you for the report. I'm running about 15W RF into a 5m high, 20m long "Tee" with
two top wires. My antenna current is about 0,8A.
Easter I will be QSY-ing to IO80 locator, and I hope to be running WSPR from
there on 630m. The antenna situation in IO80 is not so good, so I will have to
experiment with some "Stealth" antennas for MF!
Dave G3WCB IO91RM > IO80DI
Ok about your interesting test with 0.5 TX Power. Sorry, I cannot copy
you on day time, due to high carrier QRM just on your transmitting QRG. On the
way now, the G3WCB signal is good around 0 dB S/N, at about the same distance
I am now transmitting 2 or 3 times to see the difference in ON7YD and
You know that I am always transmitting QRP on MF. Maximum power is 3
Watts output TX. Now I have exactly the same power as your : 0.5 Watt. On
night this winter I was mostly using below 0.1 Watt.
My large winter antenna (Inv L) is dismounted and I am using a single 25
meters vertical tube without top hat capacitance. The effeciency is around –
20 dB, so the PAR (apparent radiated power) is 5 milliwatt.
If you want to have real QRPP test, you can test WSPR at 500 micro watt
PAR, and still have lucky reports up to 1500 km.
Best 73. Andy F6CNI – JN19QB
Sent: Friday, March 27, 2015 10:29 AM
Subject: RE: LF: TXing WSPR on 630m on a Raspberry Pi, Stefan in
solid signal here, best decode was at -8dB!
73, Rik ON7YD - OR7T
I'm now running the 7667 at 13.8V supply voltage. The
MOSFET driver is easily keyed by the Raspi, directly with its rectangular
output. I measured 0.5 W TX power
at 50 Ohm. This is what i'm
running tonite on 630m.
Not a real PA, just the Raspi and this IC in a
DIL-8 case. Fascinating!...
Am 23.03.2015 16:11,
I've added a simple ICL7667CPA
MOSFET-driver to the GPIO of the Raspberry. It's power supply is 5V coming
from the GPIO itselfe. This leads to a 5V rectangular signal with lower
output impedance. I've coupled the output matching circuit so that the
output power is now 50 mW / 17 dBm, i.e. 7 dB more power then in my previous
beacon is running now on 475.685 kHz.
18.03.2015 21:45, schrieb DK7FC:
Today i've got i 3rd Raspberry Pi.
I quickly installed the WSPR softaware and since a few minutes i am
transmitting WSPR-2 on 630m, my usual frequency 475.685 kHz.
directly using the GPIO output pin, without an amp stage behind! The
rectangular 3.3V output voltage is passing a cap and an isolation
transformer (FT50-77) as well as a simple pi-filter, because it is a
Raspberry pi! ;-)
measured an output power of about 10 mW at 50 Ohm. It is now connected to
my MF antenna and transmits in a 100% duty cycle. I still have to learn
how to reduce it but this will not take long.
With 10 mW TX power i
managed decodes by 3 stations now.
Does someone have
good ears to get a decode from me? :-) It is a challenge! :-)
PS: The signal is so weak that my RX antenna frontend
is not overloaded, so at that power level i can transmit and receive to
the same time :-)
PPS: A small amp stage will follow soon, i intend to
use an BS170 running at 5
de virus dans ce courrier électronique a été vérifiée par le logiciel