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A Panoramic Adapter For the Kenwood TS-590SG
Based on the AirSpy SDR

HF ste-up

The aim of this project is to use a software defined radio as a panoramic adapter, or bandscope, for my Kenwood TS-590SG transceiver. I chose the AirSpy SDR because of it's wide bandwidth which can be up to 10MHz. As the AirSpy only goes down to around 25MHz I also needed an up-converter in order to cover all the amateur HF bands, rather build one I bought the HamItUp converter. To be of real use we need the SDR to tune with the TS590-SG and this can be achieved using Omnirig.

I also use OmniRig / Ham Radio Deluxe Bridge by WD5EAE to ensure that Ham Radio Radio Deluxe works at the same time as HDSDR. After some messing around I determined that, for my set-up (Windows 7 Pro, i5 laptop), I need to turn on the programs thus: HRD followed by HRD Bridge then HDSDR. HF ste-up

At the time of writing the up-converter is on a ship wending it's way across the Atlantic (or stuck in Customs) so the current set-up has only been tested on the 10m and 6m amateur bands. The image right shows my overall set-up from antenna to laptop screen (click images for larger versions).

The TS-590SG can be programmed from the Menu to split the antenna and feed it to the DRV phono socket on the rear panel as well as the RX. (MANUAL: Page 52, Press and hold down the METER (DRV) button to switch to Antenna output, an * will appear on the right hand side of the TS-590 display. The antenna will now be split (-3db) between the RX and DRV socket.) Playing with this output and the AirSpy plus HDSDR revealed that the AirSpy sees a large signal, S9+20db, when the TS-590 is transmitting CW at 5 watts CW output and the AirSpy input is open circuit. So something needed to be done to protect the SDR from overload:

input protection

The circuit, above, shorts out the input of the AirSpy (eventually, the up-converter) when the TS-480SG is transmitting. It makes use of the normally closed relay contacts of the REMOTE socket on the rear panel and this holds the transistor switched off. input protection (MANUAL: Page 73, Menu Item number 59, select option 2 to switch relay on.) On transmit the relay contacts open and the transistor conducts and the relay is energised. The contacts switch the AirSpy input to Ground and 100 watts of CW now produces only an S5 on the HDSDR S meter. All these levels are mainly due to radiated RF and 100W CW at 28MHz into a dummy load produces S3 on the HDSDR S meter.

The next issue I encountered was QRM from the the walwart that powers the dedicated USB hub, whilst not particularly high it does add clutter to the HDSDR display. So I decided to build a linear power supply using a 7805 regulator which would suppply 1.5A at 5 volts. Currently under construction, I expect the PSU to be a lot quieter that the original walwart. input protection

The image below shows the AirSpy and it's control box sitting atop the TS-590SG, the display show HDSDR with both the SDR and TS-590SG tuned to 28.501260MHz.