Hi Stefan !

The maximum antenna current was about 500mA but at this power the
transistors got very hot, showing that there is still something wrong
with the matching. My usual PA has an output resistance of 2 Ohm in
Briged-Mode, while this Mono-PA has 4 Ohms per default.

Though I have some taps on my primary coil to match impedance, I think I
still have to optimize a bit. Maybe by using more windings for the
primary. This test was just to ensure, that the PA is working and there
is still a lot of room for improvements.

73
OE3GHB
Gerhard



Am Montag, den 19.03.2012, 01:14 +0100 schrieb Stefan Schäfer:
> Wonderful! I like the daily short stories about the various technical 
> challenges on the different sites. Also the weak and sloooooow but 
> visible traces on a wavelength of 33444m are very relaxing :-)
> 
> Gerhard, what is the output power and antenna current? That's a stylish 
> guitar amplifier, right? Actually we should define a nostalgical day and 
> use tube amps or keyed spark generators (don't find the correct word in 
> english now but you know what i mean).
> 
> 73, Stefan/DK7FC
> 
> 
> Am 18.03.2012 17:49, schrieb Gerhard Hickl:
> > Hi Markus!
> >
> > You are right, I did a test in the afternoon. I obtained a Audio-PA
> > (Warwick Sweet15) from the scrap-yard last week and both of the
> > complimentary power-transistors were dead. I replaced them yesterday and
> > now the PA is working. I tried to connect it to my coil today and was at
> > least partially successful. I didn't use a GPS-locked carrier because
> > for the general test of the PA this wouldn't be necessary.
> >
> > 73
> > OE3GHB
> > Gerhard
> >
> >
> >
> >
> >
> > Am Sonntag, den 18.03.2012, 17:29 +0100 schrieb Markus Vester:
> >    
> >> Lubos, it looks like Gerhard is starting up now...
> >> http://members.aon.at/grabber/VLF/index.html
> >> http://www.ok2bvg.cz/vlfgrabber/
> >>
> >> 73, Markus (DF6NM)
> >>
> >>
> >> From: Lubos OK2BVG
> >> Sent: Sunday, March 18, 2012 11:40 AM
> >> To: _RSGB_LF
> >> Subject: RE: LF: OK2BVG_8970
> >>
> >>
> >> Hello Markus!
> >> Yesss, I have seen my signal on your grabber. I am pleased! I just
> >> finished "K". The weather is still perfect, so I will go my
> >> transmission on. The another "K" will be transmitted.
> >>
> >>
> >> 73!
> >>
> >>
> >> Lubos, OK2BVG
> >>
> >>
> >>
> >>
> >>
> >> ______________________________________________________________________
> >> From: [email protected]
> >> To: [email protected]
> >> Date: Sun, 18 Mar 2012 11:15:30 +0100
> >> Subject: Re: LF: OK2BVG_8970
> >>
> >> Lubos, today I've set up my VLF grabber
> >> http://www.mydarc.de/df6nm/vlf/vlfgrabber.htm a bit faster (1.9 mHz)
> >> to provide a bit of a challenge for your signal ;-) Your "K" is now
> >> well visible while the noise is decreasing from hour to hour.
> >>
> >> Good luck,
> >> Markus (DF6NM)
> >>
> >> From: Lubos OK2BVG
> >> Sent: Saturday, March 17, 2012 10:48 PM
> >> To: _RSGB_LF
> >> Subject: LF: OK2BVG_8970
> >>
> >>
> >> Hello VLF!
> >> If the weather is as nice as today, I will be active on VLF tomorrow:
> >>
> >>
> >> ***INFO***
> >>
> >>
> >> Date: 12.03.2012
> >> Time: 08:00 UT - 11:00 UT
> >> Antenna: Marconi L 24m up + 220m top load
> >> PA: 120W
> >> Identification: K
> >> Mode: DFCW 3000
> >> FRQ: 8970.040
> >> Shift: 5mHz
> >>
> >>
> >> I hope, the propagation will be good. All reports are welcome!
> >>
> >>
> >> Lubos, OK2BVG
> >>      
> >
> >    
>