Heathkit - Very Accurate Digital Display DFD-2 DIY Kit- Processor and PCB

Description

You are bidding on just the 'bare bones' printed circuit board and a pre-programmed and thoroughly tested PIC16F628A processor - which when assembled from parts that the
builder has to purchase
-  will provide a very accurate display of the frequency of your SB / HW or HR Heathkit radio.  It's much better than the devices that just measure the VFO frequency alone because the PIC computer chip periodically measures the High Frequency Oscillator from which it subtracts the BFO and VFO frequencies.  With it operating,
you'll always know
exactly
where you are
- no guessing, cussing or interpolating analog dial division hash marks.
This is a proven, time tested design.
The PIC chip which comes along with it contains two  (switch or jumper selectable) frequency calculating programs.  One program provides 10 Hz accuracy with LCD updates 3 or 4 times / second.  The other program provides 100 Hz accuracy with updates about 10 times / second, and is much more preferable for fast QSY activities.
Note:
An additional enhancement worth mentioning (over an earlier, similar design once offered by another - now out of business vendor) is a new feature which updates the LCD display - ONLY IF the actual frequency has changed.  Simply put, continual and unnecessary display updates won't cause 'chirping' interference while you are listening on frequency.
Interfacing with your radio is easy, specifically:
- For Heathkit
SB-300, 301
or
303
radios, the display can simply be plugged right into the HFO, BFO and VFO jacks on the radio's rear panel.  Provide a source of 12 VDC and you're there.
- For the Heathkit
HW-104
, the display will work if the proper connections are made to the VFO (LMO), BFO and heterodyne oscillators.
- For the Heathkit
SB-100, 101, 102, 313, HW-100, 101
(
these are all vacuum tube radios
) - some minor additional work is required consisting of placing 27 pf capacitors on the cathodes of the VFO, HFO and BFO oscillator tubes, installing rear panel jacks, etc.
CAUTION:
- if you are unsure, unfamiliar or unable to work safely within a
tube radio
where potentially lethal voltages lurk, please don't consider this product unless you have a competent and experienced (often called an 'Elmer') helper with you.
I will not be responsible for any harm to either you or to your radio as a result of attempting this conversion.  If you have
any
doubts - don't try it.
- For the
Heathkit HR-1680
- the phono jacks need to be added tor the rear panel and two simple source or emitter follower interface circuits for the BFO and HFO oscillators need to be added (see the schematic) - 13 volt power is also available within the HR-1680 itself.
A complete schematic is attached as one of the pictures.
Please carefully review it.
Note: The
shipped
package
will contain a
reference
to my
website
which provides a
parts
list
and step-by-step
instructions
on
constructing
the digital display and
interfacing
it with your radio.
NO international shipping right now
. - No returns.
Once again, you are bidding on just the 'unpopulated' printed circuit board and a pre-programmed processor.
The other photos have been included to show how the completed unit may look after the required components are purchased separately.  Mouser, Digikey, eBay or even your junk box are excellent sources for the necessary parts.
As far as I know, this is the only kit of its kind.  It makes for an excellent project and it has sold well.
Check my feedback and bid with confidence.
Be safe and have fun!