ADE-1 Mixer prototype PCB received
Got my diode ring mixer PCB and my ADE-1 mixer PCB from Diz this
afternoon. Diz sent the ADE-6 LF mixer as planned; I built that
first. I left out the IF diplexer and just put BNC's on all 3
ports with added jumpers and tested it on the bench with my 50 ohm
test gear. The mixer starts to rolloff right at 50 kHz which is
the MCL low frequency spec for this mixer. Since LF and VLF
atmospheric noise is pretty high, the mixer will work fine down to
12 kHz or so even with the increasing mixer loss below 50 kHz.
There are some Russian VLF navigation signals that are turned on
now and then, 11.9, 12.65, 14.9 kHz--the lowest frequency
non-hobbyist transmissions currently in use. I can hear them here
in S. AZ when they're on, so this 50 kHz mixer should be able to
also get them when used in an LF upconverter. I've been listening
to VLF and LF as a primary radio-listening interest since the
1980s. My primary radio that has sensitivity down to VLF is the
AOR AR-7030 so I don't normally need to use an LF upconverter but
I have built a number of them over the years. Normally I use a
regular DBM like the MCL ADE-1 but reverse the RF and IF ports (IF
used as the input port since most DBM's go down to DC for the IF).
This is the first time I've tested a DBM rated to go down to 50
kHz on the RF port.
I used a 4.01-4.50 MHz LO; RF input was set to -30 dBm; LO to +7
dBm. A Siglent SA was used to see the upconverted 4.02-5.00 MHz
RF input IF output
500 kHz -35.0 (-5.0 dB conversion
400 kHz -35.0
300 kHz -35.0
200 kHz -35.0
100 kHz -35.0
50 kHz -35.35
40 kHz -35.7
30 kHz -36.2
20 kHz -37.3
10 kHz -40.9
OK great...so the ADE-6 is working as expected.
I'll be documenting the Diplexers next...how to tune etc.
On 1/12/21 12:07 AM, Steve Ratzlaff wrote: