The device for connection of the external SW & MW aerial

[Siber]

I made an easy device for connection of external SW & MW aerials to portable receivers.
I can give some comments.........

[richard]

Hi Siber,

You will not probably achieve any advantage using this coupling arrangement, compared to just connecting the external antenna directly to the telescopic antenna. Indeed it may give a worse result, as high frequency signal loss will occur in the ferrite, unless it is a low permeability type. If you need to boost the signal from the external antenna, you may be better having a larger number of turns on the telescopic antenna side (this presents a higher impedance, compared to a coaxial line).

Some care needs to be taken to ensure that the signal from the external antenna is not overloading the receiver. This depends on the antenna are you using. These are my thoughts, anyway.

Richard

[Siber]

Hi, Richard

You will not probably achieve any advantage using this coupling arrangement, compared to just connecting the external antenna directly to the telescopic antenna.
Such way gives following advantages:
1. Noises from an electric network due to the transformer are eliminated.
2. There is an opportunity to connect a coaxial cable.
3. There is an opportunity to connect an external magnetic loop.
4. Due to inductive communication of the ferrite core with the magnetic antenna of the receiver there is an opportunity to connect an external MW aerial.

. Indeed it may give a worse result, as high frequency signal loss will occur in the ferrite, unless it is a low permeability type.
I agree with you, but at use of ferrite with magnetic permittivity 400 it has not given negative result up to frequencies 22 MHz.

If you need to boost the signal from the external antenna, you may be better having a larger number of turns on the telescopic antenna side.
Maybe, but this way the signal from the external antenna is not overloading the receiver.

I did not put the problem to reach the ideal decision. The problem was: to recieve DRM signals using an usual portable receiver. I have solved it. The external aerial was necessary for this purpose.
The truth the receiver is modified under the same scheme a little differently. (look the appendix).
I live in the ferro-concrete house and very far from the DRM transferring centers I live near to lake Baikal. There was no point to buy DRM receiver , and I have decided to fulfil system of reception independently. I equipped the portable receiver with the external aerial and has developed the converter. The arsenal of the stations received by me look in the appendix. The sound signal is decoded seldom, only at good propagation of radiowaves

Vladimir

[richard]

Hi Siber,

I can see the advantage if you are also trying to couple the external signal to the ferrite antenna inside the receiver, rather than just applying it to he antenna input.

Obviously, if it works well there is little point modifying it.

Richard

[Siber]

Hi, Richard

The majority of portable receivers have no jacks for connection of external aerials. (including DRM receivers) Therefore to me such device was necessary to invent . Thanks for your attention to my device and valuable remarks. In the subsequent I shall try to eliminate lacks specified by you.

Vladimir