(9V battery not included)
DFD1-Hammarlund
A custom version of DFD1   for Hammarlund radios.

Available options.

LED backlit display module
 

Any DFD is available assembled for an additional $20.00

With exceptional accuracy and stability

TCXO Reference Oscillator option included
  • Works for Models :
    • HQ-100 IF=455KHz 
    • HQ-105 IF=455KHz 
    • HQ-110* IF=455KHz/3.045MHz 
    • HQ-120 IF=455KHz 
    • HQ-129 IF=455KHz 
    • HQ-140 IF=455KHz 
    • HQ-145 IF=455KHz/3.035MHz 
    • HQ-150 IF=455KHz 
    • HQ-160IF=455KHz/3.035MHz 
    • HQ-170* IF=455KHz/3.035MHz 
    • HQ-180 IF=455KHz/3.035MHz 
    • HQ-200 IF=455KHz 
    • SP-110 IF=465KHz 
    • SP-200/210 IF=465KHz 
    • SP-400 IF=455KHz 
    • SP-600* IF=455KHz/3.955MHz

*Does not work on 6 Meter band

    Click model numbers in blue
    for installation suggestions.
    Do not have suggestions
    for models in black.
You simply adjust a 15 turn trimpot
until the model of your radio is
displayed ie: SP-600 . 
No other adjustments required.
(See TWEAK mode below)

It is easy and stable since
there is nearly a full turn of the pot 
per model.

For those models that are dual
conversion on some bands
DFD1-Hammarlund automatically
detects the band and changes the
IF offset. It has no controls.

DFD1-Hammarlund uses a 20 MHz
TCXO reference so it can be easily
calibrated by zero beating its
oscillator against 20 MHz WWV's
carrier.

Jumper selectable 10Hz/100Hz 
resolution.

Digital filtering to eliminate flicker
due to round off uncertainty.
 

TWEAK MODE
provides optional accurate calibration capability.
The frequency (F) to which the radio is tuned is computed as
F = Local Oscillator freq +/- IF freq

DFD1-Hammarlund assumes the IF frequencies shown in the chart above are the
actual IF frequencies of your radio.  However, some types use a crystal filter or
crystal controlled second conversion which make the actual IF frequency a function
of the frequency of those crystals which can vary a few hundred Hz from radio to radio.

A jumper on the PC board enables TWEAK mode. In TWEAK mode there is a 15 turn
trimpot which allows adjustment of the IF frequency +/- 12.8KHz in 100 Hz steps.

For dual conversion radios there is a separate TWEAK control for each IF frequency.

To adjust TWEAK mode, tune a known frequency (crystal calibrator etc.) for maximum
signal and adjust TWEAK control to cause correct frequency to be displayed on DFD.

PRICES: Available NOW

Complete kit $49.95 Add $2.50 S/H U.S.A. and Canada ($7.00 S/H foreign)


 Universal Interface makes it nearly plug-n-play (after you have installed it in a suitable cabinet)


OTHER possible connections
Several customers have reported success getting local oscillator signals from tube radios by wrapping a few turn of insulated wire around the tube.
Make sure the insulation can take the heat.

HQ-180

Most Hammarlunds use a 6C4 local Oscillator
(as in this HQ-180).
Connecting DFD1-Hammarlund to the cathode 
through a small capacitor should work.

You Don't even have to modify the radio. Just pull the tube,
wrap one end of the capacitor around pin 7
and plug the tube back in.
Run some RG174 out the back to the DFD.

Using a single diode to rectify the 6.3VAC filament supply
with a large (>100ufd/25V*) filter capacitor
you can power DFD and even the backlit display option.

*May have to use 1000ufd with backlit option
Here is another easy way WITHOUT using the preamp:
DFD coupled via two one-inch lengths of pvc-covered
hookup wire twisted together, at the oscillator tuning gang,
connected through 2 ft of RG-58 to the DFD. The twisted
wires read about 2pF on my AADE LC meter.
(I suspect this means right on the main tuning capacitor
section, C1c,  for the local oscillator.)
 NC-183D shows correct on all bands except 6 meters.
On 6 meters it shows a bit over 40mHz, but this does not vary when I tune the radio.

This is how the radio shown below was done.

HQ-180.jpg (59968 bytes)

Many of the Hammarlunds use a 6C4 in a Hartley oscillator configuration.  This should make them easy to tap at the hot cathode using as small a coupling capacitor as possible while obtaining proper operation on all bands.

HQ-100\110

HQ110.jpg (19685 bytes)

Try connecting to the cathode, pin 7 of V10.
Use as small a coupling capacitor as possible. 
Test on the 10 Meter band.

