EMP and our Radios – From an Email Discussion

With Paul AE5JU I’ve been discussing by email what I’ve read in EMP literature.

There are three types of EMP energy risks. Each with their own mechanisms and countermeasures.

Some sources:





And less formal but useful sources:








As EMP E1,E2,E3 are very different with different effects and countermeasures, I’ll post some of our thoughts down the road in relationship to each type of EMP and Ham Radio.



K9ZW Portable Kit In the Making

K9ZW Portable Kit In the Making

I’ve been assembling the parts for a field kit to do Digital HF and today I laid them out to take first measurements as I refine my design & layout.

The NUE-PSK Modem does several Digital Modes and will do CW. Kit includes a Keyboard, Thumb Drive for Logging, Cable to the SGC 2020 TX, and various Battery Packs.

An SCG 2020 Transceiver does duty. Heavy Mil-Spec type of radio transceiver.

TGE built voltage regulator handles the power control tasks.

Another SGC product, the 237 Antenna Tuner and SmartLock remote handle some of the tuning tasks.

A Communications Speaker and a SWR Meter from the spares box will fill in those roles.

Gamma Power Supply is very small and light, using Super-Capacitors as the technology.

End Fed 10/20/40m Antenna is one of four set aside for this project.

There are other antennas (thank you Paul AE5JU!!) and an optional ThinkPad to include in the design.

Presently I am thinking of modules, with the #1 having the core & deployable on its own, and #2 & #3 respectively adding capabilities and options.



GUEST POST – AE5JU on Boy Scout Jamboree on the Air

Another welcomed GUEST POST – AE5JU on Boy Scout Jamboree on the Air




BEARS W5BMC Jamboree on the Air

The BEARS (Bayouland Emergency Amateur Radio Service – W5BMC) had the great pleasure of hosting 15 Boy Scouts and their Scoutmasters at the BEARS station for Jamboree on the air. They spent about 2 hours with us while we showed them everything from generator and antenna tower to cases of MRE’s, bottled water, and 1st Aid Kit. “Be Prepared” is the Scout motto, and so it is with the BEARS.

The Scouts were all courteous, attentive, and just good kids. They raised their hands to speak and asked some very good questions. Just good kids.

We explained the use of, and differences between broadcast radio and amateur radio, propagation and use of HF, VHF/UHF radio, and various modes of operation. I flashed through my personal stack of QSL cards, showing contacts all over North, Central, and South America, the Carribean, and Europe.

We brought the Scouts into our radio room and listened on 20 meters, then dialed through 17 meters, and on up to 15 meters, making note of the stations working JOTA. One ham, VE3AXW on 17 meters, really caught my attention in the way he was working the JOTA stations, talking to the Scouts. I remarked, “This is the guy we want to try to talk to.”

While waiting our turn to contact VE3AWX we explained various ham terms used, comparing terms such as QSL or 73 to texting terms like LOL or K. I pointed out the map on the wall showing the numbered areas, and the Scouts quickly found the “3″ area in Canada.

When we heard Tony give his 73 and finish his contact with another station there was finally a pause. I called, “VE3AXW, this is AE5JU” and Tony came right back us.

Tony VE3AXW is a class act! He talked to a number of the boys who patiently waited in line for the mic to be passed to them. The Scouts got to see that you really can talk to other countries, in this case over 1100 miles, with just 100 watts from a radio (Icom 718) that can be purchased for about the price of a laptop computer, with a homebrew wire antenna (80-10m Windom).

As the Scouts talked to Tony after a few exchanges each would say, “I’m handing the mic to the next boy.” And Tony would do it all again, asking about Radio Merit Badge, interest in ham radio, how long a scout, age, etc. And “So, what do you think about ham radio?” And the Scouts asked Tony some good questions, too.

Tony will be sending enough QSL cards so that each Scout who participated will get his own card.

We have arranged for some of the Scouts to take license classes.

Also, for the Scouts to earn their Radio Merit Badges one of the required activities is SWL. They have to listen for a total of four hours in both daytime and evening sessions. We have arranged the loan of an Icom R75 and my Field Day antenna, along with some suggestions of frequencies and times to listen.

