Idaho Amateur Radio
Emergency Service
   
Operating Tips

OPERATING TIP 1  

DMR: NETWORKS ARE A SHARED RESOURCE

Networked DMR communications is a shared resource, with imposed latencies (delays) that require a high level of ETIQUETTE applied to radio operation. Operators must visualize that their communications may not only be heard by hundreds, or thousands of DMR users, but that resources are being tied up by communications and may deny other users access. Users should invoke a higher level of operational courtesy, and a stronger adherence to structured protocols to avoid denying access to other operators.

 
 
OPERATING TIP 2  

DMR: ACCOMMODATING BREAKING STATION WHERE LARGE LATENCIES PREVAIL

Because of latency that is introduced by digitally encoding of digitized voice communications with Forward Error Correction codes at the transmitter, the application of Forward Error Correction to decoded data at the receiver, and the delay inherent in internet traffic, significant and noticeable latency (delay) is inherent in DMR communications. An analogy can be drawn to analog FM repeater communications, where protocol demands delaying until the repeater squelch tail drops, and voice must be delayed after keying to accommodate tone decoder delays. Similarly, DMR requires that you wait after a transmission stops, and before you start a transmission, to accommodate breaking traffic. It should be noted that there is no repeater squelch tail with DMR. Operators should wait for a minimum of 2-seconds after hearing the end of a transmission before initiating a transmission, and then wait an additional 1-second after keying the transmitter before speaking. Remember, users of any DMR repeater, or any DMR hot-spot device, on a world-wide basis, may wish to break in. Failure to adhere to delaying transmission may result in denying other operators access.

 
 
OPERATING TIP 3  

DMR: THE ART OF LISTENING FIRST

Nowhere is the importance of listening first more applicable to radio operation as it is with DMR, and especially networked DMR. When you arrive on channel, listen for a minimum of 30-seconds to get a sense as to whether the repeater, or the talk-group is in use. If the repeater or talk-group is in use, listen for a while to acquire conversational context, and then intelligently decide whether you can or should interject in the conversation. Do not interject to mislead or take-over a conversation. Rather, wait until the conversation is completed before interjecting if you mean to change topics or focus.

 
 
OPERATING TIP 4  

DMR: AVOID EXCESSIVE ANNOUNCEMENTS

Announcements should be used sparingly. Many operators on DMR are in the habit of announcing their presence on DMR. Many of these announcements occur without applying the Listen First technique described above. There is a time when such announcements are sensible, but far more often than not, such announcements are disruptive and annoying. An announcement may be necessary to notify other repeater users that the repeater is now on a specific talk-group. But for most other purposes, such announcements are unnecessary. If an announcement is made, for the sake of notifying other repeater users that a specific talk-group is in use, the announcement should be made only once, and should not be periodically repeated. Operators should not make themselves a nuisance by periodically and repeatedly announcing their call sign and that they are listening to a specific talk-group as doing so literally drives other operators, who may be waiting for a call, to move to another talk-group. Remember: A talk-group is a wide-area resource, used far beyond the scope of your local repeater or hot-spot, and requires being courteous to other operators by using the resource sparingly. Over use of announcements tends to deter station operators from monitoring or communicating on a talk-group.

 
 
OPERATING TIP 5  

DMR: DO NOT POUNCE

The Last Heard resource that is available on the BrandMeister Network web-site is a powerful resource to determine when a specific operator is available or when a specific talk-group is in use. However, operators should take care to apply the Listen First procedure when switching to a talk-group observed on Last Heard before interjecting into a conversation.

The DMR-ID of a station appearing on the talk-group may be displayed momentarily on your radio. This can be a consequence of the other station moving a dynamic talk-group on a repeater, or a hot-spot (such as a SharkRF OpenSpot), to the ARES-ID talk-group, and occurs when the station momentarily keys their transmitter to move the repeater or hotspot to the target talk-group. Such display of DMR-ID, or additional identifying information that may be programmed into the radio contact list, is not an indication that the station wishes to be called. The station may only wish to monitor the talk-group. Stations switching between repeater channels and/or hot-spot devices also will key to inform the network servers how to route a private call.  It is difficult to determine what the station intends.

In summary, do not force a QSO, but allow a station to move to the talk-group with the purpose of monitoring. Do not give the impression to other operators that you are waiting to pounce every time they appear on the talk-group.

 
 
OPERATING TIP 6  

DMR: ALLOW OTHER STATIONS TO COMPLETE A CALL

DMR latencies can make it difficult to complete a call if another station responds to a call that is not directed toward them. Unlike other operating modes, such as analog FM simplex or analog FM repeater operations, a station that is not targeted in a call and that responds, even with a simple query to ask if they were called, can cause the targeted station to not be heard. There may be no indication that doubling has occurred. If you think that your station may have been called but are not certain because you did not actually hear the call, it is important that your first response is to wait in order to allow for the targeted station to respond. It is far better to wait 10 or 15 seconds, and then, if the channel is clear, make a query to ask if your station was called than to respond when uncertain and deny the calling station and called station the opportunity to establish contact. This operating principle employs the primary Amateur Radio operating skill of always listening first.

