Where would amateur radio be had Heathkit not produced the first really good gear that they provided in the 1970s and before. By todays standards these old rigs were not so nice, but for their day, they were the affordable source that amateurs turned to. Many of these are now idle and have become collectors items just for old-times sake. More often than not, the only real problem is that the frequency stability and operating convenience is not anywhere near that of modern radios. On the other hand, if you ignore this glaring shortcoming, they have a nice operating feel. It all comes down to the VFO or LMO in the SB- series. If the VFOs and LMOs could be improved, these would be nice rigs again. Well, the N4YG DDS system was designed especially for this purpose, to be integrated into the old Heathkit gear. When LMOs and VFOs are replaced wilth the N4YG DDS system, it opens up a whole new world for these old radios, providing not only stability never thought possible and features that these old boat anchors never had. Features like dual VFOs and Split operation. The features provided by replacing the VFO or LMO in a Heathkit transceiver, receiver or transmitter with N4YG DDS system are:

- Dual VFOs
- Outstanding Stability
- Split Operation
- No Moving Parts (Other than the incremental encoder)
- Little Change in External Appearance
- Installation in a Several Hours
- Receiver Incremental Tuning +/- 1.5 KHz
- Variable Tuning Rate for Fine Tuning and Easy QSY
- Operation from the 12.6 Volt Filament Supply
- Use of the Existing Zero Set Button to Control VFO A or B and SPLIT Operation
- An Integral Liquid Crystal Display (LCD)
- A Frequency Readout Which Incorporates Band Information and is Accurate to Within 50 Hz
- Ability to Return to the Original Unmodified Configuration (But you will not want to return!)


Click here to see a short video of the HW-101 DDS in operation .

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The steps in the installation process for the HW-10x and SB-10x are as follows:

Remove the VFO or LMO



Install Zero Set Switch, RIT Pot, Incremental Encoder and LCD

Relocate the Buffer/Amplifier (HW-10x Only)


Construct and Mount Band Sensor


Mount DDS PC Board, Connect Wires and Connect Cables


Look at this really neat installation in an SB-102 by Steve Scoggins, N9HE . Your own ingenuity can produce stunning results.

What a nice job on this SB-101 by Robert Russell, WD4PAQ. Beautiful rig. Understand it is working nicely for Bob.

Here is a great job with a SB-104 by Ulrich Graf, DK4SX. No change in external appearance, but look at the nice job inside


For detailed Instructions for Installation in the Heathkit Gear click here.

A kit for installation in Heathkit Gear may be purchased for $170.

Some installations will require extra hardware, some of which must be fabricated by the installer. Band Sensor, LCD, Zero Set Switch may be purchased separately.
The kit includes:

- A Fully Assembled and Tested N4YG DDS Board

- An Optical Incremental Encoder

- A Cable Set

- RIT Potentiometer

- Parts for Constructing the Band Sensor

- Parts for Constructing the Zero Set Switch Fixture

For more purchase options click here to go to the Order and Price List page.

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