[HBR] Receiver specs

[Ian Wilson]

After some experimentation and even a few measurements <g>,
I've learnt that a low MDS isn't hard to achieve. Taking the 6BZ6
as an example, the equivalent noise resistance (ENR) is about
1140 ohms. In a 10kHz bandwidth system, this corresponds to
about 0.2uV RMS; the MDS will be something like 2x this.
If the preselector has some voltage gain, then the MDS will be
reduced even further.

These levels are much lower than the atmospheric noise and
QRM on the lower bands. As the quoted article mentions, most
boatanchors have more RF gain than necessary, and do better
at rejecting close-in stations when the gain is backed off.

73, ian K3IMW