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
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.
Sent: Tuesday, May 26, 2015 7:06 PM
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
<[email protected]>
An: RSGB LF Group
<[email protected]>
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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