Wednesday, September 28, 2011

Scouts to Take to the Airwaves for the 54th Jamboree on the Air

Each year, more than 500,000 Scouts in more than 100 countries take to the airwaves on the third full weekend in October -- and this year will be no different. The Jamboree On The Air (JOTA) is an annual Scouting and Amateur Radio event sponsored by the World Scout Bureau of the World Organization of the Scout Movement (WOSM). JOTA is an annual event where Boy Scouts, Girl Scouts and Girl Guides from all over the world speak to each other via Amateur Radio. Since 1958 -- when the first Jamboree on the Air was held -- millions of Scouts have met through this event. Many contacts made during JOTA have resulted in pen pals and links between Scout troops that have lasted many years. The radio stations are operated by radio amateurs; many Scouts and leaders hold licenses and have their own stations. The majority of JOTA Scouts participate through stations operated by local radio clubs and individual hams.

Scouts of any age can participate, from Brownies to Ambassadors, from Cub Scouts to Boy Scouts and Venturers. Once at the ham radio station, the communication typically requires speaking into a microphone and listening on the station speakers. But many forms of specialized communication can also take place, such as video communication, digital communication using typed words on the computer screen transmitted by radio, communication through a satellite relay or an earth-based relay (called a repeater). The exchanges include such information as name, location, Scout rank, age and hobbies. The stations you’ll be communicating with can be other Scouts across town, across the country -- even around the world! The World Scout Bureau reported that the 2010 JOTA had more than 700,000 Scout participants from nearly 6000 Amateur Radio stations!

Besides being the editor of QEX, Larry Wolfgang, WR1B, is also a life-long Boy Scout; he is currently a member of his District Advancement Committee and a member of Troop 60 in Oakdale, Connecticut. “JOTA is one of my favorite operating activities,” he reminisced. “Whether I am running a station at a District Camporee, Cub Activity Day or just getting on the air by myself, it is sure to be a fun time. Just the mention of JOTA brings a flood of memories. My first JOTA was in a tent in my backyard as a 16 year old Novice, WN3JQM. Heavy rains overnight left a puddle of water inside the operating tent. When Garry, WN3JQL, and I found Terry, WN3JQK, operating with his feet in that puddle of water, we decided it was time to pull the plug! Since then, whether it was a drier operation the next year or another very rainy day at a Cub Scout activity many years later -- where Jean, WB3IOS, and I made one contact that lasted until that operator talked with every Cub Scout at the camp that day (easily more than 100) -- JOTA has been a fun time. I remember icy cold Camporees and beautiful autumn days. We’ve had groups of Scouts at W1AW, and one year, Dennis, K7BV, set up his 6 meter meteor scatter station at camp for the Scouts.”

The 54th Jamboree on the Air is October 15–16, 2011. The official hours are 0000 (local time) Saturday, October 15 (right at midnight Friday) through midnight (local time) Sunday, October 16 (midnight Sunday evening).

Stations that participate in JOTA should call “CQ Jamboree” or answer stations doing so. Any authorized frequency may be used. The World Scout Bureau recommends that stations use the agreed World Scout Frequencies:

•80 meters -- 3.690 and 3.940 MHz (SSB), 3.570 MHz (CW)
•40 meters -- 7.090*, 7.190 and 7.270 MHz (SSB), 7.030 MHz (CW)
•20 meters -- 14.290 MHz (SSB), 14.060 MHz (CW)
•17 meters -- 18.140 MHz (SSB), 18.080 MHz (CW)
•15 meters -- 21.360 MHz (SSB), 21.140 MHz (CW)
•12 meters -- 24.960 MHz (SSB), 24.910 MHz (CW)
•10 meters -- 28.390 MHz (SSB), 28.180 MHz (CW)
•6 meters -- 50.160 MHz (SSB), 50.160 MHz (CW)
* Amateurs in IARU Region 2 are not authorized to transmit on these frequencies.
These are “calling frequencies.” After contact has been made, you should move off that frequency (either above or below) to continue your contact and allow others to use the calling frequency.

The AO-51 satellite will be made available for JOTA. It will remain in its current configuration, with an understanding that contacts involving Scouts will be given first priority during this period. The current operating mode of AO-51 is as follows:

•Uplink: 145.880 MHz FM (no PL tone)
•Downlink: 435.150 MHz FM
Please keep in mind that this is not a contest to contact the most stations during JOTA. You do not need to submit your logs.

2011 JOTA Theme: Peace, Environment and Natural Disasters

How can the use of modern means of communication help save lives? How can each Scout prepare to intervene to save lives during great natural or climatic disasters? According to the WOSM, Scouts showed that they know how to quickly and efficiently react during the earthquakes and tsunamis that affected Thailand in 2004, Haiti in 2010 and Japan earlier this year: “To act accordingly to prepare youth to be confronted to difficult circumstances and reinforce the existing partnerships with National or International Humanitarian Organizations, the National Scout Organizations are invited to organize activities in partnership with locally active NGOs which operate in these three areas: Peace, Environment and Natural Disasters.”

