[Hallicrafters] Re: More questions on SX-100

Sun Jul 18 22:24:27 EDT 2004

Let me add some input to Phil's goal here. 	

He is a beacon seeking needle in a haystack variety of listener. I seriously
doubt any vintage receiver is capable of doing what he demands of a receiver.
They were never engineered for what he wants to hear.	

Most modern receivers are not even able to grab onto and pull that faint signal
he wants to hear out from among several others on, or very close to, the
frequency. Many of these low power beacon seekers use narrow CW filters cascaded
to get well below 150 Hz, some as low as 25 Hz. Factor into this eliminating
almost all receiver internally generated noises, and synthesized racket from
today's technology, and doing what Phil needs is extremely difficult to achieve.
Just to hear these super faint signals is an accomplishment, but to do this, a
noise floor of almost zero is mandatory. 	

Phil is one of those guys who enjoys finding a needle in a haystack, as his list
of beacons logged posted on the HCI web site clearly demonstrates. 	

The SX-100 is a very good receiver and it performs well, but for what he wants
to do, it simply is inadequate. The only receiver I can think of that might even
come close to working for him is the Collins R-390a. 	

----------
From: Ken Kaplan <krkaplan at cox.net>
To: Philip B Atchley <ko6bb at juno.com>; hallicrafters at mailman.qth.net
Subject: [Hallicrafters] Re: More questions on SX-100
Date: Sunday, July 18, 2004 7:27 PM

Phil,

Well I have an HQ-180AC and an SX-100 Mk 2. Both are in CCA excellent condition.

I've found that the HQ-180 is drifty compared to the SX-100. I always have to
tweek 
the Vernier Tuning on SSB transmissions. One of these days I'm going to try to
find 
out why. It always sems to drift is one direction. I can turn the SX-100 on and
after a 
short warm up (1 or 2 minutes) it will be right where I last had it and hold
reasonably 
well. I'm not so sure I can say that about the HQ-180.

Tuning SSB signals on the SX-100 is easy. Just get it close and then adjust the
Pitch 
Control. There is no adjustable AVC speed on the SX-100. I don't find that a big
deal. 
The noise limiter on the SX-100 is an on/off kind and it distorts the audio a
bit. I like 
the HQ-180 variable limiter a bit better.

Subjectively, I like the sound I get from the HQ-180 when playing with the
selectivity. 
Adjacent signals seem a bit easier to suppress with the HQ-180. I use a Heathkit

HD-1418 active audio filter which can sometimes help a lot with adjacent signal 
suppression. I should state that I'm almost exclusively an earphone user. I
don't care 
about hi-fi shortwave.

My SX-100 is my latest BA acquisition. Am I glad I got it? Absolutely. It
performs 
quite well and I think it looks great. Do I like the HQ-180? Absolutely. It also
performs 
quite well (some might call it "hot") and it looks good in a more industrial
sense. The 
HQ-180 certainly is a bigger box. Be aware that unlike the HQ-180, the SX-100
has 
some paper capacitors that may need replacement.

I find the HQ-180 to be easier to spot a particular frequency. The SX-100 has 
bandspread marks every 200 kHz on 80M. Using the skirt on the SX-100's 
bandspread knob, you can just resolve 2kHz. The HQ-180 dial can resolve to 500 
Hz. I've never had my hands on an SX-71 but its panel reminds me of a National
NC-
98 I once had. The NC-98 was not an accurate rig.

For accuracy, stability, selectivity and all of the other things we would like
in a BA, I 
find my Hammarlund HQ-215 and my R390-A are probably my best receivers. 
Problem is the HQ-215 is only a Ham receiver.

I don't know why Hallicrafters did what they did with tube selection. Maybe they
had a 
warehouse full of 6SC7's and 6K6's that they had to use up <g>. Like you, I've 
thought of giving VLF a try. I have a Heathkit HD-1420 but I just haven't gotten

"roundtoit" nor do I know much about it. My BA corral contains an SX-100,
SX-28A, 
HQ-180AC, HQ-215, R390-A and an SB-100. Yes there are a couple of "things" out 
in the shop but they don't work so they don't count <g>.

Sorry for the long winded answer. Get the SX-100. If its a good one, you'll like
it.

73 Ken kb7rgg

> Hi All,
> Please bear with me, I am much more familiar with "hands on" use of
> Hammarlund gear than I am with the Halli's as they've usually been "my
> receiver of choice" (outside of the SX-71, 5R10A and S-120 that is).
>
> The SX-100 sounds nice, but I want to be CERTAIN!
>
> 1.  For comparison I suspect the "Flagship" HQ-180A is probably
> Hammarlunds nearest equivalent to the SX-100. How do they compare in
> operation, reliability and stability (or for that matter the Hammy
> HQ-145X vs the SX-100)?  
>
> 2.  The receiver will be used EXTENSIVELY in the 80M band  with an LF
> converter for Longwave beacons.  Towards this end, what scale markings
> does the bandspread have and how accurate are they? (I.E. 10KC, 20 KC
> increments etc).  My SX-71 has 20KC increments and they aren't very
> accurate across the band.  In fact, on the SX-71, if you Cal it at 3.5 or
> 7MC etc, bandspread calibration is rather sucky.  I'd LIKE to be able to
> determine the bandspread frequency within 5KC/less without adding an
> outboard counter.  
>
> 3.  I wonder why Hallicrafters chose to use miniature tubes in the SX-100
> but stayed with the venerable 6SC7 Octal and 6K6 combo when other
> manufacturers had long switched to all miniatures.  Reason I ask is the
> 6SC7, at least in my SX-71 has proven to be noisy in BFO service,
> requiring it to be replaced 2-3 times (and yes, circuit components are
> good).  It "seems" like I have a good one in there now.  I hope it
> performs better in the SX-100. 
>
> 73 from the "Beaconeers Lair".
> Phil, KO6BB

______________________________________________________________
Hallicrafters mailing list
Home: http://mailman.qth.net/mailman/listinfo/hallicrafters
Help: http://mailman.qth.net/mmfaq.html
Post: mailto:Hallicrafters at mailman.qth.net
----
List Administrator: Duane Fischer, W8DBF **for assistance**
dfischer at usol.com
----
Hallicrafters Collectors International: http://www.w9wze.org