Will we really be hit with an EMP? (part #2)

EMP Strikenote: article first appeared in December 2015

In part #1 yesterday I laid out the case for the probability of an EMP strike on America. I started laying out the case for the severity of the impact of such a strike. This article, Part #2, finish up on the impact severity, and end with what you can do to mitigate the EMP threat.

It is probably a good idea to read Part #1 first if you haven’t already done so.

Severity –

The experts and planners really don’t know for sure just what the extent of and EMP blast effects might be. Yes, there are books written talking about a 90% die-off in the first year. But, they are writers not experts in EMP warfare, they are novel authors.

I had the opportunity to talk to a 40 year expert that worked for Motorola and was a professor of electronics at a major university. We discussed the EMP potential. He explained to me that all their own testing was different than the hype and scare that we hear about in the media and read about in the books.

He was referring to all the post-EMP books hyping pre-computer controlled cars. Granted, vehicles with all the EMP resistant BOVdifferent computer technology would be far more susceptible to being rendered useless by an EMP strike. So some cars beginning in the mid-70’s began using integrated circuits, actual computer modules were about 3 – 5 years later. Obviously any vehicle without an integrated circuit board or computer module would be far less susceptible to damage from an EMP strike.

He went on to explain that not even the cars with computers that were all “zapped” had died an electronic death. The EMP pulses that they tested with only killed about 60 – 70% of cars with computers. I found that very interesting. He explained that sometimes all they had to do was disconnect a battery and the car would survive just fine. And not all the batteries were automatically destroyed by the pulses either. So the outcome for vehicle transportation may not be as dreadful as some would lead us to believe.

Electronics were a little different in their testing. If electronics weren’t protected they usually got wiped out. But, they also discovered that protecting the delicate electronics wasn’t all that difficult. They found the concept was to direct the energy of the pulse around the electronic gadget not allowing any of the energy to come in contact with the piece of equipment.

When I asked him how difficult it was, he chuckled and said, “Not very.” He told me that placing electronics in a metal box on insulated material should be just fine.

To me the operative word was “should.”

He said there was no way to conclusively say what kind of metal box worked all the time. And the reason is the EMP pulse itself. The energy flows through the air at different frequencies. The key was to block that specific frequency of energy associated with that specific EMP blast. And he also told me that there couldn’t be any gaps in the metal box, a tight metallic seal was paramount.

By then my eyes were kind of glazing over, I was getting lost. Then he said it was pretty simple to test. He said take an FM radio, tune it to a clearly heard station, and turn the volume up. Then place it in your metal box on insulated material. Slowly start to close the lid. If the radio reception died away and you could no longer hear the radio then the box was blocking the energy frequency of most EMP pulses.

He did qualify that by saying that to the best of their knowledge at that time EMP, energy pulse frequencies were roughly that of FM stations. And that is why if you could block the FM reception, you could block the pulse energy. And technically you weren’t blocking the energy pulse. The metal box was moving the energy pulse around the outside of the box not allowing the energy to come into contact with the radio’s antenna.

He also said it would be a good idea to remove the battery and the antenna from the radio. That would further assist in keep the energy out of the radio since both of those items attracted energy. We talked about wrapping the radio in a layer of insulation and he thought it would help if there were no gaps in the wrapping.

Faraday Cages –

We talked about Faraday Cages for awhile, he was not impressed. He thought they were overrated and pretty Farday Cage protection against EMPmuch was just a fancy and more expensive version of a metal box. He even mentioned that a garbage can with no holes or cracks, with a tight fitting lid, and lined with a non-conductive material could accomplish the same thing…maybe even far better.

The idea was simply to keep the energy from entering or contacting the piece of electronic gear that you were trying to protect.

A Faraday Cage was simply a fancy metal mesh box, that might not work as well as a metal container such as a garbage can mentioned a minute ago. We again talked about steel garbage cans with a plastic lining (i.e. a plastic garbage can) as an option. He said that would probably be just fine if the garbage can lid was tight fitting and let no gaps in the lid’s seal. We talked a little more and he liked my idea of using crumpled up aluminum foil as a “gasket” to ensure that there was no gap at all between the lid and the garbage can lip.

Layer after layer –

After thinking it through for awhile I talked with another buddy of mine, a serious and intelligent prepper. And the qualifications to be called such. We talked for awhile about EMP strikes and the potential for damage. Mostly sticking to how to protect radio equipment from damage.

When as was said and done we decided that we would wrap our gear in non-conductive material ensuring that there were no gaps. Then wrap that bundle in aluminum foil without gaps or open seems. So, imagine a bubble-wrap envelope sealed tight with clear shipping tape. Then that bundle is wrapped tightly with aluminum foil with absolutely no gaps in the wrapping.

Then use the non-conducting bubble wrap again, then another foil wrap, and then finish them off with a final layer of non-conducting bubble wrap. When we were all done with that, we placed them in a metal box with a tight fitting lid that left no gaps between the lid and the box.

I thought through that a lot. Basically we would be doing what my expert buddy had talked about. End result…redirecting the energy around the piece of electronic gear you are trying to protect.

Now what?

What to do now?” is the big question isn’t it. And honestly, that is up to you. I didn’t say that to be smug or avoid answering the question. It really is up to you.