 
 
OPERATING TIP 7  

DMR: AVOID talk-group HOPPING

Talk-group Hopping, is a process where a station makes a call on a talk-group, waits a very short period of time, and then moves to the next talk-group before repeating this same process. Talk-group hopping is both disruptive to communications and an abuse of a shared network resource. Talk-group Hopping should be strongly discouraged. If talk-group hopping is a normal operating procedure for you, please do not include the ARES-ID 31016 talk-group in your talk-group hopping sequence.

 
 
OPERATING TIP 8  

DMR: AVOID UNNECESSARY NETWORK BANDWIDTH CONSUMPTION

If all parties in a QSO are operating on the same repeater, and networked resources are not required to support the QSO, move off of the Brandmeister Network talk-group and carry on the QSO on the LOCAL talk-group as configured for the repeater that you are operating on. Do not unnecessarily consume networked bandwidth. If all parties to a QSO are not on the same repeater, then this is a situation where network utilization, and the act of occupying a talk-group is justified

 
 
OPERATING TIP 9  

DMR: USE OF EXTREMELY LARGE AREA talk-groupS

Talk-groups that cover an extremely large area should not be used for conversation. Rather, these talk-groups should be used to make a call, and then move off to a less used talk-group to conduct your conversation. For example, use USA 3100 to make a call and then move off to a state-wide talk-group, such as IDAHO 3116, to conduct your conversation. Do not deprive others from making a call by using such large area resources for conversation.

 
 
OPERATING TIP 10  

DMR: TREAT talk-groupS LIKE A HOME THAT YOU ARE A GUEST IN

Networked DMR should not be visualized as a peer-to-peer resource that is limited in scope to the sphere of local repeater coverage foot-print. Networked DMR operation is a wide-area resource and demands a higher level of awareness of its wider scope, along with an extra dose of operational courtesy, to ensure that all users are accommodated and that a operations on the talk-group do not repel the very operations for which the talk-group was established.

 
 
OPERATING TIP 11  

FM: SQUELCH ADJUSTMENT

With no receive signal present, the squelch control on an FM receiver should be adjusted just to the point where the audio becomes muted. Man-made noise sources may cause the squelch to pass audio and it may be necessary to adjust the squelch control with a dependency on other equipment that may be operating in proximity to the FM receiver. For example, a computer or a cash register may present a weak signal that opens the FM receiver squelch, and you may need to temporarily increase the squelch threshold setting when in proximity with such devices.

 
 
OPERATING TIP 12  

OPS: SIGNAL REPORTS

Signal reports are never to be interpreted as a personal attack. Nor does a signal report imply that improper station performance is an intentional act. Signal reports are always intended to to be an aid to station operation. Most amateur radio operators place high value on receiving a signal report, and especially so when the report is accompanied by a technical description that explains how anomalous operation affects station performance and suggests possible root causes. In fact, most amateur operators desire to have any anomalous operation reported to them.

 
 
OPERATING TIP 13  

OPS: DUPLEX COMMUNICATION

Most radio communication occurs in half-duplex mode. Before explaining half-duplex, let's talk about the mode of communications that we all use in our conversations that are not conducted over radio, that is full-duplex.

In full duplex operation, you can hear the person that you are talking to at the same time that you are talking. In this mode of communication, you can interrupt or interject into the conversation through the simple act of speaking. With the exception of Repeaters use of full duplex operation in Amateur Radio is extremely rare.

In half-duplex operation, you cannot hear the station that your are conversing with while you are talking. This is equivalent to placing your fingers in your ear whenever you are speaking with another individual, and they would do the same.

In half-duplex operation, you cannot interrupt or interject while another station is transmitting. Nor can the station that your are conversing with interrupt or interject while you are transmitting. We cannot talk and listen at the same time in a half-duplex system

 
 
OPERATING TIP 14  

FM: CAPTURE OR DOUBLING

When using FM, the stronger of two stations will be heard over the weaker station. This phenomenon is referred to as capturing the receiver. Even in these cases, there may be a low level tone or growling in the receiver, accompanied by some level of interference to the station that has captured the receiver. The low-level tone, growling or interference is evidence that another station wants to break-in, or, perhaps, the station breaking in captured the receiver and the station you were conversing was not heard.

 
 
OPERATING TIP 15  

FM: REPEATER SQUELCH TAILS

Early repeaters used relays to key the transmitter in response to the receiver detecting that a signal is present. Some propagation effects, such as mobile flutter, or picket fencing, would cause the repeater transmitter to cycle on and off as the receive signal experiences fading and restoration of received signal. This cyclic operation would result in premature failure of the transmit relay. Further, the delay in keying the transmitter may itself be responsible for rendering a signal unintelligible when compared to leaving the transmitter keyed during periodic momentary signal fading conditions.

These problems were mitigated by implementing a squelch tail timer. As soon as the receiver detects a valid signal, the transmitter is keyed immediately. When the received signal drops out, a timer is started and the transmitter remains keyed until that timer times out. The squelch tail timer duration is longer than most periodic signal fading conditions, and is able to avoid un-keying the transmitter in instances of periodic fading conditions.

