[Milsurplus] Mackay/Federal 128AY vlf rx

Wed Mar 25 22:57:28 EDT 2009

I just dug out the manual for the 128-AY which is actually an Army TM from
1945, so my take is that it was probably used by the Army Corps of Engineers
on their vessels. They had the tendency to use civilian origin equipment.
Just as the RMCA AR-8506 has an Army TM (post-WW2) and has the Army
nomenclature R-203. I have one of these, with contract date 1952. It is in a
stand-alone desktop cabinet with shock mounts, a la Mackay 128-AY. This must
be also the Army Corps of Engineers - both manuals mention shipboard
installation.

I never saw any reference to a 128-AV however, only to 128-AX and 128-AY.

The EC-2 type Liberty Ship radio installation manual (came with my Federal
Telephone and Radio Corp. FT-102 HF radio console (Mackay 167-BY 2-24 MHz
transmitter - CW only - with a pair of 813's in the final and either an RMCA
8506B or Scott SLR-F receiver, filler panels provided with the console to
accommodate the differences between panel dimensions of the receivers) calls
for the FT-102 to be installed as an addition to the FT-101 or FT-105 IF/LF
console, and mounted by the adjacent wall, 90% to the "IF" console.
Looks like maybe the earlier Liberty Ships were only equipped with LF/MF
stations. The FT-105 and FT-101 had the Mackay 150AY IF transmitter (CW and
ICW modes) and Mackay 128-AX receiver, a second section of the console
containing the antenna transfer switch, the 123-BX emergency crystal
receiver and transmitter power transfer switch. The transmitters used the
same motor generator in the FT-101/105, using the transfer switch.

The FT-106 may be a later setup nomenclature where the HF console is the
third section integrated with the original 2 section IF/LF etc. console.
Otherwise the configuration/wiring and equipment is the same. This 3 section
console is also found in Victory ships.

Ken, the Mackay 167AY and 155AY you're mentioning are not familiar to me.
Are they WW2 Maritime Commission contracts or maybe the post-WW2 version
commercial units. Can you look at their labels?
My FT-102 with everything in it is 1944 manufacure, Maritime Commission
contracts.

Here is the photo of my - then still ugly cosmetically FT-102 which by the
way was on the air regularly last year with a homebrew power supply:
http://www.royalsignals.org.uk/photos/wf2u.htm  
 I fixed up the paint on the front panel where it was chipped off, I put an
SLR-F receiver in which I restored, while the RMCA 8506B which came
installed in the console is undergoing restoration, It worked OK before I
pulled it with some intermittent fluctuations in the audio gain. Now it's
getting the full going over and will replace doubtful caps/resistors. I'll
probably turn it back on in a few weeks and will put it back into the
FT-102, leaving the SLR-F as a standby receiver. I think the SLR-F may be
the better receiver, I'll have to compare them side by side.
The 167-BY puts out a healthy 350W CW on 80 M. and worked a lot of stations
with this setup.

73, Meir WF2U
Landrum, SC

-----Original Message-----
From: milsurplus-bounces at mailman.qth.net
[mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Ken Kinderman
Sent: Wednesday, March 25, 2009 8:29 PM
To: milsurplus at mailman.qth.net
Subject: [Milsurplus] Mackay/Federal 128AY vlf rx

Marty, I have a schematic and detailed desrciption the 128-AY which I will
send to you when I get back home early in April. Contact me off-list with
your address.

Don't know the difference between the -AY and the -AV, but they sound like
the same radio. The 128-AV was used in the Mackay FT-106 Liberty Ship
ensemble: three bays 6 feet high, 87 inches wide, and 19 inches deep, c/o:

1) The HF unit (2-24 Mcs. pair of 813's CW and MCW, also called ICW). TX:
167AY; RX: the Scott SLR-F (mil: RCH),

2) The LF unit (350 to 500 Kcs, a pair of F-123-A's in parallel for 200
watts CW and MCW/ICW) TX: the 155AY; RX: the 128-AV regenerative.

3) An additional bay c/o standby main (LF) TX, auto alarm RX, emergency
crystal RX tuned to 500 Kcs, and some power and antenna switching circuits.

Running across all three bays was an operating shelf; the center bay was
lower than the two end bays and held a Royal or Underwood typewriter (caps
only, please!)

Below were the motor generators and starters and a DC powered inverter for
the Scott radio which needed 110AC. The main MG provided 200 volts AC at 720
cycles to the primary of a plate transformer, thence to 2 866A's.

Power on the Liberty Ship's was 110 DC from several steam powered generators
in the engine room, hence the AC/DC power supply in the 128-AV.

The "Main" ensemble was the LF, as communications near shore and in harbor
was generally conducted below 500 Kcs.

A competing set, called the 4U, was made by Radiomarine Corp of America
(RMCA) with virtually the same specs and used RMCA receivers.. a superhet
for 2-24 and a regen for 15 to 650 Kcs.

Eight hefty eye hooks on the cabinets for dropping into the radio room.

I have both the Mackay and RMCA HF units, plus some other units, but not all
three bays.

Rob, take note... I have the motor generator and the GE starter. When it
comes time to fire it up I'll let you know. My idea is to use my 2KW Honda
and a very large bridge rectifier (which I have) to get it rotating.

One more interesting note: MCW was accomplished by feeding 720 cycle AC from
one of the windings on the motor-generator directly to a modulation
transformer, and keying the primary.

The above info is from a a great book called The Radio Manual (McGraw Hill,
4th Ed. 1950).

73,

Ken
W2EWL
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