One of our Marines now securing Baghdad embassy: what's he holding?

This photo.

With a fully informative caption, for once.

The loopy thing. Radio? Scanner?

Just a long, flexible antenna folded up and secured with a little velcro strap. He’s not holding it. It’s attached to a radio in one of his front pouches; the same radio that hand mic on his shoulder is going to.

Do radios work if you bunch up the antenna like that?

Yes. Their range is reduced, but they still work fine when folded up. Here’s a datasheet from the manufacturer.

Just a thought, but is “radioman” an MOS (not referring to this soldier in stable position in the photo), in a squad (? or some minimum troop number)–both as a skill (obviously) and as the designated schlepper?

I have, as always, old Hollywood war movies in my head.

ETA: nice to be in contact with you again, Bear.

That antenna is basically the same as the “blade” on your 25’ retractable tape measure. It’s coated in a rubber or plastic sleeve.

I’m a ham and we use busted tape measure blades to make easily transported beam antennas.

Here’s a plan for one.

I have read (and written) about soldiers in Vietnam jury rigging Slinkys for the same task.

Don’t want to cite myself, because … you know … I might have been wrong.

Same idea.

In the Army, each platoon and company will have designated RTOs (radio telephone operators) who are the “designated schleppers” for the radio. It will be larger radio, though, worn in a backpack. If it’s a mounted unit, the RTO might just be the person who monitors the radio link between platoon and company or company and battalion, freeing up the platoon leader or company commander to stay focused on the task-at-hand.
As far as MOS goes, there are a bunch of different jobs within the Signal Corps, including a “Radio Operator-Maintainer”, but these soldiers are more focused on keeping all the radios and communications equipment working and accounted for, rather than actually using the radio. They run and manage the commo shop, basically.

ETA: Squads won’t have an RTO, though. Just platoons and above. Sometimes, various attachments (like a Forward Observer) might also have his/her own RTO as well, however.

For the Navy, there used to be a Radioman (RM) rating. It was changed in 1997 to Information Systems Technician (IT) rating. The rating badge symbol has remained the same.

In my experience looping the antenna like that reduces the range of transmission by a guestimated 50-70% , depending on atmospheric circumstances, obstacles in the vicinoty, nearby bodies of water and a host of other factors - at least for the MH300 radios we use in Norway.

However, for most uses of such radios, when guarding say a building complex, you do not need ranges of more than a few 100m, which give you plenty of margin even when the antenna is folded. (Indeed to maintain a low EM-profile we usually use the blade antenna folded and the output amplifier turned to minimum output wattage to not broadcast longer than needed).

As an aside - that unit name was a bit of a mouth full:
Special Purpose Marine Air-Ground Task Force-Crisis Response-Central Command 19.2
The SPMAGTFCRC 19.2…

Naw, he being a Marine it would be rendered in Navalese:

SpecPurpMarAGTaffyCriRepCentCom 19.2

You can look it up in DicNavAb.