[Hallicrafters] Re: SX-115 vs 75A4

[Mark Shaum]

----- Original Message ----- 
From: "Grant Youngman" <nq5t at comcast.net>
>
> I suspect you're going to get a lot of different views there.  I have 
> both,
> and virtually always have the SX-115 powered up and almost never turn on 
> the
> 75A4.  The 115 isn't quite as selective as the A4 since it uses LC 
> filtering
> instead of mechanical filters.  But generally, I think it plays better. 
> The
> SX-115 is quite a bit later on the time-line, and benefits greatly in 
> areas
> like AGC performance.  Both are good radios, but if I had to choose one of
> them to keep, the 75A4 would be the one to go.
>

I pretty much agree with Grant.  I prefer the "feel" of the SX-115 for day 
to day use, which involves a mix of CW, SSB and AM modes when I have a 
little time to hop on the air.  Soon I hope to try the SX-115 and HT-32B 
pair on FSK.

On the A4 plus side, it has an adjustable noise limiter threshold in 
addition to a fixed auto clipping level setting, this is useful at times. 
It also has more flexibility in selectivity as there exists quite a variety 
of filters that can plug into the three available filter sockets.  It covers 
160 meters and  is known as one of the best DX receivers of all time for 160 
if you are lucky to live in a low noise area or have good receiving antennas 
for that band.  And the passband tuning is neat, although I really don't 
find myself using it very often.

The SX-115 has (I think, may need to peak at a schematic) an IF noise 
limiter/clipper similar to what I remember utilized in my Heath SB-301. 
This is thought to be more effective on SSB and CW as it clips above the 
changing peak levels of signal.  Less effective on AM.  The 115 has a more 
elegant dual loop AGC, very smooth on voice signals.  There is no AGC time 
constant selection, but the dual loop system works out ok for all modes. 
The IF notch isn't as deep as that on my A4.

The SX-115 looks way too cool sitting between the HT-32B and HT-33A.  I do 
wish I had a KWS-1 to sit next to the A4.  Not likely at today's market 
prices, unfortunately.

Drawbacks to both at my shack - both receivers are usually kept under cloth 
dust covers and disconnected from everything when not on the air.  This 
makes them a bit less convenient to fire up and get ready for use.  This is 
my choice, I feel they are too valuable to risk frying should I have another 
lightning surge that makes it's way inside the house and onto the AC mains. 
Major oops several years ago when I neglected to protect the underground 
phone line entry cost me one radio, one computer and several appliances.

73! - Mark K9TR
http://www.qsl.net/k9tr