Saturday, April 30, 2016

Operating Simplex FM

We have all listened to or participated in uhf or vhf Ham Radio nets. A common practice on a repeater net is to take mobile or portable check-in's toward the beginning of the net. This can be for any number of reasons but most specific is to allow people who have the potential of moving out of range to go first or to allow people who do not have sufficient power or antenna systems more time to relocate to make contact. (continued below...)




We depend on these nets to practice orderly and efficient relay of messages for future times of need. What we don't realize though is that many, if not most repeater sites are located in areas with smaller potential for power emergencies. Many of these areas are not prepared in the event power is not available for extended periods of time. Not to mention any weather related event could take the antenna system out of service. Then what would we do for local communication efforts?

Most Ham Radio operators do not practice simplex nets in the VHF or UHF bands. This takes a special skill and turns things around a little. I heard a couple of ham radio operators the other day joke at the fact that there were people who wanted to run UHF and VHF simplex nets. They said all repeater sites today have backup power systems and ham radio operators need to practice their nets on the repeaters. I must say these hams are misinformed. Besides, what is going to happen to their precious repeater when a major storm destroys the repeater antenna?

It is important to know the capabilities of your radio equipment if you have to operate in simplex mode. This is where you do not use a repeater and all transmit and receive is on the same frequency. You will find that the distance is much shorter.

If you are running a UHF or VHF simplex net call for the high power stations to check-in first. This will allow you to operate in a greater geographic area. The high power station may be able to relay traffic from a distant low power station. Utilization of relay stations is important on these types of nets.

The overall key is to practice in simplex mode. Know the range limitations of your equipment. Work on solutions to be able to relay messages across distances. This may require you practice with friends who are also preparing for communications disasters as well. You can even use HF operators to connect to distant stations and relay traffic to and from your VHF net. Explore the possibilities!

Have you operated in VHF or UHF nets? If so, I would like to hear about your experiences. 

Friday, April 29, 2016

External Power Sources for Portable Devices

Have you ever reached for your cellphone in an emergency situation to find out that it is dead? Believe it or not this happens more than you think. App updates on smartphone devices can increase battery drain. Being out of range of an active cellphone tower can drain your battery in a more rapid pace as it searches for available towers. Older phones do not retain their charge as long and sometimes we have used our devices much more than we thought. The result is a dead battery and no way to call or text.

Portable power has been an emerging solution for some time. Essentially most portable power packs are a rechargeable battery in a shiny case.  These portable power packs are usually charged by a USB cable connected to either a computer or a USB wall adapter. The charge time depends on the depletion of the pack and the battery size. (continued below...)




To charge a cellphone you usually need your charge cable that has your phone plug on one side and a USB connector on the other. Once you connect your phone to the power pack your phone will begin its charging process. Depending on the brand and capacity you may be able to use your phone while it is charging. 

Most battery packs allow for two or three charges before the pack has to be recharged itself. These are great tools and good to have in case of an emergency. Always have one or two of these fully charged in your go-bag.

Here are a few examples.

There are a few things to keep in mind when purchasing one of these packs. First notice the mAh rating. They can range from 2,000mAh to over 28,000mAh. The higher the rating the more charge it holds and the more recharges it can supply to your cellphone before recharging. For example, if you have an iPhone and a 2,000mAh rated battery you will not get much more than 1 charge out of the external battery. If you had a 28,000mAh rated battery you could probably charge the iPhone over 6 times before recharging.

Make sure your device can accept the voltage supplied by the pack, that it does not exceed the mAh rating of the battery, and will accept the connector type of the battery.

What has been your experience with rechargeable power packs?


Thursday, April 28, 2016

Traditional HT's Versus the Chinese Brands

There has been a large interest in the cheaper Chinese manufactured handy talkies. These new and quickly changing models seems to be more popular everyday. This has been primarily due to the low cost.  I do not blame anyone for giving these "cheaper" radios an eye in this day of rising costs and lower wages. Are these radios up to the task of being a great solution in the event of an emergency? (continued below...)


First, I want to say that any radio is better than no radio. I do not want to convey the message that people should not have one or two of these stored away in a faraday box or in a go-bag. I do however, want to caution the consumer to understand the functionality of these devices before throwing $60 or $80 for one to use as their primary radio. There are some limitations to these devices and you need to be informed before making your purchase. Think about the following items.

Many of these radios are virtually impossible to program by hand. It can be done, however it is not an easy task. Most people find the need to purchase a software program to aid in the programming. If this would be the case, you will need programming software and a programming cable. This is an additional cost. Another option of programming is to find a friend with the same model and clone their frequencies into your radio.

Because these items are difficult to manually program in the field without software you may find yourself struggling to program your radio if you are relocated in the event of an emergency. The frequencies needed may be different than those in your radio. If you do not have a way to easily program or clone it to new frequencies, then you may be stuck with the call frequency and a lucky hit on a repeater frequency.