HQ-170

HQ170.jpg (7096 bytes)

Try connecting to the cathode, pin 7 of V12.
Use as small a coupling capacitor as possible. 
Test on the 10 Meter band.

SP-600

SP600.jpg (22624 bytes)

Try tapping first at the plate, pin 1, and if 
that doesn’t work try the grid, pin 6.
Use a 5pf coupling capacitor.

 

Another Hint for tapping signal on SP-600

Neil, I have my DFD1-Hamm kit (with preamp) working on my SP-600 now.
I found that inserting a pickup wire down into the tube shield (as one of
your customers did) did not provide enough signal on the single conversion
bands although it worked fine on the double conversion ranges.  My solution
was to remove the little metal cap that provides access to the LO alignment
adjustment and stick about one inch of insulated wire down into that
chamber.  It now works fine across all receiver ranges and does not appear
to affect alignment.  (My more permanent approach will be to leave the
original metal cap in place but drill a hole in its center into which an
inch of insulated wire can be inserted.

Jim

How Richard added a DFD1-Hamm to his SP-600.

dfd1h1.JPG (10503 bytes)

 dfd1h2.JPG (5517 bytes)

He used the BIGGY display option

and mounted it in a Hammond Plastic case.

dfd1h3.JPG (16953 bytes)

dfd1h4.JPG (12805 bytes)

He added a 1000uF cap to handle the backlite.
He used a rubber caulk to hold the display in a
hole cut with a Dremel router.
dfd1h5.JPG (15713 bytes) dfd1h6.JPG (15245 bytes)

He use one of the preamp kits and

Mounted it in a 35mm film container.
dfd1h7.JPG (12139 bytes)
The only real problem Richard had was too low a voltage
from the rectifier on the preamp board.
 
This was because he is running the filaments on a lower
than normal voltage because he had the power transformer
on a higher than normal line voltage tap.
 
He solved his problems by using an external power
transformer.
The input wire is simply stuck down into the 6C4
oscillator shield. Not physically connect to anything.
The preamp is held in a metal clamp using an existing
screw.

SP-600.jpg (658210 bytes)

Here is Richards homemade wood cabinet.
 

 Try connecting to the cathode, pin 7.
Use as small a coupling capacitor as possible. 
Test on the 10 Meter band.

Neil,

Okay, so I'm just trying to share my minor triumph.  I mounted
the preamp on the chassis underside, near the 6C4 and ran it
off the filament voltage.  I found I got the best readings by
running the signal input wire alongside the lead running from
the grid to the band selector switch.  No electrical connections
now, and I've got solid frequency indications from BCB to 10m.

-Jim

HQ-129X

DFD1-Hamm DOES NOT WORK with the 129X

Use a DFD1A with offset set to 455KHz and add a switch to
control the ADD/SUBTRACT function.  The 129X switches
from high side to low side injection on the higher bands.
 
Tap the signal off the tuning gang section for the local oscillator using a very small
coupling capacitor such as 2.2pf.

HQ-160

The 6C4 is the oscillator.
Try tapping the plate.
If that fails tap the grid

SP-400

The 6J7 is the oscillator.
Try tapping the cathode.

HQ-145

HQ145.jpg (13683 bytes)
Signal should be available on cathode of V9

HQ-145 oscillator is identical to the HQ-129

HQ-200

HQ200.jpg (8349 bytes)
Signal should be available on cathode of V3

HQ-200 oscillator is identical to the HQ-129

Yellow LED Backlit Display module now available.

This module is the same size as the non backlit module and replaces it directly. You will have to supply a dropping resistor to set the current from your primary power source. The forward voltage drop of the LEDs is 4V and the maximum current is 200 ma. The unit lights up pretty good with 30 ma. At this setting it can be powered continuously from the on-board 5V regulator through a 33 ohm 1/4 watt resistor. From 12V you need an 80ohm/2W resistor for 100 ma, or a 160ohm/1W resistor for 50 ma.

For LED backlit module instead of regular module add $7.50

How to Order

On-Line (click PayPal logo below)

By Mail   Almost All Digital Electronics, 1412 Elm St. S.E., Auburn, WA 98092

AADE has an unconditional money bank guarantee even on kits (unless destroyed during assembly).

We have a free "we'll try to fix it if you just can't seem to get it to work" policy. ($4 return S/H charge)

We offer technical assistance from 9AM to 9PM Pacific time. (usually available on weekends) 

L/C Meter IIB you will love this one.

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DFD4 0-3GHz (build a bench-top frequency counter for about $70)

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