[time-nuts] Re: UTC Backbone in Europe

Poul-Henning Kamp phk at phk.freebsd.dk
Thu Nov 21 22:37:34 UTC 2024


--------
Hal Murray via time-nuts writes:
> 
> W3AB said:
> > As y'all know, GPS jamming is easy. We need to have an alternative. 
>
> How hard is it to jam Loran?  Or WWVB, JJY, MSF, and other low frequency 
> time signals?  How about the not so low frequencies?

There's no escaping the wavelength:

Hiding a transmitting antenna for 100kHz is very, very hard.

Even the "real" transmitters cheat, and use antennas which pretend to
be capacitors rather than transmission lines.

Amazingly Sweden did build a VLF jammer and tried to hide it.

They built the "RT-02" aka "Frederiksson" "Chayka" (= USSR Loran-C)
jamming system and put fake parabolic antenna on the transmitter
masts, to make it look like a microwave-link.

The only credible source is in swedish:

	https://www.fht.nu/fv_bilder_radio_rasandare_rt_02.html

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.




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