Receiving DRM with Kenwood TS-450S (II)

For those who are interested in receiving the DRM using the TS450 radio by Kenwood, here is a pdf file with the details and circuit. Remember it's also valid for TS690, TS850 and TS950 radios wich has 4th IF output at 36.891KHz for use with optional DSP-100.
I am waiting for any feedback.
73!
Here is a demo video:

RF interference from Sony TV set

I had a Sony TV set model KV-14M1E. Every time it was turned on(even in stand-by mode) I received an annoying QRM from it in my amateur radio. Since I know that the interference came by radiation one day I decided to open the TV and explored the circuit with a small loop probe. You can see how I did it in the next video:



I discovered two loops radiating RF:


Like a solution I was thinking about decoupling these loops with the right capacitor but I had got no time to do the modification, the TV set was taken away from my QTH.
Now my spectrum is clear, more or less, of human-made QRM.

Receiving the Digital Radio Mondiale with Kenwood TS-450S and series

The TS-450S radio and related series(TS-850, TS-690) has a connector in rear panel labelled as DSP2. This connector was original used to supply the 4th IF to optional DSP-100. This signal has a frequency of 36.891 KHz, so with a simple converter it can be moved to 12KHz, then sampled with a computer's soundcard and processed with any SDR software.

I use this signal to receive the Digital Radio Mondiale with Dream Software.

I made a prototype converter, based on a double balanced mixer. Now I am working in a more sophisticated mixer with less intermodulation and higher SNR.

The prototype

Yaesu YHA-63 antenna

This is the data taken with a network analyzer from the Yaesu YHA-63 antenna. This antenna come with the FT-817 package and in my opinion is a good dummy load.

S11 parameter of long version


SWR parameter


Results of the short version are the same without the 50MHz band.

Blog created

Hello all and wellcome to my blog in the net. I am EA1GHE amateur radio from Spain.
With this blog I will try to publish articles concerning amateur radio, specially technical ones.
I hope you like it.

Teleno mount(2188 m), near to my QTH.