Subject: Simplex Operations "Simplex Operation For Emergency Response" Copyright 1997, Nonprofit reproduction permitted with attribution C. Edward Harris, KE4SKY, AEC Fairfax ARES If amateurs take repeater systems for granted and depend on them, ARES and RACES may be less able to respond during an emergency, if the repeaters become overloaded or go out of service. It is difficult to manage equipment and personnel to coordinate among several jurisdictions, if everyone uses the same few repeaters. Local and regional response plans should stipulate where simplex is appropriate and include contingency plans for managing communications if one or more repeaters go down. Command functions which don't require wide area coverage should be conducted on simplex, to ensure that limited repeater resources are maintained for higher priority traffic. Individual operators need to know assigned, coordinated simplex frequencies for local subnets, which follow approved band plans. Most public service events can be run easily by a net control and multiple HT operators on a repeater, but realistic disaster training anticipates that some or all of the local repeaters may be unavailable. In the aftermath of a severe storm, repeaters may be operating on back-up battery power, which must be conserved. Don't expect repeaters to always be available to compensate for the deficiencies of individual stations. When the Repeater Goes Down... If a repeater goes off the air, operators should have adequate power to continue on simplex, including listening for and relaying traffic from weak stations. They should meet initially on the repeater output frequency while the NCS calls for emergency or priority traffic, then for officials, liaisons and stations with traffic, either direct or via relays. NCS doesn't take routine check ins to build a roster, but determines resource needs, routes for traffic, assesses which stations can assist and deals with it as it comes. If the net is not busy, traffic may be passed on simplex there. When traffic is heavy, NCS will direct some stations to handle their traffic off frequency while the net proceeds. Sometimes the entire net may move in unison to an alternate repeater or a designated simplex frequency, but this should be considered a last resort because some stations WILL get lost in the shuffle. Use of simplex during the NCAC 1997 SET demonstrated the need for simplex stations to have adequate antenna height and power to overcome distance, terrain and ground clutter. Directional antennas and portable masts are best in outlying areas. Intermod suppression is very important. Easily understood guidelines are needed for repeater vs. simplex operation. Operators must be able to operate effectively in a simplex environment to include NTS message handling and procedures for routing local inbound traffic via simplex from outlying sub nets to liaisons for each County, tasked with prioritizing what goes out via a repeater, packet or HF. Guidelines For "Elmering" New operator classes should stress basic operating skills and procedure in addition to the minimum knowledge needed to "pass the test." ARES and RACES provides a pool of "Elmers" to help new licensees to become responsible, skilled and effective operators. Training nets and exercises should teach when simplex is appropriate and demonstrate how and when to change from repeater to simplex operation. Instruct operators to listen on the repeater input frequency. If both stations have good copy, change to simplex instead of tying up the repeater, if there is no need for others to monitor your traffic. If an event covers a radius of only a few miles, the entire group should use simplex. New operators need to be shown how to program a new frequency, offset and CTCSS tone which may not be in memory. It is recommended that an ARES and RACES reference card be issued to all operators to program their rigs, identifying primary and secondary repeaters designated for ARES, RACES and SKYWARN, also listing coordinated simplex and packet frequencies in their local area and neighboring jurisdictions. Frequency Coordination Is Important ARES / RACES should use only coordinated simplex frequencies which follow approved band plans and channelization. Doing otherwise causes adjacent channel interference. Served organizations may need to monitor your traffic and will be frustrated if unable to do so on commercial equipment unable to receive nonstandard channels. This does nothing to encourage good relations or demonstrate our operating competence. If your District has portable repeaters, use the SNP (shared, non protected pair), CTCSS and/or DTSS access. Each District needs a shared, common-use simplex frequency for use between counties. Counties need to ensure they have adequate coordinated VHF and UHF simplex channels for command, sub nets and mobile cross band links. Train on Simplex We started a weekly Virginia District Two simplex net a year ago, following the examples of previously existing nets in the Richmond area and in Montgomery Co., MD. The purpose of our net is to encourage simplex operation, teach correct operating procedures, provide guidance to improve station performance and enhance basic skills. Members are encouraged to check using other than fixed stations and commercial power. When used to operating on repeaters, people forget that on simplex you must open your squelch, to hear the weak stations, instead of keeping the squelch tight to reduce random noise. New operators also need to develop judgement on how much power is needed on simplex compared to what they use on a repeater in the same area. We always stress using the minimum power needed to maintain reliable communication, but with simplex, the emphasis is on RELIABLE! There is a lot to recommend buying full-powered mobiles as first rigs. A modern mobile rig costs little more than a "good" HT, but has much better simplex performance. Having "only an HT" usually limits the user to nearby repeaters or local simplex within a few miles. While measures can be taken to improve simplex performance, such as better antennas, an HT is not adequate as a primary rig for emergency communications. For VHF simplex nets to covering several counties it is recommended that most operators have either 50-watt mobiles equipped with 5/8 wave antennas or equivalent ERP fixed stations, capable of operation on emergency power for at least 24 hours. Hand helds can participate with reasonable effectiveness at 5w using a directional antenna such as 3 or 4-element yagi; or with an outside mounted omni directional gain antenna, such as a J-pole, aided by a 30w brick amp. If an outlying station or HT signal is so weak that it cannot be copied, it takes double the air time and