Hello Clemens,

What did i say...

+6 dB, so now you're getting twice the antenna current with the same power?

73, Stefan/DK7FC


Am 19.01.2014 16:11, schrieb Clemens Paul:

Hi Wolf,

I've tried the T-Antenna mode this weekend.
It was excited against PE (protective earth of the house).
Matching was surprisingly easy by a series C of around 1340pF,
R (the real part)  happened to be 50 Ohm (in dipole mode it varies between 60 
and 70 Ohm).
The effect was dramatic in any sense.
Ground wave signal strength went up by ~ 20dB as measured on a remote Perseus in
Amberg (nr Nürnberg) this afternoon.
Sky wave signal strength during last night went up by at least 6dB,maybe 10dB
(diifficult to measure because of qsb while changing the configuration) in DL 
as well
in OH (1900km distance) on a remote Perseus.
Now the downside:Rx noise level went up by roughly the same amount (day/night)
and funny things happened when TXing with full power.
The TV and some lights in the living room went off and on,there was hum in the 
telephone
etc.
The RX noise problem could easily be solved by switching the two antenna modes
automatically with the PTT line and a few relays.
The EMI problem perhaps by a separate earth?

73
Clemens
DL4RAJ

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of wolf_dl4yhf
Sent: Saturday, January 11, 2014 11:32 PM
To: [email protected]
Subject: Re: LF: RE: Clemens on MF!!

Hi Clemens,


Am 11.01.2014 22:58, schrieb Clemens Paul:

The dipole is a horizontal 90°V, 8-15m high and according to

EZNEC it has a spheroidal

pattern with no nulls.

Ok... that makes a difference.

The vertical part of the feeder is only about 6m long.

So the rainworms will be cosy and warm around the lower parts of the
antenna, hi..

Tomorrow I'll check the impedance of the antenna aagainst

ground with both feeder wires

connected
and see if I can match it to 50 Ohm,dependent on the available parts.

That would be a good indicator for the ground conductivity.
At the local antenna farm, the total resistance (after
compensating the
reactive part with a series coil) went up from 26 to approx 35 ohms
within a few months.
During transmit, I simply use the PE (plus possibly the underground
cables) as counterpoise. During RX, the PE is disconnected from the
antenna's own 'ground' which consists of a few buried wires,
to prevent
QRM from the mains creeping in. Another remote RX antenna is already
planned, most likely it will be a small active loop or a system of
crossed loops.

Cheers,
   Wolf.

( where is everyone .. now hearing only "  -...  ..  .-  "  ? )