Here’s how I see it…

  1. If you take your radios and EMP proof them in a metal box, then you don’t get to use the radio. You don’t get the operational practice or get to have fun with the radios.
  2. The EMP pulse, if it does occur, might be on a completely different frequency than what you have prepared for. Therefore your box is a complete failure and your radios get fried anyways.
  3. We may never get hit with an EMP pulse. Remember, it is rated in the low or very low probability category. So you wasted all that time, effort, and money for nothing.
  4. Or you can hedge your bet. The Baofeng UV-5RA radio is very inexpensive. Buy a set to use with all the right accessories, etc., especially the programming software. Get them all set up and enjoy them. Then buy just the radio itself, a back-up  for each radio you actually use. Program them, wrap ’em up, box ’em up for that potential EMP strike. And just to be on the safe and plush side…throw in the old family laptop with RT Systems programming software loaded on it, along with the cable and DVD.
Become obsessive?

No! While the potential for an EMP strike severity could be quite high if we are struck, the probability of being struck is still quite low. So there is no reason to start obsessing over being hit with an EMP.

And honestly, what part of your preps are truly dependent on electronics or batteries? For me it is:

  • Radios
  • Tactical flashlights
  • Solar generators
  • Night vision
  • GPS

Yup! That’s it for my dependency on electronics and batteries. So I have to ask myself the question, “Could I survive without all of the above?”

“Of course I could!” is the easy and accurate answer. Would it be more convenient with them? Yes. But we could get long without them.

So you really have to ask yourself the same questions –

What preps of your depend on electronics and batteries?

Could I get by without those things?

Summary –

As far as priorities go I would put EMP-proofing your electronics way, way down the list. I would say look into it after; a year’s worth of food, water, and garden seed. And then after, considerable medical supplies, weapons, and 1000’s of rounds of ammo. Then put in water filtration and purification capability, a good tents, clothing, and quality tactical gear. Then…and only then, would I consider worrying about protecting my gear from an EMP.

This has been a really long article on EMPs, but I thought it prudent to go through it in detail. But, by now you also have a pretty good idea of what you need to be doing about it.

Now…just go do it!  “whatever “it” may be.




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Will we really be hit with an EMP? (part #1)

EMP Strike electromagnetic pulse note: article first appeared in December 2015

I’ve pretty much stayed away from the whole EMP subject over the years. I’ve been asked about it a bunch of times but given some pretty vague answers. I guess it is time I get serious and share my real opinions on it.

Background –

My EMP opinion has changed over the years. Remember, I worked with intelligence information when I was in the Navy back in the 1970’s. I can tell you that back then during the Cold War there wasn’t any war-based “measured response” option. There also wasn’t any of thought of a weapon to do little damage to conquer the Soviet Union or any East Block country. We were in it to win it! And that meant nuke the crap out of them.

Sure, they knew about EMP effects for nuclear explosions even back then. But that was a distant concern, issue, or topic. What we wanted was to devastate them, their military, their people, their infrastructure, just basically blow em up.

But, as times have changed I have looked at what would Russia want to do to us in terms of war-based destruction. Russia is short of resources, all kinds of resources with the possible exception of fossil fuels. That being the case, I don’t think Russia would want to slick us off like glass with nukes. Well, with one possible exception, if we hit them first. If we would throw our missiles at them first, they would throw everything they had back at us as fast as they could turn keys and push buttons.

If you think about it, why would Russia, or even China, want to turn us into a nuclear wasteland? I simply don’t think Iran Nuke weaponsthey would.In all reality…they would love to have access to our resources…natural and man-made.

Iran on the other hand has the stupid 12th Imman, end of the world thing as part of their Muslim Shia beliefs. Those crazies would nuke us just to fulfill their desire to expedite the end of the world. But, Iran would hit Israel before they would hit us.

The crazies in North Korea, although crazy, don’t do anything without the approval of China. NK won’t nuke us unless China tells them it’s OK. North Korea really doesn’t want war. They know they would lose. But, they want the attention and associated power that comes with threatening war.

We are China’s biggest customer of the goods they produce. We spend huge amounts of money buying their stuff year in and year out. China loves those dollars! Why would they want to blow-up their best customer?

Well, there actually is a point when China might make a move against us. China has been an empire for 1000’s of years. Yes, China is currently a communist country, but it no less an empire now than it was 500 or 1000 years ago. When it comes to international politics China views everything in a very large context. I am talking in terms of 100’s of years to accomplish something, for sure decades.

Let there be no doubt in your mind, China expects to be a, if not the, world dominating empire. It is only a matter of timing for them. When China decides that the timing is right, they will use all appropriate tools available to them to accomplish their goals. And using nukes against us is seen as a strategy, nuclear weapons are nothing more than tools to them. Albeit maybe not their first or most desired option.

That being said, I do not think that China wants to slick us off either. It just wouldn’t fit their history-based reputation. Sure, they want to beat us, and beat us decisively, but I don’t see them going into “annihilation mode” on us. I think they want to subjugate not eliminate. They like our natural resources and ability to grow lots of food.

You also have Pakistan and Turkey as nuclear armed countries. While they are both supposedly secular governments, they are both Muslim countries. Pakistan has really moved towards being a Islamic government, Turkey is now maybe the most Muslim of both countries. When Pakistan completes its total transition to an Islamic state, then I would move them into a similar category as Iran. Same would be true for Turkey. I think it won’t be long for both of them to finalize that transition.