There are Scout groups nearly everywhere, well organized, with good contacts in the local community. The Scouts are usually trained in basic first-aid medical techniques and orienteering. They have the material that is needed to set up a temporary shelter quickly, such as tents, cooking material, construction material. This equipment used for recreational camping can also be used in an emergency.

How Can I Participate As a Scout?

In the US, JOTA is primarily a Boy Scout event, though girls are welcome to participate, too. The best way to get involved is to contact your local BSA Council and see what may already be planned in your area. You can also contact a local ham radio operator or a local Amateur Radio club. You can find a searchable database of clubs here. Your local club may be able to direct you to its planned JOTA activities. These can include ham stations set up at camporees or other events. If there are no planned activities, you can either work with them to get something set up or arrange to visit a local radio operator’s ham shack at a scheduled time to participate in JOTA.

How Can I Participate as an Amateur Radio Operator?

Contact your local BSA Council and see what may already be planned in your area and how you can help. You can find your council here. If nothing is currently planned, or if current plans aren’t reaching your area, you can work with the Council or a local unit (Pack, Troop or Crew) to set up a JOTA station or arrange for visits to your ham shack. You can also participate just by making QSOs with the many JOTA stations that will be on the air.

More Information Available

Here are some links where you can find more information on the 54th Jamboree On The Air.

•The ARRL’s JOTA web page: http://www.arrl.org/jamboree-on-the-air-jota
•The World Organization of the Scout Movement’s JOTA web page: http://www.scout.org/en/information_events/events/jota/the_54th_jota_2011
•The Boy Scouts of America’s JOTA web page: http://www.scouting.org/jota.aspx
“The best JOTAs have been when I was able to gather a group of Scouts around a radio and let them take over the controls as they found other Scouts and operators to talk with,” Wolfgang said. “Whether it is an SSB contact, or operating CW or digital modes, everyone loves to see how far they can reach. There are always plenty of stations on the air for JOTA, so gather some Scouts and have a wonderful time. Try a new mode, show the Scouts how to run PSK and let them take over the computer, send SSTV images of the Scouts or put them on a local 2 meter repeater. No matter what you try, the Scouts are sure to have a great time, and you may just hook some new operators for your efforts.” -- Thanks to the World Organization of the Scout Movement, the Boy Scouts of America, the Girl Scouts of the USA and AMSAT for some information

Sunday, September 25, 2011

The Effects of VSWR on Transmitted Power

The Effects of VSWR on Transmitted Power

By James G. Lee, W6VAT

vswr-n.gif (1493 bytes)o matter how long you have been a ham, sooner of later you will be involved in at least one discussion of something called the Voltage Standing Wave Ratio, or VSWR, of an antenna system. There is a lot of good information available on VSWR as well as a lot misconceptions about what it is and what it signifies. Probably the most often misconception is that your VSWR should be as close to 1:1 as possible, otherwise " you won't get out very well." A 1:1 VSWR implies a perfect match between all elements of the antenna system. The only problem is that it is possible to have a low VSWR and still have some very serious things wrong with your antenna system. Other misconceptions such as a high VSWR causing television interference, or other unwanted problems are often heard and can cause unnecessary worry. The concept of VSWR is easy to grasp and its importance in an antenna system does not require an engineering degree to understand.

WHY VSWR EXISTS
Early in electronics you learned that to get maximum power into a load required that the load impedance match the generator impedance. Any difference, or mismatching, of these impedance would not produce maximum power transfer. This is true of antennas and transmitters as well but, except for handie-talkies, most antennas are not connected directly to a transmitter. The antenna is usually located some difference from the transmitter and requires a feedline to transfer power between the two. If the feedline has no loss, and matches BOTH the transmitter output impedance AND the antenna input impedance, then - and only - then will maximum power be delivered to the antenna. In this case the VSWR will be 1:1 and the voltage and current will be constant over the whole length of the feedline. Any deviation from this situation will cause a "standing wave" of voltage and current to exist on the line.

There are a number of ways VSWR or its effects can be described and measured. Different terms such as reflection coefficient, return loss, reflected power, and transmitted power loss are but a few. They are not difficult concepts to understand, since in most instances the are different ways of saying the same thing. The proportion of incident (or forward) power which is reflected back toward the transmitter by a mismatched antenna is called reflected power and is determined by the reflection coefficient at the antenna. The reflection coefficient "p" is simply a measure of this mismatch seen at the antenna by the feedline and is equal to:

P =(Z1-Zo)/(Z1+Zo)

Here Z1 is the antenna impedance and Zo is the feedline impedance. Both Z1 and Zo are complex numbers so "p" is also a complex number.

You remember from elementary AC mathematics that a complex number has a "phase angle" associated with it. The phase of the reflected signal will be advanced or delayed depending upon whether the antenna appears inductive or capacitive to the feedline. If the antenna appears inductive the voltage will be advanced in phase, and if the antenna is capacitive, the voltage will be retarded. The reflective signal travels back to the transmitter and adds to the incident signal at that point.

