More Receiver Help Needed

[David, K3TUE]

I posted a while ago looking for advice on choosing a receiver.  For the longest time I wanted a one-rx-does-it-all solution, but am coming around to the idea that this is not likely, and should get an RX good for AM work, and one for CW.  I wish to thank all those who offered advice and opinions.

I have read W3JN's JN receiver guide and found it very informative (even if it is just one man's opinion).  I know that nothing will help me more in finding the receiver(s) I need than listening/trying/buying, and there are so many nice receivers out there.  And since I am not blessed with a wealth of either space or money, I have to do my best to choose wisely.  This is why I have turned to this group for your advice and experience.  

Given all of my researching since my last post I would like to ask what I hope to be a few more refined questions.


Tube:

1)  The idea that the R-390A seems to be the standard barer seems to meet little argument.  But setting aside the complaints about it's dial readability, is the Hammarlund considered a close second, or simply at the head (or not even that) of the rest of the pack that trails way behind the R-390A?

2)  Is the only difference between a Collins 51J-3 and a 51J-4 the mechanical filters in the -4?  And does the -3 have it's LC filter adherents like the Hammarlund Sp-400 seems to have?

3)  I have this suspicion that the HRO-60 is just a mighty fine receiver, and that if one did not have to deal with the coil drawers, it might be a more popular choice as a primary/sole receiver than a Hammarlund SP-400 or Collins 51J-4 based on RF and AF performance.  Or is this just not true?


Transistor:

4)  W3JN mentioned steering clear of early solid state receivers, but listed the HRO-500 as an exception.  Interestingly, I have read more than a few complaints about it's audio (but that may be just on CW and SSB).  They seem quite rare (at least that I have seen none on eBay).  Are they worth considering?


Synthesized:

5)  I have been reading the experiences of SWL'ers as well (flame away), and the Drake R-8B and the Icom R75 seem to take top honors among many of them (the AOR AR7030+ has it's proponents, but the usability of it seems to get too many swipes to warrant considering for me).  Any good advice from the AM community on the R-8B or the R75?

6)  The JRC NRD-515 seems to be getting a little attention lately in these same circles, but seems to be shaping up to be an over-priced collectable (last one on eBay went for over $1200) like the Hallicrafters SX-88 (last one on eBay went for over $3300).  Any avice/opinions on the NRD-515?

*)  I have a Palstar R30C for my bedside and it does a wonderful job for something so basic in features.  I'm hoping the Palstar AA30 Active Antenna will help me make it that much nicer in this position.  But it seems almost a shame to even consider buying a second of the same receiver for the shack, what with so many interesting receivers out there to choose from.


Thanks in advance.

[W1GFH]

is the Hammarlund considered a close second, or simply at the head (or not even that) of the rest of the pack that trails way behind the R-390A?

IMO...the R-390 is respected because of superior build quality, component quality, stability, design, and performance.  Bear in mind it is mil-spec, and originally designed for military apps - not AM work or SW band cruising. I prefer the vastly less sophisticated SP200/400 because of its "no mods needed" hi-fi AF section and relative ease of tuning.

3)  I have this suspicion that the HRO-60 is just a mighty fine receiver, and that if one did not have to deal with the coil drawers, it might be a more popular choice as a primary/sole receiver than a Hammarlund SP-400 or Collins 51J-4....based on RF and AF performance.  Or is this just not true?

I can't see that the SP400 or 51J would prove *crucially* more sensitive in normal AM use than the HRO-60, or visa versa.

My advice is do what most people do...buy whatever boatanchor rcvr you are interested in and use it for a while. If it's not suited to you, sell it and buy something else. It's the only way you'll really find out which is best for you.

[w3jn]

David - wlcome to amfone.net.  This kind of discussion is exactly why we're here.

My guide is meant to give you a framework for evaluating a receiver.  Your final decision all depends on what kind of listening you want to do and what you want out of it - and, to a large extent, what's available at a reasonable price when you take the plunge.

For example, I'd take a battered old $30 HQ-129 way before I'd spend $600 on a R-390.  If you're serious about having only one receiver, though, perhaps it warrants spending that much on an R-390.

The R-390 and SP-400 really are not comparable receivers.  The frequency readout, tuning rate, stability, and sensitivity at the higher frequencies really disadvantage the SP-400.  OTOH if you're gonna use it mainly for 160/75 AM work the SP-400 is really hard to beat - and it's typically 1/3 the price of an R-390.   The SP-600 is more in the SP-400 class, except its stock audio is much poorer than the SP-400.