So what about the EMP thing again?

Remember, I look at “threats” as “risks.” And I then look at all of it in terms of “risk mitigation”. Risk is judgement based on probability and severity of the risk actually occurring. I look at an EMP strike the same way.

Probability –

I see the risk of us being hit by a nuclear weapon that generates an EMP as low…very low at this time actually. The reason I give it such a low probability is their fear of retaliation. Russia and China have no desire to exchange a nuclear strike with us. Iran would probably love it but they aren’t ready for that yet. Pakistan and Turkey probably aren’t ’t too far behind Iran but they are maintaining a resemblance of normal behaviors. North Korea, well, they are complete nuts jobs in that country, so I don’t expect them to actually launch a nuke at us.

So based on all of that, I see the probability as pretty dang low. However, 20 years ago I would have given it a zero chance. 10 years ago, slightly more than zero. When Iran did the nuke deal with Obozo I believe Iran’s potential use of a nuke against another country went to 100%. Their use of a nuke against us is maybe at 50%. Iran nuking Israel………..just a matter of time. It’s not an “if”……it’s a “when.”

So now I have to rate the probability as on the chart.

Severity –

Here is where it could get ugly. If anyone launches a nuke at us and it actually detonates on US soil, it will be devastating regardless of where it hits. It will be the blow against us that challenges, and perhaps negates, our super-power status. If we are hit, and we don’t hit back, we will be re-categorized to the group that includes France, England, Italy…maybe worse. If we are hit and we hit back, then we can expect WWIII. And should that happen, an EMP is the least of our problems.

So let’s look at the severity if it is just an EMP. By the way, it would be more along the lines of North Korea going rogue and hitting us with an EMP without China telling them to. However, there is a potential scenario where China would tell them to hit us with an EMP just to weaken us and test out retaliation resolve.

Whatever the reason we were hit, the outcome would be very damaging. The damage would be two-fold. 1) the EMP-Strike hits our power gridactual direct result damage to infrastructure, 2) the economic fallout.

Economic Collapse from an EMPThe economic damage would be far worse than the direct damage. The stock markets would crash, the economy would nose dive. It would be economic Armageddon for awhile. Mostly due to banking being out of business. Yeah, completely out of business. Modern banking is all computer based with that information being transferred between customer and banks, banks and business, etc. entirely by electronics (i.e. the Internet). An EMP would fry most large-scale electronic systems, including the Internet and telecommunications.

EMP Strike effectsThe direct damage is a little less clear. EMP damage is directly related to a few things:

  1. The size of the weapon as described in “megatons”
  2. The altitude above the surface of the earth
  3. Your relative location to the blast area

The absolute worse location to be at the time would be directly under the atmospheric blast. As the zone expanded outward, the impact would lessen. But, that would be in direct relation to the size of the detonated weapon. The bigger the weapon, the larger the affected area. However, the further away from the blast you were, the more diminished the impact would be.

Now is when it gets blurry. And I will cover that tomorrow when I finish this 2-part series.




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Radio Antenna Storage Case

Radios stored in Hard Casenote: article first appeared in November 2015

Earlier this year I did a series of posts that showed how I store my radios long-term for safekeeping. I put them in military grade SKB iSeries hardcases. I really like those cases, very sturdy and less expensive than Pelican cases. But what I neglected to show you was how I store my radio antennas. So here you go…

The stated mission for this is –

“The ability to safely store and transport ‘stick’ antennas that match the radio storage and transportation system.”

First thing I did was put all the antennas in one location so I could see what I have. Then I measured each antenna to assess what was the length of the tallest antenna that would be stored in the case. That measurement was over 50″. Next I had to figure out where to find a reasonably priced hardcase solution that would work.

The first place I looked was the SKB cases, then Pelican cases; both of which were out of the question. I kept looking for other conventional options and either couldn’t find the “right” option or they were far too expensive to be realistic. I gave up…or rather took a break of several months.

One day I was working in my storage shed and low and behold, what did I see? Yup, an old plastic gun case. I had picked it up at a garage sale a long time ago and put in the shed for storage. It was in great shape, padded, Antenna hard Case - gun caselockable, and ready to be used.

Its interior usable space was 9” x 48” so it was plenty big enough. Too short for the longest antenna, the Diamond CR8900A. But then I remembered that the Diamond CR8900A “breaks” at the base so it can folder over while attached to a vehicle for clearance issues.

Once I folded the Diamond CR8900A at its base…BINGO! It fits just fine. The case is padded to keep everything from being damaged. The padding also kept all the antennas getting jumbled around. Looked like the perfect option. Into the shop it went.

I got all the antennas back out and started arranging them in the gun case. It only took about 15 minutes to get Ham radio Antenna Case hardcase gun caseeverything in the right place, the lid closed without any binding, and it locked up tight. A perfect solution!

So here is the picture of the gun case with all of the antennas in it. I hope it gets you thinking of a solution for you radio antenna storage and transportation needs. For me, this option will allow me to grab my radio cases and my antenna case and know that I can transport them safely and securely wherever I might be headed.

