Have you ever had to DF and ELT that you couldn't "hear?"  You may wish to modify your practice beacon to simulate realistic malfunctions.  One of the more difficult scenarios for a DF team is trying to find the carrier-only signal.  That means the unit transmits without the ELT-type swept tone.  This makes the signal may hard to identify from the noise on nearby frequencies.  You may or may not be able to audibly identify a carrier-only signal, but you can tell for sure if you have reliable deflection on your DF set (airborne or ground).  DFing a carrier-only ELT is an advanced technique, so only give that to prepared teams.   See the SAR Wars Stories for a real-world example of a carrier-only ELT.  If you'd like to practice these skills, follow the directions below. 

This project is not for the faint of heart or for the unskilled.  If you wouldn't do this to something you own--don't do it.  If you don't own it and you wreck it, you might just have bought it.  A practice beacon costs over $150.

Step 1.  First, you will want to review the Pointer 6000 Circuit Diagram courtesy of Pointer, Inc.  It will familiarize you with the layout of the circuit board.

Step 2.  Next, you need to mechanically access the practice beacon.  Remove the six screws from the back of the box with a phillips head screwdriver.  Remove the cover and disconnect the battery with a gentle pull.  Remove the battery to give yourself room to work.  When you are finished with this step your practice beacon will look like this.

After you're complete with this, connect the battery and close everything up in the reverse order that you opened it up.  Test your beacon by turning it on and flipping the sweep switch back and forth.  You should hear the sweep go away while shorted and come back when open!  Of course you'll need your trusty Little L-Per, Jetstream, or other receiver to hear the signal on 121.775.  Next, try DFing it and have your friends do the same!

"PULL LOCKING SWITCH LEVER WHILE CHANGING POSITION" 
Apparently this sentence written in plain English isn't plain enough for some individuals.  Sooner or later its almost a given that your practice beacon will have its master power switch broken off by someone who thinks, "if it doesn't move ... push harder!"  So far my personal beacon still has its original switch, but I've been in at least two squadrons where the switch had to be replaced--luckily that task has only fallen to me once.

Training will help prevent this problem, as will not allowing the beacon to be handled by anyone untrustworthy.  Interestingly, most real ELTs don't have a locking-type switch.  Instead they have a 3-position switch (ON, ARM, and OFF).

Once you have a suitable replacement switch, refer to the photos above to locate the backside of the switch.  Unsolder the wires from the switch.  Unscrew the switch from the front of the beacon and install the new switch in its place.  Be sure to orient the switch properly so that the closed position corresponds to "on" on the front of the beacon.  Solder the wires back to the switch. 

If you short the capacitor shown here, your practice beacon will transmit a single-tone that is moderately pitched in comparison to the familiar sweep.  This is different than the carrier only sound, which sounds like "silence."  A carrier only signal sounds like someone has depressed a microphone on a two-way radio but isn't saying anything.  You get your practice beacon to transmit carrier-only by performing Modification #1 on this page.

Like the other mods on this page, you could wire a switch to the short, with closed being the modified tone and open being a normal sweep.

This mod makes for an interesting "broken ELT" type sound.

Many users wish to power their practice beacons by something other than the batteries provided by Pointer.  Please note that doing so will void your warranty! 

The original battery supplied by Pointer is a "real" ELT battery and will therefore have an expiration date.  The original battery is Part Number 2020, and costs around $25 - $35 US.   You will find that this battery will generally last a long time.  Additionally, the supplied alkaline battery pack specifically designed to endure short term extreme thermal variations and mechanical shock.  The bottom line is that it is a good battery, but is expensive over the long haul.  Since it is usually much easier and cheaper to pick up batteries from your local retailer, modifying your beacon to use a different power source may be for you.

There are a great number of options available to power your beacon.  If you wish to have a new battery, another ELT manufacturer makes batteries for Pointer ELTs.  The manufacturer is Artex, Inc., and the part number is 00-30-006.  