At the end, Jackie KA5LMZ (BEARS President) and I signed cards confirming the Scouts had completed part of their Radio Merit Badge requirements (a visit a radio station).

All in all, a great learning experience for the Scouts.

No Scouts were injured or killed in this activity.

Paul – AE5JU

GUEST POST – The Best Part of Ham Radio by Paul AE5JU

Another Guest Posting by my Friend Paul AE5JU

Many thanks to Paul for taking the time to pass on his experiences, sharing with us all!




The Best Part of Ham Radio
by Paul – AE5JU

Steve has asked me to write a bit about my experience in becoming an amateur radio licensee… a ham. One facet of this hobby has been the skills I have acquired, and of course that is important. And there is so much more to learn out there. But the really important thing about this has been the many great people I’ve met.

Of course, my first QSO with my good friend, mentor, and “Elmer”, Steve K9ZW is important to me, but that same day I had another interesting experience. My first few QSO’s that day had been with Steve and a few other hams I knew locally. I had been listening to shortwave for some time, including the ham bands, with an Icom R75 receiver so I knew a little about contests. There was a fellow calling CQ for my state. I figured I’d help him out and just happened to slip through the pileup. He replied with my call. After exchanging name, location, signal reports, he asked (oh, how could he tell?), “Is this your first QSO?” I replied, “Oh, heck no! This is my sixth!”

Now he could have just given a quick “73″ and continued with the pileup, but things were very quiet suddenly as he took time explaining contests, how they worked, the jargon, etc. The other hams waited patiently as the experienced ham “showed the ropes” to the newbie (me). He could have made another 10 or 20 contacts for his contest log in the time he spent with me, I’m sure. And in the end he warmly welcomed me to ham radio, said 73, and was back to the pileup. When I grow up to be a real ham I want to be just like him.

Another day I held an informal solitary “Field Day” in the city park. It was the end of January, and a beautiful sunny day here along the Louisiana Gulf Coast. I had set up my radio, a homebrew portable antenna, and battery power, totally “off the grid”. I had a few odd looks from passersby, a few asked what I was doing. And though city police drove by and looked, not one was curious as to what I was doing.

I spoke to one fellow in upper state New York who used to live down here and worked for one of the larger TV stations. We had a great 30 minute QSO, 5-9 both ways, and discussed how the area was recovering after Hurricanes Katrina and Rita. He missed the great seafood and was craving a good oyster Po-boy (that’s like a big “submarine” or “hoagy” sandwich for you Yankees). And we discussed stereo gear, too.

Another fellow was doing the same thing I was, having a leisurely afternoon, same radio I had, his portable antenna, while sitting in a lawn chair on the sandy beach on Assateague Island off the coast of Maryland. Assateague Island is famous for its wild horses, possibly arriving from a wrecked Spanish galleon several centuries ago. I’ve learned a lot of interesting geography and history since being licensed as a ham.

And Cubans! The Cubans LOVE to talk on the radio! Especially PSK31… one of my favorite modes. I can generally make a contact with a Cuban any time of the day or night. One interesting fellow, Professor Arnie Coro, CO2KK, and I had a very nice contact. He described his very simple digital interface made by gluing a 2″ speaker to one end of a piece of 2″ pvc pipe, and inserting a computer microphone element into the other end, floating in foam rubber. This gives not only isolation from room noise, but also protection from ground loops. One of these going each way and you have PSK31! Then later I remembered the name… Arnie Coro! THE Arnie Coro that does the Radio Havana show “DX’er’s Unlimited”. You’ve probably seen some of his articles on the “broomstick antenna” and others for Short Wave Listeners. More recently I saw that Arnie was coordinating emergency relief for Haiti.

I had been exchanging some emails about antennas and other odds and ends with a new ham in the ham radio subforum of an outdoors forum I frequent. After a number of emails I found that not only did he work and live nearby, but we literally shared the same back fence at work. The next day after work I drove around the corner and found him at his place of employment, and we had a nice chat for a few minutes. We had to cut it off, he had to go back to work, but still, what a cooincidence.