Antenna Case legend




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Emergency Radio Cache

Radio Cache for emergencies, disasters, and grid-down baofeng radio cachenote: first appeared in November 2015

I’ve been asked many times, “What kind of radios should I buy?” Or, “How many radios do I need?” And, “Where can I find radios that set-up ready-to-go?” And, “What accessories do I need to get the most performance out of my radio?”

I’ve written extensively on the Baofeng UV-5RA radio. I think it is simply the best value for the most people who are looking for a good alternative communications capability. And not only that, it really makes a great radio for a variety of purposes. Some of those are:

  • Family emergency radios.
  • Hunters & campers.
  • Church service groups.Ham Radios being used by Family
  • Neighborhood Watch
  • Emergency response teams.
  • Prepper groups.
  • The list could go on and on…

One of the situations that keeps coming up is buying a number of radios for a “cache” to be used as needed, properly and safely stored when not being used. Best possible answer to that is what I do right now for the group I am responsible for. If you have read my bio you know I am responsible for emergency preparedness for a 13-congregation church group; we call that group a “Stake” in our church. The 13 congregations are spread out over a three-county area.

In a perfect world each congregation would have their own cache of radios ready to go. But the world is rarely perfect. So the alternative is for me to maintain a radio cache that is ready to deploy when, where, and as needed. I thought the best way provide an answer is to show you a working example..the “8-Radio Cache”.

The mission for the radio cache is –

“Provide sufficient communications gear for two teams of four people to communicate while on the ground or traveling, and to provide that capability for a minimum of five days without the need to recharge any batteries.”

Requirements & Restrictions –

  1. Radio must be proven dependable.
  2. Radio must be able to operate on dual bands (2m & 70cm) simultaneously for use with a cross-band repeater.
  3. Radio must be able to programmable and cloned.
  4. Radio should be able to be programmed with NOAA, FRS, GMRS, and MURS frequencies.
  5. Radio should be able to receive FM band commercial and government broadcasts.
  6. Radio operations must be sustainable for five days with fully charged batteries.
  7. Radios must be operational from inside a moving vehicle by two separate teams.
  8. Radio operation must have “privacy” capabilities where no communication sounds can be heard by anyone but the user.
  9. Radio cache must have secure and protected storage capability that easily moved and transported.
  10. Radio operations must be easy to understand and easy to operate with minimal training.

The concept for our use is along the lines of the Incident Command System principle of operational teams. In this case two teams consisting of four people for a total of eight people. Each of the two teams would travel in separate vehicles. This ensures that each team also has vehicle radio operational capability as well.

However, a smaller team, say 3 people, could utilize a leader who had a radio while the remaining team members do not have a radio. This would be acceptable if all team members worked in close proximity to each other.Handheld Radio used by Firefighter

The radio needed to be sufficiently rugged to handle most emergency operational environments but not be subjected to “submersion” capabilities, etc. The Baofeng UV-5RA is a sturdy radio but isn’t made to operate in harsh environments such as structure fires, wildland fires, or where the radio is excessively exposed to the elements.


To meet all these demands here is what the cache consists of –Baofeng UV-5RA radio for sale

  • 8 x Baofeng UV-5RA radio kits. Each kit contains:
    • 1 x Boafeng UV-5RA radio
    • 1 x charger cradle
    • 1 x AC charger adapter
    • 1 x Stubby antennaBattery - Powermall 3800mAh
    • 1 x 14.5” antenna
    • 1 x ear piece w/lapel mic
    • Baofeng UV-5RA antenna : ExpertPower XP-771 Elite 14.5-Inch Dual Band Antenna (144/430Mhz U/V SMA-F)2 x 1800mAh batteries
    • 1 x 3800mAh battery
    • 1 x 12vDC charger cradle adapter
    • 1 x Radio pouch
  • 1 x RT Systems Programming Software CD with cable
  • 2 x Tram 1185 Vehicle magnetic mount dual-band antennaTram 1185 Amateur Dual-Band Magnet Antenna Baofeng UV-5R antenna on car roof
  • 2 x MPD adapter cable
  • 2 x Tenq vehicle battery replacement adapter
  • 2 x Vehcile “4-to-1” cigarette adapter multiplier
  • 1 x Vaultz Secure Roller Case

Then there is the documentation –

  • Cache Inventory Sheet
  • Radio Check-Out/In Sheet
  • Quick Start User Guide
  • UV-5RA User Manual
  • UV-5RA Programming Guide
  • ARRL US Amateur Radio Bands chart

Then I custom programmed the radios using the RT Systems programming software. The programming meets all the requirements listed above in the “Requirements & Restrictions” section.

Here is each component in the cache –

♦  Baofeng UV-5r handheld radioBaofeng UV-5RA radio, stubby antenna, ear piece w/lapel mic, charging cradle, AC adapter, 1800mAh battery

  • Frequency Range: 136-174 / 400-479.995 MHz.
  • Full height two-color LED definition display. The screen has exquisite clarity.
  • Field programmable from keypad.
  • Programmable via computer software.

♦  ExpertPower XP-771 Elite 14.5-Inch Dual Band Antenna (144/430Mhz U/V SMA-F) Boafeng UV-5RExpertPower XP-771 Elite 14.5″ Dual Band Antenna.

