John,
Why don't you just disconnect the battery when the car is standing still
in the field? :-)
Well, i was thinking about investments into this old car and if it is
still worth or not. But having not such a nerving CANBUS is one argument
for investing into this car! Why the hell do i need a sensor that shows
me if the door is open? If it is open i see it or hear it. Just useless
inventions by the automobile industry!
73, Stefan
Am 04.01.2011 10:25, schrieb John Rabson:
Hello Stefan, Wolf , LF,
I have a diesel Renault Kangaroo [no - KANGOO - obviously an Australian
designed this dictation software]. I have found it impossible to make
weak-signal field strength measurements on 136 from the vehicle.
There appears to be some kind of data bus to communicate between a central
control unit and sensors which indicate (for example) whether the doors are
open or closed. Something seems to be running even when the engine is switched
off. My solution is going to be a portable receiver and antenna which can be
carried a few metres away from the car, otherwise I cannot measure field
strengths with any usefulness at a distance of more than about 2 km from the
transmitter.
There is even a problem on some longwave broadcast stations.
73 John F5VLF
On 30 Dec 2010, at 16:34CET, Stefan Schäfer wrote:
Hello Wolf,
Nice email ;-)
Well, no it is a benzine car, an almost 22 years old VW Golf II !! ;-) You
could know it from the VLF pictures, HI :-) So there is no internal electric
bus! And i have a car radio (ALDI!) that receives on VHF/MF/LF and i do not
have QRM by the ignition coil! Once i made holidays at the Nordsee (JO33) i
drove with the car and listened to DLF/153 kHz during the whole tour without
problems. Only HV transmission lines above 110 kV cause QRM.
So maybe i have a little better situation to receive DF6NM on LF /m. Otherwise i
have to drive on the highway, lets say 180 km/h (the maximum of this car) and have
to switch off the engine during Markus' transmission that must be short then until i
have to accelerate again at 90 km/h :-)). If this will not work i have to drive to a
highway near Nürnberg :-)
The magnet foot antenna is already ordered and i am curious about the results
;-) Mostly i need it for receiving LF during the VLF experiments, e.g. to the
xband QSO 9/137 with DF6NM, and maybe DF0WD? :-)
73, Stefan
Am 30.12.2010 12:03, schrieb wolf_dl4yhf:
Hi Stefan,
you wrote:
This should allow me to easily receive 137 kHz while driving the car!
Hopefully there is not to much QRM during engine is running.
So maybe i can try a crossband QSO with DF6NM TXing on 137 and me answering on
30m while beeing on the highway :-)
Maybe, it's a Diesel engine, and the alternator properly low-pass filtered. I tried this
years ago, and the QRM from the ignition coil, and / or the alternator was horrible. No
big surprise that car radios with AM LF broadcast receivers have disappeared. And
weak-signal reception "LF mobile" is even more a challenge.
In my Corolla, I would even have to disconnect the battery (!) if I was to
receive VLF (and, most likely, LF too) because some internal digital bus (most
likely CAN or LIN) remains active, with the ignition and everything else turned
off. For temporary V(!)LF operation on a remote site, I use a simple FM
oscillator at the transmitter now, and listen to the VLF signals in the car's
radio, using a distance of 10 m or so.
Cheers and a happy new year,
Wolf DL4YHF .
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