Spurred on by my Tri-Link antenna design and the tuned, elevated ground radial concept, I thought about a 40M NVIS version. I had been thinking about this for while and when got to looking at the over all shape of this thing, it reminded me of the Great Sphinx of Giza!

The crazy thing is, this antenna was pretty much already dreamed up by Greg KJ6ER as an adaptation to his POTA PERformer antenna. Our designs aren’t exactly the same but it’s very close. You can email Greg and get all of his antenna designs.

My version is completely made of wire and I deployed the elevated radials about 90° apart whereas Greg recommends the radials should be placed close together and used in conjunction with an adjustable whip.

The Build

This build follows the same concept I used with the Tri-Link. It has a little plastic project box to accommodate the BNC connector and the wire connections. The main radiating element is connected to the BNC center while the ground radials are soldered together to the BNC ground.

I cut all three wires the same length, around 10m. I had three different colors of 18AWG in stock so I used them. It’s a simple trick for wire antennas but makes life atleast 17% easier when trying to figure out which wire goes where. In this case red and blue were the radials and yellow was the main radiator.

The Deployment

Because this is for NVIS propagation, you don’t need a very tall mast. Even a short tree would work. I used my old broken crappie pole ‘mast.’ I put a paracord loop up at about 10’ high for the radiating element to go through. The box was secured to the mast with a ball bungee at about 6’ high. 3’ electric fence posts supported all three wires.

I fed it with ~25’ of RG316 coax with a choke at the feed point.

Testing

NanoVNA Sweeps

I did the initial test and tune and it was really close right out of the gate. I trimmed a bit of wire off all three to bring it in to resonance. The entire 40M band was 1.8:1 and under for SWR. Not too shabby.

WSPR

I waited for twilight before running my standard 20 minute, 1 watt WSPR test. The antenna was deployed East-West with the main radiator to the East and the ground radials towards the West.

DATA:

TOTAL CONTACTS: 273

TRUE NVIS CONTACTS: 30 under 700km in SK, MB, AB, MT, ND

I was totally blown away by the WSPR results! It gave a very even, omnidirectional pattern which was anticipated. I had coast-to-coast coverage in Canada and the USA. And, low and behold, a decent number of true NVIS contacts under 700km.

Conclusions

I’m really happy with the results from this test. The antenna accomplished its goals. It’s super easy and fast to deploy. It would be pretty impervious to a big wind load too. The question remains though: how would this compare to a good ol’ inverted vee dipole?? Is this design worth the extra 10m length of wire? That remains to be seen.

73 de VE5REV

“It’s a great antenna!” “That won’t work!” “That’s wrong!” “I make all these contacts!” “I’m really getting out there!” “If it works, it works!”

We’ve all heard these things and said these things. But is there actually any objectivity to these kinds of statements about antennas? Often we live in the realm of subjectivity. I think this or I feel this, etc. But how can we know for sure? This post outlines a few things to consider about Antenna performance.

Key Factors to Consider

Here are the main performance metrics to compare, ranked roughly by importance for most hams:

Use Case

What is the antenna’s main goal: DX on HF, local ragchewing, VHF/UHF contesting, portable operations, mobile use? A high-gain Yagi might crush a dipole for long-distance work but be useless for short-range NVIS. Always define your use case first.

Radiation Pattern (Directivity)

Shows where RF energy goes (main lobe, sidelobes, nulls). Includes takeoff angle (critical for HF skywave) and 3D vs. 2D views. A high-gain antenna concentrates power in one direction; a low-gain one spreads it more evenly.

Gain

Maximum forward gain in dBi (isotropic reference) or dBd (dipole reference). Higher is usually better in the desired direction, but only if the pattern matches your needs.

Efficiency

Percentage of input power actually radiated (vs. lost as heat in wires, ground, traps, or matching network). An “efficient” antenna can outperform a “high-gain” one if the latter wastes power.

SWR Match

How well does the antenna matches your feedline (ideally <2:1). The closer the match, the better the power transfer (efficiency).

Bandwidth

How many frequencies can the antenna work? The Q-factor or quality factor shows if the antenna is narrow vs. broad bandwidth. Preference depends on your use case.

Front-to-back Ratio

For directional antennas, how much rejection off the back/sides and how narrow the main beam profile is.

Deployment

Height above ground; ground quality; nearby objects; wind/ice loading effects; physical size/cost/installation ease.