battery consumption from others to provide relays, repeats and fills to get the traffic through. Operators should use adequate power to get their traffic through the first time, without wasting the battery using far more power than necessary and causing interference to stations they cannot hear. Equipment discussions are always popular. Our members have found the Cushcraft AR-270 dual-band vertical one of the best antennas for attic installation in condo or townhouse developments having restrictions on outside antennas. Favored mobile antennas are anybody's 5/8 wave whip, the Diamond SG7900 and Hustler CG144 collinears. Small 3-4 element yagis are favored for low power, portable stations and operators in fringe areas of the District. I sometimes act as NCS while "rover" from 80 miles away at Mills Gap, 1083 ft. AMSL, in Berkeley Co. West Virginia. I have no trouble getting across the Shenendoah Valley and Blue Ridge into Fairfax, Arlington, Prince William, Loudoun and Fauquier counties using a 4-element Cushcraft 124WB on 15 ft. mast, driven with my 50-watt mobile. A regular net check-in from Warrenton powers a 5w hand held and 30w brick amp from a deep cycle battery, feeds a 4-element yagi on 20-ft. mast with 9913F and produces "solid copy" to the net from 30 miles out. ARES Training Objectives Initial training objectives for our simplex net during its first year were to teach new ARES operators to use plain language, correct "pro words" and ITU phonetics on phone, become proficient in directed net procedures, NTS message handling, to routinely provide relays as needed and operate effectively in a simplex environment. Several "regulars" have learned to operate "tactical mobile," or what contesters would call "rover", through interest in our net. We are trying to set up a regular NCS rotation among all counties in the District, instead of it being shared mostly among Fairfax, Alexandria and Arlington. This way we hope to encourage more participants from outlying counties, so they will be able to hear net control direct and not be discouraged by frequently needing relays. Working contests in the field is great practice for disaster deployment. Powering a mobile rig from the car battery works well for a few hours, but it is wasteful to run the engine for 10 minutes every hour to keep the battery charged. One option is to equip a vehicle with dual batteries, a control box and isolation circuitry obtained from a boating or RV supplier to separate the "starting" battery from the "comm" battery. Others carry a separate, boxed, deep cycle marine battery with attached trickle charger and mobile power cord in the trunk, "go kit," antenna, coax and military portable mast with tripod adapter. Operators know their primary set up location, can deploy and call up a District-wide net on short notice. Battery Basics: It is basic to emergency operation that stations have backup 12V battery power for at least 24 hours. To determine battery needs take the total equipment current load in amps times the duty cycle in percent, times 150 percent. For instance a 50-watt VHF mobile requires 10 amps on transmit and 2 amps on receive. Assuming 25% duty cycle over 8 hours, two hours of transmit time requires 20 amp hours; plus six hours receive at 2 amps is 12 amp- hours, which equals 32 amp-hours times 150 percent means 48 amp hours for an 8-hour shift. You then need TWO such batteries so you can use one to power your station while charging the other, unless you have three such batteries or one monster stationary battery to run continuously for 24 hours without charging! If you add a 150 watt VHF amp to the package, you should rotate between two batteries on 4-hour duty cycles. Small gel cells of less than 5 amp-hours should be charged at the same rate as equivalent nicads to prevent over-heating. A common rule is to charge at the rated battery voltage + 15% using current of not less than 10% and nor more than 25% of the amp/hour rating of the battery, for a charging time equal to the amp-hour rating of the battery + 25%. A 12V, 2 ah cell is charged at 13.8V/500ma/5 hours. Gel cells larger than 5 amp/hrs can be left continually on a 12-14 volt, 1 to 1.5 amp, marine type "smart" charger or "maintainer" without harm. For a portable station at a shelter, two 33 ah wheel chair gel batteries can be transported easily by one person and permit extended operation of an HT and 30w amp or typical mobile rig at low or medium power, scanner, laptop computer and TNC. If AC mains are lost, two such batteries in parallel run a mobile on low power, plus laptop PC and a TNC for 2 days if you are truly miserly about power use. If AC power is lost for more than 3 days, you either need generators, adequate fuel, power strips and cords to distribute the "juice;" or solar panels or a home made "pedal generator" made from an old bicycle frame and auto alternator to keep your large deep cycle battery topped off. Efficient Antennas and Feed lines Save Power Best simplex performance always results from the most efficient antenna, at the greatest height above ground elevation and shortest run of lowest loss feed line, to provide the highest ERP for the least battery consumption. A unity gain, quarter wave mag mount thrown on top of the nearest metal object may work fine for a local repeater, but on simplex will be lacking. On simplex you need more than QRP, and the antenna should go outside, away from people, as high as you can get it. With an HT, rig a gain antenna, such as a J-pole up in a tree before hooking up that brick amp. For a mobile rig, use a portable mast mounted base antenna or yagi. Increased antenna height and gain enables you to use less power to save your batteries. Most 2-meter mobiles draw about 10 amps of current for 50w out. At a 25% duty cycle a 50w mobile draws down a 6.5 amp-hr. "Power Station" in 2.5 hours. Using a 10 db, 4-element yagi, you can reduce PEP to 10w, for the same ERP as a 50w into a 5/8 wave omni, but draw only 5 amps, so the battery will then last 5 hours. New operators must be "hooked" first by a net before they appreciate that knowing how to ask for or provide a relay is a good thing. We want to hear from others who conduct nets or exercises on simplex so that we can share ideas to keep our nets productive and interesting. Then we all can provide an opportunity to practice net control and NTS traffic handling. We invite amateurs from any jurisdiction to check into the Virginia District Two ARES Net, 2030 hrs. Fridays on 146.415. By training to operate effectively on simplex, ARES is more flexible and, if needed, able to maintain emergency communications, without dependence upon repeaters. For further information see the Virginia ARES web page at: http://www.aresva.org