Instruction: Answer the given question using the supporting document.

Input:
Question: Does the radio have single side band? And does it have an RCA adapter for an external antenna?
Document: It sounds crisp and looks sharp, performs well on SSB, and includes a power adapter and an external reel antenna that can be connected either by a jack or a clip. It also comes with a well written and fairly large-print operation manual. The radio is on the expensive side, but that's the way it goes.
I purchased this radio principally for SW use. I received it yesterday and had already been testing a Grundig G3 since last weekend. Side by side, the 909X has superior SW reception than the G3, to make the price difference of $125 worth it for me. I felt the G3 had a decent reception for its price, specially relative to my previous SW radio from years ago. But clearly the G3 reception is inferior to the 909X. The external antenna included with the 909X makes the signal even stronger.
I received the 909X in a timely manner and so far the Radio has met my expectations. I use the the Radio for Shortwave listening anduse an external Antenna for that purpose. Most of my listening is in a Basement room. So the internal Whip antenna is not used whileI'm on Shortwave. The whip antenna is used for FM all the time. The Broadcast AM Band Ferrite Bar antenna works fine for all local AM stations. The Audio is outstanding for this small of a radio.
works great on the shortwave bands with my external long-wire. handles the strong signals from a good antenna well, no spurious signals detected.. be careful using an external speaker. as the instructions state if not careful the medium wave band will be damaged as i can personally attest to, my MW reception has been damaged by using an external speaker and an external antenna
A very feature packed little receiver with superb FM Stereo. Upper and lower Side Band in SW is also nice. A real value in my opinion.
really nice radio.. direct entry..or VFO.. memory scan, nice large display.. very solid case..  receiver very sensitive.. I use a long wire for portable  around 50 ft, soldered a 3.5 mm connector on the wire,plugs to the radio,  battery charger built in,  am, usb, lsb mode's..  comes w  case, ac adapter,  and  wire antenna..  a great deal
However,for me that is not an issue. The Radio comes alive on Shortwave when hooked to a small External antenna.
I am glad there are 27 FM memory presets, but I wish there were more because I have already used all 27 FM memory slots! The audio quality is pretty good for a radio of its size. I like that a travel pouch is included with the radio as well in addition to headphones and an external antenna.
There are not a lot of stations that reach us, so this may not be an issue for users in Europe, for instance. The whip performance increases marginally at night, but during the day it was near-useless. Using just the supplied long wire via the external antenna jack made the Sangean's sensitivity quite good day and night, and slightly surpassed the Tecsuns' reception with their shorter whip antennas. It makes the Sangean sort of like a table-top radio in disguise.
An inexpensive DSP-based radio like the Tecsun PL-310 or PL-390 "hears" much more, especially daytime MWDX, than this radio costing several times as much. Even on FM with a shorter antenna, the Tecsun models were hotter. I realize that I can always add an external antenna, and of course that is the usual technique for SW listening, but I was not going to fiddle with an external loop antenna just to bring MW reception up to par.
Answer: Yes, it does have single side band; no, it does not have an RCA adapter (neither for an external antenna, nor for the AUX input). The AUX input is 1/8" female, stereo. External antenna input is 1/8" female mono.