[Milsurplus] TBX-6 vs. TBX-8

[Ray Fantini]

TBX-8 and the TBX-6, First let me start off by saying that I am not proposing that the eight is somehow inferior to the earlier sets, or that the older sets are somehow better. I am just saying that my personal preference for the Non-eight is biased on personal feelings and not military logistical needs. And please allow me to just concentrate on the TBX-6 as a comparison of why I like the six over the eight and not concentrate on all the small differences between all the radios that preceded the eight and just use a generalization that all of the non-eight radios share very common characteristics that were eliminated by the development of the eight.
And at this point don't want to get into the theory of if the eight was developed in time for use in WW2 or too late for that conflict.
I think the thing that appeals to me the most about playing around with this stuff is that most military radio equipment by design is scaled down to the functional limit of the task required, with no extra frills or ornate aspects.
As a pre-war design the six is a master work of engineering. But in order to produce that radio the designers had to deal with several issues in a unique way. That results in items that were more or less unique to that family of pre eight radios not the least of them being the use of a specialized high output carbon microphone along with huge high current crystals for the transmitter.
All pre eight radios used manual switching between the receive and transmit mode that had to switch several connections that required manual local control and this makes it impossible to remote control.
And the 34 tubes used throughout the receiver were already obsolete by 1940
The TBX-8 solved all these problems. It used a separate oscillator tube so smaller "regular" crystals can be used. It had a microphone pre-amplifier eliminating the need for the special huge high output microphone and maybe most important of all there was a switching relay that allows Push to Talk and the ability to easily remote control the radio.
The modern tubes for the receiver were smaller and no longer required the use of an external filament rheostat.
So, on the surface it appears a "No Brainer" to say the eight is an all-around better radio, and you are more than welcome to think that.

I like the six for all the wrong reasons, first I like the fact that the receiver only uses two types of tubes the 1C5 and four 34 tubes. The 34 tube is amazing that it draws only 60 Ma @2.0 volts for the filament and works with a plate current under 3 mA and is designed just for using in battery powered sets.
The entire receiver only draws 300 mA on the filament that can be provided by two D cell batteries and  the B+ supply with a total current drain of under 10 to 15 mA and can be powered with a set of stacked nine volt batteries in series.
The 837 carries over to the eight but in the non-eight you have to use the big round crystals but so what, the radio has three positions in transmittC1, C2 and MO and I used the MO for all AM operations. Found that I can set the MO to 3885 at home and lock it and it was always on frequency in the field.
I never had the high output microphone but took a regular T-17 and installed a signal transistor in it and that gave plenty of gain to modulate the set as much as any of the field radios of the day. I have no problem modulating at seventy and eighty percent peak and have no desire to drive to the point of splatter anyway. Would think it's just about impossible to overmodulate a suppressor modulated radio anyway.
And the manual switching between receive and transmit, I don't ever plan to use the radio in a tactical set up with the remote so happy to not have a relay and added circuitry.
And that may be the last item is that the simpler layout, design and less complicated TBX-6 is in my opinion cleaner and a more logical layout then the eight where they had to start stuffing items into the case to make it all fit.
All that said the radios are not perfect. The receivers are broad by design and the mechanical tuning for the receiver is very touchy, would think that when operating CW that would be a issue and perhaps the one item that's the biggest problem for me is the lack of a AVC system. When operating in a NET like out at Dayton where you have multipole low power set like BC-611, MAB and DAV along with some people running higher power sets you are constantly adjusting the gain control to try to copy everyone.
All that being said I have not owned a TBX in about ten years but al this talk has got me thinking about one again. The non-eight is a great example of where we were in terms or radio just before WW2 and know if I had one today would have several new ideas for powering it. Can't help be seeing the WS-11 as a very similar radio.

Ray F/KA3EKH


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