Secondary to this function, the squelch tail serves a second purpose in providing a queuing signal to indicate when a user station may begin transmission. Stations may begin transmitting after the repeater squelch transmitter drops. This can be identified by the sound of the repeater squelch decaying being retransmitted by the repeater transmitter when the receive signal drops out of the repeater receiver, followed by a delay that is equal to the duration of the squelch tail timer, and then the sound of the squelch decay heard directly on your radio when the repeater transmitter drops. Although the squelch tail timer duration typically is approximately 1.5 seconds long, shorter and longer squelch tail delays may be present on a given repeater system.

This double decay of squelch circuits, resulting in short noise bursts that are separated by a 1.5 second delay, is often referred to as a ker-chunk sound, or simply the squelch tail (it is not a come-back).

The squelch tail is used in repeater operating protocol to indicate first, that the transmitting station has ceased transmission as evident by the first squelch decay noise burst, and second, that the repeater transmitter has stopped transmitting as evident by the second squelch decay noise burst. Conversing stations should not start transmitting until the second squelch decay noise burst occurs. Breaking stations should transmit in the interval between noise bursts, as conversing stations will be standing by to wait for the repeater transmitter to drop, in order to make their presence known.

The sequence to hear is a CH sound, followed by silence for a count of one, one thousand, two, and then a CH sound.

If the audio queue from the squelch circuit decay is difficult for you, watch your signal strength meter or receiver active Light Emitting Diode for an indication that the repeater transmitter has dropped before keying your transmitter.

 
 
OPERATING TIP 16  

REGULATORY: Why does the repeater drop out on long transmissions?

Individual repeater transmissions are limited to a maximum duration (by FCC regulations, there is a 10-minute maximum). This is enforced by a timer in the repeater control circuitry. If a transmission exceeds the maximum allowable duration, the repeater transmitter will drop at or before the maximum duration is reached. The repeater transmitter will stay un-keyed until the signal at the repeater receiver drops.

To avoid the timer invoking a drop out of the repeater transmitter, be sure to let the repeater transmitter drop at the end of the squelch tail.

 
 
OPERATING TIP 17  

DMR: SHOPPING FOR A RADIO

All DMR repeaters require compliance with DMR Tier II.  A DMR Tier I radio will not provide repeater access.  DMR Tier III supports Trunking operation (rarely used on Amateur Radio).  When shopping for a DMR radio, make sure that you purchase a DMR Tier II capable radio.

 
 
OPERATING TIP 18  

OPS: THE LANGUAGE OF AMATEUR RADIO

Because of Amateur Radio's close relationship to Emergency Communications, and to a lesser degree, Public Service communications, it is vital that we, as Amateur Radio operators, are understood by those agencies and organizations that we serve. The day to day operating habits that we establish will prevail in NET operations, or in an Emergency Communications or Public Service role. Further, since many Amateur Radio communications are international in nature, the use of anything other than standard english serves only to cause the break-down in communications.

This is why it is critical that we use Plain English. Further, training from the Federal Emergency Management Administration (FEMA) mandates that Plain English be used.

 
 
OPERATING TIP 19  

OPS: ALWAYS LISTEN FIRST

Of the utmost importance is to listen to the frequency prior to making a call. If you observe that the frequency is already in use, wait until the frequency is no longer in use before making a call. If someone else made a call, allow time for the station that they called to respond before making your call (note that the calling station will likely repeat the call). If the call is an emergency, you may break in at any time to make an emergency call. If the call is not an emergency, but is urgent or time critical, you may break in and, when acknowledged, explain that you would like to make a quick call and will vacate the frequency shortly if allowed to make a quick contact (most Amateur Radio operators will accommodate such a request). If the frequency is not in use, you are free to make a call.

 
 
OPERATING TIP 20  

OPS: USE OF THE PROWORD BREAK

Do not use the proword BREAK to break into a conversation.  The proword BREAK is used to indicate a separation of text from other portions of the message.  To break into a conversation, simply key and say your call sign.

In an emergency, use the phrase BREAK BREAK.

 
 
OPERATING TIP 21  

OPS: What Do I Do When Nobody Responds To My Call

If you wish to make another call, you may do so. If you do not wish to make another call, you may simply cease operation. Clearing off the frequency is optional, but usually not necessary.

 
 
OPERATING TIP 22  

REGULATORY: How Should I Identify My Station

When your transmitter is active, your station must be identified once every ten minutes. Identification, while in conversation, usually occurs When establishing initial contact, once every 10 minutes while in conversation, or when terminating contact.

 
 
OPERATING TIP 23  

OPS: Use of the Phonetic Alphabet

The use of the ITU/ICAO Phonetic Alphabet is the standard phonetic alphabet for Amateur Radio operations. Although some Amateur Radio operators make up phonetics, there is no proof that these achieve better results in achieving clarity. Further, making a habit of using non-standard phonetics can create the habit of using non-standard phonetics, and may carry over to emergency communications and public service communications.

 
 
OPERATING TIP 24  

OPS: What is a FIPS code?

The Federal Information Processing Standard (FIPS) county code is composed from a 2-digit state code and a 3-digit county code. The state code for Idaho is 16. County codes are usually assigned in numerical sequence, using odd numbers to accomodate changes or additions without upsetting the existing order, derived from an alphabetical ordering of counties that starts at number 1.

 
 
OPERATING TIP 25  

OPS: What is a directed NET?

