Comms after dark

When and if Cooms nationwide go dark, there is a little known method of communication known as HAM RADIO, furthermore there is an even smaller known method known as “Winlink” or "Radio Email"

Radio email is a process in which one can connect a laptop to a HAM radio in order to send email worldwide even in the even of catastrophic internet and networking failures.

It is HIGHLY ADVISED that you grab a cup of coffee sit down, PAY ATTENTION and learn as much as you can… someday you will thank me because when Shit Hits The Fan, you will be one of literally only a few handfuls of people in the world able to communicate with anybody of importance, which could mean life or death.

Winlink is…

…a worldwide radio email service that uses radio pathways where the internet is not present, and is capable of operating completely without the internet–automatically–using smart-network radio relays. Winlink provides its users email with attachments, position reporting, weather and information bulletins, and is well-known for its role in emergency and disaster relief communications. Licensed Winlink operators/stations use both amateur radio and government radio frequencies worldwide. The system is built, operated and administered entirely by licensed volunteers. Support for the system is provided by the Amateur Radio Safety Foundation, Inc., a US 501©(3) non-profit, public-benefit entity. Winlink Global Radio Email®️ is a US registered trademark of the Amateur Radio Safety Foundation, Inc.

Using EMP-Hardened HF Ham Radio to Send/Receive E-Mail During Nationwide Outage- Part 1, by PrepperDoc

SURVIVALBLOG CONTRIBUTOR MAY 13, 2016 Print This Post Email This Post

There are multiple possible scenarios that may result in a regional an/or national combined loss of Internet connectivity and cell/telephone service, during which you would probably wish to maintain communications to loved ones and others. EMP may destroy routers, cell towers, and power sources; solar coronal mass ejection (CME) may remove power from all communications systems; cyber warfare may have similar outcomes. Travel in some of these circumstances will be difficult, or dangerous to impossible.

Ham radio VHF/UHF repeaters may go down, due to power outages or EMP. Direct, point to point simplex VHF Ham radio will still work (even after an EMP, if hand-held radios were at all hardened or protected) over modest distances. Long range HF direct Ham radio communications will work (possibly after a delay of any EMP), presuming you had protection (if EMP) and have your own power. However, they will be of less usefulness if you haven’t established communications plans, frequencies, modes, and protocols with your loved ones. Without prior pre-arranged schedules, connecting directly with your intended recipient may take precious hours of transmissions, create immense interference to others, use precious power, and provide a very easy radio signature from your location.

It would be really nice to be able to reach people via asynchronous email, so that direct radio contact and simultaneous radio communications aren’t necessary. You’d prefer to connect to a server, digitally send your message, and have your intended recipient be able to do the same at times that are convenient to both of you. Such communications may allow you to set up direct communications (if desired), or pass crucial information or requests. If you are not familiar with Ham radio digital communications, this reference may help:[1].

The WINLINK system[2], which is available to all Ham radio operators, was designed over the last 20 years with this exact capability, and it currently serves ships at sea as well as anyone who has a communications need that requires radio contact. Their system is provided by volunteers and is free and reliable, though not without controversy, as some object to what they see as automated interference to their activities in the name of providing free email to “yachtsmen”. Critics do not recognize the catastrophic scenario benefit. WINLINK has the ability to do intelligent automated radio forwarding from server to server, completely independent of but similar to the Internet, and thus it provides a fairly comprehensive alternate communications system. Email attachments are allowed; in the event of national emergency, you might be able to attach encrypted material, which is not legal under current FCC regulations. This may not even be necessary, as the request/acknowledgment packet handshakes make it difficult for anyone but a very capable and well-funded foe to decipher your communications. Users specify to three “message pick up stations” (MPS) where their mail will be delivered and from which they can retrieve it. You might want to pick a couple within your geographic area and one that is totally out of your nation.


It is extremely likely that the WINLINK system will continue to operate in some form after most catastrophes. Their five central servers are distributed across multiple continents. Their volunteer RMS email-server high frequency Ham radio stations are located all over the world, and these stations function with different equipment of different vintages and manufacture. There is a very good chance that some of them will either be unaffected or have equipment that is impervious to the catastrophe, with some stations likely EMP-hardened. Since HF signals can easily span continents and oceans, you will have multiple options to make the necessary contacts. The flip side is that HF radio communications modems are relatively slow, compared to the broadband connections to which much of us are accustomed. Transfer speed is back to what you may remember from the old telephone modem days. However, for email, it works!