The only real difference between the 51J-3 and -J4 is mechanical filters.  The R-388 is the much more common version of the 51J-3 although the front end design is somewhat different.  The J-3 does use L/C filtering in the IF, much like its other contemporaries such as the HRO, Super Pro, etc.

The HRO-50/60 are both outstanding receivers.  If you are bothered by the idea of the coil drawers, a NC-183 or NC-183D are perhaps 85% of a HRO (the electrical circuits are very similar, but stability and tuning rate in the -183s are less than the HROs).  There are other older Nationals that are pretty decent as well - the NC-2-40, NC-100, etc.  

I wouldn't go for a HRO-500 as your first/only receiver.  It's somewhat fussy, and every one I've had has needed synthesizer work.  Not a show-stopper, but it does require decent test equipment to troubleshoot.

If you find a Drake R-8, R-8A/B for a reasonable price snap it up.  It's much better, IMHO, than the competing Icoms or Kenwoods.  I havne't used a JRC receiver so I can't comment on these.

Bottom line is NO receiver is perfect, and I think what ever you buy will dissapoint you in some way or another (at least that's my experience).

[K8SWL]

David,  
   I purchased my first receiver 44 years ago. Since then I've probably had 70 or 80 receivers pass through the shack.I'm still looking for the ultimate one receiver does everything rig. I keep looking, but the truth be known, I don't think it exists.
   My primary interest is Shortwave Listening, but I also want decent performance on the ham bands. Over the past few years I've downsized the shack and parted with most of my hollow state gear. As far as modern receivers are concerned, the Drake R-8 performs quite well. I also have the Drake SW-2 which is really a sleeper. When it first came out I didn't think much of it because it didn't look like a Drake. I picked one up used a couple years ago and was totally impressed. The sync detector is far better than the R-8. I've also been running a Tentec RX-320 PC controlled receiver for the past 6 or 7 years and find it to be a good box. I recently pcked up a Tentec RX-321 which was custom manufactured receiver for Globe Wireless. It's an RX-320 on Steroids and is without a doubt the best receiver I have in the shack. A liquidater sold about 300 of them on Ebay over the past few months and I'm sure some will be cycling back through the system.
   Have you considered a software defined radio ala flexRadio? Lots of potential there.
   This is just one guys thoughts and I'm sure you will get recommendations of many other recievers from others. Thats what makes the hobby fun.

Good luck
Mike K8SWL

[nq5t]

  This is just one guys thoughts and I'm sure you will get recommendations of many other recievers from others. Thats what makes the hobby fun.
Mike K8SWL

It is what makes it interesting.  Every one of us have out own reasons and opinions about what makes one radio preferable in some sense to another.

For AM, my hot buttons are stability and IF response.  Stock audio response is less of an issue because that can be fixed in a heartbeat -- by tapping the radio's audio at the detector and feeding an external toob amp.

My preferences for AM:  R-390 (non-A), R-388, HRO-50.  Nice wide IF and no mechanical filters.  Of these, I no longer own the 388 or HRO, and passing them on was a mistake.  The plus of the the 390 compared to the others is that it does have a better narrow IF if the window is a bit crowded.  The NC-303 is good, too, if you use external audio, and also plays pretty well on CW/SSB, but it suffers from other problems like exceptionally poor image rejection, especially on 20M.  

There are a lot of compaints of 390 "wrist", but if one is properly cleaned, adjusted and lubricated the issue almost goes away.  They don't tune like an NC-303, but they don't require a crowbar either.  The downside is if you , like me, are not an expert at 390/390A restoration, the cost of having an experienced 3rd party do the work can be considerably higher than the acquisition cost of the radio.  I have more invested in my R-390 and R-390A in total than any other radios in the house, but these aren't your typical eBay or fester versions of these radios, either.


My preference for SWL'ing:  SP-600, but perhaps that's because it was the first radio I brought back from the dead about 10 years ago, and see it as a thing of beauty in its own right instead of comparing it to everything else.  

