Neil - There is no 'padding', this is more typical of broadband, solid state receivers.
The limitation on the Drake R-4A is a result of the tuning range of the Preselector. This control drives a four section variable L/C network in the Input and Output of the RF Amplifier and in the Input and Output of the PreMixer of the receiver. It's THERE narrow the bandwidth and protect the front end from 'powerful nearby broadcasters', both commercial and strong amateur signals. It was designed to cover from 1.8 to 30 Mhz, with a little extra on each end, appropriate for a 'shortwave' receiver.
It would be possible to add fixed capacitors across the ones switched in for BAND 1.5 to lower the RANGE, but at the expense of covering the high end of that band. The caps in question are C5 and C32 for the RF stage, and C44 and C123 for the Premixer. Possible, but NOT a trivial task.
There are LOTS of broadcast band receivers available out there! 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs <www.k4oah.com> Neil M Califano wrote:
I am able to tune part of the medium wave band on the Drake R4A, but the stations are weak even though they are powerful nearby broadcasters. I thought I saw that the sensitivity is padded below 1.6 Mhz. Is this true on the Drake?
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