[Boatanchors] FT-101

[Rodger]

Barrie,

The bottom scale on the meter should be .5 amps (500 mils) full scale so 
set the bias where it is just over halfway between the 0 and .1 on the 
lower scale.

Sweep tubes hold up fine if you are careful with them.  One of the most 
common mistakes is to reduce loading to reduce power which results in 
damage to the screen so you want to load it fully for rated input and 
then reduce power by reducing drive.  Tune-up must be done quickly to 
avoid overheating the tube.  I think most of the FT-101 series came with 
a cooling fan for the finals, if not it is best to add one.

If you are using it only for a driver for a class C rig it is possible 
to increase the bias and thus reduce the plate idle current.  This will 
increase tube life and decrease the heat generated somewhat.  Drake 
provided advice about doing this for some of their 4 line equipment when 
it was used for novice CW operation at reduced input.   You would have 
to set the bias back to normal if you ever use it for SSB.  For using 
you FT-101 as an exciter for a class C final you could adjust the bias 
to the point where plate current is almost cut off and this would be the 
most efficient operation as an external VFO.

73, Rodger WQ9E

Barrie Smith wrote:
> I tested both of the newly aquired FT-101s over the weekend.  Into a dummy load, I got in about 120 watts, according to the Bird.  I think I could have gotten more, but I was using a 60 watt dummy load and I didn't want to burn it out.
>
> A couple of questions:  According to a set of tune-up instructions I found on the web, the bias is to be set at 60 ma.  On the FT-101 meter, I see on the top "60 db", the next line is .1, .2, .3 etc.  The third line down is ALC.  There is no line on the meter that reads ma.
>
> I think the second line down, and .6 would be 60 ma?
>
> I was going to sell both of these rigs (the FT-101E & EE), but now I'm thinking of keeping one of them as a VFO and driver for push-pull class C rigs (not linear amplifiers).
>
> I've never owned a sweep-tube until now, so I wonder how well these tubes would stand up producing 50 to 100 watts (in CW mode) continuously for several minutes?
>
> 73, Barrie, W7ALW
>
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