[CW] Mackay 3010B tube receiver

Sun Sep 15 21:46:01 EDT 2019

   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
> 
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> =30=
> 

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL