Alan, G3NYK wrote:
Mike G3XDV, mentioned using DCF39 as a standard signal for comparing aerial
performance, in a previous exchange which culminated in the fascinating
article and results reported by Dick PA0SE. This has just surfaced again
for
me as I have had another packet contact with F5MLP. As you may remember he
has erected a 300m wire in anticipation of getting a permit for 136. He is
disappointed in its performance, and has sent a bull round the packet
network asking for other stations reading of the strength of DCF39.
It occurs to me that this is a fairly meaningless quest unless the stations
replying are really 'switched-on' to LF aerial tuning and performance. It
also occurs to me that a definitive list of measurements on the station
from
different locations might form a useful guide to newcommer's to the band
as well as lazy old ones like me!)
I don't want to clog the reflector with what many might regard as junk, so
I
am suggesting that I am willing to collect and collate (via e-mail to my
personal address below) any reports that you would like to send to me
direct.
As a guide may I suggest :-
Call Locator Aerial Receiver (S-meter ) DCF39 DCF39 noise
level
Calibration) (day)
(after
dark) (quiet day)
There is a lot of room for discussion on what is important and what is not,
but maybe this could serve as a basis to collect some guidance data.
I know we think that there is not much difference in the day and night
signal from the station, but does everybody find it so? As for the s-meter
calibration I am thinking of something like 'S-9 = 50uV' or something
similar. If the formula that Dick refers to does work we should be able to
work out the field strength at any location in the reception area of DCF39.
Qualifying comments accepted, if you care to add them.
When I have collected a reasonable number of reports I will post the
results
as a digest to the reflector for all to see.
I hope you will see this as a worthwhile exercise and deluge me with
reports!
73 de Alan G3NYK
[email protected]
I don't think this is a reliable method. I have measured the field strength
of DCF39 at my location as reported in my e-mail of 15-7-99 15.28.
The power of DCF39, as deduced from the field strength was unlikely high.
In a telephone call Gamal Soegiono pointed out that the signal I received
from DCF39 was not only by ground wave but also by skywave. I had not
expected this because the day to day variation of the signal, as measured by
my selective level meter, is very small, less than 1 dB. At least during
daytime; after dark the variations become much larger.
Gamal Soegiono's remark is supported by Vaino, OH2LX. He has professionally
measured the signal of DCF39 for more than 10 years, 24 hrs a day, at a
location 1545 km from DCF39. The graphs Vaino has sent me show large
variations from day tot day and also over the 24 hrs of a day.
I will be happy to send the graphs to anyone interested with a direct e-mail
as the reflector does not accept messages with attachments of large size.
So near DCF39, where the skywave is very weak as compared o the ground wave,
the DCF39 signal could probably be used as a kind of yardstick. But al large
distances, and I suppose that applies to the UK, one should be careful in
interpreting the results.
I am also compiling the interesting info Vaino has given me into a single
e-mail without attachments. You will receive that via the reflector one of
the coming days.
73, Dick, PA0SE
JO22GD
D.W. Rollema
V.d. Marckstraat 5
2352 RA Leiderdorp
Tel. +31 71 589 27 34
E-mail: [email protected]
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