transmitter

All posts tagged transmitter

It’s alive! After three hair-pulling days, the radio finally works. I received the box on Thursday night; no time then to start, but I got to it after my daily work session on Friday. Late that night, I had completed the filter board, one of the three circuit boards.

I must here explain what an Elecraft K1 is.. Though it sounds like some fighter plane name, it is a receiver/transmitter (a “transceiver”) which transmits, and receives CW (Continuous Wave) Aka “Morse Code.” It is very small, and covers up to four Ham radio bands. Mine has two, 40 (7Mhz) and 20 meter (14Mhz). The power output is fairly low (7 Watts), but that is sufficient to bounce your signal around the earth.. Imagine seeing a 7 Watts light bulb thousands of miles away! Somehow, it works. CW punches through further than “phone” (voice). The K1 is in a class of radios called “QRP,” meaning low power, usually 5 to 10 Watts. It is only sold as a kit, so if you want one, you must build it, or find a used one.. I chose to build it..

Elecraft K1

Elecraft K1

I don’t understand the fear about winding toroids. I find it very easy and relaxing; it hurts much less than it sounds. All you have to do is count how many times you thread a wire through a ferrite core. How easier can it be? Then, you burn the enamel off the leads with a lighter, clean them up with your snipping tool, and solder.. I was very exited that night about the project. I thought it would be a walk in the park.. Not quite..

The front panel was next. The only difficulty there was soldering the LCD display. Attaching the wires to the ten-turn potentiometer also required some dexterity. About wires.. There are very few in the K1 kit: The potentiometer lead wires, speaker wire, and one coax jumper on the back of the board, that’s it. Everything else is connectors. I like that. Soldering wires is always a pain in the butt.

The RF board was the biggest and longest one to build. It took me from around 10-am on Saturday to about 2:30-am on Sunday to complete it! And it didn’t work! In retrospect, I should have only completed the receiver part that day, leaving the transmitter for Sunday. When tired, your brain plays tricks on you, and you make mistakes. Everything went fine with the receiver. I heard static when I turned the K1 on, no smoke. After tuning the receiver and plugging-in a long wire, I was listening to CW on both bands. I was exhausted, but proceeded with the transmitter side. It was 9-pm already, eleven hours of looking at tiny components, placing and soldering them.. Then came the time to test voltages on the RF board. Nothing on U8! Shit! Excuse my French.. That wasn’t good. I nevertheless plugged-in the filter board to test power output. Nothing.. Followed about an hour of tinkering, swearing, manual-reading, head scratching shenanigans, of which I remember almost nothing (I had been working on it for 15 hours straight). I rewound the bi-filar transformer, reheated solder pads both on the filter and RF boards, zilch! Then I gave up, and decided to complete the build for the heck of it, and call Elecraft in the morning. Yet, after putting the speaker in and closing the box, I tried again. Power on 40m! Not on 20.. Ah.. Back to it (2-am).. I think I transmitted without a dummy load and no antenna a couple times by the way, I was so tired. Anyway, I have no idea what did it, but after countless little troubleshooting steps, and more tuning of the filter board, I finally got output power on both bands. I packed it up and went to bed with a headache and slight twitching..

Elecraft K1 inside

Elecraft K1 inside

Comes Sunday morning, I had a working K1! The only peculiar thing left to investigate is some power fluctuation.. If I set the maximum output to 2 Watts, the watt meter shows 2W at first, but then slowly climbs to 2.8. I am guessing that the final transistor produces more gain as it warms up.. I even produced about 10W tuning the filter board before the output suddenly dropped! Weird.. After tuning the filter board on receive, things are a bit more stable, still with quite a power increase as transmit time increases.. It shouldn’t occur producing CW though, as this was transmitting a continuous tone in tuning mode. We’ll see..

I spent Sunday evening listening to CW outside, with a wire strung horizontally (20ft maybe) about five feet from the ground; the worst possible antenna. Still, it was easy to pick-up signals. I even heard a guy saying he was on a sailboat, and retired three years ago (I have a Morse decoder app on my iPod!).

The Elecraft K1 kit is of very high quality; much better than any other kit I have seen so far (five). Everything fits perfectly, nothing was missing. I even had much needed left-over screws (I spilled them all on the garage floor).. The box looks great, and the way the circuit boards are positioned and fastened is brilliant. I will order the automatic antenna tuner and add it in soon. For now though, I need to finish learning code, then I’ll go for the General Ham license (CW is no longer required). The K1 was the right choice, at the right price. You get a lot for your money. It might not seem so when you buy the kit, but after building it, I find it very affordable.

To anyone contemplating building one, go for it! Build a couple kits first, like a Small-Wonder-Labs Rock-Mite, and a SOTA tuner from qrpkits.com, and you’ll be well on your way. Moreover, you can test the Elecraft receiver with the Rock-Mite! Get 50ft. of wire from Home Depot for the SOTA tuner, and you’ll be all set. Follow the manual EXACTLY. Don’t skip ahead, read every line! Double-check everything. Most importantly, don’t do what I did. That was stupid. Take your time. If you feel tired or stressed, stop, rest, and don’t get back to it until much later. I was very lucky that I didn’t fry anything. Not to mention the stress and lack of sleep.. Not a healthy way to spend a week-end..