A directed NET enables the NET Control Station to prioritize requests for resources, to efficiently handle traffic from multiple stations, and to keep a centralized log of requests and responses.

 
 
OPERATING TIP 26  

OPS: Communications Skills for Passing Traffic

The goal of any communication should be to accurately communicate a message with brevity and clarity while adhering to NET protocols. Successful attainment of these goals results in minimum bandwidth consumption, which leads to the ability of the NET to handle a higher number of traffic messages, the lossless communication of information, resulting in accurate conveying of information, and minimized latency for those stations needing to pass traffic after you.

Non-critical transmissions of a casual nature have no place in emergency NET operations. Although tolerated during scheduled directed NETs, such transmissions should be held until formal NET traffic has been completed.

 
 
OPERATING TIP 27  

REGULATORY: Tactical Call Signs

Tactical call signs are used to indicate the function of a station or the location of a station. Tactical call signs are useful in that new stations can enter the NET and establish contact without knowing the station’s FCC issued call sign. Tactical call signs should be used for all emergency NETs and public service NETs whenever any participating station is not familiar with other stations or their assignments, or whenever communications can be made more efficient by use of tactical call signs.

 
 
OPERATING TIP 28  

FM: What is a repeater?

A repeater is an automated relay station, used to extend line of sight communications.

 
 
OPERATING TIP 29  

HF: What is Ground Wave Propagation?

Ground Wave HF propagation is generally limited to 60 miles or less. Terrain can significantly shorten the distance. For communications on the long end of HF ground wave capabilities, HF may be viable if VHF / UHF repeaters are not available. For communications on the short end of HF ground wave capabilities, VHF / UHF simplex or repeater operation will almost always provide more reliable communications.

 
 
OPERATING TIP 30  

HF: What is Skywave Propagation?

HF signals with a low angle of radiation, refracted by the F-Layer of the ionosphere and bouncing off the ground, can result in very long distance communications, and under ideal conditions, world-wide communications capability.

 
 
OPERATING TIP 31  

HF: What is Near Vertical Incidence Skywave, or NVIS, propagation?

Near Vertical Incidence Skywave (NVIS) propagation provides communications capabilities that overlap ground-wave coverage and extend up to 600 miles approximate. NVIS requires a high angle of radiation, usually achieved by installing a horizontal dipole antenna no higher than 1/8 wavelength above the ground.

 
 
OPERATING TIP 32  

OPS: NET Operating Resources

Always seek to obtain a copy of the NET script that is used by the NET Control Station (NCS). This document is vital to performing the function of the NET Control Station and is very helpful to participating stations, especially when the participating station is inexperienced with the NET or NET operation.

 
 
OPERATING TIP 33  

FM: DO NOT SHOUT THROUGH THE NOISE

If you are operating in a noise environment, or have poor signal strength to the station you are communicating with, do not talk louder to get through.  This only makes communications worse.  Further, you could generated clipped audio or exceed width of the receiver pass-band, which will make communications more difficult.  Instead, either talk in a normal voice, or even reduce the amplitude of your speech to avoid clipping and/or driving out of the pass-band.

 
 
OPERATING TIP 34  

DMR: What is DMR?

Digital Mobile Radio, or DMR, is a technology that supports both digital voice and digital message operating modes, with a repeater channel having two time-slots.  Simultaneous but distinct conversations can occur on both time-slots (effectively two-repeaters in one).  When networked via the internet, local, regional, national and international communications are possible.

 
 
OPERATING TIP 35  

FM: SIMPLEX NET OPERATIONS

When participating in simplex net operations, be sure to adjust the squelch to accommodate weak signals.  Also be sure to have all strong stations periodically stand-by so that the NET control station and all participating stations can listen for weak stations.

 
 
OPERATING TIP 36  

FM: DO NOT OPERATE SIMPLEX ON A REPEATER INPUT

Operating simplex mode on the input of a repeater will cause interference to a repeater.  In a dispute, the FCC will always favor the coordinated repeater user over the non-coordinated individual user.  Move to a simplex channel to conduct simplex operations.

 
 
OPERATING TIP 37  

FM: ADHERE TO THE 2-METER FM BAND PLAN

If a band-plan is published by the frequency coordinating body, the simplex frequencies specified in the band-plan should be used for simplex operations.

If no published band-plan is available, this does not indicate that no band-plan exist.  We just need to reference a repeater directory to determine the band-plan model that is implemented in order to determine what simplex frequencies are available.  Looking at the spacing between channel allocations for coordinated repeaters to establish the channel spacing, and the repeater channel allocation to determine both a base frequency to establish the set of simplex frequencies and the frequencies that are available for simplex operation.  2-Meter simplex occupies the frequency segments between 146.400 to 146.599 MHz and from 147.400 to 147.599 MHz.  This range is left as unallocated for repeater use, in part, because of the 600 kHz split between repeater transmitters and repeater receivers.

With 2-meter repeater allocations occurring on 20 kHz channel spacing, and projecting that channel spacing into the simplex portion of the FM band-plan, this would seem to indicate the following as viable simplex channels on 2-meters:


146.400146.500147.400147.500
146.420146.520147.420147.520
146.440146.540147.440147.540
146.460146.560147.460147.560
146.480146.580147.480147.580

The 20-kHz channel spacing is optimized to accommodate a standard FM deviation that does not encroach on an adjacent channel and cause interference.  Operation on frequencies between these channels will result in improper channel spacing and can cause interference.  For example, operation on 146.430 will cause interference to both 146.420 and 146.440.