Getting Started

If you have (or can borrow for your initial learning curve) a newer, solid state HF Ham radio transceiver with digital frequency readout, you will have little trouble learning and using this system. After the initial setup of your equipment and software (follow the directions in the videos on the WINLINK site!), it will take you less than 30 minutes to have it all figured out. Many new solid-state Ham rigs include their own sound card that will work with RMS-EXPRESS and its embedded WINMOR software terminal node controller (TNC). However, If your rig doesn’t have a built-in sound card, you can a buy Signalink-USB, which works with any Windows computer that has a USB port. In either case, download the free RMS-EXPRESS software from their web site[3], carefully watch the videos on their web site to understand how to use the system and create a free account, and you should be good to go. You may want to do your configurations by going step-by-step through the videos, which lead you through the process. Note that you must USE your new account, via either TELNET or actual Ham radio contact, at least once every 400 days or it will lapse. You automatically get your own WINLINK email account, to which you can set size limitations so as not to overburden your downloading ability. The system resists spam wasting precious bandwidth by using “white lists” of email addresses allowed to send to you; until you send to THEM, they can’t send to you. Otherwise, it works just like any other email account and receives and sends regular Internet email.

Making It EMP-Hardened

Now let’s shift focus to the more important point of this article: getting older, EMP-resistant vacuum tube gear working well with the WINLINK system. The most vulnerable portion of your communications equipment is the part connected to long wires: the transceiver. It has an unavoidable connection to antennas, which may deliver thousands of volts and amperes for nanoseconds in the event of an EMP. Thus, we focus there primarily. The computer and other equipment is more easily protected. (We’ll discuss this later).

Although it is frequently claimed that you should not try digital Ham radio using an older vacuum tube transceiver, those are exactly the systems that will best survive the EMP scenario, and it turns out that once configured properly it really isn’t difficult at all to send and receive email via the WINLINK system using 40-50 year old vacuum tube single-sideband Ham radios. I use them routinely with 40+ year old Heathkit SB-102/101/100 and HW-101/100 style vacuum tube gear that is relatively immune to EMP with minor protection additions.[4] This article is designed to help you discover how to take advantage of these inexpensive, older and readily available Heathkit rigs, with their inherent hardening to EMP. Entire stations can often be obtained from eBay for $200-$300. The remainder of this article is predominately devoted to the review of each hurdle and how to overcome them.

Frequency Control

You must have a stable transmit/receive frequency. This can usually be achieved by letting your radio warm up for 20 minutes or so. You must be within 200 Hz of the correct frequency, and preferably within 100 Hz; otherwise, the automated RMS server station will not acknowledge your connection attempt. The “dial accuracy” of older vacuum tube gear cannot hope to meet that accuracy. There are at least three possible solutions to achieve this frequency accuracy:

  1. Easiest: Simply measure your transmit frequency using an accurate digital frequency counter. You can use FLDIGI or similar program to send a 1.5 kHz (upper side band) audio tone, and use a bit of wire as an antenna on your counter to measure your own transmit frequency, which should be adjusted to exactly the published “center frequency” of the RMS server you want to try to reach. You can even transmit into a dummy load for this purpose.
  2. Next easiest and quite slick: Purchase the DD-103 universal digital dial from Electronics Specialty Products.[5] Tap into the LMO output with a 15-20 picofarad capacitor to the cathode of V5A (first transmitter mixer), and route the signal to the DD-103 with some RG174 flexible coax. For EMP protection, I would recommend adding back-to-back signal diodes (1N914’s or anything similar) between center conductor and shield, to clip signals more than a volt or so. Use MOV protection as appropriate on the power supply voltages to the DD-103. Follow the instructions included with the product to accurately adjust its measurements.
  3. Least expensive but far more work: Build the Pacific Antenna DIGITAL DIAL from[6] kit, and use it to give your vacuum tube rig a digital dial. Beware, this kit is surface component mounted. You may wish to grind your soldering tip to 0.025” or so and obtain rosin core solder of that or more slender size. A “third-hand-held-magnifying glass” helps a lot. As above, a 15 pF capacitor from the cathode of V5A (first transmitter mixer) will give you plenty of the 5.0-5.5 MHz VFO signal for your Digital Dial input; use coaxial RG174 cable to get the signal to the Digital Dial. Just as with the DD-103 above, protect the DIGITAL DIAL from EMP by adding back-to-back 1N914 diodes between its input RF signal and ground as input clippers, by providing it with metal-oxide-varistor 20V clipping on its 12V power input, and by mounting it in a metal case. After adjusting your Heathkit’s crystal calibrator by beating against WWV (using a 2nd receiver), you can tune to exactly the bottom of a frequency band (e.g, 3.5, 7, or 14 MHz), memorize the VFO frequency within the DIGITAL DIAL, then choose the third option to subtract, and the counter will read just like a digital dial. The Heathkit HW- and SB- series used a reverse direction VFO that was 5.5 MHz at the bottom of a band and 5.0 at the top; the Digital Dial kit allows to subtract the current measurement from the memorized VFO frequency, making the reading correct.




[3]RMS-EXPRESS client software for Windows:

[4]See for example, and

[5]Digital Dial,

[6]Universal Digital Dial,

Using EMP-Hardened HF Ham Radio to Send/Receive E-Mail During Nationwide Outage- Part 2, by PrepperDoc

SURVIVALBLOG CONTRIBUTOR MAY 14, 2016 Print This Post Email This Post

Transmit-Receive Frequency Offset

This should be zero. Synthesized digital radios have no problem accomplishing this; however, vacuum tube rigs may struggle. Surprisingly, the less expensive HW-series transceivers and the SB’s with the vacuum tube based LMO (VFO), in my experience, have little shift between transmit and receive. Later SB-series transceivers with the solid-state VFO may have an offset. If this offset is > 100 Hz, you’ll notice it during SSB conversations (“leapfrogging” as you chase the fellow you’re talking to), and you’ll want to fix that for digital communications. Happily, the solid state LMO includes a FSK (frequency shift keying) terminal where a small trimmer variable resistor of (say, 25K or 47K) from “FSK” to chassis ground will easily adjust the frequency a few hundred Hertz. To make this automatically switch in and out for transmit/receive, add a small transistor switch (2N3904) between this resistor and chassis ground and switch this by driving the base with a 1 Mohm ½ watt resistor to +300VDC available on one of the sections of relay RL2. Choose the connection in order to move the transmitted and received frequencies closer together, then adjust the variable resistor until they are within 25 Hz or so. The problem is solved. A friend on a SSB contact can help you figure out when you sound “right”. Otherwise, you can measure the frequency of a second (solid-state) transceiver’s transmissions to which you’ve tuned, and then compare the frequency of your vacuum tube rig (when both are sending the same audio tone). You can do this with two rigs both connected to dummy loads; send an audio tone into the reference rig and tune the receiver of your test rig until the tones match. Then measure both transmitters’ frequencies.


You need to switch from transmit to receive in under 250 mSec, and preferably around 100 mSec, to keep up with the handshaking responses. The RMS server to which you connect will be firing responses back quickly, and if you miss them your throughput and connection suffer badly. Your Heathkit, when controlled by the Signalink, will usually achieve this (assuming VOX delay and Signalink delay are all minimized), but if you make a small modification to the T/R receiver control circuitry within your Heathkit you’ll have latencies below 100 mSec. V14A audio preamplifier is turned off by a large negative voltage to grid during transmit (through relay RL2), charging capacitor C322 (primarily) to that negative voltage. When the relay moves to “receive” position, a substantial delay occurs because that voltage is leisurely bled to ground through 3.3 Mohm R336. Heathkit purposefully created this delay, to avoid clicks and thumps in the speaker while the relay repositioned, as extremely low latency wasn’t needed then. You can dramatically speed up the transition by wiring a 1N4007 diode in series with a 100K resistor and putting this assembly in parallel with R336 3.3 Mohm resistor, with the cathode of the diode oriented toward V14A (or away from the relay contacts). An alternative solution would be to change the 0.02 microfarad C322 to .001 microfarads. Your latency, as measured by WINMOR, will drop below 100 mSec with this very simple upgrade.