A very good option is to use expired batteries for real ELTs.  ELT batteries must be periodically replaced by an aircraft maintenance technician.  If you ask around at your local airport's Fixed Base Operator (FBO), the mechanics there may be willing to donate the expired batteries that they remove from actual ELTs.  Providing they are the same type, they will work wonderfully in your Practice Beacon.   It shouldn't take too much convincing for the FBO since they would throw these batteries away otherwise.  In fact, they likely will not have any lying around and will have to specifically save them for you.  Please note that if you are disposing of ELT batteries in bulk that they are considered hazardous waste and need to be disposed in an environmentally friendly way (by law).

If you use the battery supplied by Pointer or another ELT battery, you will not be able to modify the power output of the beacon.  Pointer even talks about home-made battery packs and some of the options you might want to consider on their Pointer 6000 web page.   This short page also discusses the frequency reassignment that was required more than a decade ago.  In summary, it states that in designing a power source you should use 8 volts maximum.  At 7.5 volts, the nominal power output of the beacon will be 150 milliwatts.  The original batteries supplied by Pointer test at 7.5 volts as well.  You might wish to note that by specification the power output of most ELTs is 100 milliwatts (TSO C-91 and C-91a beacons ELTs), and 25 milliwatts for 406 MHz ELTs (TSO 126).  To simulate a beacon that is transmitting at low power, Pointer suggests using a 6 volt power supply.  They further suggest that you can shorten the telescopic antenna to simulate a broken antenna.

If you're still reading this and your eyes haven't glazed over, you likely already know that a fresh AAA, AA, C, or D cell alkaline battery supplies approximately 1.5 volts.  Therefore, for a 7.5 volt battery back you will want to use 5 batteries in series.  For a 6 volt battery back you would want to use 4 batteries.  Rechargeable batteries (such as Ni-Cads) typically output 1.2 volts apiece, so adjust your planning accordingly (5 x 1.2 = 6.0, 6 x 1.2 =7.2).  Of course, D cells will last longer than the other types.   D cells may also be more likely to give sufficient voltage in cold weather.  D cells can be rapidly replaced, are readily available just about anywhere (such as the gas station at midnight), and are small enough that you should be able to fit a spare set inside of an ammo can setup.

Begin by unscrewing the back panel.   Use a voltmeter to ensure the polarities between your battery pack and the original battery match.   If you improperly connect the wires, you will damage the practice beacon.   Of course, you should be able to determine positive and negative terminals from the way the original batteries are shaped.   It is always better safe than sorry, though, so run the voltmeter.  

At this point you have several options.  They are:

Option 1: Keeping the battery pack inside of the beacon housing
Using this option allows the most portability of the beacon.  Externally the beacon will be identical to a new beacon as shipped from the factory.  This will allow for the easiest use as well.  A battery holder for AA batteries will fit inside the case.  Unless you fabricate a battery pack as shown below, that is just about the only option (excluding, of course, the standard p/n 2020 battery from Pointer).

Option 2: Place the power source outside the beacon housing.
This is the most common option.  You will need to solve several problems for this to work well.  First, you will need to determine how you will run wire from inside the beacon container to your battery pack.  You will probably have to drill a small hole in the casing of the Practice Beacon to admit the wires.  This will compromise the waterproof seal of your practice beacon, so liberally apply hot glue or another sealant if this is important to you.  You could also mount a barrel-style power adapter that can connect directly to the beacon.  For example, Radio Shack part #274-1563, "DC Power Jack, panel mount, Size M."  You will be able to find the electronic components listed on this site at an decent electronic parts house, to include internet catalogs.  Radio Shack part numbers are included because a Radio Shack store can be found nearly anywhere in the nation.

