Initial Comments:

 Introduction

Antenna and Mixer Input Components:

 Antenna Coil L1 and Mixer Coil L2
 Capacitors C1 and C2

Local Oscillator Components:

 Oscillator Coils L3 and L4
 Crystals
  Testing the Local Oscillator

Power Transformer:

 Power Transformer T1

Miscellaneous Components:

 Carbon Film Resistors - Through Hole
 Ceramic Disc Capacitors
 Lug Style Terminal Strips

Electronics Parts Sources

Mechanical Parts Sources

Coils L1 and L2:
Coil L1 (left photo) is wound on a coil form made from 1/2" ID CPVC plumbing pipe that has been lightly threaded on a lathe at 32 threads per inch. The primary consists of 3 turns of #23 magnet wire. The secondary consists of 15 turns of #23 magnet wire separated 1/32" from the primary. Mixer coil L2 is identical to L1 except that it has 4 turns on the primary.

When measured with an MFJ antenna analyzer, both secondaries measure 3.74 uH at 10.1 MHz and resonate at 10.1 MHz with 66 pf of capacitance. They measures 4.47 uH at 14.0 MHz and resonates at 14.0 MHz with 28 pf of capacitance.

It isn't necessary to have the grooves cut in the plumbing pipe or to use #23 enameled wire. As long as the correct number of turns is used and the secondary windings are spaced out over about 1/2" the coil should be fine. The primaries should cover about 1/8" and be about 1/32" from the secondaries.

You can test a coil by placing the secondary in series with C1 and use an antenna analyzer to make sure the combination resonates (zero reactance) at the frequency or frequencies of interest. Or place the capacitor and secondary in parallel and use a grid dip meter to make sure the combination resonates at the frequency or frequencies of interest.

Capacitors C1 and C2:
Capacitors C1 and C2 are 100pf units. Mine were originally made for screwdriver adjustment, but I epoxied a 1/4" shaft on to each of them.

These capacitors should not be larger than 100pf. If they are, the tuning of the ANT and MIX controls becomes sharp and difficult to control. On the other hand, they must be at least 75pf if operation on the 30m band is desired.

Oscillator Coils L3 and L4:
In this picture, coil L3, the 30m coil, is at top, and coil L4, the 20m coil, is at bottom right.

Coil L3 consists of 38 turns of #29 magnet wire close wound on a 3/8" diameter powdered iron core coil form. It has an inductance of 10.6 uH with the slug fully out and resonates at 3.21 MHz with a 240 pf capacitor across it.

Coil L4 is a North Hills 120-8 coil. It is rated at 3 uH -5 uH. With the slug in the middle of the windings it measures 5.54 uH at 10.24 MHz and resonates at 10.24 MHz with a 43 pF capacitor across it.

It is unlikely that you will be able to find coils or coil forms exactly like these. The main thing is to, by experiment, come up with some kind of adjustable coil with a capacitor across it that resonates at the crystal frequency. As long as the coil/capacitor combination resonates at the crystal frequency, it should be fine, but test it as shown below.

Crystals:
In this picture, crystal Y1 (3146kHz) is on top and crystal Y2 (10240kHz) is barely visible underneath. See the page on choosing crystal frequencies to see why these frequencies were chosen.
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Testing the Local Oscillator:
Before permanently mounting any of the local oscillator components it is highly recommended that you breadboard and operate the oscillator with the actual components being used.

The oscillator can be breadboarded using a standard white breadboard. Temporary wires are soldered onto the tube socket and plugged into the breadboard. The oscillator can be powered with the converter power supply or with a bench supply and a dropping resistor to reduce the voltage going into R8, the 1kohm resistor, to about 125V.

Proper operation can be verified by connecting a wire loop to a frequency counter, grid dip meter (in detect mode) or oscilloscope to pick up the signal. Do NOT make any direct connections to the oscillator because this may affect or stop its operation.

In this picture the 30m components are being tested. The large 3W, 47k resistor (yellow-purple-orange-gold) drops the bench power supply voltage down to 125V.

The blue and purple wires carry 6.3V AC for the tube filaments. The 30m coil and capacitor, L3 and C13, can be seen at top center. The 3146 kHz crystal is at bottom right.

Transformer Unrestored:
Power transformer T1 was salvaged from a gutted Heathkit VTVM. It was mounted on a printed circuit board, and as a result the leads were very short.

Transformer After Restoration:
After measuring the secondary voltages and determining that the transformer was suitable for the 6x2C, it was was cleaned up and extension leads were attached to the transformer leads. Orange was used for the filament secondary, red for the high voltage secondary, and black for the primary. Heat shrink tubing was used to insulate the connections.

Power Transformer T1:
After restoration the transformer was installed in the converter. As you can see in the photo, the transformer has Heathkit part number 54-23 stamped on it.

The approximate transformer ratings are as follows:
Primary: 120V AC
HV secondary 125V AC at 15mA
Filament Secondary: 6.3V AC at 0.75A

Carbon Film Resistors - Through Hole:
All of the smaller resistors in the 6x2C converter are carbon film through hole resistors. They are more stable than the older carbon composition resistors and are readily available from suppliers such as Mouser Electronics and DigiKey.

When searching for these at, for example, Mouser Electronics, be sure to specify that you want carbon film resistors - through hole. Otherwise you will probably get listings for the surface mount resistors.

The ones I used in the 6x2C converter are the Xicon brand from Mouser Electronics.

Ceramic Disc Capacitors:
There are many ceramic disc capacitors in the 6x2C converter. They are readily available from suppliers such as Mouser Electronics, DigiKey, and Surplus Sales of Nebraska. A rating of 500V or 1000V is typical for these.

Terminal Strips:
Building vintage equipment is impossible without the use of phenolic lug type terminal strips. They are used throughout the converter to mount components and to provide wiring tie points. They are made in a wide variety of styles. Different numbers of lugs are available and the lugs can be grounded or ungrounded. In the photo at right a 3-lug terminal strip with a center ground connection is being used. On this strip the middle lug is grounded and the outside lugs are ungrounded. They can sometimes be found at hamfests, and, as of July 2023, these terminal strips were available from Surplus Sales of Nebraska, Antique Electronic Supply, and RF parts at the following links:

Terminal Strips at Surplus Sales of Nebraska
Terminal Strips at Antique Electronic Supply
Terminal Strips at RF Parts