I work offshore, an engineering type job aboard drilling rigs in the Gulf of Mexico. I landed on the heliport of a rig recently, and was greeted by the rig’s safety officer who introduced himself to me by his call sign… hah! Another fellow I work with told him I was a ham, and… well, you just never know where you will meet up with other hams, do you?

On another rig my office was shared with the communications equipment. They were in the midst of updating the phone/internet gear, and the technician that was doing that was a ham, too. He gave me a great lesson on how to install N connectors, and some other tips.

I’ve known Steve K9ZW for quite some time as we are both saxophonists. Naturally, when I became interested in ham radio again (was really interested as a teenager, but no cash to pursue it), I went to Steve for advice. But since then I’ve run into many others. Gary K5GLS, our ARRL Louisiana Section Manager, is also a saxophonist.

Other hams have been checking out my QRZ page and asking about “the big sax”. This happens so often that for PSK31, I have had to make a “macro” about it. When asked, I clicked the macro button for that reply, and first thing I knew, PILEUP!!! Saxophonists and other musicians from all over the US were lined up. By the time I finally waded through all of that four hours had passed. I went in the house and my wife asked, “What are you smiling about?”

And I’ve just gained new friends from all over. As a “SWL’er” (Short Wave Listener) I heard a guy say, “Q – R – Zed?”. Hmmm, QRZ, what does that mean? I did a google search and found the list of Q-signals, and found that means, “Who are you?” or “Come back with that call sign again?” But also it is a popular ham website where you can look up hams by their call signs. (eHam.net and others have similar call sign lookups)

I had begun listening to a regional net, the HiFivers Net (“the friendly bunch”), http://www.hifivers.net, which meet on Sunday, Tuesday, and Thursday evenings on or about 3.908 Mhz. The official net starting time is 8:30 pm local time (Central), but “early bird checkins” begin at 7:30. These guys sounded like a load of fun, so I emailed one of the Net Controls, Charles N5YHQ, and asked, “I’m studying to be licensed. When that happens, how would I go about joining the Hifivers Net?” Charles answered, “When you hear us asking for check ins just say your call, and the Net Control will recognize you. But remember, a Tech can’t talk on 80 meters. You have to be at least a General to be legal to use phone on that band.”

I didn’t need any more encouragement than that. I emailed back, “Well, I suppose I’ll just have to study harder.” I did, passing the Tech, General, and Extra in one sitting. Had Charles not said that I would have just studied for the Tech and perhaps lost momentum somewhere in there. I buckled down on the study guides, found a test location – a hamfest three hours drive away – and in October of 2008 was licensed as an Extra. I had to go offshore for a few weeks shortly after, but in early November I made my first checkin with the HiFivers Net.

And Charles and I have become good friends! I recently was able to meet him face to face at a hamfest in his area. “The next time you come to town you aren’t staying at any hotel. You tell me when you will be here, and if I’m not around I’ll mail you a key. You can stay at my house any time,” he said.

Well, if I do that I had better bring him some good South Louisiana seafood, right?

And in the past 18 months my email account address book has at least tripled in size.

All in all, I have fun every time I turn on the radio. And the last year and a half, since making my first contact on the air with Steve, has been a real blast!

Paul – AE5JU

GUEST POST – Weatherproofing Antenna Coax by Paul AE5JU

I’ve asked my friend Paul AE5JU to author a few posts as With Varying Frequency approaches One-Thousand Web Posts, and he has touched up a piece he had done on Coax Connector Weatherproofing.


I’m performing a little antenna maintenance today.

Here I’ve already peeled off the top layer of electrical tape, exposing the gummy butyl rubber wrap, which is Scotch 3M 130C. A similar product is sold called “Coax Seal”. This tape just from heat of the sun, bonds to itself forming a solid rubber mass.

Old Scotch 3M 130C Coax Seal

Old Scotch 3M 130C Coax Seal

The rubbery Scotch 130C has been sliced, peeled back, exposing another layer of electrical tape.

Peeled back

Peeled back

Now the electrical tape has been removed, revealing a nice, clean plug and socket.

Tape removed

Tape removed

Nor is there corrosion inside the plug and socket. The last time I had this down I had squirted in some Corrosion Guard.