Thus, any mismatch at the antenna gives rise to a second 'travelling wave' which goes in the opposite direction from the incident wave. When Z1 = Zo the reflection coefficient is zero and there is no reflected signal. IN this case all power is accepted by the antenna and this is the ideal situation where VSWR is concerned. The problem is that this condition is rarely, if ever, achieved and so "p" will have a value different from zero. Note that "p" can have negative values, but in calculating VSWR from the reflection coefficient, only the "absolute value" is used - which is a positive value lying between 0 and 1.

As the two travelling waves pass each other in opposite directions, they set up an interference pattern called a "standing wave". At certain places on the feedline the voltages will add producing a voltage maximum, and at others their relative phase difference will cause a voltage minimum to exist on the feedline. These maximum and minimum points occur 1/4 wavelength apart. In the days when open-wire feedlines were used these points could easily be measured with simple indicators. Coax cable however presents another problem since the "inside" of the cable is not readily available for measurements. Consequently, VSWR measurements on coax are usually made at the transmitter end of the feedline. Therefore you are presented with the VSWR of the entire system which includes all losses associated with the entire system.

INTERPRETING WHAT YOU HAVE READ
Many VSWR meters are calibrated to read FORWARD power as well as REFLECTED power. They may actually be measuring voltage, and simply have the scales calibrated in power. The important point is to understand what the meter is actually telling you. Assuming for the moment that the VSWR meter contributes no errors, the FORWARD reading is the SUM of the forward power and the reflected power. As a result, it is greater than your actual power output. The REFLECTED power reading is that amount of power which was not initially absorbed by the antenna and has been sent back down the feedline. At the transmitter end it encounters the transmitter output circuitry and is re-reflected back towards the antenna. This happens because you do, in fact, have a VSWR greater than 1:1 as seen by the transmitter. When the re-reflected power encounters the antenna, a portion of it is absorbed and the whole process starts over again.

Ultimately then, most of your signal is eventually absorbed by the antenna. You might be tempted to think that all of this bouncing back and forth would cause "smearing or blurring " of your signal but this is not so. The average transmitted signal appears as a "steady-state" signal to the feedline and antenna. Remember your signal is travelling at a significant fraction of the speed of light. For instance, the velocity of propagation of RG-8/A is 0.66 or 2/3 the speed of light. The speed of light is close to 1000 feet per microsecond, and a dot or voice peak takes milliseconds to complete. If the speed of light were 20 miles-per-hour then the situation would be completely different and we probably wouldn't have radio transmission at all. (Ed. Note, it would be as fast as the mail then.)

Given the reality then that almost all power launched down a feedline reaches and absorbed by the antenna, one has to wonder why VSWR is all that important. The importance is due to the fact that feedlines have losses and, antennas have something called radiation efficiency. They are what make proper interpretation of VSWR important. Power is lost due to feedline attenuation and this loss goes up as the VSWR goes up. The efficiency of an antenna is determined by the ratio of its "radiation resistance" to its "loss resistance". Antenna efficiency can simply described by the following equation:

% Efficiency=[Ra/(Ra+Rloss)] X 100

The radiation resistance is Ra, and Rloss is made up of any associated losses of the antenna such as loading coils and ground systems. How well you "get out" therefore depends more on low losses and efficient antennas than on what your actual VSWR is as the following example will show.

THE EFFECTS OF ATTENUATION ON VSWR
Early in this discussion the statement was made that your VSWR may appear to be very low and yet there could be serious things wrong with your antenna system. Figure 1 shows how this can happen. The curves in the figure represent the forward and the reflected voltage on an antenna which has a feedline loss of 3 dB. and a reflection coefficient of p=0.5. In this example the actual value of voltage is inconsequential and can be considered to be "E". We are only interested in relative values of "E" in any case. The length of the feedline is also arbitrary since we are only concerned with its total loss between transmitter and antenna.

Figure 1


The signal voltage "E" starts out at full value -1.0 E - on the feed line and is attenuated at a 3-dB rate. This means that the voltage will only be 71% - or 0.707E - when it reaches the antenna terminals. Remember that while 3-dB is a factor of two for power considerations, power is proportional to E-squared, consequently E will be only 0.71e when it arrives at the antenna input. The top curve in Figure 1 shows the FORWARD voltage decay as it travels down the feedline to the antenna input.