For everything else (CW, SSB):  There are a lot of choices.  SX-115 is probably the best overall.  The R-4B/C and 2-B are excellent, as is the SX-101A, HQ-170/180 and many others.  For the typical selling price, it's hard to beat a Drake 2-B.  I'm not a big fan of the 75A4, although I'm in the minority on that one I think :-)

Grant/NQ5T

[ka0pad]

And for the sp-600 the lack of frequency resolution is easily solved with the AADE digital readout. It's about a 70$ cost adder but it was well worth it to me. Goes in with no wires under the chasis, just tap off the osc at a tube socket with a thin resistor lead.

If anyone wants details on installing one of these let me know.

http://www.aade.com/

Larry

[Steve - WB3HUZ]

The only real difference between the 51J-3 and -J4 is mechanical filters.  The R-388 is the much more common version of the 51J-3 although the front end design is somewhat different.  The J-3 does use L/C filtering in the IF, much like its other contemporaries such as the HRO, Super Pro, etc.

Just to clarify, the J3 does have LC selectivity. But since the LC part is just the IF transformers, there's only one bandwidth, not selectable bandwidths like the SP-600 or continuously variable bandwidth as in the SP-200 and SP-400.

The bandwidth on the 51J-3 can be reduced from that provided by the IF transformers by kicking in the crystal phasing filter. Up to 4 or 5 additional, sharper steps of selectivity can be selected this way. However, in my experience, the crystal phasing selectivity is too narrow for good AM reception. And it seems with the crystal phasing filter out, the selectivity provided by the IF cans is often too wide (too much QRM).

IMO, if you can get a 51J-4 instead of the J-3, do so. If you want hi-fi with the J-4, snag a 9.4 kc mechanical filter and replace one of the more narrow filters (like the 3.1 kc or 800 cps, if your J-4 even has them).

For extra hi-fi, just place an RC network in place of one of the mechanical filters. Here your IF bandwidth will be defined by the IF cans (just like in the J-3) and it's pretty wide. I've done this with my J-4. I have three good bandwidths for AM, 6 kc (via a mechanical filter), 9.4 kc (via a mechanical filter), and 12-13 kc (via the IF cans). I can still go more narrow than the 6 kc bandwidth by engaging the crystal phasing filter (although this won't compete well with the 3.1 kc or 800 cps mechanical filters found in some J-4s).

I suppose a switching method could be devised that would allow you to keep all the filters in the receiver 800 cps, 3.1 kc, 6kc, 9.4 kc and 13 kc. Then the J-4 would make a pretty good CW and AM receiver.

[W1GFH]

The NC-303 is good, too, if you use external audio, and also plays pretty well on CW/SSB, but it suffers from other problems like exceptionally poor image rejection, especially on 20M.

IMO the NC300/NC303 really didn't get a fair shake in the JN review. Slight handicap is it's a ham-band-only rcvr. However...good range of selectivity from battle-mode to wide. Q-multiplier and CW/SSB w/ prod detector is a bonus. Noise limiter is unspectacular, but decent. I like the Collins-ish slide rule-tuning dial - functionally accurate and very convenient for a fast QSY. A hot rig when aligned, sensitivity is good on 10 meters too. And really no need for outboard audio fuss, the 6AQ5 AF stage is quite satisfying when driving a good 12" speaker. Spacious under-chassis layout is easy to work on. Plus, an AF TONE control to play with. Pat, WB9GKZ first recommended this recvr to me - and when I got one for myself I wasn't disappointed. A good first AM receiver IMO.

[K1JJ]

As a passing thought...

I realize youse guys are talking about classic tube boatanchor
receivers, and the R-390 and SP-600/400 are on the top of the list.
I own an SP-600 myself.

But probably the best receiver I've owned for small size, cheap price
and overall general coverage and performance is a solid state  
Kenwood R-1000.  AM/LSB/USB.  

I tapped off of the detector and it sounds great. You can pick them
up for about $200 or so on eBay.  About the size of large book
and lightweight.

Great RX as a side receiever at the desk or bedside. [to piss off
the XYL or dog].


"The Kenwood R-1000 covers 200 kHz to 30 MHz in thirty 1
MHz bands with 1 kHz digital display resolution. Solid
performance, straight forward operation are the strengths
of the R-1000. Stable operation and good selectivity combine
to make this radio suitable for demanding voice or RTTY
applications. Refinements include: S-Meter, 12 hour
clock-timer (with remote activation), Noise Blanker, Dimmer,
three position attenuator and tone control.

The carry handle can be swung-away to the top or bottom.
The rear panel has antenna inputs for coaxial or hi-Z wire
antennas. 120 VAC. UL listed."



T

[Steve - WB3HUZ]

I agree. I like my NC-303. I think it is the best all-around receiver I own. It's not the best at anything, but does everything pretty to very well. It has good freq read out, good stability, a good selection of bandwidths for AM, SSB and CW. The product detector works very well on SSB and the selectable sideband feature is nice. The notch filter is very effective. I'd say the weakest attribute is the audio. That single 6AQ5 and tiny output transformer just don't quite do it on the low frequencies. Tapping off the detector and an external amp makes a big difference.

The NC-303 is probably the best $50 I've spent, at least on radios!

IMO the NC300/NC303 really didn't get a fair shake in the JN review. Slight handicap is it's a ham-band-only rcvr. However...good range of selectivity from battle-mode to wide. Q-multiplier and CW/SSB w/ prod detector is a bonus. Noise limiter is unspectacular, but decent. I like the Collins-ish slide rule-tuning dial - functionally accurate and very convenient for a fast QSY. A hot rig when aligned, sensitivity is good on 10 meters too. And really no need for outboard audio fuss, the 6AQ5 AF stage is quite satisfying when driving a good 12" speaker. Spacious under-chassis layout is easy to work on. Plus, an AF TONE control to play with. Pat, WB9GKZ first recommended this recvr to me - and when I got one for myself I wasn't disappointed. A good first AM receiver IMO.

[nq5t]

IMO the NC300/NC303 really didn't get a fair shake in the JN review.  <snip> However...good range of selectivity from battle-mode to wide. Q-multiplier and CW/SSB w/ prod detector is a bonus. <snip> A good first AM receiver IMO.

I agree with that.  I probably gave it short shrift, too.  The 303 is really a VERY respectable radio overall.  My biggest gripe is the number of SWBC stations (images) that fill the 20M band at times -- the tunable image trap does a VERY mediocre job.  I've often though about building a reject filter in front of the thing to solve that problem.  Even with that, though, I don't plan to part with my 303 any time soon.  On SSB in particular it is a MUCH better radio than the NC-300, even with some of the mods in the 300 outlined in ER some time back.

Another radio I like a lot, in the same general class of the NC-303 and SX-101A, is the RME 6900.  As an AM radio it is borderline with a maximum IF bandwidth of 3.5 Khz (too bad they did that), but if you tune towards one or the other sideband on AM it gets fairly respectable, and plays very well on SSB/CW.  Plus, its' PRETTY  

Grant/NQ5T

[w3jn]

IMO the NC300/NC303 really didn't get a fair shake in the JN review. Slight handicap is it's a ham-band-only rcvr.

I chose to concentrate more on general coverage receivers as I believe they're of more utility than a ham-bands only receiver.  Other than the afore-mentioned crummy front end and less-than-stellar audio, the NC-300/303 is a FB receiver.  

I prefer the -303 to the -300 as it has selectable sideband.  However I prefer the Hallicrafters SX-101 to the -303/300.  My prejudiced opinion only... as my standard disclaimer goes, if you find one you like and the price is right, BUY IT.

73 John

[Glenn K2KL]

Hi David;

As far as solid state receivers go, if you want to get maximum bang for your buck, you can't go wrong with one of the Racal 6790's available now for a song on the surplus market. Excellent AM recovery, selectivity. Your chance to own a great Mil receiver for not much money. You can shove just about any 455kc filter in there as well. Slots for 6 filters  

The Icom R75 is also a good choice but it requires some mods/filters to make it a better performer on AM.

[WA1LGQ]

Dave, I own an Icom R75 that I use as my "bedside shortwave". It would be excellant as a main station receiver also. The unmodified audio is very good, especially on the low end. On the high end they have a low pass filter around 5K, I have'nt bothered to mod mine yet, it sounds good the way it is. It does have a mute connector on the back, so it is suitable for use with an old buzzard transmitter with the usual relaying setup. The 6kHz filter is good for most AM use, but sometimes it would be nice for a little tighter selectivity. The narrow setting is just a bit too narrow for decent AM, but useable. The dsp is somewhat useful, but not a day and night improvement. It works fairly well with static crashes, so its nice this time of year. The sync detection does not work well at all, but there are mods and kits available to fix that. Check out the R75 group on Yahoo. The dual pass band filter is a real nice feature too. You can set the freq display to 1Hz resolution, put it in SSB mode and with the good low end of the audio you can  zero beat an AM signal within 1Hz. You will notice ANY freq drift of the transmitter. Its nice when there is fading. Of course the usual modern features like digital readout and memories are nice, and don't forget it receives up to 60MHz, and the LF performance is good too. The RX is quite compact too, though most old buzzard transmitters will make it look like a toy, and it certainly does not have the charm of a nice tube receiver.  Someone on Ebay sells rack mount kits for the thing, but you can do that yourself if you want to.............Larry