Effectiveness

Efficiency is how much power you radiate. Effectiveness is how well that radiation reaches the other station (pattern + propagation + takeoff angle may matter more than raw efficiency in many cases).

Testing

Simulation

Antenna modeling can give a good idea about how an antenna design may perform. Lots of software exists for this.

Real-World Measurements

Simulations and modeling are useful tools. But you never actually know what the antenna is going to do in the real world. So actually build the antenna. Deploy it and see.

NanoVNA

Sweep for SWR and Smith Chart readings. Make the necessary adjustments for resonance.

WSPR

Do a transmit test. Run the WSPR mode for a period of time. This will visually show you your antenna pattern. It provides a wealth of real-world data (max, min, avg) in the SNR reports and distances of the contacts.

A/B Testing

• For comparing two antennas, strive for an apples-to-apples approach.

• Mount both antennas at the same height and location.

• Use the same radio, power level, feedline, and time window to eliminate variables. Don’t run one test for 20 minutes, then the other. Conditions may change a lot in that time. Run transmission tests back to back. Antenna A, then Antenna B. JS8Call works great for this. Record your SNR reports for each transmission in series.

73 de VE5REV

I decided to make a Vertical Tri-Band antenna using my snazzy antenna links. This vertical has two raised & tuned ground radials. It’s basically a ripoff of the KJ6ER POTA PERformer antenna but is linked for the 15M, 17M and 20M bands. This is a decent solution if you don’t have an antenna whip (which I still don’t).

The Build

The Wire

18AWG Speaker Wire that I had in stock from a previous build. I cut 1/4 wave wire length for the 15M band. Then added the chunks for 17M & 20M.

These were cut to science. But in reality, by 20M chunk was a bit short so I brought it up to ~1.29m

I cut three of everything.

Junction Box

I ordered some el-cheapo plastic project boxes from Amazon. The lids just pop off with a screwdriver. Definitely not weather sealed. But for this temporary antenna it’s just fine. The main goal of the box is to provide a decent amount of strain relief for the wire. I drilled it out for a BNC connector and strain relief holes.

I decided to directly solder the wire to the BNC connector. I fished the wire through the strain relief. I soldered the ground radial elements together and to the ground of the BNC. Then I soldered the main vertical radiator to the center. This way there is never any direct strain on the solder connections.

Put the lid on and voila! Very clean and super lightweight.

Tuning

I set it up in the backyard and did some quick tuning. The 15M and 17M bands were perfect as cut to science lengths. The 20M band needed some tweaking as mentioned above. Each band is completely under 1.6:1. No tuner needed. I used 25’ of RG-316 with an integrated Type 31 choke.

Finishing Touches

After the tune up, I tinned all the wire ends. This is a really good thing to do to make sure the wire doesn’t splay or get damaged as you use the links.

I added some hanging loops with 95 paracord and heat shrink. This gives a convenient way to support the vertical and the radials when deployed. I used blue for the vertical and orange for the radials, just as a way to instantly see which wire goes where.

Testing

NanoVNA Sweeps

15M

17M

20M

Each band looks pretty good. I could have adjusted the 15M a bit more, but otherwise I’m pretty happy with these results.

WSPR Testing

All of the WSPR tests were performed at 1 Watt for 20 minutes. Antenna was deployed with the radials facing south, approximately 45° angle.

CONDITIONS:

Conditions were not great.

DATA:

PATTERNS:

15M

17M

20M

Conclusion

This is an absolutely banger antenna! Having the snazzy links really solves a lot of problems. You get true multi-band performance that is ultra efficient with no harmonic weirdness. It’s relatively easy to build and deploy. In fact, this would make a great second antenna for a ham to build (right after the token dipole). As a vertical, it will most definitely have great take off angle for DX. And not needing a tuner will make it awesome for POTA and light weight portable setups.

73 de VE5REV

I came across an even better approach to One Time Pad Encryption: Diana.

This system uses letters instead of numbers and makes use of a “speed square” to do the encrypting. You can check out the full YouTube vid from AmRRON here.

Like any One Time Pad, use it once then destroy it. It is completely unbreakable encryption if you keep this one key rule.