IMPORTANT: 146.460 is used as a repeater input within the southern half of Idaho.  All operators should avoid simplex operation on 146.460 MHz in this region in order to avoid creating interference to a repeater.

Information in contained in this operating tip, regarding the Idaho 2-Meter band-plan, can be found under the Resources menu on the Idaho ARES web-site.

 
 
OPERATING TIP 38  

DMR: What is a talk-group?

A talk-group is like a chat room, and usually is specified to cover a geographical area.  For example, talk-group 3116 covers all of Idaho.  Any operator on a DMR repeater or DMR hot-spot that is actively connected to a talk-group can establish communications with operators on any other DMR repeater or DMR hot-spot that is on the same talk-group.  Talk-groups are a shared resource, and require a higher level of operator etiquette.  See the DMR section under the RESOURCES menu for more details.  The ARES ID talk-group has been established on 31016 to support Idaho ARES operations.  It is essential that operators be familiar with the published article on this talk-group, which can be found under the RESOURCES menu.

 
 
OPERATING TIP 39  

DMR: Dynamic, static and timed static talk-groups

A repeater can have a set of talk-groups that are always active, and these are referred to as static talk-groups.  A push-to-talk talk-group will temporarily apply the talk-group that is specified by the programming of your radio, and this is a dynamic talk-group.  In the absence of activity, dynamic talk-groups remain active for 15 minutes.  Traffic on a static talk-group can always be heard.  Traffic on a dynamic talk-group can only be heard while that talk-group is active.  The repeater administrator can also program TIMED STATIC TALK-GROUPS, where a talk-group is made to become static based on a schedule.  TIMED STATIC TALK-GROUPS are usually used for scheduled NETs, and allow the NET to be heard beyond the 15-minute period and without requiring activity that would be necessary to keep a dynamic talk-group active.

 
 
OPERATING TIP 40  

DMR: EMCOMM AND DMR

With time-slotted operation, and the ability to have simultaneous but distinct conversations on time-slot 1 vs time-slot 2, a DMR repeater is especially well suited to serving EMCOMM operations.  A NET can be held on one time-slot, and any traffic can be moved off to a channel on the opposing time-slot, ensuring that communications will not be lost (since the same repeater is being used).

 
 
OPERATING TIP 41  

FM: Multipath Phase Distortion

Multi-path phase distortion occurs when a signal takes multiple paths to the receive point and where each of those signal paths are a different length.  The different signal paths arrive at the receive point out of phase, resulting in distortion.  Usually there is a direct path and multiple reflected paths, where the reflected paths may bounce off of buildings or terrain.  In some cases, there may not be a direct path.  It seems counter-intuitive, but REDUCING POWER may provide the best relief.  The goal of reducing power is to cause the weaker reflected paths to become so weak that they are no longer received at the receive point, and this can greatly reduce multi-path phase distortion.  If the station you are working reports multipath phase distortion on your signal, try reducing power.

 
 
OPERATING TIP 42  

FM: EMCOMM SIMPLEX NET OPERATIONS

During simplex operations, it is extremely useful to dispatch a mobile station to a local hill top to act as a relay for NET operations.  If it is SAFE to do so, consider volunteering to drive to a higher location to act as a RELAY station to enable wider coverage by NET operations.

 
 
OPERATING TIP 43  

DMR: RADIO SHOPPING, CHANNEL COUNT AND CONTACTS COUNT

Although often absent from the radio specification, support for a large number of contacts on DMR radios is a necessity.  Group contacts are used to select a talk-group (similar to a chat-room, and often organized geographically and/or by function).  Private contacts are used to display an alias that shows the call sign and name of the operator currently being received.  Private contacts can also be used in channel programming so that traffic is routed to a specific operator (this is not encryption, simply routing, and can be received by a DMR capable scanner).  Because of these three use cases for contacts, support for a large number of contacts is necessary for DMR radios used in the Amateur Radio service, and often the Amateur Radio requirement exceeds the requirement of the LMR / FCC Part 90 service.  At minimum, the radio should have the capability to store as many contacts as channels.  Optimally, the number of contacts should far outnumber the number of channels.  Please consider this when comparing DMR radios.

 
 
OPERATING TIP 44  

HF: 60-METER HF DIGITAL OPERATION

Amateur Radio has a secondary allocation on the 60-meter band.  The primary allocation is to Federal stations, and through the National Telecommunications Information Administration (NTIA), not the FCC.  As such, the FCC rules for Amateur Radio use of 60-meters follow the NTIA regulations.  All digital emission modes must be centered on the channel bandwidth allocation.  Although not specifically mandated, the implication is that all digital communications occupy the exact same frequency, and therefore require sequential, and not simultaneous use, by all stations.  With Amateur Radio holding a secondary allocation, should a Federal station appear on frequency and issue an order to vacate, Amateur Radio stations must vacate.  This is a rare occurrence, and usually only temporary.  Should this occur, the Federal station is likely to indicate when the frequency is free.

