[MRIC] Some advice, please

[brett.hammond]

Hi Bob,

I'm not sure if I understand your question, but regarding choosing a new frequency to use that would not interfere with someone else, I suggest looking at the MRIC Frequency list which contains the frequencies used by all RACES stations in Maryland, and choosing a frequency that is not being used by another nearby RACES station. This list is forwarded to all MRIC members every time it is updated (after almost every meeting). If you can't find it, I can forward another copy to you.

Regarding Winlink frequencies, the guidelines we approved at MRIC suggest at least an HF Winlink station at your EOC. The best bands to use are 40 and 80 meters because they are the most popular for Winlink, but 10, 15, 20 and others are still usable. A complete list of all available Winlink RMS Internet Gateway frequencies that you are allowed to connect to in order to send email, is available via the winlink.org website.

In addition to the HF Winlink station at your EOC, many jurisdictions are planning on installing a local UHF or VHF Winlink network in their county so Winlink stations around their county can communicate to each other without having to use HF. Since that would be entirely within a county, and does not involve interoperability, MRIC has not addressed the subject of local UHF/VHF Winlink stations. To communicate to other jurisdictions in Maryland, HF is recommended, and you can forward your email to any RMS in the world-wide Winlink network that has a current Internet connection (they won't let you connect if their Internet is down). When other jurisdictions connect to a Winlink RMS, your email will automatically be forwarded to them, no matter where they connect in the Winlink network (that is one of the purposes of the CMS sites).

In Talbot County we have 5 Winlink stations that communicate to our EOC via UHF at 9600 baud. We use VHF for local voice communications in Talbot County, so we install one dual-band antenna at each shelter/hospital/etc. and talk VHF voice and UHF Winlink simultaneously over a single antenna and feedline without interfering with each other (assuming you have 2 radios and a duplexer). We have tested this and can actually transmit both at the same time without interferring. Other counties prefer to use VHF for local Winlink because it goes a little farther, but in a flat county like Talbot, the weaker UHF works just fine and gives us a little more privacy, and less interference with our neighbors. If you are installing antenna on mountains, UHF will work fine unless you are going very long distances through dense woods, even then, I think I might still use UHF, just transmit higher power.

Also, you will need to set up one Winlink computer to support "local hubbing" so that it acts as an email server to all your other UHF/VHF Winlink client sites, and forwards email between them. We use our EOC Winlink computer for HF, as well as local hubbing for our UHF/VHF stations, as well as the gateway to the Internet, when the Internet is operational. When the Internet goes down, it automatically uses HF to get our emails to/from the Internet (we are still working on our HF link). You can think of your local county UHF/VHF Winlink network as a star network architecture, with the local-hubbing RMS at the center of the star.

Pick a UHF/VHF frequency for your local Winlink network that is not being used by a neighboring RACES station, and that fits into the TMARC band plan. Bring it to the next meeting and we'll add it to the list, as long as their are no objections.

Alternatively, you can join efforts with a neighboring jurisdiction and share a single local-hubbing UHF/VHF RMS.

If I didn't answer your question, let me know and I'll try again.

Brett Hammond
410-829-6749


On Fri Oct  8 19:42:29 2010, <rjlong61 at myactv.net> wrote:
> 
> We are having to coordinate some frequencies with one of our facilities 
> providers.
> 
> In the near future we hope to add a packet node and if necessary a node 
> to pass Winlink traffic.
> 
> 1.  Do we need to have 2 different nodes (this will just be a 2M 
> forwarding node we will not interface with an HF radio at this site)?
> 
> 2.  What frequencies would best interface with the rest of the state?
> 
> I need your suggestions.
> 
> Thanks,
> 
> Bob,     RO WASH
> 
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