  • Frequency Range: 144-146, 430-440 MHz
  • VSWR: less than 1.5
  • Gain: 2.15dBi (144-146 MHz), 3.5dBi (430-440 MHz)
  • Maximum Power Input-watts: 50 W
  • Height: 14.4 inches


♦  Battery - Powermall 3800mAhPowermall 3800mAh rechargeable battery. The 3800mAh battery will last about 3 – 5 days while the battery that comes with the radio will last 2 – 3 days. Of course that will depend on your actual usage, which is mostly predicated on how much time you spend transmitting.


Baofeng UV-5RA Radioshop888 12vDC vehicle adapter♦  Radioshop888 12vDC charger cradle adapter. Radioshop888 12vDC charger adapter you now have the ability to recharge your batteries from any 12vDC source. Examples would be; vehicle cigarette receptacle, solar charger unit, portable power pack, etc.


Military surplus flashbang grenade pouch used to carry a Motorola Family Radio♦  Flashbang Radio Pouch. The radio pouch is a really convenient way carry the Boafeng UV-5RA radio. It is a perfect fit and the pouch’s flap provides additional protection from rain. You won’t accidentally drop or lose your radio while it is secured in the pouch. The pouch is MOLLE II compatible and the same attachment can be used to secure it to your belt as well.


RTsystems3♦  RT Systems Software Programming CD with cable. to be used effectively it also requires the ability for you to program the radio. Programming is accomplished either manually through the keyboard or via a laptop computer/software. I far prefer the computer method, but it does require software.

.Tram 1185 Amateur Dual-Band Magnet Antenna Baofeng UV-5R

♦  Tram 1185 Vehicle magnetic mount dual-band antenna. The Tram antenna is the solution for radio operation in a vehicle. Even with the ExpertPower 14.5” Tram 1185 Amateur Dual-Band Magnet Antenna Baofeng UV-5R antenna on car roofantenna on the radio, the reception and transmission capabilities of a handheld radio are greatly diminished due to the vehicles metal body. Getting the antenna outside of the vehicle’s body makes a huge difference. And the vehicle’s roof is also usually higher than a normal person holds a radio so you get the increased antenna height as well.

♦  MPD Digital antenna adapter cable. The Tram antenna mentioned above comes with a cable that is long enough to reach inside the vehicle but you need to connect that cable to the radio. That takes a special adapter cable to connect the antenna cable to the RF coaxial cable SMA female to UHF SO239 PL259 female RG58 radio itself. There are other cables out there, some less expensive. But I like the MPD Digital cable (RF coaxial cable SMA female to UHF SO239 PL259 female RG58 20 inches). They are well-built, quality materials, and made in the USA.


♦  Tenq vehicle battery replacement adapter. Tenq® Baofeng Vps-001 Vehicle Power Supply Dual Band Car Battery Eliminator Simulator for BaofengThe Tenq power supply unit is a very handy piece of equipment. This option allows you to run the radio directly off of a 12vDC power supply. You remove the rechargeable battery from the radio, slide this unit into the radio where the battery normally goes. Then connect to a 12vDC power source via a cigarette adaptor and you are up and running. This type of operation would be very convenient for vehicle operations or while using the radio as part of the mini communications center.”

Cigarette Lighter Auto Socket Duplicator♦  Vehcile “4-to-1” cigarette adapter multiplier.

  • Plugs into car cigarette lighter! 1-into-4 12V DC auto adapter, charge all four team radio batteries at cone.
  • Includes adapter plug, 50″ cord.
  • One USB port with 5 Volt/ 1 Amp output to charge USB compatible devices.
  • Built in fuse for circuit protection.

♦  Vaultz Secure Roller Case. Baofeng radio cahce Vaultz Secure Roller Case radio cache

  • Highly mobile, with wheels and telescoping handle.
  • High-capacity locking chest.Vaultz Secure Roller Case radio cache
  • Double combination locks.
  • Rubber feet prevent skidding and surface scuffing.
  • Handles on the sides make carrying easy.
  • Large flat top is great for a working surface.

baofeng UV-5RA Radio CacheThis radio cache meets the needs of our emergency responders whether it is a small emergency or major disaster. And when a “grid-down” event occurs…we will be ready and able to communicate!

Now, let your thinking begin…design a radio cache that is right for you and your group.




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No reproduction or other use of this content 
without expressed written permission from AHTrimble.com
See Content Use Policy for more information.

Cross-Band Radio Repeater – Part #2

cross-band repeaternote: first appeared in early 2015

I really saw a need for “repeater” capability when a bunch of individuals got together and all they had was handheld radios.  Distance and Line-of-sight always limited their usefulness.  And when it came to responding to a disaster or emergency situation handheld radios are virtually essential.  But once again, they have limited transmit and receive capability.

When I stumbled upon the Baofeng UV-5R handheld radios <click for more info> a few years ago I knew I had in my hands an invaluable resource for “preparedness”, especially after “grid-down.”  I cannot stress enough what the ability to communicate will mean then or even during less dramatic disaster situations, or even while hunting or camping.  I was aware of “repeater” technology through my government day-job but it was appeared to expensive and complicated.