In the early models of these radios there were numerous quality issues from software bugs to complete failures. For example, if you look across the Internet for problems with Baofeng, you will see many complaints with squelch, noise, and receiving issues. It appears the cheaper radios do not have the quality filters and receivers as some of the higher priced name brand competitor's products. Keep in mind as each new version of the radios is released many of these problems are corrected. As higher quality filters and receivers are added to these radios then the price will gradually climb.

If I was in the market for a new HT today that would be my primary radio, I would consider the following:

  • What radios are easily programmed by hand?
  • What radios have a strong receiver and good filters to protect against intermod? (In high RF areas this is a major problem)
  • How many bands do you want to RX/TX on the HT?
  • What output power do you want the radio capable of?
  • What features do you want in the radio? (dual watch, scan, cross band repeat, digital, APRS, etc.)
  • What are the Internet reviews of the models you are interested?
  • What is the quality of the customer service? (Try it our before you buy)
  • What is your budget?
Do your research and homework. You do not want to be a Ham Radio operator that wishes he or she would have bought a different radio in the event of an emergency. 

Don't forget you usually get what you pay for. 

Wednesday, April 27, 2016

How to Build A Faraday Cage

Faraday Cages are fairly easy to build and do not require a lot of material. Most people probably have most of the items lying around the garage or can obtain them at the surplus or hardware store. The idea of a faraday cage is relatively simple. Shield the object from electromagnetic energy with a metal cage or mesh. There should be minimal or no gaps and the object cannot touch the shielding that surrounds it. (continued below...)



Different items can be used for the metal shield. Some people have had success un using an ammo can while others have taken a cardboard box and lined it with multiple layers of heavy duty aluminum foil. Depending on what is used aluminized duct tape may also be needed. The following are only a few of may ways to build a faraday cage.

Metal Trash Can
Metal trash cans with metal lids are one option. The solid metal container not only provides a weather shield but also does well in protecting against a strong electromagnetic pulse. There are a couple of items to consider. First make sure the lid seals completely against the can itself. The better can and lid combos are the ones where the old overlaps the can. The concern is not air-tightness but rather to eliminate any major gaps in the container.  Second, make sure you line the interior with something like cardboard to create a gap between the metal and the items in the can. If the can is large enough you can put the items inside a cardboard box and set the box inside the can. Remember the protected items cannot touch the metal of the can.

Metal Lined Cardboard Box
Obtain a cardboard box the size necessary to store the items you wish to be protected. Any cardboard box can be used, but thick cardboard would be preferred. NOTE: The thickness of the cardboard does nothing to shield electromagnetic signals but rather offers a greater gap between the shield and the items you wish to protect. Remember the items inside the cage cannot make contact with the shield. Next, obtain a metal shielding material. The following are adequate items for the shield (pick one):

  • Heavy duty aluminum foil (need enough for three or more layers around the box)
  • Fine wire mesh
  • Reflective mylar from a cheap space blanket
If using aluminum foil, then wrap the outside of the cardboard box with three layers of the heavy duty material. Otherwise using the wire mesh or reflective mylar, completely enclose the outside of the box with the selected material. Make sure there are no gaps where the materials connect against each other. Also make sure the material holds to the cardboard. Insert any items into the box that needs protection. 

Ammo Can
Find an ammo can at a surplus store, gun show, or sporting goods store. Make sure the ammo can is metal. A plastic ammo can will do no good. Line the inside of the can with cardboard to insulate any device from touching the outside of the can. Place items that need protection inside the can. Obtain aluminized duct tape (or any conductive tape) and tape around the lid to conductively seal the can. 

Some people have said that a microwave oven can also make a good faraday cage. In theory this should work because the lining of the microwave is designed to keep harmful radio waves from exiting the unit when it is in operation. The same lining should help protect sensitive equipment from outside electromagnetic energy. However some have reported their testing of microwave ovens did not perform as expected. Note that the microwave oven is designed to shield the energy produced by the magnetron at its frequency of operation. Also assume the quality of some ovens may be in question. Therefore don't stand too close when nuking your leftovers.

If possible, ground your faraday cage by attaching a conductive wire from the box/cage/can to a ground rod in the ground. This does not aid in shielding your equipment but it does help in making the box safe. If an EMP occurred and the box was not grounded it is possible that the box become energized with no way of escape. This energy could be transferred to you by making contact with the cage soon after the event. 

The success of the faraday cage depends on a number of things. The following checklist of questions is important: 
  • Is the cage well sealed with little or no metal gaps? 
  • If using aluminum foil, are there sufficient layers of foil on the box?
  • Is the equipment to be protected isolated from touching the metal of the cage? 
  • Is the box grounded for safety?
If you have assembled your box you can test basic functionality by putting a small radio inside the box. Make sure the radio is on and the volume turned up. Sealing it inside the box should cause the radio lose signal. This is a basic test and not all inclusive. Keep in mind that a faraday cage will not remove all frequencies and therefore is not the perfect solution in all applications. But it can help protect against certain wavelengths of electromagnetic energy. 

