[Boatanchors] FT-101

[Carl]

You can reduce the bias on either tube to work with lower drive and lose 
virtually no efficiency. There is no reason, other than generating key 
clicks and harmonics, to run in a deep, hard limiting Class C for CW. 
You can still run C but slide more to B or even run a hard B2 if 
desired.

What do you consider a low cost exciter? You cant get much cheaper than 
a Heath SB or a Drake T4 (no letter) if you dont mind building the PS. 
Ive seen both well under $100.

The Halli HT-37 and HT-32 are also dirt cheap if you look around a bit. 
I picked up a HT-32A for $75 that had a bunch of mods that I removed 
most. Thats now running with the SX-115 (a $100 purchase) that run with 
the NCL-2000 ( an engr prototype Ive had since 1964) for vintage SSB 
fun.

A big benefit of using a Class AB exciter is a clean keying waveform and 
low harmonics.

Carl
KM1H



----- Original Message ----- 
From: "Barrie Smith" <barrie at centric.net>
To: <revcom at wbsnet.org>
Cc: <boatanchors at mailman.qth.net>
Sent: Wednesday, September 03, 2008 3:07 PM
Subject: Re: [Boatanchors] FT-101


>
>
>
>> How much drive you need? Or, what are you wanting to drive?
>
> I'm working on two rigs right now.  Number one is a push-pull pair of 
> VT-127As, which are an early radar tube.  They have the plate of a 
> 100TL, and the grid and filament of a 250TL.
>
> It's possible that I'll need up to 75 watts of drive there.
>
> I'm also slowly rebuilding a push-pull pair of 450TLs that I first 
> built in the early 1990s.  It was driven by a 32V3, both RF and audio, 
> and worked very well.  However, due to the "old style" of 
> construction, with very little shielding, it was an enormous RFI/TVI 
> generator.
>
> I'm sure I'll need at least 120 wattas to drive that rig, but that's a 
> ways down the road.  I could build a buffer stage there.
>
> 73, Barrie, W7ALW
>
>
>>
>> Rod
>> K0EQH
>>
>>
>>
>>
>>>  By the way how can you own a Bird watt meter and not have a good
>>> dummy load? A light bulb?
>>>
>>> I do have a good dummy load, but it's just 60 watts.  Use it mostly 
>>> for
>>> setting-up 432 and 1296 transverters, and such.
>>>
>>> What's wrong with a light bulb?  That's what most of us used back in 
>>> the
>>> 1950s.
>>>
>>> Anyway, thanks for all the information, guys.
>>>
>>> Sounds as if the 101 won't make a good VFO/driver.
>>>
>>> That leads to another question:  What affordable rig would make a 
>>> good
>>> VFO/driver for a class C final?
>>>
>>> 73, Barrie, W7ALW
>>>
>>> _______________________________________________
>>>
>>
>>
>>
>
> _______________________________________________
>