 
 
OPERATING TIP 45  

HF: Near Vertical Incidence Skywave (NVIS) Communications

Near Vertical Incidence Skywave (NVIS) provides propagation on HF, from ground-wave propagation distances out to 600-miles.  The highest frequency that NVIS communications can occur on is called the foF2 Critical Frequency, and is usually near 1/3 of the Maximum Usable Frequency.  NVIS communications are rarely possible above 11 MHz.  NVIS provides great potential for intra-state communications for Idaho ARES. NVIS is achieved by raising the angle of radiation, and is best achieved with a horizontal antenna by placing the antenna no higher than 1/8 wavelength above the ground.

 
 
OPERATING TIP 46  

TECH: What is desense?

Anytime a transmitter and receiver are operating on different frequencies and in close proximity to each other, the transmitter can cause a reduction in receiver sensitivity. This reduction in receiver sensitivity is called desensitization, or desense.

Desense can occur when two stations are operating very close to one another while using the same repeater. When this occurs, one station might not hear the transmissions of the other station because of the loss of receiver sensitivity.

Avoiding desense from other nearby operators requires increasing the physical separation between stations

When desense is present in a repeater system, the repeater receiver is more sensitive when the repeater transmitter is not active. When the repeater transmitter becomes active, the repeater receiver may become less sensitive. If the received signal at the repeater receiver is not sufficiently strong to be heard when the repeater transmitter is active and desense is present in a repeater, the operator may bring up the repeater but cannot hold the repeater up. A repetitive cycle of (A) the repeater hears the operator signal when the repeater transmitter is inactive and then keys the repeater transmitter, and (B) when the repeater transmitter becomes active, the repeater no longer hears the operator, and the repeater un-keys the transmitter after the appropriate squelch tail timer expires, then (A), (B), (A), (B), etc. This cyclic keying and un-keying of the repeater transmitter (often referred to as cyclic ker-chunking, because of the sound that is heard in the receiver that is listening to the repeater, terminates only when the transmitted signal becomes to weak to be heard by the repeater when the repeater transmitter is inactive, the operator ceases transmission, or the transmitted signal becomes sufficiently strong to be heard when the repeater transmitter is active.

Desense in a repeater, and particularly on bands where the frequency separation between the repeater receiver frequency and repeater transmitter frequency is relatively small (such as occurs on 2-meters, where the split is only 600 kHz) is extremely difficult to avoid. Isolation between receiver and transmitter must be very large, on the order of -95 dB, to avoid desensitization in the repeater system. Common methods of addressing this issue is to increase isolation by installing better cavity duplexers, adding additional pass/reject cavity filters, and separating receive and transmit antennas along the axis of polarization.

 
 
OPERATING TIP 47  

TECH: Hand-held antennas should be vertical for best performance

When operating hand-held portable, a non-vertical antenna will become directional.  When supporting EMCOMM operations while portable, hold your hand-held radio so that the antenna is vertical to avoid directional effects that may attenuate a signal, or to avoid attenuation due to cross-polarization of antennas.  For best results, do not hold your hand-held so that the antenna is at an angle or horizontally.

 
 
OPERATING TIP 48  

TECH: Cyclic Multi-Path Fading

When conducting mobile operations where multi-path is present (i.e. a transmitted signal takes multiple paths to the receive point), there may be cyclic fading of signals.  When this cyclic fading causes the signal to periodically fade into the noise, the signal is sometimes described as picket fencing, which is a comparison to the signal propagation to how a picket fence would block a signal for a moving station.

If you are operating mobile and this phenomenon results in an inability to communicate, pull-over and stop.  Try to stop in a position where the cyclic fading is at a minimum.  If no signal is present, move the vehicle one quarter wavelength (i.e. 19 inches on 2-meters) and try again.  If communications is not restored by moving one-quarter wavelength, repeat moving one-quarter wavelength and try again.

If you are operating portable, and the station receiving you is experiencing cyclic fading,  stop and check propagation.  Try to stop in a position where the cyclic fading is at a minimum.  If no signal is present, step one quarter wavelength (i.e. 19 inches on 2-meters) and try again.  If communications is not restored by stepping one-quarter wavelength, repeat stepping one-quarter wavelength and try again.

 
 
OPERATING TIP 49  

TECH: All GPS Latitude Longitude Coordinates Are Not The Same

When handling GPS latitude and longitude coordinates, there are three different coordinate systems, and listening for the position of the decimal point is essential to understanding which coordinate system is being used so that position errors can be avoided.

Latitude and longitude can take one of the following formats:


Degrees, Minutes, SecondsDegrees, Decimal MinutesDecimal Degrees
DDD°MM'SS.SS"DDD°MM.MMMMM'DDD.DDDDDD°
Decimal in 3rd set of numbersDecimal in 2nd set of numbersDecimal in 1st set of numbers

When communicating a latitude / longitude position, a best practice would be to prefix the conveying of the position with a statement that indicates the format.  If you receive a latitude / longitude position that was not  preceded with an announcement of format, pay close attention to where the decimal place appears in the sequence of position figures (numbers).

If you need to convert between coordinate systems, a Coordinate Converter is available under the Resources menu on the Idaho ARES web-site.

