Receiver for AM

[W0BTU]

It would be interesting if some people who knew their receivers would put their heads together and compile another list of AM receivers, like the one at http://www.sherweng.com/table.html (the titles of many of the columns would be different, yes.)

Some columns would be audio quality, shape factor (selectivity), whether or not it had continuously variable selectivity, intercept point, ? (fill in the rest. :-)

[w3jn]

Board member Jay, W1VD has done a lot of work in this area.  See this page http://www.w1vd.com/BAreceivertest.html

[w3jn]

Some you might not want are the Phasing type rigs like the SX100 or SX101.  There are others.  They are limited down in bandwidth and for decent fidelity you need a spot on perfect alignment. I own both.  When I use them, I miss the SX28 or SX42s audio.  

The SX-100 and SX-101 are filter receivers, not phasing.  The filters are cascaded 50.5KC LC networks, with switch-selectable coupling for the selectivity positions.

To me, One really important feature is the antenna loading Adjustment.  Most hallicrafters rig had this. The SX42 does not.  As a result, Its not a perfect match to the 50 ohm input on the tuner and the performance suffers. On the 28, you can just peak the Antenna matching knob and get peak performance on any band to the antenna you are using.  I am thinking of adding this to the SX42.

The antenna trim control isn't an antenna matching adjustment, per se; it trims the capacitance in parallel with the first RF input transformer to compensate for tracking error.  This can be caused by any number of things, antenna reactance being just one.

One of my old favorites is an SX110.  Cant get any simpler, here.. Single conversion, Super het reciever. It has Xtal filter and it has fantastic audio.  The audio from this old radio is way up there with the best of them in my opinion. Its great for good band conditions and hifi am.  Its not good for a ground band, A real weak signal work or a band that is crowded with SSBers.  These go for $60 to $100.  The SX110 has the Antenna matching knob.

The SX-110 is basically the same circuit as the SX-99 and many other Hallicrafters radios.  It shares lineage with the S-20.


 

[KM1H]

For contemporary matching to a Valiant the 75A3, HQ-140/150, NC-183D, NC-300, HR0-60 are within that range of years.

Other earlier ones would be:

Pre SP-600 Super Pros if you have room for that overkill PS used with the military versions. A BIG negative is no calibrated BS but digital readouts are available plus oscillator stabilizers. All Hammarlunds drift.

NC-173, NC-183, NC-200, NC-240D, HRO-50, HRO-50-1. The 173 is often overlooked since it was just a mid priced radio but it runs circles around a HQ-129X for sensitivity on the higher bands. The others mentioned all have PP 6V6 audio and are all priced reasonable. The HRO-50-1 has 3 IF stages with 4 tuned circuits per stage so the skirts are pretty steep.

HQ-120X, HQ-129X. Older versions of the 140, etc but just fine thru 20M without mods. All HQ's from 120 to 150 have 3 IF stages for fairly good base selectivity.

GPR-90 if you can find one and afford it.

My notes show the NC-183D, NC-300, SX-28, SX-101/101A, HQ-129X/140X or XA leading the pack in actual QSO's Ive had.

Carl

[W8IXY]

FWIW,

I am content with using either a vintage HQ180A, which matches the Valiant's size, or a Kenwood R5000, about 8 of which would match the size of the Valiant.  Both work well for what they are.  I also use a K3 for its synchronous AM receive ability.   (Plus the K3 sounds great on AM driving an amp.)  The 13, 6 and 2.7 kHz filters in the K3 allow for a lot of flexibility.  Just my $0.02.

I use external audio processing with the Valiant, but the internal processing on the K3 sounds really quite good on AM.

73
Ted  W8IXY

[K9PNP]

Use a HQ-110A with my Viking II.  Not bad for AM if you let it warm up enough.  Have an S-85, but selectivity is bad; same for the S-77.  75S-1 is OK.  None of these have the audio quality of the older PP 6L6 audio output rigs. Have not found one of those I could afford yet.  Homebrew receiver is great for AM, but need to add a better audio section than the original one I put together to get it running.  The 30's through mid 50's rigs are probably the best as far as audio goes, it's just dependent on what you want to pay for good RF sections ahead of it.

[KM1H]

Board member Jay, W1VD has done a lot of work in this area.  See this page http://www.w1vd.com/BAreceivertest.html

True but most are not ones he did the restoration work on and got to peak performance. Nor does it cover any that have had well known performance mods.

[Steve - K4HX]

What are the well known performance mods for a Mackay 3010B?

[ke7trp]

I would like to test the performance of some of my old Receivers.  How do I get started?   


Time to open the handbook again.

[KM1H]

Ask JN, this is a ham forum

[w3jn]

A couple of HP 8640Bs, a bunch of step attenuators, a good VTVM, an audio distortion meter, a S/N or SINAD meter, and a good scope.

A HP service monitor would do most of it, but the phase noise of the sig gen is fairly high in comparison to the 8640B.  To do it right you need extremely low phase noise RF sources.

Test procedures are in any later ARRL handbook.

[ke7trp]

Great. I actualy own most of that gear including three Step attns. I also have a Motorola service monitor.  Just need to read up on how to test. I do not have a distortion meter. I used to have one but its been missing for years.

Carl, I dont understand your comment.

C

[w3jn]

Don't try to use the sig gen in that Motorola for measuring dynamic range, blocking, or S/N - it's crap.  Use 8640Bs or one 8640B and a homebrew xtal oscillator.

[Todd, KA1KAQ]

Nor does it cover any that have had well known performance mods.

Which would be a moot point as that would disqualify the receiver based on known performance. Instead, it becomes that receiver in name and visual appearance only. Buying one based on this or doing the mods after using it for a while would make more sense.

A couple of major factors come into play in deciding: HiFi audio and on-air, battle mode performance. Between Johnny's receiver list and Jay's performance testing, you can get a very good idea of where to look. There are a number of great receivers out there, but IMO no one receiver handles it all well.

I'll throw in with what several have already said: the pre-war Hammarlund Super Pros (SP-10, 100, 200, and the postwar 400, not the 600) are as good as it gets audio-wise, with their push-pull 6F6s and variable bandwidth out to 16 kc. In top trim the crystal filter helps quite well with interference. But for hand-to-hand combat conditions, it's tough to beat the combination of mechanical filters and passband tuning offered by the 75A-4. The audio can be improved somewhat with a wider filter and a few other changes, but it will never come close to sounding as nice as a Super Pro. The R-390A is probably the best weak signal receiver out there but a PITA to tune around much with, and weak signal AM isn't a lot of fun for me. 

As Slab indicates, trying to do it all with one receiver will involve trade offs. All the more reason to have a few on hand to choose from.

[KM1H]

Carl, I dont understand your comment.

I was replying to Steve

[Steve - K4HX]

Don't worry, most people don't understand my comments too.

Carl, I dont understand your comment.

I was replying to Steve

[KM1H]

I'll leave the finer points of getting the exotics to play well to you and Johnny. My experience there is nil.