IF YOU HAVE THOUGHT ABOUT "PRESERVING RADIO," CONSIDER BEING A MEMBER OF AT LEAST ONE RADIO HISTORICAL SOCIETY. I AM A MEMBER OF THE "ANTIQUE WIRELESS ASSOCIATION" THAT HAS A FABULOUS MUSEUM.

TOPICS ON THIS WEB PAGE --

1. MY "NEW" HAM STATION TABLE

2. THE "LINDSAY" EXPERIMENTER'S 1938 VINTAGE SUPERHET -- ALUMINUM FOIL, CARDBOARD AND ALL

3. SOME HOME BREW PERIPHERAL STUFF TO MAKE HAM LIFE EASIER

1. MY HAM STATION (NEW) TABLE

Pictured above is my ham station operating niche, in an 11 X 10 room that doubles as a small library and the family computer hub. This setup has a number of useful features for those who have little space, must operate with family around and must also keep down the nerdy side of the hobby, notably wires going all over the place. I rebuilt my original table by adding paneled side legs with caster wheels on them. Now I can roll out the table from the wall and easily work behind it, routing the wires where I want.

As for the “back side” of this setup, I have attached hooks, loops and other wiring harness helpers so that I keep audio, 12 volt DC, 117 volt AC, coax and other control wiring in discreet lines. Still, it ain’t pretty, but nothing is visible from the front. The table top is simply a kitchen counter top with the back splash removed just to leave a ½ inch lip back there to keep things from sliding back too far. I constructed an all wood “I” beam of 1X6’s and 5/4 strips for the top and bottom of the “I”. The beam is extra secured to the side leg panels by 45% strips of 2X4, angled in. It extends the entire length of the table and is situated about 2/3 of the distance back, to take the weight of the equipment, straight on. The legs are simply 2X4’s front and back, each side, with birch veneered ½ inch plywood (caster wheels on the bottom of each 2X4 upright. A sliding keyboard tray is screwed into the underside at the place where I need to sit.

On the topside I have built a scaffolded rack to fit the equipment I had in mind, and a couple of cubbies for general stuff to come along later. I have one large bay at the bottom left to accommodate almost any larger transceiver. The rack simply sits on top of the table. On either side it sits about ½ inch in from the right and left edges of the table. It ain’t-a goin anywhere. On the inside walls of the rack, and at the back, I have two 12VDC busses to accommodate fused power.

2. THE NEW GUY: THE HOME BREW SUPERHET TAKEN FROM BOOK 5 OF THE 6 BOOK LINDSAY SERIES ON BUILDING HAM GEAR:

(On my "first night out" I easily pulled in an OK2 - Czech Rep. - and an XE2 - Mexico - at RST 579. The LO tuning - at right - is a bit touchy, but I will re-tap the coil for more bandspread.)

Surprise! It really works, and it's really true that if you take your time and attend to detail - getting all the IF solenoid coils identically wound and the cardboard enclosures made to the same dimensions - you WILL be able to align the 80 meter receiver and you WILL pull in DX signals with a decent 80 meter antenna and an antenna tuner stuck in between. For a ham who understands that things can be touchy in the home brew world, this is an adequate 80 receiver to do CW, SSB and AM QSO's. Break out your old XMTR, build the simple transmit-receive switch featured in the Feb. 2012 QST and you will have loads of fun.

I spent more than I should have when getting this rig together. But after the fact, I must admit that I could have scrounged more screws and bolts from my ham stash to build it for pennies. What do you REALLY have to buy or put up with? First, you or the spouse have to work through 6 rolls of Saran Wrap to get the coil forms. When you buy the last one, stop down the isle and pick up some Reynolds Heavy Duty wide aluminum foil. Visit your version of the mega-hardware store and buy small lumber pieces: 3/4 inch plywood, or 1/2 inch; scrap wall paneling board; a short 1X2 inch length of wood; a fiber board or plywood board about 18X30 inches; a brand new, empty metal gallon paint can; a 3ft length of 3/8 inch aluminum rod; waterproof wood glue; an Elmer's Glue can of rubber spray cement, and that's about all.

(You HAVE TO build a coil winder before you even begin the radio stuff. Be sure to give the cardboard forms two coats of shellac, inside and out, after you have dried them out a few minutes in a warm oven. Then, immediately shellac in the garage and hang them up on little hooks to dry.)

