For Sale: Factory Built K7DYY Junior 150
watt carrier class D AM transmitter. It comes with a 3.885 Crystal. It gets around 450 watts PEP out
put. It comes with a very old Astatic D 104 microphone ( metal Logo) with one of Bruce's audio boards installed.
This little transmitter
works just fine. All you need is a antenna with a 1:5 to 1 or less SWR. Do not
use with higher SWR readings.
I had it pared it up with a
little Palstar R30 receiver. This combo makes a very compact high power AM
station. Of course you can use any AM receiver of you're choice.
It includes a relay to
switch the antenna from the receiver and this transmitter. A normally open RCA
cable is installed in the relay box to mute you're receiver. K7DYY no longer
makes this transmitter. His new Super Senior costs $1,400.00 . If you want to
change frequency just plug in a different FT-242 crystal.
It is being sold as-is with
no returns, but again it works just fine and I always get great signal reports
If you have any questions
about this transmitter please feel free to ask before you bid on it.
I prefer to use Fedex for
shipping, but I will use a shipper of you're choice. Note: The on-line calculator is for UPS. Fedex may be slightly different.
Payment must be sent with-in 4 days.
If you don't have Paypal contact me for other payment options
Check K7DYY's Web-Site for more information on his transmitter
Bruce was the guy who manufactured
the Index Lab QRP Transceiver years ago.
The audio processor uses
high gain, high impedance circuitry. It must be mounted in a shielded enclosure
to avoid hum pickup.
- The mounting holes in the PCB are spaced to fit the
base of Astatic D-104 microphones.
- Alternately the processor can be mounted in a 2" X
4" die cast aluminum box.
The processor requires 8 to
15 volts DC at 20 mA. This is supplied by the class D transmitter or a battery
can be used. The supply is connected between terminals +V and G on the PCB.
The audio output is
designed to drive a load impedance of 600 ohms or higher. It can be plugged
directly into the microphone input of most transmitters and even modern
The input is high impedance
(6.8 megohm) and can be connected directly to crystal or ceramic elements. The
schematic diagram shows how to adapt the unit for use with electret elements.
If using the processor with
a vintage transmitter, it is best to leave the transmitters mic gain control at
it's normal setting and adjust the mod level control, in the base of the
microphone, for full modulation. This will make A/B comparisons easier.
The Processor Board mounts in
an Astatic D-104. The processor matches the D-104 and drives the Senior
directly. Power is supplied by the Senior.
This board sells for $50