Since the antenna in this example has a reflection coefficient of 0.5, this means that 1/2 of the incident voltage will be reflected back down the feedline. This value is (0.5 X o.71E) or 0.35E volts. The feedline has no way of knowing which way signals are traveling, so this reflected voltage will suffer the same 3-dB attenuation on the return trip. When it arrives back at the transmitter end of the feedline its value is only (0.71 X 0.35E) or 0.25 volts. The VSWR meter sees this value and since

VSWR=(Efwd + Eref)/(Efwd - Eref)

the VSWR meter will read 1.67:1

That value of VSWR is guaranteed is to make almost everyone happy, but your antenna system is not very good. The 3-dB loss down the feedline means only 1/2 of your output power reaches the antenna, and if your antenna has significant losses, something less than 1/2 of your power will be radiated depending upon how bad the losses really are. If for instance, the loss resistance equals your radiation resistance, the antenna is only 50% efficient meaning only 1/4 of your output power is actually radiated. Yet that reading of 1.67:1 looks fine. A reflection coefficient of p =0.5 means your antenna is not well matched to the feedline. VSWR can be calculated from the reflection coefficient by the following:

VSWR = (1+p)/(1-p)

Using this formula shows your VSWR at the antenna is 3:1, quite a different value than your VSWR meter reads. The difference in the input and output VSWR values is due to the loss introduced by the feedline. Figure 2 shows how this loss can cause you to get a different VSWR depending upon where you measure VSWR in a feedline. You can measure VSWR at the antenna end of the feedline, but it is usually impractical to do.

Figure 2


You can use 1/2 wavelengths of coax between your VSWR meter and the antenna because a 1/2 wavelength of cable repeats the impedance it sees. The only problem is that you are introducing other possible elements into your measurements. But let's assume that your VSWR measurement at the feedline is reasonably close to what is actually occurring on the feed line, and that your feedline losses are not great. The burning question still is "how good or bad is the VSWR reading?"

VSWR AND TRANSMITTED POWER
Let's assume you have an efficient antenna, fed with a low-loss feedline so that the VSWR meter at the transmitter gives you a true reading of 1.65:1. There is no real reason to try to lower it, in fact the same would hold true if the reading were 2:1. Figure 3 is a chart showing the equivalence of VSWR to RETURN LOSS(dB), REFLECTED POWER(%) and TRANSMISSION LOSS(dB). Return loss is related to reflection coefficient by the equation:

Return Loss = -20log10(p)

It is just another way of measuring VSWR. For example, with a perfect 1:1 VSWR there would be no reflected power consequently the return loss on the feedline would appear to be infinite. A short or open circuit at the antenna is the worst case scenario since the reflection coefficient would be p =1.0. All incident power would be reflected, and with a lossless feedline the return loss would be 0-dB. this is what the RETURN LOSS (dB) column refers to

The most informative columns in Figure 3 are the REFLECTED POWER(%) and the TRANSMISSION LOSS(dB) columns since they provide an answer to our question of whether further reduction of VSWR is worthwhile. Figure 3 shows that for a VSWR of 1.65:1 the reflected power is only 6.2% of the incident power, and the transmission loss is only 0.27 dB. In more familiar terms, if you count an S-unit as 6 dB, then the 0.27 dB loss is only 1/22 of an S-unit. A reduction of the VSWR to 1.5:1 would provide only a 0.09 dB reduction in transmission loss. This is not worth the effort it would take to achieve such a miniscule increase in power.

Figure 3


VSWR
Return Loss (dB)
Reflected Power (%)
Transmiss. Loss (dB)
VSWR
Return Loss (dB)
Reflected Power (%)
Transmiss. Loss (dB)
1.00
oo
0.000
0.000
1.38
15.9
2.55
0.112
1.01
46.1
0.005
0.0002
1.39
15.7
2.67
0.118
1.02
40.1
0.010
0.0005
1.40
15.55
2.78
0.122
1.03
36.6
0.022
0.0011
1.41
15.38
2.90
0.126
1.04
34.1
0.040
0.0018
1.42
15.2
3.03
0.132
1.05
32.3
0.060
0.0028
1.43
15.03
3.14
0.137
1.06
30.7
0.082
0.0039
1.44
14.88
3.28
0.142
1.07
29.4
0.116
0.0051
1.45
14.7
3.38
0.147
1.08
28.3
0.144
0.0066
1.46
14.6
3.50
0.152
1.09
27.3
0.184
0.0083
1.47
14.45
3.62
0.157
1.10
26.4
0.228
0.0100
1.48
14.3
3.74
0.164
1.11
25.6
0.276
0.0118
1.49
14.16
3.87
0.172
1.12
24.9
0.324
0.0139
1.50
14.0
4.00
0.18
1.13
24.3
0.375
0.0160
1.55
13.3
4.8
0.21
1.14
23.7
0.426
0.0185
1.60
12.6
5.5
0.24
1.15
23.1
0.488
0.0205
1.65
12.2
6.2
0.27
1.16
22.6
0.550
0.0235
1.70
11.7
6.8
0.31
1.17
22.1
0.615
0.0260
1.75
11.3
7.4
0.34
1.18
21.6
0.682
0.0285
1.80
10.9
8.2
0.37
1.19
21.2
0.750
0.0318
1.85
10.5
8.9
0.40
1.20
20.8
0.816
0.0353
1.90
10.2
9.6
0.44
1.21
20.4
0.90
0.0391
1.95
09.8
10.2
0.47
1.22
20.1
0.98
0.0426
2.00
09.5
11.0
0.50
1.23
19.7
1.08
0.0455
2.10
09.0
12.4
0.57
1.24
19.4
1.15
0.049
2.20
08.6
13.8
0.65
1.25
19.1
1.23
0.053
2.30
08.2
15.3
0.73
1.26
18.8
1.34
0.056
2.40
07.7
16.6
0.80
1.27
18.5
1.43
0.060
2.50
07.3
18.0
0.88
1.28
18.2
1.52
0.064
2.60
07.0
19.5
0.95
1.29
17.9
1.62
0.068
2.70
06.7
20.8
1.03
1.30
17.68
1.71
0.073
2.80
06.5
22.3
1.10
1.31
17.4
1.81
0.078
2.90
06.2
23.7
1.17
1.32
17.2
1.91
0.083
3.00
06.0
24.9
1.25
1.33
17.0
2.02
0.087
3.50
05.1
31.0
1.61
1.34
16.8
2.13
0.092
4.00
04.4
36.0
1.93
1.35
16.53
2.23
0.096
4.50
03.9
40.6
2.27
1.36
16.3
2.33
0.101
5.00
03.5
44.4
2.56
1.37
16.1
2.44
0.106
6.00
02.9
50.8
3.08