Then, you will need to look in your silly-man collection of utterly junky things you picked up at hamfests: three variable caps for tuning, each between 100 and 125 pfd at full mesh; four small varicaps (8 - 70 pfd) or the small variables out of old commercial radios that were used for tuned circuits (up to 100 pfd max); four silver mica caps at about 50 pfd, and a handful of smaller values (which you probably won't need); old soldering binding posts from junked old radios (get ten of them, some with 5 posts- with one to ground); hook-up wire of different colors from old radios; one 4-pin coil form and one 5 pin coil form; also one bakelite tube base with 4 and one with 5 pins (these will be for the antenna coil and the Local Oscillator coil); some old tuning knobs no one wants anymore; some scrap aluminum sheet or copper PC board sheet; four large rubber/plastic "feet" to go under the radio's large breadboard; about 30 or 40 feet of 22 guage insulated magnet wire for the two coils described; a LARGE roll of insulated magnet wire, such as #28 or #30 (the 5 solenoid coils will require 348 turns each!); real crystal earphones, two or one ear for high impedence; female binding posts and male pins - about 8 of each - any color; AND OF COURSE three tubes - 6SA7 (metal) - 6SK7 (metal) - 6C8 (glass tube with the grid connection on the tube cap).

(Cut each side piece separately, secure them with blue painter's tape and then glue the seams on the inside with an Elmer's type wood glue that won't dissolve in water - although you won't be floating these on the bounding main.)

You will need to buy three plastic 8 pin bases normally used for relays. These have a minimum of metal in them and are great for breadboard mounting. If you can't find the magnet hookup wire at a swapmeet, be brave and break open several HV transformers to scrounge the HV secondary wire. It will work!

(Notice the large space from the top of these IF coils to the future top of the enclosure. These are the "hot" ends and should not have metal close by, to maintain a high Q for each inductor. I cut two inch square openings for the necessary cross-talk. It worked! These baffles must be grounded.)

(Also, I used wooden toothpicks to center these coils into the bases before I secured them with hot glue. I also built square spacers for the tops. Tight as Fort Knox.)

First, from Lindsay's book 2 build the test oscillator to set at 400 kHz and the separate but simple audio tone generator. You really need these. (You will be able to get these going, and align using a newer general coverage ham receiver tuned to 400 kHz. If you just can't get this to work and another ham can't help you do it, then stop right there and call it a night for this project.

(Here is the alignment oscillator - identical to your future BFO oscillator. Don't ground the bottom of coil or ground the ground of the PC board for the circuit to the aluminum of the enclosure. BUT, you will ground the bottom end of the BFO to its enclosure, when you come to that. The little computer switch box houses my quickie audio generator.)

But hey, you will do it. Suggestion: the audio generator calls for a dual potentiometer. You won't find it. Instead, make up two sets of resistors in parallel, both at exactly 750 ohms, or thereabouts. Insert them into the circuit where the dual POT is to go and you will have lift-off. No need to vary the audio pitch anyway.

(You will ask yourself, "Why did I get into this? I thought I was building something electronic, and here I am, a remodeler.)

You will need to give some time, however to your method of mounting the variable caps for the antenna tuning and the Local Oscillator. I did not want to fashion metal to screw to my copper front panels, so I used wood blocks. I made many mistakes, but stayed with the original blocks, altering the drilled holes. In the end, the blocks were too thin (!), so I added neoprene washers to the bottom to bring the shaft up to my pre-drilled holes.

(When you hook the wires to the power supply to test, be happy with 90 volts B+ after warm-up, or even 75. The PS has NO voltage regulation, so I re-resistored the first voltage divider resistor down from 2000 ohms to 300, giving me about 122 volts. Then, with the radio as load, I measured 95 volts. Notice the purple 6.3 volts for the heater; they are twisted to reduce hum - I have minimal to no hum ! Other plug-ins here are for different B+ voltages for other experiments. My antenna is an end-fed 140 ft wire with a 7 ft counterpoise and a tuned circuit, fed with coax - used primarily for QRP.)

Build the power supply last. You will need to find the two appropriate transformers, each to handle minimum 1 amp: 117 to 12V-center tap; and 117 to 9 volt center tap. You will have to find an old beat up chassis, a couple of 117 volt power switches; some circuit tie in posts; two 10 MFD electrlytics at MINIMUM 250 volts, four 1N4007 diodes; and a variety of 5 or 10 amp wire wound resistors (2000, 1500, 1500, 1000, and some at 100 and 150 for experimentation; a fuse holder; a power cord, the older computer plug-in type; and the appropriate male connector for the chassis hookup.

