[CW] Mackay 3010B tube receiver
D.J.J. Ring, Jr.
n1ea at arrl.net
Sun Sep 15 21:53:10 EDT 2019
It was my understanding from reading manuals years ago that the C model
added product detector.
Now is over 40 years ago, so my memory might be corroded.
73
DR
On Sun, Sep 15, 2019, 21:46 Richard Knoppow <1oldlens1 at ix.netcom.com> wrote:
> Check to see if its really a C. About the only difference is
> the addition of a TC cap in the VFO. The manual for the C says B
> on it but has the additions for the C.
> There is a manual with specs at BAMA under MacKay.
> I don't know who actually built these but probably Federal
> Radio, who was the manufacturing division of ITT.
>
> On 9/15/2019 6:13 PM, D.J.J. Ring, Jr. wrote:
> > I have a Mackay 3010B that Quincy Electronics gave to me in hopes
> > of selling it.
> >
> > Info here: http://www.w1vd.com/Mackay%203010B.html
> >
> > *Mackay 3010B*
> >
> >
> >
> >
> >
> >
> >
> > *Front end attenuator OFF:*
> >
> >
> > *Band* *MDS* *Blocking* *Two-tone D.R.*
> >
> >
> > *(20 kHz)* *(20 kHz)*
> >
> >
> >
> >
> > 80 meters -146 dBm 93 dB 68 dB
> > 40 meters -141 dBm 96 dB 67 dB
> > 20 meters -140 dBm 102 dB 68 dB
> >
> >
> >
> > *Front end attenuator ON 1st position:*
> >
> >
> >
> >
> >
> >
> > *Band* *MDS* *Blocking* *Two-tone D.R.*
> >
> >
> > *(20 kHz)* *(20 kHz)*
> >
> >
> >
> >
> > 80 meters -135 dBm 94 dB 66 dB
> > 40 meters -128 dBm 98 dB 69 dB
> > 20 meters -126 dBm 103 dB 69 dB
> >
> >
> >
> > *AM Audio S/N:* 43 dB
> >
> >
> >
> >
> > *AM Audio Frequency Response: *
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > *100 Hz* *200 Hz* *400 Hz* *600 Hz* *800 Hz*
> *1 kHz* *2
> > kHz* *3 kHz* *4 kHz* *5 kHz* *6 kHz*
> >
> >
> > -4 dB +1 dB 0 dB +2dB +2 dB 0 dB -2 dB -10 dB
> -24 dB
> > -40 dB -
> >
> >
> > *AM Audio Distortion: *
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > *Mod%* *100 Hz* *200 Hz* *400 Hz* *600 Hz*
> *800 Hz* *1
> > kHz* *2 kHz*
> >
> >
> > 30% 13% 8.9% 7.1% 6.3% 5.6% 4.5% 4.0%
> > 50% 13% 7.9% 6.3% 6.3% 6.3% 6.3% 7.9%
> > 70% 20% 13% 11% 10% 7.1% 6.3% 7.1%
> > 90% 32% 22% 16% 14% 11% 7.9% 7.9%
> > 100% 40% 25% 18% 16% 13% 8.9% 8.9%
> >
> >
> >
> > *Notes:* This receiver is pretty uncommon so a few comments are
> > in order. With 0 dB front end attenuation and maximum i-f gain
> > this receiver has extraordinary gain and sensitivity - especially
> > at the lower frequencies. Designed mainly as a shipboard receiver
> > it is likely this receiver would have performed well on 500 kHz
> > with the ships antenna fully encrusted in ice and laying on the
> > deck! Words can not adequately describe the unbridled gain of
> > this receiver - you'll just have to try one for yourself.
> >
> > The receiver is extremely well built on a cast aluminum
> > foundation in which individual stages occupy their own
> > compartments. DC and bias voltages enter through feedthrough
> > capacitors and signal openings from compartment to compartment
> > are kept as small as possible. One wishes all receivers were
> > built this way!
