[Milsurplus] TBX info

[Ray Fantini]

With all this talk about the TBX did want to take the opportunity to sing parse to the design of the receivers in the early versions of the TBX like the 4 or 6.
That receiver was a simple super heterodyne designed largely around the 34 tube and although lacking a AVC system and prone to overloading in close proximity to other radios the simple design, use of only three different type of tubes in the receiver and the ability to operate from 90 volts at under 10 mA was always an amazement to me. That along with the transmitter that produced ten or so watts CW and a couple watts AM with just one 837 tube also blew me away. I operated a TBX-4 a couple times at Dayton netting with BC-611, pogo sticks and newer radios and found that radio a fun set to use. I had built solid state inverters to provide the 500 volts for the transmitter and the 90 volts for the receiver along with couple D cell batteries for the filaments and a 12 volt gel cell that ran the 837 filament and the inverter. Cannot imagine the sheer terror of trying as a "radio squad" to carry all that stuff ashore at Tarawa and one keep it dry, two get all the parts like the hand crank generator for the transmitter, dry battery case and antenna assembly in place and then attempting to hear the receiver with open headphones of the era in combat but in operating the radio by itself with modern accessories it's a great box to play with. Don't know why but the TBX-8 with its loctal tube line up and three tube transmitter never appealed to me but the older TBX family of radios point to that prewar design mentality and can see if not directly related to the FPS radios you can still see the family linage. If the FPS radios had super Het receiver's regardless of the layout they would be cousins.

Ray F/KA3EKH

-----Original Message-----
From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Hubert Miller
Sent: Wednesday, February 15, 2017 3:37 PM
To: Military Surplus Mail List <milsurplus at mailman.qth.net>
Subject: Re: [Milsurplus] TBX info

No - SPF is not being confused here. Yes, it does tune around 3 - 3.3 MHz. Yes, i still have 3 in the wooden storage "kit boxes" i bought from you way back when.
It occurred to me that the model SP ( i think sometimes called SP-1938 ) due to its horizontal format looks "something" like the format of the TBX. However, resemblance does not imply  any other connection. I think if someone gave a presentation where this was claimed, that claim is simply unfounded. Both models of SP had a regenerative receiver. 
Ah yes, the "Yellow Sheets". I well remember opening it as soon as it arrived and looking for the bargains.
-Hue 

-----Original Message-----
From: George Babits [mailto:gbabits at custertel.net]
Sent: Wednesday, February 15, 2017 6:34 AM
To: Hubert Miller <Kargo_cult at msn.com>; Military Surplus Mail List <milsurplus at mailman.qth.net>; w8au at sssnet.com
Subject: Re: [Milsurplus] TBX info

Is the SPF being confused with something here?  It bears no resemblence to 5 meters at all.  If I remember right the SPF covers around 3 to 5 MCs give or take.  The last couple I had were crystaled up for the "back country" 
freuency around 4.6 MC.  As late as 1984 the forest service still "claimed" 
3.325 as one of their frequencies.  I've seen pictures of CCC guys using them pre-war.  They continued in use well into the 1960s and I've known several people who used them in the field.  Back in the 1980's I probably rounded up a8 to 10 of them locally (Salmon, Idaho.  I wouldn't be suprized if those Hue has came from me via the Yellow Sheets.

73,
George
W7HDL

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