mm) or division
> of?
>
> Regards
> John
> _______________________________________________
> Sheffield Linux User's Group
> http://sheflug.org.uk/mailman/listinfo/sheflug_sheflug.org.uk
> FAQ at: http://www.sheflug.org.uk/mailfaq.html
>
> GNU - The Choice of a Complete Generation
>
_______________________________________________
Sheffield Linux User's Group
http://sheflug.org.uk/mailman/listinfo/sheflug_sheflug.org.uk
FAQ at: http://www.sheflug.org.uk/mailfaq.html

GNU - The Choice of a Complete Generation