Further examination of the chart shows that a VSWR of 2.6:1 results in only about 1 dB of transmission loss. A high VSWR of 6:1 shows just a 3 dB transmission loss, but this is 1/2 an S-unit. You will still be getting out but this is becoming a significant loss. Your feedline will be dissipating more power than it should, and there may be other serious things wrong with your antenna system.

Throughout this article you've noticed the use of the term "antenna system". The word "system" means you must pay attention to other things besides just the VSWR and your power output. Each component of your antenna system must be optimized to get the best results. Many factors must be considered such as operating frequencies, bandwidth requirements of the antenna system, heights, and directivity, all of which affect its efficiency. Since the height of your antenna, and your operating frequency determine both the length of the feedline and its losses the interfaces become very important. So there are a number of trade-offs which must be considered when you contemplate putting up a good antenna system, but these are tales for other times.

You can build or buy your own VSWR meter, but make sure that you understand what it is measuring and what it is really telling you. Then once you are satisfied that you have put up a really efficient antenna, fed with a low loss feedline, you can sleep well knowing that to try to reach the ultimate 1:1 VSWR is only an ego trip. As a rule of thumb, any accurate VSWR reading under 2:1 is probably not worth the effort to achieve if the other elements of your antenna system are the best you can make them. In fact you might be surprised to find that you really do have a low VSWR when you put up the best antenna and feedline you can. There is an old saying in ham radio that "a dime in the antenna is worth a dollar in the transmitter any day". Try it and see if you don't agree. -30-


Editors note:
W6VAT has a lot of good points, and careful attention should be paid to what is covered in his article, as it can make a difference in your signal. A case in point involves a ham club that I belonged to many years ago. They had just gotten the license for their repeater, and the only antenna that was available was a commercial antenna fed with ancient heliax. The antenna had only a small amount of reflected power and it seemed to get out well. Everyone was happy, and all was well with the world. Until my boss who was a ham and I took the liberty of checking out the repeater with the equipment from the two-way shop. When I disconnected the RG-8A pigtail, water poured from the heliax for about 5 minutes. But the Bird showed no reflected power with a 10 watt element and 50 watts forward. This was met with extreme disbelief when the club members were told of the water cooled coax. No one wanted to spend the money to replace the antenna and coax. However, since we had a very heavy rain just before the meeting, duplication of the waterfall was easily achieved.
To the extreme displeasure of the older members who wanted to "patch the feedline and connections" a motion to spend the money to replace the old antenna and coax with new everything. After the purchase of a Ringo and some 1" heliax and the installation of same, the repeater range was tripled. The grumblers did not like the Ringo, as "it was not good enough". And, after I had left the area, they spent nearly two hundred dollars for a commercial antenna cut for the frequency, which they purchased from a club member who ran a two way shop and was adamant that the Ringo was no good. They were totally destroyed to find out that the high dollar antenna gave them no more range than the Ringo.
The moral to this story is things are not always as they seem, especially when it comes to VSWR, coax, and antennas that seem to work on frequencies that they shouldn't. Never take anything for granted, especially when it is your RF going up the flue. -30- http://www.antennex.com/copyrigh.htm K5CNF.

Friday, September 23, 2011

The Betrayal of New York's Bravest

In 2003 Police, Fire, Ambulance, and Transit in the Victoria area (BC Canada) went to a Motorola Digital radio system. The system was designed, implemented and maintained by a corporation called Capital Region Emergency Services Telecommunications (CREST). The corporation included representatives from the local municipalities, Provincial government, Povincial Ambulance Service, BC Transit and the CRD.

