Hello Geri!
Thanks for very interesting informations and for your ERP
field-measurements. It is really incredible, that I can take snapshot DI2BO in
as good quality as I sent you some days before.
It is fine, you practice DI2BO with 1.7mW ERP only. DI2AG and
BHZ are more stronger (DI2AG especially) and it is useful to have a chance testing
RX, ANT and PC receiving signal near the noise.
(I have got Praecitronic GF61, MV61, SV61 as well. Good for
my LF experiments!)
GL and 73!
Lubos, OK2BVG
**********************************************************************
-----Original Message-----
From:
[email protected] [mailto:[email protected]] On Behalf Of Holger 'Geri', DK8KW
Sent: Sunday, April 15, 2007 2:27
AM
To: [email protected]
Subject: LF: [500 kHz] DI2BO has
1.7 mW ERP!
Hello Dave and also all the others
observing DI2BO (and the other beacons on 500 kHz),
Today the weather was fine and I
took the chance to drive around and do some ERP field-measurements.
Technically I used the MV-62
Measurement Receiver that reads the signal strength in dBu. As an antenna I
used a simple open loop with 1 m diameter. To measure the distance to DI2BO I
used a Garmin XL-45 handheld GPS system.
Mathematically I used a set of
formulas that Markus, DF6NM helped me to develop (thanks,
Markus!). These formuals come up with the EIRP, the effective
radiated power above an isotropic radiator. For those interested in the
forumas, please find attached a samle XLS file. For techical details, please
ask Markus, he is much of an expert in this than I am ;-)
Next I used some ITU definitions to
convert EIRP to ERP (DEFINITIONS OF RADIATION IN LF, MF AND HF BROADCASTING
BANDS), in which is stated:
The value of the e.r.p. is related
to the e.i.r.p. by the _expression_:
e.r.p. = 0.61 e.i.r.p. (linear scale)
e.r.p. = e.i.r.p. – 2.2 dB (logarithmic scale)
Here are the results, measured at three different
locations:
1,02 km distnce: 1,63 mW ERP
1,57 km distance: 1,85 mW ERP
2,01 km distance: 1,56 mW ERP
The average of these three measurementsis around 1,7 mW ERP!
This makes alle your observations even more
astonishing. I would not have guessed that a 500 kHz at that ERP level signal
would span that distance, espeically audiably. With this low power level
it also shows the important efect of QSB from variations in the ionosphere.
Until further notice DI2BO will transmit on 505,015
kHz with 1,7 Watt ERP day and night (24/7), so please keep watching and
observing and keep thos reports coming in.
Best 73
Geri, DK8KW / DI2BO
DI2BO: antenna system is a "long wire",
simply about 8 m wire vertically up to a 10m mast, then another 8m wite
horizontally to the roof of my house. OOutpur power is around 10 Watt (DEBEG
7121 on "reduced power").
----- Original Message -----
Sent: Saturday, April 14, 2007 7:39
AM
> Just to report that when I came
back into the shack at 2100z DI2BO
> was clearly audible to my ears, peaking 439 here in Bracknell IO91PJ.
> I was rather amused to clearly hear it send its CW id 'DI2AG' !!
> GI4DPE was also heard beaconing in normal CW around 501.15.
>
> This maybe highlights the problem with QRSS on 500kHz. I have already
> noted slow and very deep QSB on many signals. While I was watching
> DI2BO on Argo last night I found that it would pop above my noise
> level for only 1 out of 3 or 4 callsign sequences and between that
> there was little more than the odd dot visible. When it appeared most
> but never all of a complete call was visible and it clearly peaked
> quite strong for just a few characters. If I had not known what the
> call was I would have had to listen a long time to postively identify
> it. However when it sent its ID on normal CW when listening without
> Argo later that was copyable in its entirety (admittedly wrong!).
>
> 73 Dave G3YMC
>
>
>
> http://www.davesergeant.com
>
>