Clean connection

Clean connection

Here are the materials required to put this back together. Note… for the electrical tape I use only Scotch 3M brand. It does not turn gummy and let loose with age and heat. This tape lasts far longer than the cheap stuff. The Scotch 3M 130C is in the larger box, and is quite thick and rubbery. Unlike “Coax Seal” it does not have a liner that must be peeled away. The silicone grease is by GC, there are other brands, and has high dielectric properties. Universal Radio sells a product for this purpose called “Stuf”.

Materials required

Materials required

Here I have squirted the silicone grease into the socket, and onto the plug, as well as onto the threads. It is difficult to see in this photo, but the idea is to fill all the cavities so that water doesn’t have a place to seep into even if it gets past all the other stuff we are putting on the connection. When I screwed it together some oozed out here and there. All of the excess was wiped away with a paper towel.

Silicone Grease Applied to connection

Silicone Grease Applied to connection

Start wrapping first with a layer of electrical tape, as stated before, Scotch 3M brand. Begin down on the coax and wrap with overlapping layers going up. But wait! There’s a twist! No, a real twist!

Begin the wrap with the tape stuck to the coax, and then twist the tape 180 degrees so that it is sticky side out. The reason for this is so that when you redo all of this next year there is no sticky residue all over the connection. Pull, stretch, and wrap the tape, overlapping by half, from the bottom up. When you get to the top make sure you have covered the threads. To finish, DO NOT pull and break the tape. It will be stretched and will later want to pull back and the end come loose. Relax the pull on the last wrap, then CUT the tape with a knife or scissors.

And alternative, suggested by a long time ham and TV station engineer, is to make this first wrap with plumber’s teflon tape.

3M Elec Tape sticky side out

3M Elec Tape sticky side out

Scotch 3M Elec Tape Wrapped

Scotch 3M Elec Tape Wrapped

Now, wrap the connection with the Scotch 130C (or Coax Seal), beginning at the bottom just below the electrical tape using overlapping wraps. Pull and stretch the tape as you go, and cover the threads at the top of the wrap. When finished mold the tape down smoothly with your fingers.

Scotch 3M  130C Wrapped

Scotch 3M 130C Wrapped

Now wrap one more time with electrical tape, only this time sticky side in, no twist. Begin down on the coax just below the 130C butyl rubber tape, and pull and stretch as you make overlapping wraps going up. When you have gotten to the top make one more turn, relaxing the pull, and then cut the tape, smooth it down with your fingers.

Scotch Elec Tape Wrapped sticky side in

Scotch Elec Tape Wrapped sticky side in

Put a Ty-Wrap over the end of the tape, just in case. It can’t hurt.

TyWrap prevents unwrapping

TyWrap prevents unwrapping

Weatherproofed Connection Hoisted Back Into Place

Weatherproofed Connection Hoisted Back Into Place

Now, doesn’t that give you a warm fuzzy feeling?





Thank you Paul AE5JU – do remember that Paul lives on the Gulf in major weather country where good weatherproofing is the difference between operating at will or having everything corroded & in-op.




GUEST POST: A Field Day Antenna by Paul AE5JU

Field Day Antenna


Paul – AE5JU

This past Field Day the club tried to use a folded loop that just didn’t work. All contacts were made on my portable antenna. The club asked me to make something for them that would work on 75, 40, and 20 meters.

Let’s skip right to the conclusion.  I used this antenna to check in with my favorite regional net on 75 meters with my Icom IC-718 operating at 100 w SSB from a RBC-6 sealed lead acid (“gel cell”) battery.  Net control and assistant net controls reported that I sounded good, one giving a signal report of “10 over” from nearly 400 miles away.

This antenna will work on 40 and 20 meters without tuner, and with a little assist from a tuner will work on 17 and 15 meters, too.

Here it is:

This is a Field Day / Portable / Emergency antenna I just finished trimming. An antenna analyzer made for easy trimming.

AE5JU Field Day Antenna

AE5JU Field Day Antenna

AE5JU Field Day Antenna Graphic

AE5JU Field Day Antenna Graphic

This is a multiband inverted V dipole. The club president and I had discussed bands that needed to be covered, so it was decided that 20 meters, 40 meters, and 75 meters were most important. Anything else is extra.

