Without fail, daily at noontime, on 7.204 MHz, the Jefferson Noon Net Convenes. The name Jefferson in itself is an interesting side trip. Long ago there was a group of Californians who wanted to split California in half. The lower half (where all the coastal lefties live) would retain the name California and the upper half, for those of the other persuasion would form a new state called Jefferson. I suspect some of the founders of that movement were also hams. Several years ago a ballot petition initiative was underway to make that happen but it did not go forward.
I split my shift at the Board and Care Facility so that I am home during lunch time. Thus, I usually tune in this net if only to have some connection with ham radio, slim as that is. Today the net is non-political and offers signal reports and takes general information. If you check into the net, you are usually asked to answer the question of the day.
Within the past week here were two of the questions. 1) Did you ever build a Crystal Set? and 2) What was your first ham rig you put on the air?
The day the Crystal set was the topic of the day I did not check in but in case you wonder what a crystal set is, it looks like this.
For just a handful of us, our very first radio may have been a Crystal Set. Batteries were not included or required.
The schematic is pretty simple with a tuned network (L1 & VC1) connected to an antenna and ground where D1 takes the RF signal from the tank network, rectifies it and sends it to a pair of headphones.
Don't get too excited as this only works on AM signals as those signals include a carrier for demodulation. Without a BFO this simple setup won't copy SSB or CW. Now if you included two diodes arranged as a product detector plus a BFO it will copy SSB or CW as in a direct conversion receiver.
Now D1 in the early days was a chunk of Galena and it was held in a lead cup like holder and a Catwhisker wire probed the Galena until a "hot spot" was found. At that point you would hear either voices or music. No Batteries required.
Galena Cup
Later the D1 was sold as a fixed unit and one of the most popular fixed diodes was from the Philmore Company. Think of a stack of 10 quarters with two screw terminals on top. Later we had the 1N34 Germanium diode for D1.
In our 1st photo it looks like a Toilet Paper Roll wound with many turns of fine wire (#28 or #30). I have doubts about the coil in the photo with the slider wire to form a tuned circuit.
Real Crystal sets had a Quaker Oats Box instead of the toilet paper roll and you first had to soak the Quaker Oats cardboard cylinder in many coats of Varnish to make it stiff. Next you did a trial run with the slider over the coil to just barely nick the wire. Then with a piece of fine Sandpaper folded over you followed that line to expose the wire BUT you were careful to not go so deep as to have a 1 Turn coil.
So OK, why the slider? The tank network can be tuned by either varying the capacitor VC1 OR varying the inductor L1. It was cheaper and more easily done by homebrewers to vary the inductor.
[Some builds using the Quaker Oats box had the box itself as the enclosure like this one. Note the Catwhisker and Galena Crystal on the top of the box. The Slider is mounted on the rod.]
If you lived in a remote area, to copy the Broadcast Band you needed lots of wire in the air. If you lived close to a transmitter site, then the antenna was less of an issue.
My dad as a kid built many crystal sets and after WWII when he was home from the war, he built a Crystal set and let me listen to the magic of radio. It was about 1947 and I was like 6. The transistor would have to wait a year before being invented at Bell Labs. In 1950 we moved from an apartment to a home and then things got serious about building crystal sets with proper antennas. I was fortunate in that KDKA in Pittsburgh, was only 20 Miles from my home and was running 50KW clear channel. I found that by connecting the antenna to my exposed bed spring mattress I could copy KDKA on a set of Brush Headphones.
Every night I would fall asleep listening to a talk radio program on KDKA (The Ed and Wendy King program).
I was never very successful in perking up the tuning so you could copy other stations in the Pittsburgh area nor turn it into a short-wave Crystal set. One of my ears has a kink in it and that was from laying on the earphones while I slept. In the early 1950's I took my newly built CK722 audio amp and installed that on the crystal set. Hey, my first transistor radio!
A radio using two CK722's
There are many radio enthusiasts who build and/or collect Crystal sets today. Some rare sets fetch thousands of dollars. As with our ham rigs some are pretty crude while others border on works of art.
So, the question for February 29th, was what your 1st ham rig was. I checked in with my Al Fresco SDR rig tickling the SB200 to 100 watts. I gave my call and name and said my 1st rig was a BC454 (80M ARC-5) for a receiver and a 6V6 on a wooden chassis and a single crystal on 3.709MHz for the transmitter. Still have the crystal and note that frequency was in the Novice band in 1959.
80M ARC-5 Receiver
[I bought my BC-454 (NIB) from Meshna Electronics is Malden MA, for $3.50 and the AC power pack which Sub'd for the dynamotor was$7.5o. A total of $11 bought me something more than a Crystal Set.]
A 6V6 (6L6) Transmitter from QST
The net control said I never heard of either one of those but that was a long time ago -- yes it was, about 65 years ago. Then I said I am using a homebrew SDR transceiver today and I could just imagine the question mark on his face -- a homebrew SDR -- you mean it is not an ICOM IC-7300? In the span of 75 years a journey from Crystal Sets to FT-8 and Homebrew SDR Radios. It sure is fun when you know stuff.
73's
Pete N6QW