From the outset users reported problems with "bonking", unheard transmissions and garbled transmissions. The downtown core reported the most problems due to the amount of buildings and heavier call load. It became so bad that the Presidents of the Victoria Fire and Police unions sent memorandums to the Capital Region Emergency Services Telecommunications (CREST) putting them on notice that they considered the system a threat to the safety of their members.

Some upgrades to the system were made but the problems continued and in fact became worse as reported by the users.

The frequency used by CREST (VHF 136-174 Mhz) is a commercial band of channels. These channels, unlike the 800 Mhz, are congested with interference which will increase as time goes on. So in our case we aren't just dealing with the problems inherent in the Motorola Digital systems on 800 Mhz, we are also dealing with a frequency which does not give us priority.

The system shut down completely in 2003 and again on October 27th 2005. We also know, as does the CREST board, that in the event of an area wide disaster or critical incident the system will not tolerate the volume of radio traffic and there will be no emergency services comms. This is highly ironic in that the system was put in place to address the need for a system which would allow all the jurisdictions to communicate during an area wide incident. When the system is most needed it will fail.

The CREST corporation is now in a financial deficit and will have no funds available for several months and possibly years.

Also, given the frequencies we operate on and the experiences of places like Miami and Philadelphia it would be fiscally irresponsible to pour more of the tax payers' money into an unfixable system.

We have close calls on a daily basis where officers are calling for cover or help and are not being heard.

On one occassion officers called for assistance multiple times while fighting with a male who had slashed himself and was covered in blood. The male managed to grab the beanbag shotgun from one of the officers. After many failed attempts on the radio one of the officers called 911 on her personal cel phone. The cel phone worked in the building. This happened two years ago. Nothing was done to improve coverage in the building which is notorious for calls involving violent and sometimes armed persons. The problem remains to this day.

On another occassion one of our Sgt.'s made multiple calls for help while he wrestled with a violent mentally deranged person. He was finally able to subdue the suspect.

Also on a daily basis members tell me that they have told their spouses that should they be hurt or killed as a result of the radio system that they should retain a lawyer to pursue CREST and Motorola.

Some Police and Fire officials are supportive however, due to the political backdrop there is a limited amount they can do.

CREST's response to the unions has been a "quit your whining" attitude with an underlying hostility. CREST has conducted an independent review which downplays the concerns of the users and states that due to financial issues they will be "unable to do anything any time soon".

All we can do is pray that something is done before one of our members is hurt or killed. The fact that it has already happened elsewhere doesn't seem to bother those who continue to defend the system.


Read more here

Saturday, September 10, 2011

Digital Radios - Failures?

