[Boatanchors] Available Tube VLF Rcvrs

[Bill Stewart]

Can anyone recommend a  tube type VLF rcvr which is still available at a reasonable cost. I'm not real sure what a practical low limit would be, but low enough for most beacons and up to 500kc plus. Would the SAQ 17.2kc freq be considered 'practical'.  Also, I expect the weight should be a consideration if shipping is involved. Tnx for your opinions. 
73 de Bill K4JYS