Signalink Connections

Because Hams typically made up their own mic and speaker connections to Heathkits, Tigertronics provides an unterminated shielded multi-twisted pair cable (RG45 to fit the Signalink) similar to CAT6 computer cable. You’ll need to make your own connections to the microphone and speaker wiring. If you can find shielded CAT6 cable, you can use that. Connect the foil shield to the chassis ground of the transceiver.

RFI Prevention

All of these digital phase or frequency-shift signals over audio are fairly sensitive to radio frequency interference, including the Signalink and your computer running the RMS EXPRESS software. If you have trouble connecting to WINLINK servers, and your frequency is correct, this is the most likely cause, and it is very insidious. Use the best grounding RFI prevention techniques you can to insure success. There are two additional items that may make a huge improvement, and you should do these pre-emptively. These two pre-emptive actions are: adding an effective “RF Isolator” to the coax line out of your transceiver, and adding ferrite snap-on cores around ALL signal lines. There are multiple manufacturers of RF isolators.[7, 8]. Ferrite snap-on RF chokes can also be found in various sizes and from many suppliers. Representative chokes can be found here:[9]

Speed Considerations

The least expensive method of getting digital connection to the WINLINK system is certainly via the WINMOR software-based TNC (terminal node controller), which can use a sound-card type interface such as the Signalink. For most purposes, this provides adequate throughput, somewhere north of PACTOR II. With the email overhead, even a simple message will take a minute or two to transmit. If you really need speed, you can get faster performance by moving to a hardware-based TNC, using PACTOR protocol III (or if outside of the United States, using PACTOR protocol IV). PACTOR is a patented protocol; an example is the P4-DRAGON 7800[10], which is widely available commercially, as it is used by many sea-going sailors. Used PACTOR II or III capable SCS modems are sometimes available at greatly reduced prices. Your transmit-receive latency may not be quite up to what solid state rigs can perform and are normal for PACTOR. Your preferred RMS server station sysop may be willing to adjust upwards their delay (default: 30 mSec); there is an option for them in their Trimode software settings that allows up to about 80 mSec of delay.

Solid EMP Protection

Once you get this all going, you’ll want to add some sort of metallic Faraday protection around your laptop (or other computer used to generate, send, and receive your email) and the Signalink, as well as any power supply for the laptop. Pass the AC power wires from the computer through a small perforation through the Faraday enclosure and put ferrite chokes on the AC wires both just inside and just outside the perforation. Pass the wires from the Signalink to the Ham transceiver through minimally-sized holes through the Faraday enclosure, and add another shield around them all the way to the transceiver (using aluminum foil or copper braid) and connect that shield to the Faraday enclosure. Apply ferrite chokes on the Signalink wires just inside and outside the Faraday perforation, just like the computer AC wires. The Heathkit transceiver needs an appropriately-chosen gas-discharge surge arrest or connecting the coax center conductor to shield (350 volts is reasonable for just the transceiver) as EMP protection, and then it probably does not have to be within the Faraday enclosure. Provide three-wire MOV surge protection for the AC lines feeding the Ham rig and the computer. If you are unable to support a vacuum tube transceiver and attempt to use a modern solid state transceiver, significant additions will need to be made to the transmitter output and receiver input circuitry. The antenna feedline is likely the source of your greatest incoming surge, because the antenna is specifically designed to absorb electromagnetic energy.


Being able to maintain access to world-wide email abilities, including attachments, completely independent of the wired Internet is a significant step toward guaranteeing communications redundancy for yourself. Thousands of users have already succeeded, and tens of thousands of messages are handled every month, all over the world, in boats on many different waters and on land in many situations. Many emergency coordinators are also turning to this option. This is a great capability for a prepared individual to attain!


[7]T4+ isolator from RadioWorks:

[8] FJ-2912 wall mount balun RF isolator.

[9]Ferrite snap on chokes that accept up to a 0.250” diameter cable.