In the mean time, like they say over there, “Everything is fine in the best of worlds.” I am a happy, proud builder and owner of an Elecraft K1. The satisfaction of building something that complex with your own hands is priceless..

After my semi-success with the DC20B, I decided to tackle the Rock-Mite from Small Wonder Labs. I also got the Mighty Box. The kit is very small and has no toroids to wind. It does however have a surface-mounted integrated circuit. Winding toroids is actually very easy. I don’t know why people make such a big deal of it. Maybe they just haven’t tried. Soldering the SMT circuit, while not that hard, was stressful. That being out of the way, the rest of the kit was a breeze. Being fairly confident of my abilities, I installed the circuit board in the box without trying it first. This way, I could use all the connectors for testing. To my satisfaction, it worked the first time!

My goal with this Rock-Mite is two folds. First, it is a stepping stone to building an Elecraft K1, which I have just started, and second, it provides me with a small emergency radio for my bug-out bag.

I can’t really compare the DC20B to the RockMite as far as performance is concerned, but building the Rock-Mite is easier, and there is no tuning required. The circuit board is slightly smaller. I replaced q6 with a 2sc799. R18=2.2 ohms for a little more power. The keyer is the Pico Keyer from http://www.hamgadgets.com.

I am very exited about building the K1. More on that later…

Since I am on a radio kick (funny how old hobbies resurface..), I decided to dig my old CB radio from storage. I bought it around 1989-90, and hadn’t turned it on since. I was worried it would go up in smoke when I turned it on, but to my surprise, it worked. I hooked up a 3ft. balcony antenna to it and heard… Nothing but static. Maybe it had not aged so well after all. In radio, the antenna is everything. My little three footer wasn’t going to provide stellar performance. Unless I could get it high enough. I ended-up on my deck, swinging a wrench attached to a nylon string, aiming for a promising branch above the roof. Five minutes later, I was listening to stations from Mexico, Costa Rica, and New Mexico. That was of course using Single Side Band (LSB or USB). There is nothing left for me on the regular AM band. At least on SSB, you hear much less obscenities, and conversations are more “professional.” A CB with SSB modes thus is a good choice for emergency communications (yes, I changed my mind..).

Anyone around Sarasota wanting to chat on SSB, post in the comments below!

As far as radios go, I would suggest that you stay away from “export” models, which have more channels and power than legally allowed. Not only could you get in trouble with the FCC, but you could also create interferences on other legitimate stations or electronic devices nearby. You don’t need more than the legal 12 watts SSB to reach stations thousands of miles away. Forty channels isn’t much, that is true, but I would rather operate legally with these limitations than face a fine I probably can’t afford.

We are now at the peak of solar activity, which creates ideal propagation conditions. We will probably get decent propagation for the next couple years. The solar cycle lasts eleven years. It was at it’s peak in 1980 when I bought my first CB, and again in 1990 when I bought my second one. It is peaking again right now, isn’t that convenient! You can still make long distance contacts during low activity, but it doesn’t happen as often…

Here are the current conditions (look at 11m for CB):



 
My choice of “newest” radio is the Galaxy DX 979.
Galaxy DX 979

Galaxy DX 979


It is a legal radio, CB of course, so you can use it without any license. I’d like to replace my “shorty” antenna by a Solarcon Imax 2000 (24 feet long), but that will have to wait. Like I said, the antenna is everything. For situations like camping or temporary base operation, I would get a “Double Bazooka” wire antenna. For a car, the K-40 is a proven design, and you don’t have to drill a hole in your roof! Don’t forget to get an SWR meter to tune your antenna (if your radio doesn’t have one built-in) or you could fry your transmitter.

A good channel to listen to is 38 LSB, here is a video of an operator making contact from PA to NC:



 
My old transceiver will be mothballed in a Faraday cage, waiting for an EMP Doomsday that may never come. If it did happen, information would be worth it’s weight in gold !? ;-). A good battery and a 12v solar panel would provide power. With all electromagnetic interferences gone, the radio frequencies would be very quiet, but for the few prepared individuals still on the air with working transmitters.

I clearly remember twenty years ago, or ten, even five. I did not then have any of the concerns I have today. The future was bright with no clouds on the horizon here in the United States. I don’t think the world is going to end this December twenty first, or next year for that matter. The Mayan who wrote his calendar must have been tired that night, and his wife was complaining about how much time he spent on it, so he probably just thought it went far enough and left it at that.. I am no doomsday preacher.

There is a certain unease among us however. The media is broadcasting multiple disaster and prepping shows. The economy isn’t going better. Five years ago, I had five ounces of gold, bought for less than $1500. Today, those coins would be worth close to $10,000. Only five years later! I am still hitting myself on the head for selling them before the increase. We may wonder why the value of the dollar hasn’t gone down by a factor of six or seven. The government is trampling on the constitution. One only has to watch foreign agencies news, not the dog-and-pony show we have here, to start worrying. Watching CSPAN can be more entertaining than “Doomsday Preppers,” and certainly scarier. Five years ago, there were few signs of trouble, none before September 2001.

