Icom's old IC-706 (I use one of the first Mk1 models) is a good, cheap radio for receiving on 136kHz and 472/500kHz. Its sensitivity is not good enough for a poor antenna, but if you have a decent size tuned Marconi suitable for transmitting, it is more than adequate. The receiver pre-amplifier even works at 136kHz.
One advantage is its impressive frequency stability - after a few tens of millihertz warm up, my 706 stays within 10mH forever! Tuning steps, and readout are 1Hz. These features make it very suitable for the extremely slow Morse (eg QRSS60) used for intercontinental working on 136kHz.
The main drawback is its intermodulation performance, especially in view of the very weak amateur radio signals found at LF/MF compared to the strong signals out-of-band signals received by the antenna. In my case the principle problem is the medium wave broadcast transmitters located at Brookman's Park, just 10km or so away (LF guru M0BMU is less than 1km from this station), and these can cause problems on 500kHz and 1.8MHz. To improve the suppression of unwanted signals, I use a G3YXM tuned preamplifier for 136kHz, and have just added a parallel-tuned circuit across the antenna coax when using 472/500kHz.