[wa2zdy]

Where would one find a Racal receiver?  I was exposed to Racal Decca Marine stuff in the 80s and man, that stuff was BUILT, though not all of it was that hot.

[K6JEK]

Why one?  Room?  It can't be room.  There is always room for one more receiver.  This is the fun of it, getting one more until you trip over them.   And you guys who got NC-303's for $50 are killing me.

You can lift it with one hand so it maybe shouldn't be mentioned in this forum but the Drake R4-C is really something.  With a few little mods (like replacing the audio out with the Sherwood module) it is really really good at just about everything except heft.  That said, the best AM receiver I have is the SX-62 -- spectacular sound and a gorgeous slide rule dial.  The best SSB receiver I have is the Drake 2-B, LC filters and wide bandwidth make the great sound put out by my buddy's CE 100V's worth listening too.   I also have several Nationals, some Collins, have had an SP-600.  All that said, the R4-C gets more action than any of the rest.

Jon

[W1GFH]

"The preferred product of buffs and celebrities, the company's amateur products soon became known as the "Cadillacs" of the ham radio field. Many of the Drake receivers, transmitters, and transceivers manufactured in the fifties, sixties, and seventies are still in active use today."

from http://www.dproducts.be/DRAKE_MUSEUM/the_story.htm

Judging from shack pix in QST, 1 in 3 hams had Drake gear, it was quite popular in the 60s and 70s, tons of 'em sold. Wonder why they are almost forgotten now, and Halli, Hammarlund, Collins, Heath, etc. get the lions share of the attention from the BA crowd.

[Jim, W5JO]

"Judging from shack pix in QST, 1 in 3 hams had Drake gear, it was quite popular in the 60s and 70s, tons of 'em sold. Wonder why they are almost forgotten now, and Halli, Hammarlund, Collins, Heath, etc. get the lions share of the attention from the BA crowd.

Maybe the transmitters have a sweep tube problem.  Only reason I can think of.  Good equipment otherwise.

[kc2ifr]

A couple of observations about receivers. Seems like a lot of the opinions about receivers for AM concerns the audio response. While I think that is important, I have found that much of the time I have to squeeze down the bandwidth because of crowded band conditions. The narrow bandwith now defeats the wide frequency response. I want to copy the station Im talking to reguardless of how good he sounds. My point is that copyability is more important than that "HI FI" sound. I have 4 receivers that I use.........an SP600, a 75A4, an R390A and an NC303. I usually stick with the 390A BUT when I need a battle receiver, I love the 75A4. It has 3kc, 6kc, and 9kc filters installed. It also has a passband tuning control which I find to be one of its best features. That used with the 3kc filter allows me to pull out an am signal with no problem. I know that with other receivers, u can tune off to the side of a station when the receiver is narrowed down but the A4's passband tuning works much better.
Anyway folks.........that the way I see things!!!!!
Have a happy and safe 4th.
Bill

[WA1GFZ]

A properly set up RA6790 is a hard radio to beat. There are a number of them around on epay. Usually they need some TLC. The service manual is free down load. Easy to work on but you need to know what you are doing.  Also plenty of modules around for spares. 7 filter positions.
I sold all my tube stuff when I discovered the RA6830 10 years newer and 1/2 rack. A good R390A is still the best tube RX in my book.
RF590A if you have the bucks. Premium RX with all mil parts.

[David, K3TUE]

This thread was so helpful.  Thank you to everyone who helped.

The R-390 and SP-400 really are not comparable receivers.  The frequency readout, tuning rate, stability, and sensitivity at the higher frequencies really disadvantage the SP-400.  OTOH if you're gonna use it mainly for 160/75 AM work the SP-400 is really hard to beat - and it's typically 1/3 the price of an R-390.   The SP-600 is more in the SP-400 class, except its stock audio is much poorer than the SP-400.