The Code

Diana One Time Pad Generator:

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#!/bin/bash
#
# Generate a random 5-letter key (uppercase A-Z)
key=$(cat /dev/urandom | tr -dc 'A-Z' | head -c 5)
echo "-----------------------------"
echo "| ONE TIME PAD - KEY: $key |"
echo "-----------------------------"
echo
# Print 10 lines of 5-letter groups (first line starts with the key)
for i in {1..10}; do
    if (( i == 1 )); then
        # First line re-uses the same key
        printf "%s %s %s %s %s\n" "$key" \
            "$(cat /dev/urandom | tr -dc 'A-Z' | head -c 5)" \
            "$(cat /dev/urandom | tr -dc 'A-Z' | head -c 5)" \
            "$(cat /dev/urandom | tr -dc 'A-Z' | head -c 5)" \
            "$(cat /dev/urandom | tr -dc 'A-Z' | head -c 5)"
    else
        printf "%s %s %s %s %s\n" \
            "$(cat /dev/urandom | tr -dc 'A-Z' | head -c 5)" \
            "$(cat /dev/urandom | tr -dc 'A-Z' | head -c 5)" \
            "$(cat /dev/urandom | tr -dc 'A-Z' | head -c 5)" \
            "$(cat /dev/urandom | tr -dc 'A-Z' | head -c 5)" \
            "$(cat /dev/urandom | tr -dc 'A-Z' | head -c 5)"
    fi
done
# Generate Several DOTPs at once
#for i in {1..5}; do
#./DOTP.sh >> DOTPs.txt
# done

You can copy & paste this code into a file. Then save it as with a script extension, something like DOTP.sh then just make it executable in the shell.

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chmod + x DOTP.sh

To run the script and generate the pad, you just run the script in the shell.

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./DOTP.sh

It also includes some loop code that you can copy into the terminal to generate 5 DOTPs at a time and save them as a text file. The code in the script is commented out so it doesn’t run by default. That code is:

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# Generate Several DOTPs at once
for i in {1..5}; do
./DOTP.sh >> DOTPs.txt

The “Speed Square” Generator:

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#!/usr/bin/env bash
# The separator is 77 characters long
SEP="-----------------------------------------------------------------------------"
echo "$SEP"
# Header row: A  B  C ... Z (Two spaces between letters)
header=""
for i in {0..25}; do
    char=$(printf "\\$(printf '%03o' $((65 + i)))")
    if [ $i -eq 25 ]; then
        header+="$char"
    else
        header+="$char  "
    fi
done
echo "$header"
echo "$SEP"
# Generate Table Rows
for ((row=0; row<26; row++)); do
    row_upper=$(printf "\\$(printf '%03o' $((65 + row)))")
    line=""
    
    for ((col=0; col<26; col++)); do
        # The magic math:
        # Start at 25 (z), subtract the row index, then subtract the column index.
        # Adding 52 (26*2) ensures the result is positive before the modulo.
        val=$(( (25 - row - col + 52) % 26 ))
        
        # Convert result to lowercase (a=97)
        lower_char=$(printf "\\$(printf '%03o' $((val + 97)))")
        
        if [ $col -eq 25 ]; then
            line+="${row_upper}${lower_char}"
        else
            line+="${row_upper}${lower_char} "
        fi
    done
    echo "$line"
done
echo "$SEP"

You can save this script as per the instructions above. You can also save this output as a plain text file:

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./SpeedSquare.sh > SpeedSquare.txt

The Tutorial

The phases of encryption with Diana are:

• Plain Text > Cipher Plain Text > Encrypted Text

1. Run the script to generate a One Time Pad

It spits out a 5 digit key and 5 columns of 5 letters in 10 rows. This OTP will allow you to encrypt a message up to 250 characters. Also run the Speed Square script to generate the cipher table:

2. Plain Text to Cipher Plain Text:

You don’t want to use the key text itself as it is your Pad identifier. So start with the column to the right of the key identifier.

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Plain Text: HAM RADIO ROCKS
Cipher PT:  GHO HZAUS HJZOS

You want to format your message into 5 character groups. In this case, our plain text message is two characters shy of the 5. So we will pad them with the letter Z.

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Plain Text: HAMRA DIORO CKSZZ
Cipher PT:  GHOHZ AUSHJ ZOSKQ

3. Encrypt the Cipher Plain Text Message

• Using the Speed Square conversion table, convert your message. The Plain Text letter is the top header row, then scroll down the column to the matching Cipher Text letter. The lower case letter is the Encrypted Text.

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Clean PT:  HAM RADIO ROCKS
Formatted: HAMRA DIORO CKSZZ
Cipher PT: GHOHZ AUSHJ ZOSKQ
Encrypted: MSZBA WXTBC YBPQK

This system is incredibly fast and intuitive. It will be less prone to error too because the eye has less tracking across the grid during encryption.

