[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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