SDR puzzle

20-Oct-14 11-10-15 AM

Just starting with SDR, so forgive my ignorance. Here is a HDSDR puzzle:

I installed HDSDR and hooked the RTL-SDR adapter up to my TS-590 on the tune connector CN303 (1st IF on RX-2, 73.095MHz). Cable is a normal coax cable with on the center a 100pF cap (don’t know what it’s for, but they told me to put that in). Final objective is to use HDSDR to see the spectrum and to tune the radio.

At first i thought things were not working because i didn’t hear anything on the SDR. Then i tuned in between 70 and 75MHz. Turns out that i hear my TS-590 when i tune the SDR on or around 75.550MHz. First question, why is that? Why is it not 73.095MHz?

Ok, so now i hear my radio. Let’s tune to a frequency where i have good reception and where there is always traffic, 28.120MHz, the PSK31 frequency on 10 meters. Nothing. I do hear my PLC, so i suspect that the frequency i am listening to is far below 28.120MHz. Dialing up i hear truckers on 28.230MHz. They tend to be on the CB band, so that confirms my suspicion that i am listening to 1Mhz below what my radio tells me.

I looked for a strong station on the 10m band and noted down frequencies. This is what i found:

  • Real frequency where station is transmitting: 28.465MHz
  • Frequency displayed on the radio: 31.350MHz
  • HDSDR LO is set to 75.550MHz
  • HDSDR Tuned frequency is 75.1275MHz

Now i need to understand what is happening and calculate the various offsets you can set in HDSDR.

To be continued…

Two new projects in the pipeline

tcxoOne is the installation of a chinese TCXO unit. The original Kenwood SO-3 TCXO units are around 150 euros and i never saw the purpose for it. But now people on the Kenwood TS-590 Yahoo group bought and tested a chinese SO-3 replacement. They seem to work as good as the Kenwood ones but they are a lot cheaper. I got mine from eBay and payed 17 euros for it. The come including a small board so you don’t have to solder them unit in. So, even if i will never see the need for the TCXO unit, for 17 euros i upped the value of the radio with a 100 bucks.

Second project is hooking up the TS-590 to an RTL-SDR receiver and being able to look at the whole band using SDR software. From what i understand from this video the “only” thing i need to do is hook up a wire to CN303 on the board and get that wire into the antenna in of the RTL-SDR. Let’s see if i can get this to work. Any hints, corrections, potential risks, etc up front would be appreciated.

Glad to be back on HF

Couple of things to report:

1) I got bored on 11 and 10m because “propagation was bad”. I don’t know if i got lucky, but the last week i was ONLY on 10m making lots of really nice DX contacts. Worked several new countries. So what is the cause? Propagation or the quality of the radio? Check out my log for the new DXCC. And all this with my 1,25m “dummy load”.

2) Regarding PLC noise, Wimo boxes and stuff like that. Check this video. This is with an idle PLA and no Wimo, just the NR from the radio itself. Amazing. On the HAM bands i hardly have any PLC noise, but if i get some i know the radio can handle it.