4. Decrypt

To decrypt it is just the opposite procedure. The Encrypted Text is across the top header row. The Cipher Plain Text is down the column. The lower case letter is the Plain Text. Simple!

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Encrypted:  MSZBA WXTBC YBPQK
Cipher PT:  GHOHZ AUSHJ ZOSKQ
Formatted:  HAMRA DIORO CKSZZ
Clean PT:   HAM RADIO ROCKS 

73 de VE5REV

My Antenna Link design was well received in the Ham Radio community so I thought it was time to put the design into practice in the real world with a linked EFHW antenna. The one I had in mind is what I’m calling the “WARC Wiz” - a linked EFHW antenna for the WARC Bands. This build covers the 12, 17 and 30M bands - perfect for WARC Band Wednesday or Winlink Wednesday or, for a limited time only, both!

The Build

The Base

VE5ARV 3D printed me this nice little base. It’s actually a bit small for this core. It’s meant for QRP tiny cores. But I got it to work.

The Core

I decided to build this on a Type 61 core (2661102002). It’s a more of a bead than a typical toroid. I built a couple of iterations of this transformer. I first went with a 64:1 ratio (3:24) to see if the extra induction would help it on the 30M band (which you can see below that it did, but not without side effects). In the end I used a 36:1 ratio (3:18) for the final build. I used 18AWG enamel wire and a 120pF capacitor for each iteration.

Counterpoise

The 30M band only needs around 55” of counterpoise for the EFHW configuration. I was trying to decide if it would be better to include a dedicated wire on the ground terminal or use unchoked, length-specific coax. This is my preferred way of constructing EFHW antennas. Even if you add a dedicated counterpoise, you still need to have a 1:1 choke at the feed point to force the common mode current onto the counterpoise and keep the antenna pattern clean. I decided that in this case, I would include a 4’ piece of counterpoise hardwired into the build. This way you just slap on a 1:1 choke (along with a 12” coax jumper) after the transformer, which is simpler than keeping track of a shorter piece of coax.

The Wire

I wanted to make this build as a go anywhere, light as possible antenna, fitting the bill for EMCOMM or for POTA. I decided to use 26 gauge BNTECHGO wire.

The wire sections are as follows. These measurements are to science, not reality and not accounting for velocity factor. They are cut for the center of each WARC band.

So you start with the 12M and add a section for 17M and a section for 30M.

Then you go to work tuning each section for each band, building on the preceding section. The Wago antenna link is the cat’s pajamas for this process because you simply trim and strip your wire and slam it back into the Wago. When you’re all tuned up, remember to solder your wire tips to keep the antenna wire from fraying.

Deployment and Testing

The weather broke and I did a temporary setup in the backyard. I was able to tune up the 12M and 17M sections. I didn’t have enough room for the 30M leg but the initial setup and tune up went very well. The antenna links are super, super easy to make adjustments. Just trim the section, strip back the sheathing, retie the knot as and voila! I brought out the IC-705 and made a 17M contact at 5W SSB into Nebraska (945km/587mi). I got a 55 signal report with crystal clear audio. This was very encouraging.

NanoVNA Readings

12M Section

So the original 64:1 ratio with this core was really bad for the 12M band. No matter what I did, I could not get it resonant. It was hovering around 3.6:1 SWR and quite capacitive. After some discussion on Discord, I concluded that intra-winding capacitance was building up and throwing off the matching. I went back to the drawing board in the opposite direction and went with a 36:1 (3:18) ratio. It was a much more workable compromise for all 3 bands of this build.

17M Section

The 17M section matched up quite well.

30M Section

The 30M section is OK, but could be better. It was absolutely superb with the 64:1 iteration. If I was going to build a monobander for 30M, I would go with the 64:1 iteration.

Digital Tests

I operated FT8 and ran my standard 20 minute, 1 Watt WSPR test on each of the legs. The antenna was deployed in a sloper configuration.

12M

174 12M Contacts:

17M

It should be noted that the 17M test was done at grey line.

150 17M Contacts:

30M

207 30M Contacts:

POTA Activation

I used the WarcWiz on all three bands for a 10 Watt FT8 POTA Activation at CA-5082 the TransCanada Trail. I was aiming for 12 contacts on each band. I ended up with one extra on 30M. All in all everything went very well. Changing bands in the field was extremely easy with the links. The average SWR was just under 1.5:1 on each band.

