Mackay 3007A receiver schematic

[D.J.J. Ring, Jr.]

As picture and attached.

73

DR

[John Davies]

This would have been a nice receiver to use though I never did. Single conversion superhets are quieter than dual or triple conversion because there is only one mixer, and mixers produce noise.

The choice of 1.7 MHz for the  I.F. is a good one as it is high   enough for decent image rejection, but not too high for achievable narrow  filtering on CW. 

Looks like a classic too with the ergonomic front panel. Very nice indeed.

John 9V1VV

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[Douglas L]

I had to use this Mackay 3007A receiver on several WWII clunker ships that I was

on and they were still sailing in the early 1980’s.

Frankly I didn’t think much of it:

the dial calibration was poor and the receiver was drifty. There’s no crystal control for the oscillator. Sensitivity and internal noise was

average at best.

If you note the schematic, the method of creating  more selectivity  was primitive at best.

  Overall? not a great receiver.

  Doug/WA1TUT

MREO - ex ROU 1978 to 1998.

On Feb 21, 2026, at 11:28 PM, John Davies <coup...@gmail.com> wrote:



This would have been a nice receiver to use though I never did. Single conversion superhets are quieter than dual or triple conversion because there is only one mixer, and mixers produce noise.

The choice of 1.7 MHz for the  I.F. is a good one as it is high   enough for decent image rejection, but not too high for achievable narrow  filtering on CW. 

Looks like a classic too with the ergonomic front panel. Very nice indeed.

John 9V1VV

On Sun, 22 Feb 2026, 09:24 D.J.J. Ring, Jr., <djri...@gmail.com> wrote:

<4628.jpg>

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[Douglas L]

This receiver from the schematic actually seems like it’s dual conversion. The output of the first mixer is 1700khz. However there is a crystal controlled second oscillator at 1770 Khz. A second mixer created a different 2nd IF of 70khz by using the 1770-1700 difference.

Another problem with this receiver was that B+ for the oscillators wasn’t regulated.

73,

Doug/WA1TUT

ex ROU MREO

On Feb 22, 2026, at 2:51 AM, Douglas L <spark...@yahoo.com> wrote:



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[John Davies]

Oh yes, it is double superhet. Missed the 70 kHz amp. 

Many of the UK and European receivers of that era suffered from drift also.  I sailed with the Marconi Elettra and Atalanta a few times. You had to chase the CW around a bit even when they had been left on standby for hours. 

John 9V1VV

To view this discussion visit https://groups.google.com/d/msgid/radio-officers/F98B8F8D-54E1-40FB-8736-551823DC13FC%40yahoo.com.