Message-ID: <556654AE.9040308@gmx.net>
Date: Thu, 28 May 2015 01:35:10 +0200
From: Tobias DG3LV <DG3LV@gmx.net>
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References: <394FEA4DA5AA4542828CB5F63AEE2C88@F6CNIToshiba> <474231660.434744.1432735092592.JavaMail.yahoo@mail.yahoo.com> <556640CA.1080101@posteo.de>
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Subject: Re:  LF: MF mobile ?
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Hi Stefan !

> but most likely there is a LOT of
>> QRM when driving...

It depends on the type of car. While testing /mobile on 160m I did not 
hear QRM from my 23 year old Diesel. At the Autobahn, far away from 
cities there is almost no QRM from outside. I had a lot of fun, and a 
lot of QSOs. (Antenna Pro-Am 160m, PA 300W). The HF-QRM-situation on 475 
should not be worse.

A capacity head (with skirt) as large as possible and a top loading coil 
should be possible to build (4m x 1.6m, 1.5mH). It certainly will look 
somewhat similar to the foto from F6GEX. For legal reasons your car + 
antenna may not be higher than 4m, this leaves 2.6m for the vertical 
part at the 1.4m rooftop of the car. The mechanics would be a challenge.

73 de dg3lv Tobias

Am 28.05.2015 um 00:10 schrieb DK7FC:
> Hmm, i find someone should do a real mobile (mobile-mobile, with a
> velocity > 0) experiment. A 1.5 m long CB antenna with a special
> preparated feed point should work. And i think that the wire works
> better with a fixed C in parallel, even if this reduces the efficiency.
> But it stabilises the SWR or better said, the voltage on the wire.
> Corona? Where is the problem with corona? :-)
> Markus, could you calculate the ERP when 10 kV rms is applied to a 1.5m
> high antenna on a car roof? I bet you have all the formulas in your mind :-)
>
> Maybe the antenna has 10 pF. I remember i have a 470pF/16kV capacitor at
> home. So if C = 470 pF and f = 475 kHz, L = 239 uH With 470 pF parallel
> to the antenna, a moving wire (= changing C) does not make a significant
> effect i think.
> 10 kV at 239 uH at 10 kV is 14A. If P = 200 W, the losses must be 1 Ohm !
> With a good RF litz wire, this is possible :-)
>
> What would be the ERP and possible distance?
>
> It would be interesting to try that in WSPR / QRSS-60 :-) I would also
> drive to someone for making a CW QSO but most likely there is a LOT of
> QRM when driving...
>
> More ideas?
>
> 73, Stefan
>
>
> Am 27.05.2015 15:58, schrieb John Langridge:
>> Andy,
>>
>> >Perhaps a 2 meters whip is a bit too short ?
>>
>> The smallest antenna that I have experimented with was a base loaded
>> vertical that was almost 3 meters long and I observed reasonable
>> success with about 100w TPO.  The radiator was a 2 cm diameter
>> aluminum antenna tube so charge was distributed pretty well and no
>> corona was observed.  There was no additional top loading in the test.
>>   I was using a fair radial system at the time but perhaps its time to
>> try this same arrangement in a fixed mobile setting as you have done
>> here.
>>
>> I look forward to hearing about your further experimentation.  I hope
>> you will conduct this test again in the winter.
>>
>> 73!
>>
>> John KB5NJD / WG2XIQ
>>
>> ------------------------------------------------------------------------
>> *From:* Guyé André <andre.guye1@aliceadsl.fr>
>> *To:* RSGB LF Group <rsgb_lf_group@blacksheep.org>
>> *Sent:* Wednesday, May 27, 2015 7:05 AM
>> *Subject:* LF: Fw: De F6CNI : WSPR Test using mobile on MF to night.
>>
>> Hello Markus.
>> I am sad about my experiment, only one station copied my very loud
>> signal last night : F5WK at 72 km. Perhaps a 2 meters whip is a bit
>> too short ?
>> For a next experiment, F6GEX just give me an other mobile antenna
>> shape idea. Intesresting indeed ! Be sure, I’ll give to you also the
>> results of the doppler effect. HI.
>> Best 73 de Andy F6CNI.
>> image
>>
>>
>> *From:* Markus Vester <mailto:markusvester@aol.com>
>> *Sent:* Tuesday, May 26, 2015 7:06 PM
>> *To:* rsgb_lf_group@blacksheep.org <mailto:rsgb_lf_group@blacksheep.org>
>> *Subject:* Re: LF: De F6CNI : WSPR Test using mobile on MF to night.
>> Great Andy, this is a wonderful experiment!
>> If you could persuade yourself to drive on a highway while
>> transmitting, would we be able to measure your speed using Doppler
>> effect? Probably not using WSPR, but surely with QRSS-60...
>> 73, Markus (DF6NM)
>>
>>
>> -----Ursprüngliche Mitteilung-----
>> Von: Guyé André <andre.guye1@aliceadsl.fr>
>> An: RSGB LF Group <rsgb_lf_group@blacksheep.org>
>> Verschickt: Di, 26 Mai 2015 1:47 pm
>> Betreff: LF: De F6CNI : WSPR Test using mobile on MF to night.
>>
>> Hi to all.
>> I’ll be testing this evening WSPR 2 and at times WSPR 15 on MF using a
>> short mobile antenna. My call be F6CNI/M.
>> Of course, I don’t drive my car, it is resting in my garden…
>>
>>   * TX power 2 Watts ;
>>   * Antenna is a 2 meters long whip ;
>>   * Total Antenna Z = 85 -16610 j. Using base L tuner to 50 Ohms ;
>>   * Antenna base current = 145 mA, base voltage = 2400 Volts RMS ;
>>   * Average expected soil up to the Fraunhofer zone : 0.003 S/m and 13
>>     for dielectric ;
>>   * Effeciency about – 43 dB. Maxi lobe is -40,5 dBi at 22° site ;
>>   * Apparent radiated power is about 150 micro Watt, and the E.I.R.P.
>>     is about 270 micro Watt.
>>
>> Reports be appreciated.
>> Begining the experiment this evening at 2000 TU to next morning, but I
>> think the best period is around 2300 to 0200 TU.
>> Best 73.
>> Andy - F6CNI – JN19QB
>> .
>>
>>
>> ------------------------------------------------------------------------
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