> >
> > Unfortunately, the blocking and two-tone dynamic range numbers
> > tested disappointingly low - even with the i-f gain of the
> > receiver cut way way back. Considerable time was spent to insure
> > that the receiver was functioning, as best as one can tell, to
> > factory specifications. All voltages were correct, as was LO
> > injection levels when compared with the figures given in the
> > manual. The rf circuitry used is somewhat unconventional. The
> > receiver covers from 70 kHz to 30 MHz and uses up conversion to a
> > first i-f of 38 MHz. The main signal path includes a manually
> > switched front end attenuator, manually switched front end
> > bandpass filters that feeds a single stage 7788 tube rf
> > amplifier. Signal from the plate of the rf amplifier passes
> > through a 14 section 30 Mhz low pass filter. This is applied to a
> > 6C4 cathode follower that feeds the first mixer - a quad of 1N82A
> > 'VHF' diodes in a balanced design. The signal is amplified and
> > filtered by two tuned circuits, a single 6688 amplifier tube and
> > two more tuned circuits. A 6BL8 triode section forms another
> > cathode follower which feeds the grid of the 6BL8 pentode section
> > as the 2nd mixer with an output at 5.94 MHz. A somewhat unusual
> > arrangement has the LO injection in series with the rf signal to
> > the grid. The plate of the 2nd mixer passes through a 6 kHz wide
> > crystal lattice filter. From there it's on to the third mixer - a
> > 6BE6 converter stage - for the final i-f of 455 kHz. Here, the
> > signal encounters the Collins mechanical filters for either SSB
> > or CW. No additional filter is used here for AM - just the 6 kHz
> > filter in the previous i-f. The remainder of the circuitry is
> > pretty straightforward. One nice feature of this receiver is that
> > it does have a product detector.
> >
> > This receiver was on loan so it was only possible to observe its
> > performance - not modify the receiver to try to improve it. In
> > order to locate the source of the poor dynamic range a high
> > impedance probe / spectrum analyzer setup was used to 'sniff' IMD
> > stage by stage. The culprit turned out to be the 6BL8 second
> > mixer stage. With simple tests and limited time I was unable to
> > determine the exact cause of the poor IMD performance but would
> > suspect the 6BL8 biasing, or more likely the crystal filter in
> > the plate circuit or the VFO amplifier which has it's output in
> > series with the rf signal. Even if the IMD could be improved in
> > the second mixer, next in line is the third mixer - a 6BE6
> > converter - generally a dynamic range 'show stopper' in receivers
> > where it's used. This would be one fun receiver to modify for
> > truly high performance!
> >
> > The AM distortion numbers show the somewhat typical increase at
> > lower audio frequencies - most often caused by the low audio
> > frequencies riding on the AGC line. Also there is the usual
> > increase in audio distortion as the modulation percentage
> > increases. This is due to the detector's inability to cleanly
> > demodulate the higher amplitude levels although this receiver
> > does pretty well.
> >
> >
> >
> >
> > It probably works but there is no schematic and there is no power
> > plug. The power plug it appears is like a vacuum tube octal
> > plug. It has no outer cabinet, it's rackmount.
> >
> > Obviously there are other connections there as well.
> >
> > I'd have to crate it - either in wood or cardboard.
> >
> > Then mail it - it's heavy.
> >
> > You have to either pick it up in Marshfield, MA or have me pack
> > it and post it.
> >
> > Cardboard is cheaper but I know a carpenter who can make a box as
> > long as the box keeps the package under 70 pounds, it's good to go.
> >
> > Inside the crate will be anti-vibration materials.
> >
> > You're paying for all of this if you want me to post it.
> >
> > Or you can pick it up where I live. Free no extra cost..
> >
> > Make a reasonable donation $100 or more and agree to pay the
> > shipping cost and it's yours.
> >
> > 73
> >
> > DR
> >
> > ______________________________________________________________
> > CW mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/cw
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:CW at mailman.qth.net
> > CW List ARCHIVES: http://mailman.qth.net/pipermail/cw/
> > Unsubcribe send email to
> > cw-unsubscribe at mailman.qth.net
> > Subscribe send email to cw-subscribe at mailman.qth.net
> > Support this email list: http://www.qsl.net/donate.html
> >
> > =30=
> >
>
> --
> Richard Knoppow
> 1oldlens1 at ix.netcom.com
> WB6KBL
> ______________________________________________________________
> CW mailing list
> Home: http://mailman.qth.net/mailman/listinfo/cw
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:CW at mailman.qth.net
> CW List ARCHIVES: http://mailman.qth.net/pipermail/cw/
> Unsubcribe send email to
> cw-unsubscribe at mailman.qth.net
> Subscribe send email to cw-subscribe at mailman.qth.net
> Support this email list: http://www.qsl.net/donate.html
>
> =30=
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/cw/attachments/20190915/3dcaaded/attachment-0001.html>
More information about the CW
mailing list