I made my calculations, cut my wire to length, etc. Left a few feet on the ends so that it could be let out.

The 4 legs are all about the same overall length. 40 meter legs go one way, and the 75/20 meter legs are at right angles. The wires double as the guys, with insulators out at the ends, and then 550 parachute cord going on out to tent stakes… or anything else you can find to tie to.

The 75/20 legs have coils in the middle of each leg. These are placed at about where the ends would be if the wires were cut for 20 meters only… traps or chokes. They also act as loading coils so that the overall length will work for 75 meters.

When dipoles are this low (about 22′), proximity to the ground lowers the antenna’s impedance, which causes havoc with SWR. To counter this, like the Buddipole, the feedpoint is just off center, enough to bring up the impedance a bit closer to 50 ohms. The legs connected to the “hot side” of the coax are a little longer, and the coil on the 75/20 meters leg has a few more turns on the coil than calculated. The legs connected to the “shield side” of the coax are a little shorter, and the coil on that shield side 75/20 meters leg has a few fewer turns than calculated. This off center feed allowed for a minimum SWR of 1.3 to 1.4:1, which could not have been achieved otherwise.

Let’s see if this theory works out…

20 meters resonated too high, needed lengthening.

Due to the way this antenna is made it was decided to lengthen the 20 meters segments first by unwinding a turn from the inner side of one coil.  The coil former, 2” pvc pipe, has J-slots cut in each end so that wire may be let out or taken in.

Letting out one turn, lengthening that side by about 7″, brought resonance down some, but not enough. Letting out one more turn on that same side resulted in these figures:

14.000 mhz 1.6
14.100 mhz 1.5
14.200 mhz 1.4
14.300 mhz 1.5
14.350 mhz 1.5

Next I tackled the 75 meters segments, which were tuned by cutting off the ends of the wire on these same segments. I took off about 2′ on one end, and about 18″ on the other to give:

3.900 mhz 2.3
3.910 mhz 1.7
3.920 mhz 1.4
3.925 mhz 1.4
3.930 mhz 1.5
3.935 mhz 1.6
3.943 mhz 2.0

There are some emergency nets on 3.925 – 3.935 mhz.

20 meters was rechecked, and remained unchanged.

40 meters was adjusted by removing about 10″ from each end to give

7.000 mhz 2.9
7.100 mhz 2.3
7.150 mhz 1.8
7.200 mhz 1.5
7.250 mhz 1.4
7.300 mhz 1.5

After these changes all three bands were checked again to make sure nothing else needed to be fine tuned.

15 meters was found to be in the 3.5:1 to 3.0:1 range. A tuner can take care of that quite easily.


AE5JU Field Day Antenna Coil

AE5JU Field Day Antenna Coil

Loading coil. These coils are close wound on 2″ ID pvc with 14 ga insulated wire. There are J slots on each end to allow adding or subtracting turns of wire.

Once the coil tuning was settled it was wrapped with 3M Electrical Tape.

AE5JU Field Day Antenna Detail 1

AE5JU Field Day Antenna Detail 1

AE5JU Field Day Antenna Detail 2

AE5JU Field Day Antenna Detail 2

AE5JU Field Day Antenna Detail 3

AE5JU Field Day Antenna Detail 3

Center insulator made from cheap Wallyworld kitchen cutting board.

100′ of RG-8X coax was used, which is approximately 1/2 wavelength at 80 meters. Also, there are five Palomar Engineers FSB-1/4 ferrite snap on beads on the coax up by the feedpoint. These act as a “choke balun”.

AE5JU Field Day Antenna Stand

AE5JU Field Day Antenna Stand

Base, PA Speaker tripod. The mast is 5 sections of fiberglass pole sections. These are military surplus camo net poles, an Ebay item.

AE5JU Field Day Antenna Termination

AE5JU Field Day Antenna Termination

End insulators. Ordinary ceramic dogbone type.  “550 Parachute Cord” extending out to tent stakes.

The recipe:

Wire used is 14 ga stranded insulated wire, the 500′ roll for $25 from Home Depot.

I had a lot of black parachute cord, but will buy some more orange for the end rope on this. Also, my plastic tent stakes are green. Difficult to see in the dark. I’m going to get some bright yellow tent stakes.

