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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