WASHINGTON — Caught in thick smoke in a burning suburban Cincinnati home, veteran firefighter Robin Broxterman and her novice mate, Brian Schira, tried to summon help on their Motorola digital radios. She called four times, he another half dozen, according to radio logs from the 2008 incident.
For seven long minutes before concluding that contact had been lost, the Colerain Fire Department's incident commander heard nothing discernible from Broxterman and Schira, certainly no urgent "mayday" calls for a rescue operation, an internal investigation found.
In the ensuing rescue effort, Broxterman, a 37-year-old mother of two, and Schira, 31, were found dead in the basement, covered with rubble from a collapsed floor.
"No firefighter should have to die because of a radio that doesn't work," said Arlene Zang, Broxterman's mother and a firefighter herself, while conceding that other factors influenced the tragedy.
Many of the nation's biggest fire departments, spooked by allegations that Motorola's digital radio failures contributed to the deaths of at least five firefighters, the disabling of a sixth and scores of close calls, have limited use of the glitzy gadgets acquired in a post-Sept. 11 emergency-communications spending splurge.
The headlong, federally backed push to buy tens of billions of dollars in digital equipment, including radios priced as high as $6,000 each, gained momentum despite the lack of any government standard ensuring that they'll perform for firefighters. Multiple investigations and tests have since found flaws in the equipment made by Motorola and its rivals.
Fire departments in New York City, Chicago, Los Angeles, Boston, Phoenix and Boise, Idaho — communities that have spent tens of millions of dollars on the new equipment — are so leery of problems that they won't use digital radios at fire scenes.
Boston firefighters "are not to use digital radios," said Joseph Brooks, radio supervisor for the city's Fire Department. "They don't have them because I said no."
Analog technology, whose radio waves mimic sound waves, is stable and proven to be reliable for firefighters, he said, while computerized digital radios are "great for public works and building inspectors whose lives don't depend on their radios."
While a number of companies sell digital radios to public safety agencies, most of the focus falls on Motorola, long the industry's dominant player and holding an estimated 70 percent to 80 percent of market share.
Schaumburg, Ill.-based Motorola Solutions, Inc., which took over Motorola Inc.'s public safety-communications segment in a recent spinoff, stands by its digital radios, the most sophisticated of which it boasts are waterproof and can withstand the force of a bowling ball dropped on them again and again. In a statement to McClatchy, the company pointed to its more than 80-year history of providing public safety agencies "with reliable, state-of-the-art equipment and innovative solutions."
"While other vendors have come and gone, Motorola has remained committed to serving these dedicated professionals and has closely listened to public safety's needs," the firm said.
Motorola declined to quantify its U.S. public safety business, but said it served more than 1 million first responders worldwide.
Motorola's newest generation of digital devices offers a full range of features and costs "without ever compromising first responders' safety," the company said.
Despite those assurances, numerous firefighters say that Motorola's digital radios have failed them when they most needed them: for "mayday" calls to be rescued from burning buildings.
The digital radios' shortcomings are so widely known that they've acquired nicknames. There's the "digital cliff," when a radio is out of range and the connection ends without warning. There's "bonking" — also dubbed "the sound of death" by some Philadelphia firefighters — when an important transmission gets rejected because too many other radios are using the system. Then there's "going digital," when a radio emits a garble of beeps and tones instead of a voice.
Another problem, documented in tests by the National Institute of Standards and Technology, a federal agency that works with industry, is that digital transmissions can be rendered unintelligible by loud background noises, including the piercing alarms that firefighters wear to alert supervisors if they're nearly out of air or incapacitated. In one 2008 test with alarms sounding, firefighters correctly understood just 15 percent of the words spoken.
Despite recent manufacturer-led improvements, intelligibility tests still show that digital radios under-perform radios that have been in use for years, said Dereck Orr, a NIST program manager for public safety communications systems. Tests have shown that the gap is still about 15 percent.
A "noise-canceling" feature in new models may offer improvements but NIST hasn't yet tested it.
Some firefighters said that "trunked" systems, in which multiple users share the same radio frequencies to improve efficiency, could prove disastrous for fire operations because nonessential traffic could block radio lines, as occurred in the Colerain fire.
"Trunking is like having five kids at home and three beds," said Brooks, Boston's radio supervisor. "As long as someone schedules who sleeps when, it's fine. But if more than three kids want to sleep at the same time, you're in trouble."
A spokesman for Motorola Solutions declined to respond to questions about these various problems with its digital radios.
The shift to digital began in the 1990s, but it surged in response to calls for radio upgrades after the communications chaos that greeted hordes of first responders converging on the flaming towers of New York's World Trade Center on Sept. 11.
In 2004, the 9/11 Commission recommended overhauling public safety radio systems in New York, Washington and other cities considered "high-risk" terrorism targets to avoid another Tower of Babel-like snarl.
Congress and the Department of Homeland Security have taken a broader approach. The department has required state and local governments to submit plans for improving the ability of police, firefighters and medics to communicate with one another and has scored their progress in implementing the plans.
While federal agencies haven't issued a mandate for a switch to digital trunked radio systems, they've used the lever of federal funding to prod more than 60,000 state and local agencies to do so. Once Congress began approving $13 billion in federal matching funds to help finance purchases of the equipment, the rush was on.
From 2005 to 2010, the proportion of digital radios used for all purposes in the U.S. rose from 6 percent to 20 percent, according to IMS Research, which tracks the electronics industry. By 2015, it estimates, digital use is expected to reach 50 percent, suggesting that about 1.5 million first responders will depend on them.
Switching to digital requires costly infrastructure, including towers that beam radio signals for miles. North Carolina's statewide system calls for 240 towers and other infrastructure with a price tag of nearly $189 million.
Some fire departments said Motorola had successfully addressed the problems.
When digital garbling and unintelligible transmissions plagued the Orlando, Fla., fire department's new system, firefighters reverted to their older radios for years while awaiting testing, upgrades and training. Deputy Chief Greg Hoggatt said the radios were working now, and the department is 100 percent digital.
The Charlotte, N.C., fire department will migrate to digital within the next year, and department officials think that training and proper use can solve much of the problem with background noise, Deputy Chief Jeff Dulin said.
"Everything's going to go digital at some point," he said. "It's just the way of the world. Motorola has made commitments to us and to other fire organizations to remedy this, and it was not insurmountable."
Other fire departments remain skeptical.
The Philadelphia firefighters union, which alleges that two of its members died in 2004 when their mayday calls were "bonked," has resorted to using a labor contract clause to ask that an arbitration panel require fixes to the system. Tim McShea, the vice president of the Philadelphia union, said he still got two to three calls a year about "bonked" mayday alerts.
One former official of the Philadelphia firefighters union, Dave Kearney, said the digital trunked radio system was needlessly complex and "doesn't do a better job."
"Motorola is selling us a space shuttle," he said, "and what I need is a pickup truck."
The Chicago Fire Department, proceeding even more cautiously, hasn't used the city's $23 million Motorola radio system since its installation began in 2006, awaiting full testing and any necessary upgrades.
The Boise Fire Department found problems with its digital radios soon after the city bought a new radio system in 2005 with the help of millions of dollars in federal funds. Recent improvements have been insufficient to persuade firefighters that the equipment is safe to use during fires.
"We're not going to look the family members of a deceased firefighter in the face and say we knew about this problem and we adopted it anyway," Boise Fire Department Capt. Paul Roberts said.
In the Ohio tragedy, a Colerain Fire Department investigation found that, in a half-hour period, the trunked system rejected at least 43 attempted communications by firefighters, some of them because 22 agencies and 75 nonparticipants monitoring the event tied up space on the system.
Department Capt. John McNally said that when firefighters were trained on the state-of-the-art equipment, they had the impression that it would be invincible. Instead, he said, it's been rendered useless by busy signals during some large events, such as storms, and there've been unexplained "stealth" rejections by the computer.
"If you're in a crucial situation and you key that mike, and you get a busy signal, that's just a gut-wrenching feeling," McNally said.
Zang, Broxterman's mother, and her husband have sued Motorola, the homeowners and others in the Hamilton County Court of Common Pleas on behalf of their daughter's estate.
Lawyers for Motorola Solutions have denied the suit's allegation that the company's radios failed because of their "flawed" design and manufacture. The company, which declines to comment on its litigation, reached settlements for undisclosed sums with the families of the two dead Philadelphia firefighters.
Cities and counties across the country often accepted contract language from Motorola and its rivals that promised 95 percent coverage 95 percent of the time on streets. That guarantee doesn't extend to basements, subways or high-rise buildings.
Officials at a number of fire departments have grown outspoken over the lack of performance standards for such crucial equipment, noting that the breathing masks and protective clothing their crews wear must undergo independent testing to ensure that they meet rigid standards.
"A toaster has to go through more certification processes before it's sold to the public than a police officer or firefighter's radio," Boise's Roberts said.
The nonprofit National Fire Protection Association effectively sets certification standards for firefighters' protective clothing and breathing masks, standards that government agencies then adopt. Ken Willette, the manager of the association's public fire protection division, said that no one had asked the group to set safety standards for firefighters' radios.
The International Association of Fire Fighters, whose 300,000 North American members protect 85 percent of the United States during fire emergencies, is pushing for stronger regulation.
"There needs to be a performance standard, and radios need to be certified to that standard," said Richard Duffy, the assistant to the union's general president. He called firefighters' radios their "number one piece of safety equipment" and said the union advised members to avoid using digital radios inside burning buildings.


