dj0abr's blog

just got a report from Japan JA3TVF:

2016-10-13 20:22 DJ0ABR 0.475665 -25 0 JN68nt 0.2 JA3TVF PM74pc 9166 45

never have seen that before, maybe a first contact ?

Many thanks JA3TVF for this report !

Antenna used on my side:
horizontal loop, length abt. 450m with a tuning inductor, height abt. 20m.

Kurt, DJ0ABR

a minimal SDR receiver using only two chips from analog devices is now active 24/7 on 630m in JN68NT (DJ0ABR).
It contains a preselector (design:
followed by a AD8332 pre-amp and a AD8333 I/Q mixer.
Circuit diagram:

Oct 5th, 2015, 3..4:00 UTC:
many contacts on 630m over atlantic ocean.
Thanks so much to VE1HF, VE1VDM, W1TAG/1, WA3TTS/2, WE2XGR, WG2XJM, WG2XKA for spotting us.
I am using an inv-W antenna, which looks like an inverted Double-V. The balun is near the ground, then two vertical elements go into the trees (height 35m).
Then it goes down again to 3m. Total length of the antenna is 280m.
My neighbor (DH5RAE) uses a full size horizontal dipole in about 40m height, total length also 280m.
The wires are tuned to resonance with a RigExpert analyzer.

this new version comes with the newest WSPR decoder by K9AN for K1JT's Weak Signal Propagation Reporter (WSPR) mode.
This decoder has the new -d option which makes a deeper search and gives more spots.
This option is activated in wsprlinux by default.

other news:

* extended timer: up to 5 timers to select band(s), separated for RX and TX and also TX interval.
* a couple of bug fixes
* optimized caching of data to reduce network load of's data and's pictures.

Just finished our 11 Band 5 Watts beacon,
the board is using GPS and is for stationary and mobile operation.
The DDS is running from 100kHz to 160 MHz.
The 5W PA has filters for 630m to 6m (11 bands) and has a connector
for a separate receiver (a mobile WSPR RX is our next project).
Configuration software supports Win, Linux, Mac and also Android on Smartphones.
All schematics and software are available for free for all Hams.
vy 73 Kurt, DJ0ABR (