101E receiver sensitivity upgrade/mod?

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101E receiver sensitivity upgrade/mod?

Postby K7GLD » Tue Apr 12, 2011 1:31 am

I have just obtained a FT-101E "nostalgia boatanchor" to play around with - had one of the originals way back when.

On the older one I had, I had installed upgraded FET's in the receiver front end that greatly improved sensitivity on the higher bands - especially 10 meters.

I think the replacements were RCA devices, but don't remember the exact number, and am hoping someone here might have that older mod info or something similar they can share with me.

The only currently related mod I see, is the 3N211 replacing the 3SK40M's - has anyone here tried that, or any other similar devices to improve the upper band FT-101E sensitivity?
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Postby N2NF » Tue Apr 12, 2011 4:32 pm

Hi,

I have used the 3N211 in an FT-101B with good results. I'm not sure if Carol has any left in the candy store or not. I believe you are right though, the improvement is most noticiable on the higher frequencies. The Noise Figure rating for the 3N211 is better than the stock unit as well.

I have also used the NTE222 and NTE454 with good results as well. NTE has an online cross reference for semiconductors. I believe however these parts are now considered obsolete and at last check were very expensive from NTE.

73,
Bob
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Postby PA0PGA » Tue Apr 12, 2011 7:37 pm

In the original mod was the RCA 40673 mosfet used.
They are difficult to obtain nowadays, but I think Carol has some.

As far as I know, the mod worked very well on the higher bands.

73, Wim PA0PGA
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Postby K7GLD » Wed Apr 13, 2011 12:34 am

HMMmmmm - several different potential replacement types surfacing - unfortunately, without specifics or test data on any of them, it becomes a flip-a-coin selection. Guess I'll go with the 3N211's in the first RF and 2nd mixer stages, and see how much smoke I generate! :lol:
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