Conclusions

Well, I think we can have good confidence in the real-world performance of this core. It really does make for a nice and compact performer. The linking system is such a great setup as well. Tuning the antenna legs was so easy and convenient. I will definitively be using the linking system in future builds. They have excellent performance and solve the EFHW harmonic issues that can sometimes be a pain.

The Smokin Ape has begun doing some work with this core as well so be sure to check out his videos.

73 de VE5REV

I’ve been a big fan of Gaston, KT7RUN The Tech Prepper forever. I’ve always thought his focus on digital modes was very cool and extremely useful from the preparedness mindset. In some of his latest videos he setup a BBS over VARA HF. I used to connect to Bulletin Boards over dial up internet back in the day so this was right down memory lane for me.

I struggled a bit with how to connect to the BBS. But here’s a mini tutorial on how to install the necessary software.

Software

VARA HF

Gaston has his BBS accessible on VARA HF. So you need that. I have a Linux tutorial using both Gnome Bottles (if that works for you) and also Wine.

QtTerm

To connect to the BBS you need a packet terminal and that is where QtTerm comes in. For this tutorial we will download the code and compile from source.

The software is at this link. But Chrome/Brave won’t download the file. So I used the terminal like a real radio, command-line Chad.

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wget http://www.cantab.net/users/john.wiseman/Downloads/QtTermSource.zip

Then install some dependencies (Ubuntu/Mint/Debian):

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sudo apt update
sudo apt install qt5-qmake qtbase5-dev libqt5serialport5-dev qtmultimedia5-dev build-essential

In Terminal navigate to the source directory:

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cd path/to/QtTermTCP-source

Create a build directory:

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mkdir build
cd build

Generate the make file:

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qmake ..

Compile the software:

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make -j$(nproc)   # or just 'make' if you prefer; -j uses all CPU cores for faster build

This will give you a nice QtTermTCP binary file that you can move to ~/bin or usr/local/bin

SITREP

Gaston also shared a Situation Report (SITREP) format on his BBS as part of Anti-Winter Field Day 2026. This is designed to be used as a WinLink check in. I recreated it here for future use in radio excercises.

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TO: RECIPIENT 
SUBJECT: AS REQUIRED
BODY:

DATE [UTC]: <YYYY-MM-DD>
TIME [UTC]: <HHMM>
LOCATION: <GRID | LAT,LON | UTM>
TEMPERATURE: <TEMP C | F>

POWER: <GRID | SOLAR | BATTERY | MIXED>
ANTENNA: <TYPE & BAND(S)>
MODE(S): <WINLINK MODE(S) USED> 

STATUS: <GREEN | YELLOW | RED>

COMMS NOTES:
<BANDS USED, CONGESTION, FAILURES, SUCCESSES>

FIELD NOTES:
<ENVIRONMENT, CONDITIONS, CAMP DESCRIPTION>

STATUS DEFINITIONS

• GREEN: Operating as planned. No issues.

• YELLOW: Partial degredation, workarounds in use.

• RED: Operation significantly impaired.

73 de VE5REV

Just a reminder about the proper orientation of Anderson Power Poles.

Red Right, Tip Top

The Letter “A” is oriented correctly.

73 de VE5REV

Linked dipoles and EFHW antennas are a really great way to have efficient, resonant, portable antennas that are multi-banded. I’ve never come across a linking method that I really liked. I’ve had bullet connectors tear apart in the field. I don’t like stuff that is fragile for field use. I was thinking about a better linking system that was robust and still lightweight for even QRP antennas.

Wago: The Ultimate Link

I’ve used Wago lever nuts in lots of ham radio applications. They are so convenient and handy. I was looking at these double connectors and then it hit me. It’s the ideal antenna link. I prototyped the concept with a lock n’ lock plastic container. Using a hole saw drill bit, I drilled out a 1.25” circle. I hot glued a Wago 221-412 connector in the center afte drilling out the wire attachment holes. The concept is you tie your antenna wire to the plastic and then just pop an end in and out of the Wago connector to link and unlink the antenna sections. This was pretty good, very light weight but it seemed a bit bulky.

