SKYWARN Q&A

This page attempts to answer many of the frequently asked questions about our team and the SKYWARN program. If there's something you'd like to know that's not listed here, take a look at our Other Q&A Topics, check the SKYWARN Operations Manual, SKYWARN Training Portal, or send us an e-mail.

Repeaters and Area Boundaries

How are SKYWARN repeaters selected?

Repeaters are chosen based on a number of criteria. The simplest way to look at our selection process is that we try to pick the repeaters which most closely match our operational needs.

For example, some of the things we look for:

• Large coverage area
• IRLP and/or RF linking capability
• Battery or generator backup
• Other users of the repeater
• Supportive, engaged, and responsive owner/trustee
• Owner/trustee willingness to engage SKYWARN in discussions on repeater enhancements and maintenance
• Historical SKYWARN usage/existing relationships

All of these things are extremely important.

Despite the widely distributed nature of our Net Controls, we want to cover as much territory as we can with as few repeaters as possible. We also need to consider the long-term reliability of the repeater, and a well-engineered system with an engaged owner or trustee is a great starting point.

Why don't you use packet or APRS?

See our SKYWARN Nets Q&A for information.

Why don't you use D-STAR, DMR, or P25?

Some of the most common digital-related questions we get are about D-STAR. In early 2014, we conducted a survey among the EMCOMM community regarding its D-STAR adoption and found adoption to be minimal.

With recent decreases in cost of the equipment as well as improvements in D-STAR infrastructure within our CWA, these two obstacles to adoption have largely been removed, but we did not see widespread integration of D-STAR into local EMCOMM plans, though several ARES teams do have the capability, as do our partners at the Virginia Emergency Operations Center (VEOC) and at NWS Sterling (WX4LWX).

As existing analog radios fail at the SKYWARN Radio Desk, our plan is to replace them with D-STAR ready equipment. Since this is dependent on the eventual failure of the analog radios, we do not have a timeline or scope of implementation at this point.

We also get inquiries about other digital technologies such as DMR and P25. We have not studied these and currently have no plans to do so. We are aware that there are DMR and P25 repeaters in operation in some areas, including Richmond, and will be casually watching the adoption and informally evaluating the technology for any potential benefit to the SKYWARN program.

How often are repeater selections re-evaluated?

Rarely.

If there is a specific concern with a repeater's coverage or performance, we work closely with the owner/trustee to resolve it. If issues persist for a prolonged period of time we may begin to look for alternatives.

As a general rule, we don't want to change repeater allocations because most folks are creatures of habit and know exactly where to go to find SKYWARN. In some cases the repeaters we use today have been SKYWARN repeaters for a couple of decades or longer, and we have little reason to make a change.

Should repeater owners/trustees notify you of downtime or changes to a repeater?

Yes. As the most frequently active emergency communications team in the region, we depend on timely and accurate information from the people responsible for operating and maintaining our repeaters anytime a piece of equipment or a specific repeater feature is down or needs to be taken down for maintenance.

Since we don't always get this information from the owners or trustees of our repeaters, if you're aware of any operational issues or upcoming downtime involving a repeater, please send a note to our Leadership team.

How are area boundaries determined?

Area boundaries are set to roughly follow the coverage of the primary SKYWARN repeater within that area.

I can't hit my designated repeater with my HT!

Due to limited Net Control resources, our objective is to cover as much ground as we can with as few repeaters as possible. This means a potentially large area may be unable to access the primary repeater from a handheld radio.

Our goal is to provide estimated coverage to home stations in 90% of an area or better. We consider home stations to be well-engineered VHF stations with 25 watts into typical feedline (a short run of RG-8X or similar) into an omnidirectional antenna up at least 25 feet.

For mobile coverage, our goal is to provide estimated coverage to mobile stations in 50% of an area or better, with an emphasis on major highways, towns/cities, etc. We consider mobile stations to be well-engineered VHF stations with 50 watts into a short run of low-loss coax feeding an omnidirectional antenna approximately 4 feet above ground level.

We do not consider handheld coverage when choosing repeaters or designating area boundaries.

Spotters may call reports in to any SKYWARN net and are not required to utilize only the net which specifically covers their location. If radio coverage into another SKYWARN net is more satisfactory, that net should be used. Or, reports can always be sent in via e-mail, telephone, or social networking.

Spotters who only have handheld equipment but are at or beyond the fringe of a repeater's handheld coverage area may consider an inexpensive outdoor antenna such as a J-pole, perhaps suspended from a tree, chimney, or some other structure, and connected to the radio through a short run of high quality, low-loss cable such as RG-213 or LMR-400. In a pinch, a magnetic mount antenna stuck to a metal pizza pan or cookie sheet and placed in an attic can provide modest performance improvements versus a stock handheld "rubber duck" antenna.

Are area boundaries ever changed?

Yes, but not too often. Sometimes changes in repeater coverage or other events necessitate re-evaluating an area boundary. It's not unheardof for a single county to transition from one area assignment to another, or for one area to be absorbed into another.

There may be small pockets in one county where an out-of-area repeater provides better coverage than the current primary SKYWARN repeater. That alone is not justification for reassignment of a county. However, if a neighboring area's repeater provides better coverage in a majority of the most densely populated areas of a county, we may consider making a change.