I was wondering how an SP-400/600 compares with a collins 51J-4.  And is the SP-600, since it covers up to 6m, any good up on 10m or 6m?

If you find a Drake R-8, R-8A/B for a reasonable price snap it up.  It's much better, IMHO, than the competing Icoms or Kenwoods.

I already have. 

[The Slab Bacon]

David,
         I wrote the receiver "road test" article for You and others like you trying to decide on your first "AM" receiver. Please keep in mind that there is no "holy grail" of receivers. As I said in my article each and every receiver has its own distinct personality. Even sometimes you may find distinct personality differences in several copies of the same make and model unit. You must find the ones that YOU like. You and only you can decide what you like best. What I like may or may not suit your taste. Remember that opinions are like that certain part of the anatomy; everybody has one.
         You will have to start on that right of passage that myself, John, and many others who fancy the older gear have done. That is to get your hands on them and play with them. Look for reasonably priced pieces at hamfests and swapmeets, bring them home fix them and play with them. If you dont like this one, resell it and buy another. If you repeat the process enough, you will eventually find the ones that tickle your fancy. At present I have 14 receivers in my collection. Some that I use constantly, some that rarely get used. If your money is a little short, turn the ones that you dont like over and buy other ones to try. You will eventually develop favorites, and decide which ones are keepers for YOU. That is the only real way to do it. You can never know whether or not you like one until you get a chance to play with it. Written specifications dont always tell the whole story. It's all in the "road test"!!!!
                                                            73 de KB3AHE

[W1GFH]

I was wondering how an SP-400/600 compares with a collins 51J-4.  And is the SP-600, since it covers up to 6m, any good up on 10m or 6m?

I never compared them side by side, but my impression is...

-both the 51J and the SP-600 are reasonably hot on 10 meters
 
-the 51J and SP-600 have a bit tighter audio than the SP-400

-the slide rule dial tuning on the 51-J is the most convenient and accurate of the three (but remember, operating boatanchor AM does not require a lot of "precision")

[k4kyv]

The tuning rate of the 51J beats the hell out of the SP.  Also, if you want to listen to any CW or slopbucket, the stability of 51J is head and shoulder above the SP.

Repair wise, there are some cheapo capacitors in the rf module of the SP that are nearly impossible to replace, although it can be done with patience.

All Hammarlund receivers I have ever seen have had a drift problem.  Something about the design of the tuning capacitor.

An the other hand, the SP, like all other Collins receivers, has crappy audio.  The audio stage is an afterthought, at best.  Better to pick audio off the diode detector and feed an outboard audio amplifier.

[David, K3TUE]

         I wrote the receiver "road test" article for You and others like you trying to decide on your first "AM" receiver.

Yes, it, as well as JN's article have been has been most interesting and informative in many ways.

Please keep in mind that there is no "holy grail" of receivers. As I said in my article each and every receiver has its own distinct personality. Even sometimes you may find distinct personality differences in several copies of the same make and model unit. You must find the ones that YOU like. You and only you can decide what you like best. What I like may or may not suit your taste.

While I don't like to anthropomorphize too much, I can see how they are like people.  Some people are easy to get along with, but the conversation never gets beyond a certain level.  Some people are so knowledgable and good at what they do, but they are a total tedium to interact with.  Some are good life long friends,  Some you would only call if you need help with something specific.

         You will have to start on that right of passage that myself, John, and many others who fancy the older gear have done. That is to get your hands on them and play with them. Look for reasonably priced pieces at hamfests and swapmeets, bring them home fix them and play with them. [...]  You will eventually develop favorites, and decide which ones are keepers for YOU. That is the only real way to do it. You can never know whether or not you like one until you get a chance to play with it.

Sounds like a recipe for fun: Buy, Fix, Try, (Sell), repeat ...

While initially my queries were an attempt to find the ONE receiver, I have since learned that there is no such thing, as you said.  Since I have come to this understanding I have used such questions instead to try to focus my initial purchases.

I actually have a great interest, when time allows, to go through a number of different receivers (and some transmitters as well), some IRL, some just schematically, , as I deepen my knowledge of electronics as it pertains to vacuum toobs.  Digital electronics has always been so much easier in the past hobby-wise.  It all seems just about logic, timing, and state change, very discrete concepts.  Radio seems to me to have much more of a soul.  That's what I'm looking forward to learning.