Read more: http://www.mcclatchydc.com/2011/09/06/123290/firefighters-balk-at-new-digital.html#ixzz1XYHlwFOS

Tuesday, September 6, 2011

Get SET for the 2011 ARRL Simulated Emergency Test

Mark your calendars: The ARRL Simulated Emergency Test (SET) is set for October 1-2, 2011. This nationwide exercise is the chance to test your emergency operating skills and the readiness of your communications equipment and accessories in an emergency-like deployment. ARRL Field Organization Leaders at the Section and local levels -- along with many other volunteers who are active in public service and emergency communications -- are developing emergency-like scenarios in consultation with a variety of agencies for whom radio amateurs are known to provide service during emergencies.To find out how you can step up and be a part of the local or Section-level activities, contact your Section Manager. You can find contact information for all 71 ARRL Section Managers on page 16 of any issue of QST. Additional contact information may also be found on the ARRL website.
The Amateur Radio Emergency Service® (ARES®), the National Traffic System (NTS), the Radio Amateur Civil Emergency Service (RACES) and members of the ARRL Field Organization will participate and practice emergency operation plans, nets and procedures.
Building Relationships
The ARRL Simulated Emergency Test is an ideal opportunity to demonstrate the capabilities of Amateur Radio and to improve them when necessary by experimentation. Community and public service agency officials will learn first-hand by taking a role in the SET and by providing an objective evaluation afterwards from their perspective.
The ARRL has long-standing relationships with several national organizations, including the American Red Cross, the National Weather Service, the Federal Emergency Management Agency and the Salvation Army (among several others). Find more information on these and other national served agencies here.
National Preparedness Month
Once again this year, ARRL is a National Preparedness Month Coalition Member. National Preparedness Month (NPM) is in September, and this is a nationwide effort to encourage Americans to take simple steps to prepare for emergencies in their homes, businesses and schools. The US Department of Homeland Security is working with a wide variety of organizations -- including the ARRL -- to highlight the importance of emergency preparedness, as well as to promote individual involvement through events and activities across the nation. We encourage you to consider this year’s Simulated Emergency Test and all its preparations as a demonstration of Amateur Radio’s readiness and as an active participant in National Preparedness Month.
SET to Go!
In consideration of local and Section-wide schedules with agencies and many others, ARRL Field Organization Leaders have the option of conducting their local or Section-wide SET on another weekend in the fall season. Check with your local ARRL Field Organization leadership for the exact date in your area. Your help is needed, and the ARRL SET is a great way to get involved in emergency communications. Information about specific SET guidelines and reporting forms for these ARRL Field Leaders are posted on ARRL website.