So, you have a bit of food and water stored for rainy days, a generator with a few gallons of gas, your bug-out bag, and a .22 with a case of ammo. Will you be missing anything when disaster strikes? Yes, information. With the power down, no cell phones, land lines or Internet, you might be in total darkness has to what caused the blackout. Should you stay put? Is it safe? If you need to leave, where should you go and what route is the safest? If you happen to be away from your family, how do you get in touch with them? Where are they? Are they all right? Information in a disaster situation is crucial to you and your family’s survival.

I bought my first radio in 1980. It was a forty-channel CB. Back then, conversations were interesting and civil on the 11m band (27Mhz). You could talk to your neighbors, make new friends. People were helping each others. Truckers used them to inquire about road conditions and get directions in unfamiliar towns. Sure, we had some jerks, but the Citizen Band was self-policing. Ten years later it had changed dramatically. I worked one winter as a security guard, and wanted something to keep me awake at night on the job. So, I installed a 200+ channels CB radio in my car. There was still some good conversations going on, but mostly, CB had become pretty lame. I did manage to make a contact across the Atlantic once, using SSB (single Side Band), but usually, range was around ten miles.

A CB radio (AM) today is a poor choice of emergency communication in the U.S. Range is typically only a few miles and forty channels get crowded very fast. Radios are cheap however, and it is certainly better than nothing. “CBers” are no longer organized in clubs. Base stations are rare these days. Even truckers have replaced their CBs by cell phones and computers. The level of the conversations is rather low; you might not want your children to play with a CB radio… It is unfortunate, but the Citizen Band has become the black sheep of the radio world. One exception which could make CB a good choice is if you buy an SSB mode radio. Single Side Band is comprised of USB (upper) and LSB (lower) side bands. These modes offer more range, and even “skips” on the ionosphere, for very long range communications. Conversations on SSB are definitely more civil than on AM. Even with the legal 12W maximum power, you can reach stations thousands of miles away.

You probably own at least a pair of FRS (Family Radio Service) handheld radios. They are very limited in range, two to three miles typically. Do not believe the advertised ranges of twenty or more miles. That may work over water with perfect conditions, but don’t count on it. GMRS has slightly more range, but requires a license (no exam). They are useful to keep track of kids and family members within a small perimeter. Given their prices, you should get a couple pairs. Handhelds would be very useful for a neighborhood patrol, though anyone can listen in. There are better options, but in a pinch FRS can be a good thing to have.

There is no radio solution available to the public without a license that will provide you with enough range to contact anyone beyond line-of-sight. While receiving is important, and having a good short-wave receiver is a must, you still might need to call for help or inquire about a situation, or just contact a distant family member. The solution: HAM radio. Licenses require an exam, but it is easy to get started with a Technician license. It will only cost you a bit of study time and $15.

Now, a bit of technical information is needed. Transceivers (transmitter/receiver) are basically of two types, those that can broadcast beyond line-of-sight (thousands of miles) and those that usually can’t. It all depends on frequency. 6 meter wavelength and shorter are very good for local and medium range communications, from a few miles to around 200 miles. Longer wavelengths, up to 160 meters can bounce off the ionosphere around the earth. 6 meters is smack in the middle. Sometimes it will bounce, and sometimes not, but it does it all, hence it’s nickname, “the magic band.” The most common is the 2m band. As a “prepper,” I am mostly interested in the 2m and 10m bands, with my eyes on 6m. Longer than 10m, and you run into antenna length problems. Antennas become very long, and need to be strung horizontally between poles or trees. Not very discreet or practical in a survival situation, though possible with a bit of ingenuity. The basic technician license allows you to transmit on 10m and above 30Mhz, which includes the “magic” 6m band, 2m and 70cm.

By becoming a licensed HAM operator, you also become a valuable member of your community who can provide information when every other means are down. You would be the first to know what’s going on.

For anyone wanting to buy a do-it-all radio, I would suggest looking at the Yaesu FT-817ND. It is a small portable, multi-band transceiver which runs on batteries or external power. As far as handhelds, look into a couple 2m units like the Yaesu FT-270R for local traffic. Those are though and waterproof down to three feet for thirty minutes! At around $135, they are a bargain. I own one and I am very happy with it. You don’t need a license to buy them, but you can’t legally transmit, though anyone can legally use any radio in the United States for a life-or-death emergency. You would be missing out though by not getting a license, being it so easy and cheap, and get to know your fellow local radio operators.

As a prepper, you should have a spare and store it inside a grounded metal box for EMP protection (MUST READ article!). Make sure the radio is inside a dry cardboard box inside the metal one, and none of it’s parts touches the metal. Surplus military ammo cans are great for that purpose. I would also include a solar charger.

A radio is as important as your Coleman stove or rifle. You might not want to get into local HAM conversations, or even long distance contacts, but when you need potentially life-saving information, you will be glad you have one stored in that ammo can in the garage and that you know how to set it up and use it…