Option 3: Keep a battery pack inside the beacon while allowing for an external connection for power or charging
This option allows the practice beacon to run off the internal battery when disconnected from external power and also has an external adapter (as described in the Option 2) to allow for charging OR to power the beacon, depending on your design.  The  CAP Emergency Services Resources™ website is aware of a modification that allows a user to plug in virtually any low DC voltage (6 - 35V) to power the beacon and also automatically isolates the battery.  This information will be provided as it becomes available.

Since your battery pack is outside of the beacon for options 2 or 3, you will need a method of keeping everything together.  An excellent idea is to construct a Practice Beacon Box from an ammo can as outlined on this site.You must also choose what will power your beacon.  In addition to AAA, AA, C, and D cell batteries, you may also use a 6 volt lantern battery.  The advantage of this battery is that you only have to deal with the single cell and you don't need a holder.

Speaking of battery holders, if you wish to use the 5 D-cell configuration, you would probably like to know that Radio Shack carries battery holders for most battery sizes.  For example, a single D Battery Holder: Radio Shack Part #270-403 and a 4D Battery Holder: Radio Shack Part #270-396.  Arrange multiple holders in series (if required).

Run the wires from your battery assembly to the Practice Beacon.   If they are not long enough to mount them in the box, add additional wire.  You can use the molex-style wire connector from the old batteries to the new standard battery holder.   This facilitates easy swapping of battery packs.  

When complete, you will wish to secure the battery pack inside your beacon box.  Hot glue or velcro are good options.

The following is an excellent example an elegant solution using rechargeable batteries.  This information was submitted by 1Lt John C. Hill, CAWG Group 7 ES Officer.  Many thanks, John, GREAT WORK!

Thinking about converting a real ELT into a practice beacon?   Read this--from the Chief of CAP Comm--first!

The answer is "no". You can't convert a real ELT for practice purposes. The reason is because of the fact that ELTs are intentionally "sloppy", transmitting a healthy signal on the first harmonic so you can track on either 121.5 or 243.0. The practice beacons have filter circuitry to eliminate the harmonics so we can use them on 121.775 without stepping into the unauthorized 243.55. So, if someone were to recrystal a real ELT to 121.775 they would be in violation of our frequency assignments because we don't have an assignment on the UHF number.

Now, that having been said, Fred has submitted a request for the Joint Frequency Managers (DoD) to allocate 243.55 as an ELT training frequency but that hasn't happened yet. If they ever get around to doing that, then this gentleman's idea would be legal. Since we now have UHF "Trackers" a UHF training frequency would be helpful.

Thanks for checking. Let us know if there's anything we can do.

Malcolm Kyser
Chief of Communications
Civil Air Patrol
105 S. Hansell St. Callsign: Headcap 4
Maxwell AFB, AL 36112

The question was asked to other industry experts.   They indicated t that most often the bench time would often cost more than a new Pointer brand practice beacon.   Professional conversion would be required to maintain the type acceptance of the radio.  In other words, shell out the $156, which includes shipping.   You may purchase the beacon directly from Pointer.

Future Mod: While you're on the inside of your Pointer, you can also eliminate that telltale light.   Simply wire in a switch to one of the wires.   Eliminating the light will allow your batteries to operate longer and the light is unnecessary inside your ammo can anyway.  

Future Mod: The rate of the tone sweep should be able to be controlled by the voltage into the tone generator.   In this case, you would want to solder in a pot (potentiometer) to the supply line.   I don't know if this has been successfully tried--someone please let me know!  

Future Mod: Hook a solar cell to the beacon to charge/power the unit during daytime training.

Future Mod: Add a DTMF controlled circuit so you can turn the beacon on and off remotely.   When this is combined with a solar cell, it allows the beacon to be left out in the middle of nowhere for extended periods.   Other folks have put automatic timers on their beacons--not a bad idea.   It might be a wise idea, however, to mark the position of the beacon by a GPS or other very reliable means of navigation, lest you lose your beacon when it ceases to transmit unexpectedly.  

Future Mod: Modify the beacon so it sweeps "up" like an EPIRB does