When I first got my Ham radio license I began my search for the best all-purpose radio that my budget could afford.  That took me to decide the Yaesu FT-8900R <click for more info> was it.  Once I dug into it I realized how easy it was to set it up for cross-band repeater operation, I knew I had the answer in my hands.  However, I decided a used Yaesu FT-8800R was a more economical solution for setting up a field-going repeater.  And that led me to this “build” and documenting it for you in this article.

In Part #1 I covered the first five steps, in this post I will conclude the build and summarize my experience at the end.

Yaesu FT-8800r based cross-band repeater.

Finished Product – Complete with the Yaesu mounted inside.


Step #6 –

Yaesu FT-8800r based cross-band repeater.I am installing the remote head separate from the radio body.  This is to allow the rear of the radio unit to be accessed from the front of the box.  And it allows the radio to run a bit cooler since the head is separate from the body.  To get the remote head installation bracket properly installed I used a piece of 2″ aluminum angle to give the bracket a solid mounting surface.  All mounting bolts utilized star washers to prevent the nuts from inadvertently spinning off. The remote head is mounted as “dedicated” for the repeater and will not be removed for any other usage needs.

Step #7 –

Yaesu FT-8800r based cross-band repeater.This was the easiest of all brackets to mount.  My only concern here was mounting the microphone bracket where the microphone would easy to grab while keeping it out of the way of the rest of the box contents, including the wiring.


Step #8 –

Yaesu FT-8800r based cross-band repeater.Last came putting it all together as a complete ready-to-go repeater package.  Couple notes:

  1. I had double fuses in the box.  The power cable coming in had a fuse on the positive and negative.  Then the power (+) cable to the radio had a fuse as well.
  2. Notice the short antenna coax jumper cable from the “through-the-box” double male 239 to the rear of the radio.  I used an 18″, I could have used a 12″.  Using an 18″ would enable me to remove the radio unit and set it on top of the box for troubleshooting or any other reason.
  3. I built my own remote head cable since all the commercially built cables were really long.  I didn’t want all that cable coiled up in the box so I built my own 6-wire.
  4. All my wire connections are Anderson PowerPole.  I use them for everything and doing so here ensured compatibility now and in the future whatever change might come…including repairs if needed.
General Question & Answers (questions from folks that have seen the repeater) –RadioAntennaCar
  1. Can a magnetic mount external vehicle dual-band antenna be used with this repeater?  Yes.  Since the antenna connection on the exterior of the box is a standard 239, basically any antenna can be used with this unit.  I slapped a Tram 1185 Amateur Dual-Band Magnet Antenna directly to the metal box and it worked just fine. It gave the repeater a very low profile and hard to spot.
  2. What antenna do you use with this unit?  I built a highly portable antenna for use with this unit whether using it as a repeaters or as a base unit.  I built it to blend in with the desert surroundings here in the desert southwest.  I will post an article about that soon.  But any dual-band antenna will work.  The heart of the antenna was a J-pole designed by Dr. Ed Fong WB6IQN of UC Berkeley, featured in the Feb. 2003 issue of QST.
  3. What do you use to power this unit?  I built it to work with the 12v 105 amp hour Energizer AGM gel battery I purchased through Sam’s Club. I expect the radio would operate about 1 – 2 days without the need for charging. I have two 30w solar panels with a charging unit to hook up to the battery.  A GoalZero charger controller handles regulating the battery charging.  I can run the unit with my Honda EU2000i if need be.
  4. You mentioned “base station”, explain?  If I am not needing a repeater, I can use this unit as a base station. I just leave the lid off and place the box where I don’t have to lay on the ground to use it.  It has everything needed to be able to operate it just fine as a base station.
  5. Do you set it on the ground to use?  No, not really.  I would set it on rocks to get it up off the ground.  I am working on a lightweight aluminum stand with folding legs to keep it about 6″ off the ground.
  6. What water-proofing have you done to the box?  Not much.  The box itself is extremely sturdy and the lid has a rubber seal.  All the screw/bolt heads that protrude on the exterior of the box have all have silicone seal on them.  The vent holes are the weak-link; fan and intake.  Not much I can do about that except maybe place a cover over the box that would act like a roof.  I might consider that when building the stand for it.

If you love your handhelds for ease of use, you will love this repeater to extend the range of your beloved handhelds.  Enjoy!





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Cross-Band Radio Repeater – Part #1

cross-ban repeaternote: first appeared in early 2015

In my day job I use often radios over very long distances.  To accomplish this the government has installed a series of repeaters in various locations around our six county area.  Repeaters make it possible for me to talk to folks hundreds of miles away as if they were sitting around the corner.  I wanted that same capability for any disaster or “grid-down” situation that I might have to personally deal with.  That led me on the journey to come up with my own repeater capable of operating in the field for long periods of time in rough conditions.  Here is that story…

Mission –

Provide the ability of handheld and mobile radios to communicate when line-of-sight was not possible.  Provide a dual band Ham radio unit that was field-going and sturdy/rugged to use when a repeater was not required.

Requirements & Limitations –
  1. Must be capable of repeater operation on 2m and 70cm bands.
  2. Must be a rugged, sturdy radio capable of operating in the field.
  3. Must use 12vDC power.
  4. Must be very conservative on power usage.
  5. Should be easy to program, set-up and use.

Radio of choice – Yaesu FT-8800R (to read more about the radio read the 2-part article posted 3 days ago.).