3D Printed Version

I started researching to see if someone had already built this idea. As far as I can tell, it has never been used for an antenna link. But someone had already designed a 3D Printed holder for Wago lever nuts. To my delight I found the ideal piece, already done up. Sternmarke on Thingiverse is an absolute legend! I fired the files over to VE5ARV and Garvin printed one up for me to test fit. It fits the Wago like a glove. The design is almost totally perfect. A person could remix this design to fill in the spaces on the top and back if desired. However, as it is, it gives a great spot to adhere hot glue or super glue to make sure the Wago connector stays put.

This is truly an ultralight solution. The assembly only weights 4g/.1oz per link! This is awesome for the SOTA bros or anyone who does backpack portable ops.

The Files

As I mentioned above, you can get the .STL files on Thingiverse. Be mindful that he makes 3 versions of this double connector. Make sure you print the one for the model you have. I will host the files here too for redundancy/safe keeping but design attribution goes to Sternmarke. The one I used in this build was the 221-412.

• AntennaLinkSTL.zip

Thanks again to VE5ARV for bringing this concept to 3D printed glory!

73 de VE5REV

I really love loop antennas. In my Delta Loop posts, 1 and 2, I was working with a vertically oriented 20M loop. I found that a 2:1 hybrid balun was a better match than the 4:1 for using it as a mono-band antenna. But my attentioned turned to making huge, horizontally oriented loops. Our radio club still has zillions of feet of that fine aircraft cable so sourcing the wire is no problem.

For Loop Antenna theory, check out this awesome Practical Antennas article. And also see Lord Callum’s Video.

Balun Builds

Because these loops will be used for multi-band operation, I went with the good ol’ 4:1 balun. I built two of them, one for an 80M and one for a 40M loop. For the 80M loop I went with a ‘Fatty 43’ core (Size: 1.540” Dia (39.12mm) OD. Core: 2643251002) and for the 40M I went with two Type 61 cores (Size: 1.400” (35.56mm) OD. Core: 5961002701). The logic here is that the Type 43 has proven better for the lower bands while the 61 shows better results for the higher bands. Both of these builds are meant as temporary deployments. Nothing is well sealed as they should be for permanent setups.

80M 4:1

For this build I used glue-lined crimp terminals. I really like how this turned out. It was quick, clean and really secure. I mounted the core onto a piece of plastic puck board. I heated it up and put it in a vice to make the bend for the SO-239 connector. It’s a pretty robust base!

40M 4:1

For this one I built it as a hybrid balun. It includes a 1:1 choke made from a Type 31 core (Size: 1.142” (29.01mm)OD. Core: 2631801202) and RG-316 coax. I had a scrap piece of cutting board for the base and I likewise heated it up and bent it. Again, it’s a pretty robust build. I added some extra strain relief holes for the antenna wire.

Field Day Deployment

The other magical thing about these big horizontal loops is that they don’t have to be super high up to work well. Obviously, height is always might so the higher the better. But as in Callum’s video (referenced above), they will work very well even at lower deployments. For 2026 ❄️ Winter Field Day we deployed the 80M loop and it is only 15’-20’ up. We built a mast out of some spare tower sections and a McCormick-Deering tractor! The other antenna is the 160M EFHW with an upgraded Balun. The Loop was deployed from North to South in a narrowish rectangle. The EFHW was deployed West to East/South East as a lazy inverted L.

NanoVNA Measurements

With any multiband antenna, I’m always trying to get SWR to no more than 3:1 so that an internal rig tuner can deal with it. We adjusted the 80M loop until we had 20M pretty close. It showed good results from 10M-40M. 80M itself was a bit concerning. I think this had to do with deployment height. It was way too low for 80M. However, we were able to tune the low end of 80 with just the Icom 7300 internal tuner.

Field Day Results

We got to give this antenna a really good workout at Winter Field Day. We made SSB contacts on 10, 15 & 20M bands. 40M contacts were exclusively CW and they were all made on the EFHW. I include them here to show the propagation difference between the loop and the EFHW. We tried to make 80M and 160M contacts but had poor conditions. All in all we made 360 contacts.

Analysis

We were very impressed with the 80M Loop antenna! It was relatively easy to deploy and we had lots of space. The 10M and 15M bands were very omni-directional and they pattern much like a 1/4 wave vertical. 20M in contrast shows a pretty substantial null to the East. This may be because our 20M station was mainly hunting stations rather than calling. Being that we’re a pretty rare station I was able to wrack up loads of contacts on the 10M and 15M bands by calling. This may account for the wider/omni-directional spread of the other bands. The 40M EFHW contacts were noticeably more directional. This antenna was also incredibly quiet on receive. Granted, we were out in the country with very little noise, but the characteristic quietness was very pronounced. I’m thinking this could be an ideal urban antenna, particularly a 40M or 20M version which may be easier to fit in space-wise. All in all, this was a great Field Day antenna!

