LOL, how deep do we want to go down the rabbit hole?
(Full disclosure: I'm an engineer, but definitely not a naval architect. Anything you see below has a 5-20% chance of being completely wrong)
You've already said NSC-ish fit, but let's back up a little. What's this ship for? What's the mission, what's the region, what's the larger naval arm like? For example, the US Coast Guard in general is a relatively combat-capable arm, and historically has had real DOD responsibilities. This shows in her design, which is built to naval standards, has an unusually capable helo fit, extensive VBSS equipment aft, and a nearly frigate-grade air search radar and gun fit. Indeed, Ingalls has offered NSC-derived offshoots as actual naval frigates.
The USCG also operates in severe conditions and far from shore where it is valuable to have substantial bad-weather air search capability. Were we talking about, say, an Italian ship that might never leave the Med, having a big air search set might be unnecessary. Not because the Italian services are incapable or anything, but because land-based radars can largely cover the entire area at high altitude. For geographic reasons, they'll tend to have much more extensive surface search and rescue capabilities than USCG units. Different ships for different needs.
So that's a lot of words to say that NSC is maybe not the appropriate baseline. Let's build up from absolutely nothing to a frigate-class electronics fit.
I'll make references to
Valcom comms antennas and
Thales and
Kelvin-Hughes radars, mostly because these manufacturers are really friendly about sharing technical data like frequency, dimensions, and weight.
This is also a useful resource:
http://www.jproc.ca/rrp/halifax_antennas.html
Anyway,
Absolutely mandatory:
X-band surface search radar (e.g.,
CMX12-26)
VHF marine/aviation comms (e.g.,
AS-2809 and
VAS-1016A)
You just don't go to sea without these, period.
Really, really close to mandatory:
Second surface search set (either a more capable X-band unit like
SPS-73 or an S-band unit like
SharpEye)
UHF comms (e.g.,
AS-2810C/SRC)
HF comms (e.g.,
AS-3772B/U and/or wire fan antennas)
LF/MF receive (various)
Satcom of some flavor
A second surface search set is required for ships above a certain size (definitely including this cutter, I think). S-band is better than X-band in foul weather, generally. You can alternately use a more capable X-band unit to brute-force the problem. X-band has better resolution for a given size and is better at small-target detection. The NSCs went with the larger X-band unit for periscope detection and for USN parts commonality (a big deal!).
UHF comms are necessary for interoperation with military aviation; HF comms are necessary for long-range surface communication.
Satcom needs will vary, especially depending on what spaceborne assets your country has. NSC, surprisingly, does not seem to feature high-capacity UHF satcom (the ubiquitous
OE-82C), but has SHF and EHF (not sure the exact flavor, but
SURFSAT-S would seem appropriate). Omnidirectional (low-capacity) UHF satcom is nearly pixel-sized at Shipbucket scale (e.g.,
AVXD). INMARSAT (
e.g.) is also likely.
GPS is basically invisible at this scale.
Included on large cutters like NSC:
Air-search set (e.g.,
SPS-75)
Surface gunfire support (e.g.,
SPQ-9B)
Larger satcom antennas for higher bandwidth
ESM/ECM (e.g.,
SLQ-32,
Vigile)
EO/IR (e.g.,
Mirador
TACAN (
e.g.)
The utility of all of these is obvious. Note that an air search set will generally include IFF.
Not included in NSC, but maybe nice:
Dedicated fire control set (e.g.,
STIR-1.2)
Minor hull-mounted sonar (e.g.,
Kingklip)
Alternately, consider an integrated mast solution like
I-Mast. This will just solve all of your problems for you!
ORRRRRR
Just ask the US Navy
Further reading that might be interesting:
https://chuckhillscgblog.net/2015/11/14 ... ol-cutter/
https://chuckhillscgblog.net/2013/12/04 ... other-lcs/