Most GPS units can be set to one of any of the formats shown in this operating tip.  It is best if all operations can use the same format.  However, there is no standardization on format.  Each county may use a different format (check with your local SAR unit or Public Safety Dispatch [DO NOT USE 911, USE ONLY A NON-EMERGENCY NUMBER]).  FEMA promotes the use of the United States National Grid coordinate system, however, this system is not adopted by Public Safety and may present confusion when interoperating with served agencies.

 
 
OPERATING TIP 50  

OPS: DIRECTED NETS

During a Directed NET, stations only transmit at the direction of the NET control station (i.e. NCS or NECOS).  Under a Directed NET, the NET control station should call for relay traffic as part of running through the NET script.  Participating stations should not break in with a transmission that announces a relay for a station that was not heard by the NET control station, but should wait until the NET control station calls for relay traffic.  Only after the NET control station calls for relay traffic should stations make a transmission to offer a relay for the unheard station.

 
 
OPERATING TIP 51  

TECH: Did you know you can listen to HF using your web browser?

You can tune in and listen to HF SSB/CW/DIGITAL communications without a radio.  Visit WebSDR and select the receiver from the large (and growing) list of receivers located internationally.  You will need to have the Java runtime environment installed to use these.

 
 
OPERATING TIP 52  

OPS: RSID and Digital Communications

Use of a Read Solomon ID can help identify a digital mode that is difficult to identify visually on the waterfall display.  But transmitting an RSID on all transmissions, or when the mode is easily identifiable (such as PSK31) can be very counter productive.  Use of RSID should be restricted to only difficult to identify modes and then, only when making a general call (i.e. CQ or CQ DX).  Use of RSID outside of this context will result in other stations having to dismiss modal windows, or could cause their digital station to switch frequencies automatically.  Wide use of RSID can actually degrade operations, not help.  Please consider the implications of over using this feature.

Use of RSID in the context of a Directed NET that combines both Voice and Digital traffic should be avoided altogether.  In a Directed NET that combines both Voice and Digital traffic, the NET Control Station should determine the digital mode for all communications, or the two stations passing traffic should agree upon the mode prior to conducing digital communications

 
 
OPERATING TIP 53  

OPS: CHOOSING A DIGITAL MODE FOR FM

Unlike Single Side Band (SSB) operation, where the receiver pass band might simultaneously handle 20 simultaneous PSK31 signals, FM only handles a single signal at any given time.  Because FM only supports a single signal at once, the best choice of digital mode for FM is not based on limiting bandwidth, but should be made based on speed.  The only way that FM can handle a high volume of traffic is if the traffic is passed by the fastest mode available.  PSK31 is an extremely poor choice for FM operations.  Modes like PSK500RC4, which are both fast and support Forward Error Correction (FEC), are much better choices for FM operations.

 
 
OPERATING TIP 54  

TECH: What is Tone Encode and Tone Decode?

When a transmitter includes the transmission of a Continuous Tone-Coded Squelch System (CTCSS) tone, or Digital Coded Squelch (DCS), the transmitter is said to be operating in encode. When a receiver decodes the CTCSS or DCS, the receiver is said to be operating in decode.

Typically, your station will run in encode mode to access a repeater. The repeater typically operates in decode.

There are some cases where a repeater in both decode and encode. When a repeater operates in encode, it is possible for your station to run in decode. The advantage of being able to do this is that certain noise sources that are capable of opening the squelch, particularly when mobile, will not be heard when operating in decode.

It should be noted that radios that support DCS always run encode on the transmitter and decode on the receiver when DCS is used.  CTCSS can be turned on or off independently for the transmitter or receiver.  CTCSS decode should only be used on a repeater if the repeater is using CTCSS encode.  Virtually all repeaters use decode (either CTCSS or DCS), and this requires that stations wishing to access the repeater use an appropriate encode mode..

CTCSS and DCS decoders require a significant amount of time to decode the CTCSS or DCS (approximately 1/4 second).  If repeaters are linked (i.e. connected) together, these delays are accumulated through the repeater network.  For this reason, it may be necessary for stations to key their transmitter and then wait for the appropriate delays to pass before speaking in order to be heard.  Some repeaters implement audio delay lines to avoid having to have the operator delay speech relative to transmitter keying.

 
 
OPERATING TIP 55  

OPS: Avoiding Interference When Checking In to a NET with a General Call

When operating on a Directed NET, and after receiving a General Call for stations to check in to the NET, where the General Call includes a description that includes your station, you can use an operating practice that will help reduce interference and help ensure that your call sign is heard.  The procedure has the station responding to a General Call:

  1. Listen first to ensure no one else is transmitting.  If another station is transmitting, wait until they complete their transmission.

  2. Key the transmitter.

  3. Announce THIS IS

  4. Un-key the transmitter and very briefly listen to see if someone else is making a call at the same time.  The delay should be only long enough to hear another station.  If using this procedure on a repeater, the delay should not allow the repeater squelch talk to drop.

  5. If you hear another station in the above step, return to the first step in this procedure.

  6. If no other station is heard, re-key the transmitter and announce your call sign.

This procedure reduces the chance of multiple stations making simultaneous transmissions, makes copy much easier for the NET Control Station, provides better assurance that your call sign will be heard by the NET Control Station, and allows NET operations to proceed more efficiently.