Box of choice – Army Surplus 40mm ammo box in good shape, seal intact.

Yaesu FT-8800r based cross-band repeater.

Finished Product – Complete with the Yaesu Radio mounted inside.

Notes before staring – I laid out the box contents first.  I kept moving them around until I had what I thought was the perfect location for each component.  I then used a felt-tipped pen to mark the location of mounting screws.  I did this to make sure that all the holes I had to drill made sense in relation to the box itself.

Step #1 –

Yaesu FT-8800r based cross-band repeater.I drilled a hole for the double-male 239 connector to fit in and pass through the box.  This gets the antenna lead from the radio to the outside of the box while making sure the seal stays “burr-free” and actually water tight.  The hole was slightly larger than the 239 barrel diameter.  The rubber grommet was purchased at Lowes.  I won’t put in the sizes of drilled hole, grommet, etc. since your 239 double-male barrel may be a different configuration or size than the one I used.  Take the 239 to Lowes and buy the right size grommet by trying it out right there in the store.  Then you will know the size of hole to drill based on the size of the grommet based on the exact pass-through you are using..

Same thing for the power leads, buy the smallest possible grommet to get the wires through, then drill the appropriate sized hole based on the grommet size.  I wasn’t trying to make it water tight, just “tight enough” to keep dust and rain out.  If I ever make the repeater a semi-permanent installation I will slather silicone seal all over the outside of the grommets.  Based on the “finished product” picture above, I drilled the holes on the back-upper-right-top corner.  It will be approximately the same height as the ventilation holes from the ground when the box is laying on its side for operations.  I drilled the holes from the outside towards the inside to make it easier with the drilling.

Step #2 –

Yaesu FT-8800r based cross-band repeater.I wanted to move some “cooling” air around in the box to keep the radio as cool as possible.  The radio itself has a cooling fan on the rear of the radio integrated with a heat-sink.  But I wanted to move air around and through the box itself to keep the operating temperature as low as possible.  Just in case the radio fan couldn’t handle sufficient air movement on its own, I wanted to give it a little help.  The fan is to draw air out of the box by drawing air from the outside through the three ventilation holes.Yaesu FT-8800r based cross-band repeater.

The fan is a 12vDC fan for computers that I found on Amazon.  I chose this particular fan based on the large intake area of the fan and the “flatness” of its construction.  The fan sits over the radio but to the rear of the box in relation to the radio’s built in heat-sink and fan.  In the event that the fan stops working I was trying to leverage the flow of air coming off the radio unimpeded.  So I drilled the three ventilation holes above the radio’s heat sink just in case.  I was thinking that natural air flow might move the hotter air out through the holes should the fan stop working.

I cut appropriate sized hole in the upper rear corner of the ammo can to match the outlet of the cooling fan. It required a square hole, so I drilled the center, cleaned it up with a saber saw, then finished it off with a flat diamond file.  Then I used another grommet on the squared-off hole before mounting the fan.  I wanted some cushion between the fan and the box to minimize any potential problem from vibration.  If you wanted to reverse the airflow to blow cooler outside air onto the radio heat sink you can reverse the power wires of the fan and it reverses the fan rotation.

Next I drilled the holes for the two screws that holds the cooling fan housing in-place.  But I did a trial run to ensure I knew exactly where the fan housing had to be placed to match up with the square hole for the fan’s square outlet/inlet.  Notice that I used a couple of rubber grommet again on the screws securing the fan housing.  But this time I didn’t worry about putting the grommets into the holes.  I used them as a “stand-off” to properly align the fan housing and absorb vibration from the fan.  But the grommets sealed the holes anyways due to the compression from tightening them.

Step #3 –

Yaesu FT-8800r based cross-band repeater.Yaesu FT-8800r based cross-band repeater.I am concerned about moving air through the box so the radio doesn’t overheat.  But I also don’t want to run down the 12vDC battery that will be powering this repeater either. So I decided to install this temperature controlled rheostat to drive the fan. Since I am using DC to power the unit, the rheostat controller will continually pass on some minimal current to the fan.  So the fan will always be turning a little bit.  However, if the temperature is within the operating limits of the radio I don’t need the fan spinning like crazy, moving hurricane force winds through the box and eating up precious ampere hours from the battery.  So the rheostat will pass on more current as the heat rises and the fan will then spin faster.  Result – the fan doesn’t use any more juice than is needed conserving precious power for actual radio operations.  But as the temperature rises the fan spins faster pulling the hotter air out of the box through the ventilation holes located above the radio heat-sink.

I mounted the controller board close to the fan towards the rear of the box.  A picture a little later in the article will show its position.

To find the rheostat I did my search on Amazon for this little electronic beauty.  But what I noticed is these electronic parts come and go pretty quickly (i.e. what is available today may not be available next month).  So I am not quoting a specific part number of even manufacturer.  Just get online and search for a 12vDC temperature controlled rheostat, there will be plenty out there for you to choose from.  Or contact your favorite electronics site and they can direct you from there.

Step #4 – 

Picture of ventilation holes with metal mesh screening to keep little critters out.