73 de VE5REV

I have always had an interest in Cryptography, ever since reading Simon Singh’s The Code Book. Truly, it is a fascinating area of study and very necessary for secure communications, should the need arise. Public Key encryption with GPG/PGP is already a great option. But I always come back to the One Time Pad. It’s the only uncrackable code, providing you use it correctly (once).

For ultimate security, no compromise one-time pads, you should generate the numbers manually by hand with dice in a dark room with no electronic devices around. Or you can use the following script. This will run on any Linux distribution from the terminal. Ideally, you would run this code on an offline, air-gapped computer that has never connected to the internet.

The Code

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#!/bin/bash
#
key=$(printf "%05d" $RANDOM)
echo "-----------------------------"
echo "| ONE TIME PAD - KEY: $key |"
echo "-----------------------------"
#
for i in {1..10}; do
    # For the first line, reuse the stored number so it's identical
    if (( i == 1 )); then
        printf "%s %05d %05d %05d %05d\n" "$key" $RANDOM $RANDOM $RANDOM $RANDOM
    else
        printf "%05d %05d %05d %05d %05d\n" $RANDOM $RANDOM $RANDOM $RANDOM $RANDOM
    fi
done
# Without A Repeated Key
#for i in {1..10}; do
#    printf "%s %05d %05d %05d %05d\n" $key $((RANDOM % 100000)) $((RANDOM % 100000)) $((RANDOM % 100000)) $((RANDOM % 100000))
#done
echo
echo ".:EN- | DE+ | TEXT/KEY:."
echo
echo "=========================="
echo "|  CONVERSION TABLE #1   |"
echo "=========================="
echo "A-1   B-70   P-80   FIG-90"
echo "E-2   C-71   Q-81   (.)-91"
echo "I-3   D-72   R-82   (:)-92"
echo "N-4   F-73   S-83   (')-93"
echo "O-5   G-74   U-84   (,)-94"
echo "T-6   H-75   V-85   (+)-95"
echo "      J-76   W-86   (-)-96"
echo "      K-77   X-87   (=)-97"
echo "      L-78   Y-88   (?)-98"
echo "      M-79   Z-89   SPC-99"
echo "=========================="
echo
# Generate Several OTPs at once
#for i in {1..5}; do
#./OTP.sh >> OTPs.txt
# done

You can copy & paste this code into a file. Then save it as with a script extension, something like OTP.sh then just make it executable in the shell.

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chmod + x OTP.sh

To run the script and generate the pad, you just run the script in the shell.

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./OTP.sh

The Tutorial

Here is how to use the One-Time Pad to encrypt and decrypt a message.

1. Run the script to generate a One Time Pad

It spits out a 5 digit key and 5 Columns of 5 digit numbers with 10 rows.

It also generates the usage hint and a conversion table.

The hint tells you to ENcrypt you subtract (-). To DEcrypt, you add (+). And, your message text goes over (/) the key.

The conversion table allows you to transcode your plain text message into numbers.

2. Transcode Your Plain Text Message

• Using the conversion table, convert your message into numbers.
• Do not use the key as part of the encryption. Start with the numbers to the right of the key.
• If you get a negative number in the encryption process, just add 10 to the top number

3. Example

Plain Text

“Meet me at the old place”

Transcoded

• The One Time Pad Numbers Starting After The Key

Encrypted Message (Subtracted)

• Encrypted Message: 4884486692904929744474551623570795802

• You can present the encrypted text in groups of 5 to make it easier to work with.

48844 86692 90492 97444 74551 62357 07958 02

Decrypt the Cipher Text

To Decrypt, you just do the process in reverse, adding the numbers from the One Time Pad.

48844 86692 90492 97444 74551 62357 07958 02

31482 13100 09777 09318 25027 10641 00969 10

79226 99792 99169 96752 99578 72998 07817 12

“Meet me at the old place”

Generate a Few at a Time

Tucked at the bottom of the main script is some code to generate 5 of these at one time and append them to a text file. This is good for generating a few Pads at once that could be easily shared among Mutual Assistance Group and such.

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#Generate Several OTPs at once
for i in {1..5}; do
./OTP.sh >> OTPs.txt
done

73 de VE5REV