(Early in the test phase of the power supply, I measured 117 volts AC and got out 143 VDC, which would give me a much higher voltage than 90, after the voltage drop with a load. So, I exchanged the top right 10 watt 2000 ohm resistor in the lineup for two 150 ohm 10 watt resistors in series. That lowered the no-load voltage to 95 volts with the load. Caps are 100 MFD at 450 volts from my new-old-stock box. The 117 volt DPDT - use only one side - is to switch between higher and lower B+ voltages, since you use the 9 volt center tap for 9 or 4.5. Nifty. PS runs cool. Notice that I grounded the line ground wire - green alligator clip - because the old VARIAC isn't set up to do that. Stay safe with high voltage !! By the way, I am running my radio with a .5 or .75 amp fuse, nothing big. You want it to blow if there is a problem.)

This project shows you just how easy it is to build as superhet receiver and get it running. BUT, be prepared to use your non-electronic skills, like persnickety cardboard construction, easy but persnickety, lots of looking and thinking (much of which is useless for this project - it WILL work); attention to detail, as though you were building the first Mercedes - this is just so that you won't think the problem is in your construction, when the critter doesn't want to fire up at your first command. You will KNOW what you did right (for example, you did NOT ground the ground end of the alignment oscillator coil to its aluminum sheeted enclosure). You will probably have to attach the alignment oscillator directly to the IF amp (6SK7) through a .01 ceramic cap to assure signal input, but then it will happen! You will tune the appropriate varicap and BANG!, the signal will jump out at you! ALL IN ALL, I bet I could build an identical superhet schematic on an old junk aluminum chassis, using old 455 kHz IF's and a scrounged BFO in about one fourth of the time. However, I wouldn't then have this wonderful behemoth to show off and then worry where I was going to store it in the basement.

Yes, Virginia, you could go back and back to the hardware store for every screw to make it just so-so, but in the end you would know you could have used your junque boxes at home. Happiness is in one's own basement, work room or garage.

What will you get out of this project? First you will see just how utterly simple a working superhet receiver really is. Second, you will see and UNDERSTAND how a receiver works (except that feedback part - mathematically speaking). Again, you will forever lose your fear of tackling a project that self-styled geeks should think twice about, before plunging in. Next, you will see for yourself where a circuit can be improved. You will understand the placement of "bypass" capacitors, understand finally why an old AM radio has a double ganged tuning capacitor - figure it our yourself - and that you can run the radio at 65 or 70 volts DC for the B+, when the book says you need 89 volts. Last, you will come to value your odd parts cataloguing system you set up a couple of years ago to find out where those resistors and capacitors were, the screws and nuts, the washers and spacers.

3. HOME BREW STUFF TO MAKE LIFE EASIER - AND "FUNNER":

You might be interested in the Home Brew stuff here. Some of it is really useful:

• NEScaf Audio Filter (in the cream colored computer firmware box on top of the HW-9, to the left of the K-1)
• SWR Null Meter (in a black Ten Tec enclosure; see Paul Cristensen's W9AC, article, QST Feb.'10, pp. 30-32, on level 2 left of blue Sierra Norcal); EVERYBODY should have one of these in the shack; it keeps tuner-upper QRM off the band while you are matching to the antenna; it "reads" the antenna, but sends out only about 250 mW in the process; the rest of the power goes into a handy dummy load; switch it "off" and you are on the air!
• Sierra Norcal QRP (using a FAR Circuits board; in the home made blue enclosure, on level two, left cubby).
• Audio Break-Out Box (in gray Ten Tec enclosure; see ARRL Handbook 2006, pp. 19.26-28; 8 inputs, 5 outputs, on level 2 second cubby from the left); I can control audio from any rig with volume control; outputs to speaker; earphones; NEScaf audio filter; computer; 20 second revolving audio recorder; I have no ground loop problems with this.

CW Breakout Box (3 photos)

• CW Break-Out Box (using 5 opto-isolator switches, on level 2, left side of right hand cubby, next to the MFJ 492 Keyer); it is a mystery to me why no one has developed and published such a device; uses 12VDC to power the switches, 78L05, an on-board N0XAS pico keyer; inputs are from hand key, bug, paddle, computer (using CWType) and outboard keyer (yes, you can switch between inboard and outboard keyers); each of the 8 outputs is switched - a bit of over kill, but it is extra isolation, and needed(!); one of the outputs is double switched, to be used for grid block keying; computer is also isolated with a toggle switch.
• Not really home brew: I use the MFJ4726 6-by-6 antenna/transceiver switch and match it up to the Delta4 antenna switch - reversed - along with a hidden 3-way coax antenna switch to obtain 9 rig coax inputs to antennas. This eliminates the need for messing around with wires.

On the left of the table in my main photo at the top of this web page is another table where my other rigs go that have been brought to life in the bowels of the QTH and need to have a test run. A Drake 2B Receiver sits there when nothing else is being tested or played with. Have fun with your own ideas.

Bill / AA2YV

-- who also happens to be: Secretary, Antique Wireless Association (and Museum, Bloomfield NY)