Friday, September 28, 2018

We Used To Build: Rolling Your Own Radios, Part 1


The first ham radio book I bought when studying for my license had the schematic for a simple 80 meter CW transmitter using a 6LR8 tube. The schematic looked something like the one above. This was back in the early 1980s when they expected someone at Novice Class level to be able to build a simple CW rig with the help of an elmer.

In an age where the Maker Movement is rapidly gaining popularity and adopting the manifesto of If you can't fix it, you don't own it, the original DIY hobby (ham radio) has degenerated into a bunch of appliance operators using equipment made in totalitarian countries.  When the balloon goes up, all the no-code, test-pool memorizing, Extras who passed all three tests in a single sitting are going to be left out in the cold with their Chinese dual-band HTs, unless they get up to speed.

What do you need to do?

  1. Find the local elmer who has had his license for the past 60 years and still runs something like a Harvey Wells Bandmaster or something he built himself.
  2. Put together your library.
  3. Get radios that you can actually fix, as opposed to appliances that become worthless if they break because they can't be fixed.
  4. Build a kit or three.
  5. Learn the techncial aspects of ham radio.
  6. Learn CW.
  7. Graduate to rolling your own radios.
Good elmers are hard to come by. The good ones are at least in their 70s, and usually older. They still exist, however. The hardest parts for many of you are going to be a) getting the gumption to actually put the effort into looking for one, and b) not coming across as a total cock-walloping asshole. Oh well, as Frank would say, "many are called and few are chosen."

There are plenty of online sources to build up your reference library, but you'll want a few books in hardcopy format. Start with an ARRL Handbook from the late 1960s up to the 1980s or 1990s. Older and you'll get into tube gear which is cool, but probably not something you want to start with. Newer starts getting away from sold state, discrete component, thru-hole PCB construction that's easy to begin with. Shown here are ARRL Handbooks from 1969 and 1975. My oldest ARRL handbook is from 1946. The newest is 2013. Most in my collection are 1970s and 1980s vintage. Don't spend more than $10 on one, $5 for the digest-sized ones.

Second book I would get is the ARRL's Experimental Methods in RF Design. Yes, some consider it an "advanced" text. They are idiots. I have some engineering books if you want to see "advanced." The classic reprint edition contains a CD with PDF copies of Solid State Design For the Radio Amateur, Introduction to Radio Frequency Design, and a whole bunch of good BIY articles from QST and QEX.  Between this and a couple late-edition ARRL Handbooks, you are off to a good start. I could go on about good books for your library, but I already did in my book, and by now you should have downloaded a copy.

Many of the references at the end of this article will direct you to homebrewing pages with lists of suggested tools and test equipment. I would start with basic electronic hand tools and test equipment: different sizes of phillips & slotted screwdrivers, wire cutters, wire strippers, a 25-watt soldering iron, solder sucker, various pliers (needle nose, etc.), wrench set, nut driver set, VOM, frequency counter, power/SWR meter, dummy load, antenna analyzer or grid-dip meter, and signal generator. This is stuff any ham who has gone beyond owning a VHF/UHF HT should have and be familiar with.

One of the best things I've read about homebrew ham radio was the Frank and the Five Meter Liberation Army (FMLA) story series by the late Michael N. Hopkins, AB5L/SK. Here is a synopsis by the author:

"A man of the '30s awakens one night in the '90s (episode 13) with a new mission: recapture 56-60 mc. He forms a Five Meter Liberation Army from his mobile home in a Barrio trailer park run by Tom Joad of Steinback's Grapes of Wrath (episode 9), and soon draws a decidedly uncolorful bodyguard (episode 7). A six foot tall half Mexican stockbroker named for Ayn Rand makes him rich and a demonic white ferret and a half-siamese cat become his familiars. (episodes 10 and 9). The leader of all this, called only "Frank," settles down in the narrator's basement to be joined by Maj. Armstrong (episode 8), Hiram Maxim (episode 23) and one-time pals Carl and Jerry from the 1950s Popular Electronics (episode 25). His huge 1940s sedan, with contemporary plates, is immune from police (episode 13 et seq) and his breadboarded electronic creations recall those distant days when a ham built his own rig and could "fix a radio." Of course all this is crazy. No one builds anything anymore and the other things Frank stands for, like self- reliance, tolerance and a generally Boy Scout viewpoint are simply out of step. Frank knows that too (episode 20), but he does not care. If you're standing in the middle of the road and see a big brown Frazer coming at you, you better jump - one way or the other."
The story series is chock full of references to some really good homebrew articles and authors. ARRL members can access the full collection of QST back issues online, and all the back issues of 73 Magazine can be accessed via archive.org.

No one expects you to be able to roll your own right out of the gate, but instead for you to start learning about RF and electronics, upgrade to rigs that are built in such a way that they can be fixed when they break, and maybe build a kit or two.

Some of the better values in used gear are old-school kits that were previously built. Here we have a late 1970s to early 1980s vintage Heathkit HW-8 QRP HF transceiver. It puts out a couple watts CW on 80, 40, 20, and 15 meters.
A lot of these found their way into field radio kits over the years.A lot of these found their way into field radio kits over the years.


By now you might be familiar with the late homebrewer and ARRL tech writer Doug DeMaw W1FB/SK. He founded Oak Hills Research, and the (now discontinued) QRP Explorer is one of his designs. This is a simple monoband QRP CW transceiver, and an updated kit is available as the OHR-100A.
That's the inside of a QRP Explorer II, and it shows you what you want to look for: discrete components and thru-hole PCB construction. A ham operator built this with basic tools and test equipment I already mentioned, but what if you want something simpler as your first project?
A QRP transceiver that's the diameter of a tuna can from Rex at qrpme.com. Toss it with a 8AA battery pack and 40m dipole into the pocket of your field smock, and you are good to go.

All of these rigs share a few things in common. They are all HF rigs. One is 4-band, and the others are on the very popular 40m ham band. They are all CW rigs. CW remains the best way to communicate under austere conditions. It works well with QRP ops, and does not require a PC (greater electrical requirements) to decode the signal. They are all kits, designed to be built, tuned-up, and repaired with test equipment and knowledge any self-respecting ham should have. They are all QRP rigs. That makes them more portable in size and power requirements. QRO is great until you have to lug it around with all it's support equipment. For grid-down and down-grid type commo, QRP is what you should be looking at. While QRP will reach across the globe if  band conditions are decent and you do your part, you are really more interested in reaching out to your AO and surrounding regions than you are in working DX.


To be continued...

References:

http://www.arrl.org/shop/ARRL-s-Low-Power-Communication-with-40-meter-CW-Cub-Transceiver-Kit/

http://www.arrl.org/qrp-projects

https://www.mfjenterprises.com/

https://www.qrpkits.com/

http://www.qrparci.org/links/qrp-kits-bits-and-supplies

https://www.qrp-labs.com/

http://home.windstream.net/johnshan/qrp_ss_rigs.html

http://www.ozqrp.com/

http://qrpme.com/

http://www.ohr.com/

http://www.w1wc.com/homebrewing/

http://www.af4k.com/hamlynx/hamhomeb.htm


http://www.ac6v.com/homebrew.htm

http://www.wa0itp.com/crystalsetsssb.html <- This


1 comment:

  1. Thanks for the motivation Sparks. Appreciate what you do here.

    ReplyDelete