Stefan,
Very nice construction. Pleasantly astonishing to see the SWAP for the demonstrated far-field 1.570 kHz - 137 kHz (ULF, VLF, LF) performance. Altogether remarkable.
73,
Jim AA5BW
Hi Jim,
Yes, pure enjoyment.
Here is a photo of the setup for the remote LF experiment, including PA, signal source and scope :-)
http://www.iup.uni-heidelberg.de/schaefer_vlf/LF/20180909_192539.jpg
73, Stefan
Am 10.09.2018 20:30, schrieb [email protected]:
Hi Stefan,
Your ground-loop results are pure enjoyment at this spectator QTH; the numbers that you provided in your “ERP and loop efficiency” message below seem to suggest efficiency equal to or better than that of the Norway (Dazey) test. This is a most remarkable and enjoyable experiment in many ways.
73,
Jim AA5BW
Hi Jim,
(I changed the subject.)
Well, i remember there was a day where Markus transmitted on 8270 Hz, and me too. We were both visible on Paul's grabber.
Markus told me i was about 5 dB stronger there. Here is a spectrum from Pauls grabber (me on 8270.000 Hz) http://78.46.38.217/fbins3.html#p=1532887200&b=120&s=pw&m=cardioid&w=r&h=42&z1=0.34&z2=0.64&c=1&mb=632,136,655,212,1
Well the Distance from Paul to Markus is 1028 km, the distance to my ground loop is 840 km. Markus used an E field antenne, i used a H field antenna, so there may be some better filter and antenna mixing coefficients for one of the stations. Let's say, due to the different distances, i have an advantage of 1.8 dB.
Markus states he emits 10 uW (i guess that is EMRP) so my signal seems to have about 20 uW EMRP during that transmission, in which i run 550 mA antenna current.
Meanwhile i can run 1.8 A antenna current (+10.3 dB), so the signal could have 215 uW. That is with 255 W RF power. So the antenna efficiency is about -60 dB at 8270 Hz, based on Markus' 10 uW statement (?).
I have no idea if the equivalent loop area actually increases with a dropping TX frequency. On LF it seems to do at least :-)
Assuming the area is constant, the efficiency will be even 14.4 dB lower on 1570 Hz and 18.6 dB lower on 970 Hz. Uuuh i hope this is not true :-)
So the EMRP on 1570 Hz was maybe 8 uW at a -74.4 dB efficiency.
73, Stefan
Am 10.09.2018 08:19, schrieb [email protected]:
Hello Markus, Stefan, Paul,
Is there any way of guessing the ERP of the 1570 Hz (or 2970 Hz) earth-loop tests last week?
I noticed that ERP/wallplug-power efficiency of the Norway (Dazey) test at 1280 Hz might extrapolate to about 2E-8 with 1 km between electrodes (with ~ 20 ohm electrode-to-earth resistance); and though it might be informative to compare.
73,
Jim AA5BW