Yaesu FT-8800r based cross-band repeater.Yaesu FT-8800r based cross-band repeater.Next I installed the radio housing bracket on the radio unit and placed it in the box towards the left side of the box.  Don’t crowd the cooling fan and keep the radio as far to the left in the box as possible.  Don’t forget that you will have several sets of wires (antenna & power) coming out of the backside of the radio unit so don’t crowd the front of the box either.  Using a felt-tipped pen mark the holes for the mounting bracket.  Then placing the lid into position mark the center of each ventilation hole; they should be directly in front of and above the radio’s heat-sink and fan.  Drill the holes for ventilation and the mounting bracket.

To pull in fresh (hopefully cooler air) that will pass over the radio’s heat sink then out of the box via the cooling fan, I placed three 7/8″ holes in the box lid above the radio’s heat-sink but on the “side” of the box, not the top.  This would pull air over the radio’s heat-sink across the top of the inside of the box drawing the warmer air outside via the fan.  Should the box’s cooling fan fail, the radio’s own cooling fan should pull air into the ventilation holes from the outside, or push it out, not sure which.  This may create a “positive-pressure” environment inside the box which in-turn moves air naturally out of the box’s cooling fan hole.

To reduce the derbies that might come in the box that I don’t want in there (i.e. dirt, sand, leaves, critters, etc.), I placed a metal screen mesh over the holes. Making a rough calculation on the reduction of air volume due to the screen material I decided on the three entrance holes in relation to the cooling powered exit hole. I might have to drill another hole, maybe two, but I thought this was a good guesstimate. I drilled them 7/8″ to give me enough room to secure the screen to the lid on the inside. I used a metal-to-metal glue to attach the screen material to the box lid.

I may put a thin layer of cotton gauze over the holes in addition to the screening to reduce the amount of fine dirt/sand that can enter the unit.  However, I would drill more holes if I did that to off-set the reduction in airflow from the gauze.

Step #5 –

Yaesu FT-8800r based cross-band repeater.Next comes installing all the various brackets for the radio components itself. First up was the radio housing bracket.  In Step #4 I talked about mounting the radio so the radio’s heat-sink was located next to the ventilation holes in the box’s lid.  This allows for cooling air movement even if the cooling fan fails.  But it leverages the cooling fan’s movement of air when all is functioning normally.

For practicality it is also very convenient to mount the radio with the rear of the radio exposed for access to the antenna, power, and programming ports.  Yes, this means you are doing a “remote head” installation.  And in my opinion works out well as an added bonus.  The radio’s control head is disconnected from the radio and that adds to keeping it just a bit cooler.

Go ahead and take the radio housing bracket off the radio and screw it to the box.

In the next part we will finish up the build.


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without expressed written permission from AHTrimble.com
See Content Use Policy for more information.

Yaesu FT-8800R Ham Radio : Storing and Case

Yaesu FT- 8800R ham radioIn this post I will go over how I store my 8800R and what I store with it.

In two previous articles I went over the Yaesu FT-8800R radio and accessories. Both articles are worth the read.

So let’s go over my standard format, what is the mission for all of this?


Mission –

To safely store the radio and all components with which to operate the radio.

Requirements & Restrictions –
  1. Cases must be sturdy, at least to military specifications.
  2. Cases musty protect against dust, dirt, and water impingement.
  3. Cases should protect the contents against damage due to reasonable heights and rough handling.
  4. Cases should be low profile and not draw attention to them.
  5. Case should be light enough for one person to easily carry.

SKB i-series 3I-1711--68-C.The case I chose was the SKB i-series 3I-1711–68-C. These cases are waterproof and as sturdy, if not more so, that Pelican cases. And they are cheaper that Pelican cases. They come with “cubed” foam ready to be cut to size for your equipment.



SKB iSeries hard case for a yaesu ft-8800r


So this is what my case looks like for my Yaesu FT-8800R.  The case is clearly labeled for easy identification.

SKB i-series 3I-1711--68-C for the Yaesu FT-8900RYaesu FT-8800R Radio Case –

Bottom Level:

  • 1 x Power supply, AC, 19amp
  • 1 x Mounting bracket, radio
  • 1 x Microphone, MH-48
  • 1 x Radio, Yaesu FT-8800R


SKB i-series 3I-1711--68-C for the Yaesu FT-8900RMiddle Level:

  • 1 x Power cord, AC





SKB i-series 3I-1711--68-C for the Yaesu FT-8900RTop Level:

  • 1 x 5′ Power extension cable, Anderson Power Poles on both ends
  • 3 x packages various mounting screws.
  • 1 x Mounting bracket, remote head
  • 1 x RT Systems Programming CD
  • 1 x RT Systems Programming cable
  • 1 x Power cable, Anderson Power Poles to hard soldier connection (AC power supply)
  • 1 x Cable, radio head to radio body
  • 2 x Fuses, 15amp

On top of the radio I place a 8800 user’s manual in a 1-gallon Ziplock bag with the latest copy of the US Amateur Radio Bands chart.

I have given you a list of the equipment needed to run the Yaesu FT-8800R Ham radio. Is it everything you might need?  This was meant strictly for the radio equipment itself and the essential equipment to get it going.

Take this list and use it as a starting point for your specific need and mission.





2009 - 2019 Copyright © AHTrimble.com ~ All rights reserved
No reproduction or other use of this content 
without expressed written permission from AHTrimble.com
See Content Use Policy for more information.