Re: LF: Re: Testing now a new RX antenna on MF

[DK7FC <73dk7fc@googlemail.com>]

Hello Andy, MF/LF,

Very good!! I see you also like playing in the garden ;-) And i like to see that my daytime signal is of some use for others.

Interesting results.
Now, how do the 2 verticals perform compared to the K9AY?
Is there a significant gain (better S/N!) compared to a single vertical?
Do you have even more space in the garden to get some more spacing than 0.05 Lambda? :-)

Yesterday i have been at my parents QTH, now my car is full of stuff, wires, coils, ferrite cores, heavy ground rods, a sledge hammer, cord, batteries, RG58, adapters........
I guess i will also need about 1 mH to resonate the small RX antenna to MF. This will be the first test. I willl use an air coil and do some TX tests on that small RX antenna, just to check that it is accurately resonated and matched to 50 Ohm.
I will go to the garden now and play until late afternoon. Maybe you will see a weak signal on MF :-)

73, QRO, Stefan/DK7FC



Am 05.08.2014 19:08, schrieb André Guyé:

Hello dear Domenico.

 

The coupling system is very classic :

 

• At the base of each vertical, the impedance is about 25 – 3400j (including the 25 Ohms of ground rod resistance). I match that to a 50 Ohms RG58, using a L circuit with a serial 1150 µH coil and a 6800 pF parallel capacitor on the coaxial side.
• The two coaxial cables have the same length and are the two inputs coming into the phasing box.
• The « out of phasing » box includes a small single ferrite toroid of Al = 700.
  • The primary is 14 turns. The the center is grounded and connected to the both ground sides of the two coacials coming from the antennas. The center of each coaxial is connected to the A and B ends of the primary coil.
  • The secondary is 20 turns, isolated from the primary, for 50 Ohms output coaxial going to the band preamplifier ;
• The preamplifier is a common 20 dB of gain, high current type.
• The Rx is a IC 7200.

 

That is very simple. Of course, it is not a transmitting antenna, only for receiving ! I test this antenna to see the difference between it and my K9AY.

 

73 QRO. F6CNI

 

From: IZ7SLZ

Sent: Tuesday, August 5, 2014 5:29 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: Testing now a new RX antenna on MF

 

Hi , all

Andy,  impressive reception ! Compliments. How the two vertical stylus are coupled ?
Which receiver are you using now ?

Thanks in advance for your replay.

73, Domenico/iz7slz

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