I was looking for a secondary radio for RX only and I thought a SDR may be a better option. I read about upconverters but then I saw Airspy has a SDR with the upconverter onboard, and claims to have "low-loss preselection filter, high linearity LNA, high linearity tunable RF filter, a polyphase harmonic rejection (HR) mixer that rejects up to the 21st harmonic and multi-stage analog and digital IF filtering", which got me curious, since most "cheap" SDRs don't have preselection filters and are easily overloaded (this is also true for cheap HTs like the BAOFENG which, in my experience, are significantly improved by an external filter).
The specs on this radio are (I have highlighted specs which I discusse further down):
- HF coverage between 0.5 kHz .. 31 MHz
- VHF coverage between 60 .. 260 MHz
- Sensitivity: -140.0 dBm (0.02 µV / 50 ohms at 15MHz) MDS Typ. at 500Hz bandwidth in HF
- Sensitivity: -141.5 dBm MDS Typ. at 500 Hz bandwidth in FM Broadcast Band (64 – 118 MHz)
- Sensitivity: -141.0 dBm MDS Typ. at 500 Hz bandwidth in VHF Aviation Band (118 – 260 MHz)
- Linearity: +15 dBm IIP3 on HF at maximum gain
- Linearity: +13 dBm IIP3 on VHF at maximum gain
- Dynamic Range: 110 dB blocking dynamic range (BDR) in HF
- Dynamic Range: 95 dB blocking dynamic range (BDR) in VHF
- Selectivity: 150+ dB combined selectivity (hardware + software)
- Image Rejection: 120 dB (software)
- Filtering: Polyphase Tracking filters for close range interference suppression
- Filtering: New High Performance Pre-selector for HF with 4 filter banks (corners at ~DC, 5, 10, 17 and 31 MHz)
- Filtering: New High Performance Pre-selector for VHF (Air, HAM, Commercial and Military VHF)
- Filtering: New High Performance Pre-selector for the FM band (Japan, US, EU, OIRT)
- Up to 660 kHz alias and image free output for 768 ksps IQ
- 18 bit Embedded Digital Down Converter (DDC)
- 22 bit Resolution at 3 kHz channel using State of the Art DDC (SDR# and SDR-Console)
- +10 dBm Maximum RF input
- 0.5 ppm high precision, low phase noise clock
- 1 PPB frequency adjustment capability
- Very low phase noise PLL (-110 dBc/Hz @ 1kHz separation @ 100 MHz)
- Best Noise reduction of the market using state of the art algorithms
I tried to compare it to my TS-450S which, in page 6 of the manual states a sensitivity of 2uV for SSB, but it doesn't specify the bandwidth. The claims in the Airspy product specify 0.02uV a 500Hz bandwidth. That's a whopping FORTY dB improvement. Which to me sounds "too good to be true".
My kenwood also states a selectivity of "-6dB: More than 2.2khz, -60dB: Less than 4.4khz". The Airspy HF claims "150dB+", which I don't know how to compare.
In all, would this be a good addition to my shack? I believe even if the analog specs are similar to my almost-30-year-old-radio, it has the advantage of IF DSP, which is something that didn't exist back then, and something I can't afford afford at the moment.
Will it be an improvement over what I have now?