The BHEPP MARS/WL2K Emergency Radio System (BMERS. Pronounced "beamers") was created as a research collaboration between the NIH Radio Amateur Club (NIHRAC), the US National Library of Medicine (NLM)
, and the Bethesda Hospitals' Emergency Preparedness Partnership
). The project also had contributions from Army-MARS
and other hams. The purpose of BMERS is to supply the BHEPP Hospitals with a backup communications system that they can use when other communications resources such as cell phones, Internet access, and others, become unavailable over a large area around the hospitals, such as during a large disaster event.
The expected outcomes of this project are the following:
- A technical solution that provides the hospitals with access to long-haul email communications with minimum dependency on infrastructural services, such as regular telecommunications, power, etc.
- A communication system that can be simple to use and as simple as possible to enable, operate, and maintain during an emergency situation and regular emergency exercises.
- A system that provides electronic mail communications between the hospitals' Command Centers in support of their Hospital Incident Command System.
- Emergency communications support provided to the hospitals by experienced and dedicated volunteers from the ham and MARS communities.
More details about this project and the implemented system can be found in this QST
Cid V, Mitz A. "Optimizing Amateur Radio Resources for Major Disasters". ARRL QST Magazine, September 2011 issue, pages 30-34.
You can temporarily acess a copy of this article in our Resources
page. At this location you can also find a presentation
about the project, and a BMERS poster
that depicts the main components of our portable station.
This diagram illustrates the main components of our BMERS system:
BMERS has the following high-level components:
- A high-speed, hardened Local Area Network between the hospitals. This network (called BHEPPnet) was implemented via a separate BHEPP project. This LAN interconnects the hospitals' Hospital Command Centers (HCC), and it is intentionally not connected to the Internet for security and reliability reasons.
- A computer server connected to BHEPPnet, hosting a webserver, customized electronic mail server software, and the software required to use the Winlink 2000 system.
- The server is connected to our base radio station, which is equipped with an HF radio, SCS Pactor 3 modem, and a variety of HF antennas.
- The system makes use of the Amateur Radio Safety Foundation, Inc's (ARSFI) Winlink 2000 system to allow for emergency email service via ham and MARS radio.
In addition to the system described above, we developed a portable version
, which uses the same software, but implements its own LAN (wired and wireless) around the radio station and, via a Wi-Fi bridge, can extend the LAN access to the system to users located up to a mile away. The portable version can use a variety of power sources and antenna systems.
- Users can use any available computer (or tablet or smartphone when Wi-Fi is enabled) with a standard web browser to access the email service. No software needs to be installed on users' computers.
- HCCs at the BHEPP hospitals can exchange full-featured emails with attachments.
- BMERS implements a number of features aimed to manage the use of the radio link's limited bandwidth (see below).
- Users' email accounts in BMERS are all role-based and follow the staffing positions defined in the Incident Command System.
- Users can see which other users on BHEPPnet are using BMERS at any given time. The available email address in the LAN are predefined in an address book for quick access.
- Users can use a "chat" tool to send instant messages to each other and to the radio operator.
- The Radio operator has access to a GUI-based tool to manage the system. The tools allows the operator to monitor the email queues, quickly switch between ham and MARS operation, and more.
The bandwidth provided by a HF (or even VHF) radio link for sending email over Winlink 2000 is very limited. It's very easy to completely choke the link with a single large email. The radio operator can potentially remove a large email from a queue on the local radio station side to unclog the system, but there is nothing he/she can do with a large email coming from the other side other than waiting (possibly a long time) for it to be downloaded. While the radio link is busy receiving an email, no email can be sent. This situation is what we call "bandwidth catastrophe".
There are no limitations when sending emails within the BHEPPnet LAN, but to reduce the chances of a "bandwidth catastrophe" in the radio link to the Internet, we implemented a number of features in the software:
- Users need to use a texting interface to compose email messages going to the Internet. This interface has a message size limit (currently 600 characters). It displays a character counter that tells the user how many characters are left when typing a message.
- Users can only send an email to a single Internet destination (no copies), to reduce the chances of multiple users replying at the same time and clogging the link on the way back.
- Emails include instructions for replying, which include a request to keep replies small.
- The body of the message is stripped of unnecessary characters before sending.
- Headers and other control information is kept to a minimum.
Software and Documentation
You can download the latest software and documentation from our Resources page
. However, before you can install the software, you need to get a software key for Afterlogic's Webmail Pro
from ARSFI. We are currently modifying our system to use a free version of this software, so check our repository for updates. Please send an email to vcid @ nih.gov
for more details.