A couple of receiver questions

[AF9J]

Hi Everybody,

I have a couple of questions about two receivers that are interesting me.  Would any of you have info on these with regards to suitability for AM?  Both are showing up on e-bay with some regularity.

1.  Hallicrafters SX-99 -  The prices are pretty good for this General Coverage receiver, but is it suitable for AM?

2.  Drake R-4 series - I know firsthand that these are good receivers, but I never used my R-4B (when I had it), for AM (so I have no idea how well they do for AM).  The max receive bandwidth for them is 4.5 kHz.  Would this provide adequate audio for AM?

73,
Ellen - AF9J

[w3jn]

The SX-99 is essentially a S-40 with an S-meter.  Not the greatest.  Much better is an SX-100 or SX-96 - double conversion selectable sideband, etc.  None of these, though, has great audio and all have a design defect in the ANL circuit that causes plenty-o-distortion.  Easy to correct, though.

THe R-4 I had many years ago seemed to have pretty decent audio, but not what you'd call hifi.  The audio is shaped so as to cut the lows and highs.

All receivers are a tradeoff with SOMETHING.  There is no perfect radio, and I've had literally hundreds of receivers over the years.  What REALLY matters is that you like it and it fits your budget... if you see something at a hamfest or on eBay that turns your fancy and the price is right, why not?

* Although, that said, there are a few receivers that are REAL dogs that you couldn't pay me to take... almost all Heathkit receivers would be an example.

[AF9J]

Nah John,

I pretty much made up my mind to avoid Heathkit receivers, some time ago. The S-40 I remember rightly, is sort of mediocre.  Nope, I don't think so.  Thanks.

Ellen - AF9J

 

[WBear2GCR]

Imho, the Drake R4 receiver is not half bad - the main thing is that it can be modified and there are a number of well documented mods (Sherwood corp supplied some) as well as magazine articles on that receiver. Obviously most of the mods and articles are aimed at SSB, but that gives you information on how the inner workings are set up... the main thing would be to open up the filter(s) in the IF for AM use. I do not recall what the IF freqs in them are, but I suspect that one could A) make or B) buy Ceramic filters to suit. There may be wide xtal filters to be had. At one time making ur own Xtal filter was the thing to do so going back to that era and the Lew McCoy articles might work there too.

I don't even recall if it has an AM mode in receive, but that's not particularly hard to implement if it doesn't.

Certainly the audio output stage is anemic, but it's not too difficult to bypass the little AF output stage and go line level out to a small or large audio amp...

I'd say it is a pretty high performance receiver for the $$...

               _-_-WBear2GCR

PS. I think a lot depends on what you like/prefer in a receiver. Some folks like the really wide sound of "old tyme" receivers, and others prefer a tighter "battle mode" sort of IF set up. Obviously, the ideal is one that does it all...

[AF9J]

Hi Bear,

I don't mind communications or battlemode audio quality, as long as it isn't too muffled, or middy.  I hate midrange honk (it's the thrash metal guitarist in me - I always scooped the mids in my guitar setup [I still do, although not as much as I used to]).  Even in stereo setups I have a tendancy to run a semi-scooped mids audio setup.  I remember the Sherwood mods.  When I had my R4B in the early 90s, I thought about adding them to it, to make it a better contesting receiver.  I'm not really sure myself, how the sideband preselector would be set up for AM, in an R-4.

Ellen - AF9J

[Steve - WB3HUZ]

Only the C version of the R-4s had crystal filters. The others were low freq (50-60 kc) LC. It had a passband tuning arrangement that was very nice on SSB and CW. On AM you could tune it a little off to the side to get a few more highs in the audio.

[W8EJO]

My 2 cents on the Drakes:

The R4, R4A & R4B use LC filtering to provide selectivity whereas the R4C uses crystal filtering. All LC filters (CW, SSB & AM) were standard in the R4/A/B.
 
The R4C came with only a 2.1 KC SSb filter. The CW & AM filters (as well as the noise blanker) had to be purchased separately as options on the C.

The 6/60 DB shape factors of the LC filter vs the crystal filter is another big difference. The R4/A/B's AM 4.8KC position (while generally thought to be too narrow for AM) has about a 4:1 6Db - 60DB shape factor (4.8KC wide at 6DB down & about 20KC wide at 60 DB down). I thinks this accounts for it's decent & IMHO very serviceable (if not HI FI) AM.

OTOH the R4C's 6KC AM filter (if the radio is so equipped) provides a steep 1.75:1 shape factor (6KC @ 6DB - 10KC @ 60DB).  

The R4C needs a lot of add-ons & options (filtering, noise blanker)to be a good receiver. The R4A's & B's are pretty darn good right out of the box.

Bill Frost,  (WD8DFP, former service manager at Drake) & Sindre Torp, ( LA6OP, world's biggest Drake collector) prefer the R4A & R4B over the R4C. I've heard both of these gentlemen speak at the Dayton Drake forum over the years.

I've owned over the years an R4B, R4C & my current R4A.  

If you get a good R4A or B it should serve you well.

Terry
W8EJO