Another factor that would determine success of the faraday box is the power of the EMP and the distance from detonation to the faraday cage. Too close and you won't have to worry about it. 

Have fun!


Tuesday, April 26, 2016

Cell Phones in a Disaster

The question comes up all of the time. Are cell phones a good solution for communications in a disaster? The short answer is don't count on it. Cell phones do have a few characterizes that are admirable however their reliance on an operating tower in the vicinity makes them a very poor solution.

Cell phones typically have a range of no more than 45 miles. In many cases their range can be as small as 25 miles. They have to be within that distance of an operating cell phone tower. This may not be a problem in a metropolitan area but rural areas may have few options for nearby access. Cell phones are dependent on the tower itself. If the tower(s) cease to operate there will be no service and your cellphone is not much more than a glorified pocket camera. (continued below...)



In an actual disaster towers that do remain active will soon become clogged. Everyone will have the same idea and attempt to locate the ones they love. This situation could possibly shut the system down within minutes. In a clogged system the best possibility to relay a message to another person by cell phone is a text message. A standard SMS (not iMessage) has the best chance to reach the recipient. The small footprint size of text can "sometimes" make its way through a congested cell phone system. 

Keep in mind disasters can also take down the power grid. Most cell phones consume a large amount of power and must be recharged every day or two. Without connectivity to a cell phone tower the cellphone goes into search and acquire mode. This is where the cellphone is "seeking" an active tower. Typically this draws much more power and can reduce the cellphone battery operating time in half. 

For the category of dependable communications in the event of an emergency mark cell phones off your list. It can be a hit and miss depending on the circumstances. Their possibility of usefulness is better only at the beginnings of a disaster while the network isn't clogged, towers are still up, and there is enough electricity to operate the device.

There are better options. Keep tuned in for more. 

Monday, April 25, 2016

The Possibility of an EMP

EMP stands for Electromagnetic Pulse. It is created as a result of a nuclear explosion or a non-nuclear e-bomb. The result of an EMP is an overload of electrical systems and electronic devices. These systems and devices usually do not survive an EMP. Circuits and systems must be replaced with new unaffected electronics and this can take some time. The result of an area that has been hit by an EMP looks like the stone age with little or no electrical or electronic capacity. (continued below...)



Recently some stories (WND) have surfaced claiming that North Korea has two nuclear satellites orbiting above the United States. The report states that these satellites have the potential of creating an EMP above the Earth's surface. Whether or not this is true, the subject of EMP's is something to take into consideration. EMP's can disrupt the normal operation of society. Without electricity there will be no trips to the grocery store, no evening meals at the Cracker Barrel, no running water, and no watching Survivor on Wednesday nights. This is a worst case scenario.

Electronic damage from EMP's is certainly a high risk as a pulse of electromagnetic energy can enter into any electrically connected item. EMP's can also damage any item that the pulse can reach by conductivity. It would be the same way as receiving a radio signal through an antenna. If the electromagnetic pulse can propagate into an electronic circuit by over the air conductivity the circuit can be damaged. Scientific test have proven radios with antennas longer than 30" are very suseptible to EMP's.

Many online theories take the damage created by EMP's much further than the evidence supports. So be careful what you read in the area of damage possibilities. For instance some say that an EMP will disable all automobile transportation. While an EMP can certainly damage the electronics in cars it really depends on the age and design of the automobile. Newer cars with fiberglass or plastic bodies are much more susceptible to damage because of their dense electronic control and lack of adequate shielding. Older cars with strong metal bodies and minimal electronics are at a much lower risk of damage. Maybe the used car lot is looking better all of the time.

Protection against EMP's are something the United States Deaprtment of Defense is actively testing. It is known that a sealed metal barrier is effective in protecting against EMP energy whereas wood, plastic, or fiberous materials offers little little or no protection. Ham Radio groups have trained in building what is known as a Faraday box for protecting valuable Ham Radio gear. Soon you will find detailed instructions for building a Faraday box on CrashComms.com.

There are a lot of myths concerning EMP's. The best thing to do is research and understand how an EMP can effect you .

Sunday, April 24, 2016

Crash Comms

Tornados, hurricanes, earthquakes, solar storms, terrorism, power grid failures, or any catastrophic event can cause mass communication failures. All of these can occur without warning and put you and your family in the dark when it comes to contacting loved ones or getting the pulse of society around you. 

Imagine not being able to locate your kids. You last saw them when they grabbed their bags and ran out the door for school. A major catastrophic event occurred and there is no cell phone service. Land lines are down and traffic is at a standstill because of the panic in the area. What is the plan to determine the safety of your family? What is the plan to reconnect in person? 

Do you have a plan for your family in case the inevitable occurs? This site will begin to cover the necessities and the options for communication and safety. We live in a changing time and we must be prepared. In the days to come this site will begin to fill with information to aid you and your family. Check back frequently for more updates and information. 

In the meantime sign up for our newsletter. We will keep you updated.