The center insulator is cut from a cheap plastic kitchen cutting board from Walmart. A half inch dia hole was drilled in it, and a SO-239 socket screwed to it. The top of the socket was sealed with Aleene’s 7800 adhesive.

There is approximately 3″ of wire from the socket to each of the four holes, or tie points for the wire legs.

The two 40 meters segments go one way, and the two 75/20 meters segments are perpendicular to the 40 m.
40 meters segments:

AE5JU Field Day Antenna 40m

AE5JU Field Day Antenna 40m

Measurements are from the holes, or tie points on the center insulator out to the hole in the ceramic “dog bone” insulators on the ends.
75 and 20 meters segments:

AE5JU Field Day Antenna 75m and 20 m

AE5JU Field Day Antenna 75m and 20 m

This 75 / 20 meters section is wired parallel to the 40 meters section, only these legs are stretched out at right angles to the 40 meters legs.

Measurements for the inner 20 meters segments are from the tie points on the center insulator out to the first turn on the coils. The measurements for the outer wire segments are from the last turn of the coil on out to the hole in the ceramic “dog bone” insulators on the ends.

The coil formers are 2″ ID PVC pipe, which is 2.375″ OD. I have holes drilled in the pipe to secure the ends of the coils with ty-wraps. After tuning was deemed finished, the coils were wrapped with Scotch 3M electrical tape. I find Scotch electrical tape does not turn gummy and fall off with age. Good quality tape is worth the money. I made the coil formers with “J-slots” on the ends, to allow more turns to be taken off or added for tuning. Now that I have the final measurements that will not be necessary when making future copies of this antenna.

Due to the diameter of the 14 ga insulated wire, I was able to get right at 9 turns per inch, close wound, that is, turns touching each other. I used this 9 turns per inch figure in an online coil design calculator. This gave a nice repeatable build on the coils, and a length to diameter ratio of about 1.75:1, which is right in the middle of the suggested design ratios of 1.5:1 and 2:1.

Other notes:

There are five Palomar Engineers FSB-1/4 ferrite snap on beads placed on the RG-8X coax near the feedpoint. This forms a “choke balun” to stop RF on the shield.  Similar snap on beads may be purchased from Ham City listed with the coax.

The apex of the antenna is at approximately 22′. This includes the tripod base and 5 fiberglass mast pieces.  These are the common military surplus fiberglass camo net poles sold at hamfests and on eBay for use as antenna masts.

The only drawback of the coils is that the 75 meters bandwidth is narrower than if the antenna were full length. However, the antenna still covers the desired portion of the band with good SWR, and a little more using the tuner. * (see note at bottom of this post)

But the use of coil loading and the overall length of this 75 meter antenna (appx 50% of full size) causes no noticeable drop in signal.  I still got good signal reports from others I regularly talk to, so they know what I usually sound like with my full size dipole.

While this is not a permanent antenna for me, this might possibly help others fit 75 or 80 meters into a small yard.

One added note: While many say coax length does not matter, during initial testing with an analyzer I was getting good, consistent readings on 40 and 20 meters, but the 75 meters SWR readings were squirrely. Then it dawned on my… 50′ of coax. Considering velocity factor, that is very close to 1/4 wavelength at 80 meters. The next time I tested it I used 100′ of coax, and that works out to approximately 1/2 wavelength at 80 meters. SWR readings were consistent and stable.

Lesson learned: The old “conventional wisdom” to use 1/2 wavelength of coax got to be “conventional wisdom” for a good reason. I related this to one of our old club gurus and he just smiled and said, “Toljaso.” Length does matter, so use 93′ – 100′ of coax with this antenna.


* So, a thought occurred to me… What if you do want to go lower in the 75 meter band? Why not put some sort of connector near the ends, down by the insulators? Then clip on some added pieces of wire, 1′ long each, or 2′ long each, and string them on past the insulator, perhaps securing them to the parachute cord end ropes with tie wraps? That would drop the resonant frequency to a lower portion of that band.

AE5JU Field Day Antenna - Add-On Thoughts

AE5JU Field Day Antenna - Add-On Thoughts