Hi Andy,
just a small correction to the datas of previous message.. time lapses
and my memory sometimes misses something...
Rechecking my papers I recalled that I made some change in my
RF ammeter in the shack, formerly it had 2 ranges 3 and 1 A fs then I
changed the trimming (without etching a new label) and now it reads 4
or 0,5 A fs!
So antenna current is something more than 0,5 A and with the venerable
Marconi TF2604 this afternoon I found that RF voltage is 38 Vrms, on 56
ohms of impedance (in the shack) brings to abt 0,6 Arf or 25W feeding
the antenna. EIRP should be 13 - 14 dBm.
Hope this evening you can copy me ;-)
73 Marco IK1HSS
----Messaggio originale----
Da: [email protected]
Data: 2-ott-2016 13.12
A: <[email protected]>
Ogg: R: LF: IK1HSS - DF6NM WSPR 137 kHz
Hello Andy,
sorry for the local QRM, the neighbors of Markus are more fair.. hi
May be later they have a short sleep and conditions improve :-)
I have never made measurements of current at the antenna base, it is a
bit complicate because it is on the roof of the house (or according
the
definition of a friend on the Saratga deck), just recorded impedance
plots with my N2PK VNA. If I have to trust on my RF ammeter in the
shack (about 40m of coax away) it should be in the range of 1A but I
guess it is peak not rms. The antenna is fed via a transformer made
with 2 stacked FT 240-43 N1=20T and N2=14T (2:1 transformer) and
neglecting the small transformation given by transmission line the
impedance at resonance including all losses is close to 25 ohm. Of
course this nice reading is due to my single radial.. or the Saratoga
deck: the roof is made of sandwich panels (about 700 sqm at 35m from
the ground) and I spent some time placing jumpers between quite all
the
panels ;-) so the measured impedance is very close to the simulated
impedance on good ground.
Just for fun could send you by mail some pictures ;-)
Hope to see later your reports
73 Marco
----Messaggio originale----
Da: [email protected]
Data: 2-ott-2016 11.58
A: <[email protected]>
Ogg: LF: IK1HSS - DF6NM WSPR 137 kHz
Hello Marko.
I was just trying for the first time to copy your LF WSPR signal. But
I
am sorry, I have a bad local QRM just on your QRG of 137453.
I’ll try again later if this QRM gone away, HI !
Just a question about your nice antenna : dou you use for the earth
groud some radials or ground rods ? And, did you had a mesurement on
your base antenna current ?
Bets 73.
Andy.
-----Message d'origine-----
From: [email protected]
Sent: Sunday, October 2, 2016 11:22 AM
To: [email protected]
Subject: LF: IK1HSS - DF6NM WSPR 137 kHz
Hello Markus,
apparently this morning there is a Turin-Nuerberg duct!
I'm running my WSPR beacon on 137 kHz since friday evening with no
interruption, same power, same rig, same antenna, but yesterday you
missed again my sigs after the sunrise, today at 11AM (0900 UTC) you
are still copying me although a small hole from 0444 and 0626 UTC.
The TX output is about 30W (I have to measure better....) The antenna
is a 10m wire vertical (2m on the side of my metal mast) with 100m of
tophat (10 sloping wires 10m each) with a topcoil resonating on 470kHz
(not yet tuned I have to take away some turns in the coil) and a base
coil resonating at 137 kHz. Yesterday afternoon we had a couple of
hours of rain, but small retuning with the variometer were enough to
keep the antenna at resonance) :-)
I'll keep on the transmission being very curious to see how long you
can decode even if the SNR is not impressive..
73 de Marco IK1HSS
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