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... choke at the lower end results in a completely different antenna: it is a unsymmetrical dipole then, one leg given by the antenna elements of the discone and the other by the antenna cable. The feed point is in between at the discone side.

Here is the detailed report: 1) The antenna is mounted on a 1.8 m steel pole which goest through the roof and is mounted with two steel brackets to a wooden beam of the roof. There is an elecrical (not RF!)) ground tied to the pole which was wired ages ago and is connected to the general electrical...

ON5HB -Bas, That was a very good description of the "third wire" in coax cable and how it can produce common mode receive and transmit problems. Properly designed chokes, in the right place can result in considerable noise reduction. Thanks for the posting the link to the G3TXQ site and the common m...

Hi Bas, Yes, the noise did go down on (almost) all HF frequencies, I thought this would be clear from the PC screens. What I had before was that at 7/14/21/28 Mhz I had noise higher than the Beverage, while signals, when present, were lower than those from the Beverage. Now on 7/14/21/28 noise is lo...

One thing you forgot to mention. Does it work better? Did the noise level go down as I said it would? For people that have no clue what we are talking about, let me explain in simple words. Coaxial cable has 3 conductors, what you say???? Yes 3 conductors, let me show you: 1: The inner conductor, th...

... (not RF!)) ground tied to the pole which was wired ages ago and is connected to the general electrical wiring of the house. 2) At the base of the Discone there is an UHF female connector. A male UHF connector connects here carrying the RG58 coax. The coax comes in through the roof with a length ...

Here is an idea on how to construct such.

http://www.hamblog.co.uk/constructing-an-ugly-balun/

Thank you Bas!! I am going to stick a bottle choke on the roof right away & report results...

... mounted on a 1.8 m pole on the roof and comes to the RSPduo via a 20 m length of RG 58 coax cable (50 Ohm). What I immeditely noticed was that the Discone was 5 to 10 dB noisier than the Beverage and this kept me thinking all the time. Furthermore I could see a hint of signal coming in at 3.6 and ...

An excelent presentation of the fundamentals of the discone antenna, mounted on a pole, can be found here: https://www.youtube.com/watch?v=vFYVpJ9FPZ8 Please look at 12:20. Sory, it is in German. If you want to run some simulations: the total capacitance ...