What's this antenna?

[crestavega]

What is this antenna (highlighted in red box) for?

[Peter.N.]

Looks a bit aircraft'ish.

Peter

[Nymrod121]

The outer cage arrangement (open-ended) reminds me of a "sleeved monopole" design that is mentioned in my favourite go-to reference book ('Antennas' by Henry Jasik et al).

What frequency band/s are involved & the purpose/s thereof, I'm unsure.

My nephew works for the Coastguard agency down in Hampshire ... I'll send him the pic.

Best wishes
Guy

[Refugee]

It has a sort of ground wave look about it.
It appears to have quite a wide diameter so that the radiation pattern can cope with all the other deck top clutter that war ships have on them.

[MrBungle]

Looks like IFF to me.

What sort of boat was it on?

[PeterRoberts]

It looks like this one- a VHF/UHF broadband antenna. Looks similar, so possibly does the same job but from a different manufacturer.

[PeterRoberts]

Yep - it looks like the Rohde&Schwarz version here. 80 Mhz to 2 GHz.

[Nymrod121]

Bingo! - nice research, Peter - thank you
Best wishes
Guy

[sunthaiboy]

The RAF used to use some rather similar looking devices on CADF (in the 1970's) as test antennas.........VHF/UHF antennas...........bi-conical monopoles with counterpoised skirts. The E and H polars are similar. From memory they were no better than isotropic radiators. But then if you employ antennas with such a wide bandwidth (almost no VSWR across the specified range) there has to be a compromise....what else can you expect....
Forget who made them. but not R&S.

[crestavega]

Peter Roberts, thanks very much for this positive ID.
What would an antenna like this be used for in practice?

[PeterRoberts]

Originally Posted by crestavega

Peter Roberts, thanks very much for this positive ID.
What would an antenna like this be used for in practice?

Quite a few things it could be used for. It could be used for general receive coverage, but in that picture there is already a discone in the background which could be used for similar, but this one may have wider frequency coverage and could be used for transmit too. As noted by sunthaiboy the performance is not great (compared to an antenna traditionally 'cut' for a specific frequency band) as might be expected from an antenna with such a wide frequency range. So, it is either general purpose (perhaps as contingency for any new radio system brought on board or a temporary installation) or for a radio system already fitted that requires a very wide bandwidth, perhaps even one including the new JTRS waveforms.

JTRS = Joint Tactical Radio System - plenty of info on Google. Although JTRS originated in the US, NATO are also using it for interoperability with the US. Radios are coming on stream all the time that use one or more JTRS waveforms, some of which are termed as 'wideband'.

All the above is guesswork as to what it is actually being used for!