4011.5 was a USNMC MARS hf net qrg for ages, as USNMC MARS is deactivated I presume it's now USAF or Army MARS. The 4007 to 4060 range is populated with MARS nets in the early am and evenings, with lots of digital traffic for those so interested.
Here's some freqs I put together a year or two ago on the MARS nets I could hear;
FREQ NET USE QRG ZULU DATE
03.269 D/V 0100Z 03.10.14
03.390 4X9B D/V 0200Z 11.15.13
04.007 5G1B D/V 0030Z 02.14.14
04.011 1M2B D/V 2300Z 02.15.14
04.011 6E1B D/V 0100Z 03.06.14
04.011 6E2B D/V 0100Z 03.09.14
04.011 6N1B D/V 0300Z 02.18.14
04.011 6N1C D/V 0300Z 03.05.14
04.011 6S1B D/V 0200Z 02.14.14
04.011 6S4C D/V 0200Z 02.14.15
04.011 6L1B D/V 0000Z 02.16.14
04.013.5 4K2B D/V 0000Z 02.16.14
04.013.5 4F3B D/V 0100Z 03.02.14
04.018 A7I D/V 0100Z 02.14.14
04.018 A7A D/V 0100Z 03.11.14
04.018 A7A D/V 0200Z 02.14.14
04.018 A7M D/V 0300Z 02.14.14
04.021 A1A M066* 2130Z 02.19.14
04.021 A6A M066* 0130Z 03.05.14
04.024 A5M D/V M099 0030Z 02.17.14
04.024 A5A D/V M099 0100Z 02.23.14
04.024 A5H D/V M099 2200Z 02.14.14
04.027 A3A D/V 2300Z 02.14.14
04.030 A4S D/V M157 2330Z 03.09.14
04.030 A4B D/V M157 0000Z 03.26.14
04.030 A4J D/V M157 0130Z 02.14.14
04.030 A4A D/V M157 0200Z 02.14.14
04.030 A4H D/V M157 0000Z 02.16.14
04.030 A4H D/V M157 0130Z 03.02.14
04.030 A4S D/V M157 0130Z 03.02.14
04.033 2200Z 02.15.14
04.038.5 4G2B C NCK 0130Z 03.05.14
04.038.5 4H2B D/V NCK 0200Z 02.16.14
04.038.5 4A2B D/V NCK 0300Z 02.16.14
04.041 5M1B D/V NCL 2330Z 02.14.14
04.041 5M3B D/V NCL 0000Z 02.14.14
04.041 5B1B D/V NCL 0000Z 03.29.14
04.041 5N5B D/V NCL 0030Z 02.14.14
05.394.5 D/V M165 0330Z 03.05.14
06.823 A6J* TXGRD 0100Z 03.01.14
06.913 D/V M117 0100Z 03.29.14
SERVICE/NET ID MODES
FLFL = USN/MC D DIGITAL
LFL = Army/AF V VOICE
D/V BOTH
C cw
QRG DESIGNATION CALLSIGN PREFIX
LFFF = USA NNN = USN/MC
LLL = USN/MC AA_ = USA
AFA = USAF
NAVMARCORMARS
CONUS/REGIONAL:
QRG FREQUENCY NECOS DATA QRGS
NCL 4042.5 KHZ NAV NCP
NFK 7382.5 KHZ NAV, ASG NDE
NNA 14385.0 KHZ NAV, ASG
INDIANA USNMCMARS REGION 5 ECOM NETS:
QRG (TIME ZULU) USAGE
NFM (1200Z-2159Z) PRIMARY VOICE
NCE (1200Z-2159Z) ALTERNATE
NCL (1200Z-2159Z) ALTERNATE
NCO TRAFFIC
NFK (2200Z-1159Z) PRIMARY VOICE
NCL SECONDARY
INDIANA CMDNET
NCL Voice/Digital
NCU
NFG
NET STATE USAGE
A4J TENN ADMIN
* = TENTATIVE
primary center-frequency 5358.5 kHz
secondary center-frequency 5373.0 kHz