[Boatanchors] Hammarlund HQ-170A vs. National NC-300

[Peter Markavage]

I use only Lafayette tubes in my radios.

Pete, wa2cwa

On Tue, 15 Jul 2008 22:13:50 -0400 <kim.herron at sbcglobal.net> writes:
> Hi Carl,
>     Yes, you do need to pay attention to the 6C4 tube.  It is a 
> problem 
> if that tube doesn't perform.  It needs to be a Sylvania, GE or RCA. 
>  If 
> you do that, you're in like Flynn.  Second tier supplier tubes DO 
> NOT 
> WORK, PERIOD!!!.  Can you say drifty???
> 
> Kim  W8ZV
> ----- Original Message ----- 
> From: "Carl" <km1h at jeremy.mv.com>
> To: "Bob Young" <youngbob53 at msn.com>; <boatanchors at mailman.qth.net>
> Sent: Tuesday, July 15, 2008 6:26 PM
> Subject: Re: [Boatanchors] Hammarlund HQ-170A vs. National NC-300
> 
> 
> > Over on another forum many of the later HQ owners complain about 
> > having to select a 6C4 that either doesnt continuously drift or 
> quit 
> > working at the lower end of the top end band. Then the life is 
> rather 
> > short.
> > Sounds like a design problem across many models.
> >
> > National made several changes in the NC-300 and there was also a 
> > factory alignment glitch in the early ones. With the second 
> conversion 
> > oscillator switch to xtal control (every 300 that came in for 
> service 
> > had that done automatically) drift was almost nil after a short 
> > warmup.
> >
> > I used the 300 primarily as an IF for 50 thru 1296 converters in 
> the 
> > early to mid 60's when AM was still more popular than SSB on those 
> 
> > bands. I believe I paid $100 for it and the speaker.
> >
> > My own TX gear was AM/SSB and CW and mostly homebrew with a 
> converted 
> > NCL-2000 on 6 (which I still use) and a pair of  4CX250B's on 144, 
> 220 
> > and 432 with a common PS and PP 811A's modulator. The NCL ran as 
> an AM 
> > linear at ~ 400W out and the other amps were switchable from Class 
> C 
> > to AB2.
> >
> > The NC-300 lasted for about 3 years and was replaced by a 75A4 
> with a 
> > Collins NB when SSB really caught on and QRM was often intense. I 
> used 
> > 10M for the IF and not Nationals converter band.
> 
> > Those were fun days.
> >
> > Carl
> > KM1H