I know now whi I haven't kept up on this thread, tried to rread the 
quoted stuff and those damn equals 20s, I usually skip those.  The 6146 
is a good stable tube, but if you're running a couple of them, you're 
pushing them pretty hard I think.  Also, wheren't 6146 b tubes a bit 
better on plate dicipation.
73
Butch
WA0VJR
Node 3148
Wallace, ks.


On Wed, 3 Dec 2014, Howard Kaufman wrote:

> That begs the question, why is the bios not staying stable?
> Its not the tubes, its what is ruining the tubes.
> I have never used the ft-102, but I have used the ft-101.  Not sure how
> different they are, but might be a lot.
> The ft-101 did not use 6146 finals, as I recall.
> With those PI networks, its not the output that is critical, but having the
> final tuned to resonance.
> Nobody will ever hear the difference between 185 watts and 140 watts output.
>
>
> -----Original Message-----
> From: For blind ham radio operators [mailto:[log in to unmask]]
> On Behalf Of Michael Ryan
> Sent: Wednesday, December 03, 2014 7:18
> To: [log in to unmask]
> Subject: Tubes
>
> Howard:=20
>
> If you read through NC4L Mal's web pages devoted to the 102, the blown =
> fuse issue indicates a run away in the tubes. Once this starts, the grid =
> screen becomes contaminated and weak.=20 The 6146W has a plate dissipation
> of 25W and I have been pushing them a = little harder, tuning up to the
> 102's maximum 185 key down.=20 I should have kept it back a little to the
> 300MA current level instead = of 350 and limit things to no more than 150W
> key down, using the 2 times = the plate dissipation as a max.=20 However
> that's what Mal recommends and standbys them due to the enhanced = vibration
> handling capability of the W. This tube was meant for the = mobiles back in
> the 50s/60s.=20 There's another camp however that stand firm about using the
> 6146B. Its = an older tube that has a higher plate dissipation of 35W.=20
> Now RF Parts carry the Taylor 6146B in a matched set of 3 and I'm = thinking
> of giving those a try if nothing else, they will give me a = higher headroom
> for tuning. =20 I use a TW-1 for this and even though there's a couple on
> this list who = don't like them, I don't think that there's that big a
> discrepancy to = cause tube damage. In fact, my TW-1 corresponds with the
> meter in my =
> 986.=20
> As for the receiver, the FT-102 can run circles around the IC-756 Pro = III,
> TS-950 with a blocking dynamic range of 130DBM and a 3RD intercept = point
> of 19DBM. Not quite as good as the IC-7600 and FTDX series but = when it can
> beat the TS-950 and IC-756 Pro III, 20 years behind them, = that's
> something.=20 I have found that listening to my 102 the past 2 1/2 years,
> I've gotten = a new appreciation for a good quality receiver and I really
> don't think = anything is available in the 2K range. I've heard the
> IC-7700/800 on you = tube and with the speaker that was used, it came pretty
> darn close to my =
> 102.=20
> Its worth your while to google NC4L's 102 site and have a read. Then =
> you'll know why I love this radio so much. Its probably like your Drake.=20=
>
> I'm pretty sure there are times when your drake probably beats = everything
> in the shack but its the convenience of simply pressing a = button and
> hearing everything you need to hear with regards to settings = and so on.=20
>
> 73:=20
> Mike VO1AX=20
>
>
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