 
 
OPERATING TIP 56  

DMR PUSH-TO-TALK TALK-GROUPS AND STATION IDENTIFICATION

If you are using a Push-To-Talk Talk-Group (i.e. a dynamic talk-group on a repeater or any  talk-group on an OpenSpot), and cycle your push-to-talk switch to change talk-groups, DO  NOT issue a station identification until you have listened first to determine if your  identification will result in interference to a QSO that is already in progress.  FCC  regulations do require identification on a frequency, but you have up to 10-minutes to perform  that action.  A talk-group is not a frequency, and if, after listening and determining that the  talk-group is in use and not available for your use, you move to another talk-group, you can  identify (after listening first) on that talk-group and still meet the FCC requirements for  station identification.  Do not interrupt other users by announcing your call sign over an  existing QSO.

 
 
OPERATING TIP 57  

Closed Repeater Systems and Networks

When programming radios, apply proper diligence in researching the frequencies that you plan to apply to the radio programming file.  Do not include repeater operating frequencies that represent restricted closed repeater systems or networks unless you have permission to operate on the closed system.  Observing a observing that a repeater is operating on a particular frequency is not sufficient justification to use a repeater.  Consult every resource available to you, including the ARRL Repeater Directory or repeaerbook.com, to ensure that you are not operating on a restricted resource without permission.  FCC Part 97.205(e) allows repeater operators to restrict who can use a repeater system, which provides the authorization to operate a closed repeater system.  These restrictions need to be respected.

 
 
OPERATING TIP 58  

Maintaining NET Situational Awareness

During NET operations, there are circumstances where your station may not be able to hear all other stations.  Under these conditions, it is important that you, as a station operator, listen closely to activity on the NET so that you can determine when making a transmission may result in causing interference.  The following examples demonstrate contexts where making a transmission may result in interference.

  • When your station has been requested to stand-by.

  • When the NET control operator has requested a relay to a station that cannot be heard by your station.

  • When the NET control station has indicated that NET control services are not to be available for a short period of time, due to a need to perform a task.

These are just a few examples where failure to maintain NET situational awareness will result in imposing a reduction in NET efficiency upon NET operations.  This all falls within the Amateur Radio operating principle of the importance of listening.

Station operators that are participating in a NET should always maintain a situational awareness of NET context, and should always have a good sense of when it is appropriate or inappropriate to make a transmission.  When it is not appropriate to make a transmission, you should delay your traffic until such a time that a transmission is appropriate.

A failure to maintain NET situational awareness, and then making a transmission at an inappropriate time, may result in interference, and may also require that traffic be repeated.  The impact of repeating traffic is a reduction in the amount of traffic that can be handled by the NET.

Your station operation procedures should never impose a reduction in NET traffic handling capability.  Always maintain NET situational awareness and think before you key your transmitter.

 
 
OPERATING TIP 59  

FEMA Call Signs on Amateur Radio

The following call signs are assigned for FEMA operations.  If these call signs appear on an EMCOM NET, they should be given higher priority entry into the NET than standard Amateur Radio stations.


AF0EMAKF0EMANF0EMAWF0EMA
AF1EMAKF1EMANF1EMAWF1EMA
AF2EMAKF2EMANF2EMAWF2EMA
AF3EMAKF3EMANF3EMAWF3EMA
AF4EMAKF4EMANF4EMAWF4EMA
AF5EMAKF5EMANF5EMAWF5EMA
AF6EMAKF6EMANF6EMAWF6EMA
AF7EMAKF7EMANF7EMAWF7EMA
AF8EMAKF8EMANF8EMAWF8EMA
AF9EMAKF9EMANF9EMAWF9EMA

Note that each of these call signs has the word FEMA contained within the call sign, with the call district numerical designator inserted after the letter F.

This block of 40 call signs are to be considered as Federal, and are used only for emergency use.  Use of these call signs is most likely to be encountered on the interoperability frequencies that comprise the 60-meter band.

This information originated from the FEMA SHARES National Teleconference of 5 September 2017.

 
 
OPERATING TIP 60  

What does X-RAY X-RAY mean?

The term x-ray x-ray is not normally encountered during Amateur Radio operations.  However, with the availability of the 60-Meters band, and the ability to interoperate with other services directly on that band, an Amateur Radio operator may encounter the term x-ray x-ray.

When a station or station operator has a prohibition to disclose Personally Identifiable Information (PII), the station operator will respond to a query for PII with x-ray x-ray.  Personally  Identifiable Information (PII) can include name, location, phone number, or any information that  may allow someone to locate and/or identify an individual.  Federal services that my interact directly with an Amateur Radio station on the 60-Meter band may include FEMA, Army MARS, Air Force MARS, United States Coast Guard, and others.  Some of these services have regulations that prohibit disclosure of PII.

This term may be heard on 60-M interoperability NETs, when a NET control operator makes a query to disclose operator name or location.  If you are operating such a NET and receive a response of x-ray x-ray, please note the response in the NET or radio log and do not query the station operator further.

If you recognize a station operator that is interoperating with Amateur Radio stations, but not operating under an Amateur Radio call sign, do not address that station operator by name, and take care not to disclose any PII associated with that station or station operator.