National HRO Receiver
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- Опубліковано 2 кві 2022
- The information in this video has been blatantly plagiarised from the following sites. Please visit the links below for detailed information about the HRO receiver and its important place in history.
Manual Here: www.dropbox.com/sh/a06hlbog65...
www.cryptomuseum.com/df/hro/
www.radiomuseum.co.uk/hro.html
www.electronics-notes.com/art...
The National HRO was a valve-based (tube) shortwave general coverage communications receiver, manufactured by the National Radio Company (National) in Malden (Massachusetts, USA) from 1935 onwards. The receiver was intended for military and amateur use and became very popular for intercept work during WWII. Different versions of the radio were in production until the 1960s.
There are many versions of the HRO receiver and each new production run saw a number of smaller or larger modifications being made to the design. The most well-known versions are arguably the late-war HRO-5 and the pre-war variant the HRO-M, both of which played an important role during WWII and both of which are still being used by Radio Amateurs today. - Наука та технологія
I want to thank you all for watching this short video and leaving comments. For some reason UA-cam is deleting some comments and I am unable to respond. I read every comment and try to respond. My best regards Chris.
yeah mate you didnt use it rite. youll have to send it here so i can do a video to use it rite way. hahhahahahha good job oldman. iam thinkin i may have to find one of these ..
@@XPFTP I can highly recommend one of these although they aren’t great performers by modern standards. I still like the smell of hot valve tubes. These set are a lot of fun and easy to work on.
A few decades ago I had an HRO-5 receiver with the 'Doghouse' power supply. What a delight to use! An absolutely prime example of master crafted radio engineering. Being a CW man, it really was a delight to use witha set of 'Baldies' Baldwin headsets.
I have tried too master CW in the past but never got the hang of it. I am ok sending but just cannot receive I think it’s because I’m just not musical. The radio does appear to resolve CW nicely and the BFO works well. I’m looking for a dog house but they aren’t common. One will probably turn up sometime. Thanks for watching and great comments my very best regards Chris.
I have a National HRO- 5TA1 with thirteen coil packs. I inherited this excellent receiver from my father back in '94 when he passed. The only change in my HRO is the electrolytic in the doghouse power supply has been replaced by me in 2004. It still has the original speaker with the National diamond on it. I know this receiver to be more sensitive and selective than most of today's transistorized receivers because I have compared them together and found the modern stuff wanting. The only receiver that came close was the Kenwood R-1000.
That's a nice example of the HRO receiver Chris. I think they were used for the secret squirrel stuff during WW2 by the British military and intelligence services. The Hallicrafters SX-28 and 28A were favorites also. All of these sets are getting hard to find in good condition now and go for silly money if you can find a good one. ATB Doug.
This one has had some restoration but unlike many sets it hasn’t been hacked at by radio amateurs. I am looking out for the correct power supply or I will build one that looks more authentic.
The reason the doghouse supplies are so hard to find is that the cost was too much for tightwad hams, most of these were powered in the shack by a homebrew supply. Of course, that is common for many sets that were military surplus, like the ARC-5 sets and the like.
You could be right. I did manage to pick up a dog kennel for £15 but haven’t tried it yet.
That is in super condition. I've never heard one working actually, twiddled plenty of HRO tuning knobs though! Thanks for showing this beauty Chris.
Thanks Andrew. It does appear people enjoy having a look and play along with me testing these old receivers so we will try and do more of this in the future.
Fascinating stuff. Thanks for posting.
Thanks Ian I have a few old radio sets people do enjoy watching them in operation. It’s a shame so many of the stations have closed down as everything is going digital.
Very nice receiver worthy of the nice presentation. But to say these were manufactured up until the 1960's is misleading. The HRO-5 production ceased in the mid- late 1940's. The HRO's being manufactured in the 60's were very different receivers.
Very interesting, thanks for sharing. That dial is a real piece of work.
Thanks for watching and leaving a comment. Looks like people enjoyed this quick look so I will try and do a radio review regularly in the future. My best regards Chris
My friend ,Paul Clemens G4RAR ,used one of these for years and, using the phasing control ,could pick up tiny CW signals close by huge ones. These really do perform, are very stable and are reliable. I've never, personally, owned one but know many experienced CW operators who swear by them. Thanks for the video .
Bob Rogers M0/G6KKW
To be honest I don’t think they compare to a modern rig but like driving vintage car it’s more fun than the modern alternative. The frequency indirect dial reading is a pain in the bum. It was very lively on CW but I suspect it could be better. Thanks for watching and nice comments best regards Chris M0KLF
Lovely introduction to the HRO receiver Chris. The design was very interesting and well implemented. Nice to hear these old beasts still working!
It’s an average performer but I suspect it would benefit from some tweaking. I do enjoy operating these old sets. Thanks for watching regards Chris.
I agree. That was simply a lovely looking radio. I love old tech like that. 80 years old and still ticking. As they say, they don't make them like that any more.
It performs quite well but I suspect it will respond to some restoration. I sometimes find it difficult to know if the radio has a fault or if it’s work as well as it can for the technology of the day
Lovely ! I found one in my Fathers workshop, it hadn't been plugged in since the early 70s. It was brought up slowly on a variac and it still works!!
Just discovered your channel and glad I did with this video. Very fascinating story on the radio including the pics of Bletchley Park.
Welcome. thanks so much for watching and leaving a comment. Glad you enjoyed looking at the receiver there is more information and the manual in the show notes. My best regards Chris
Nice reciever despite the faffing required for tuning into your favourite stations
Yes not much use for portable but the did make a 6v version.
Have got 3 hro a very nice radio to use.coil packs are a easy to tune.
What a fantastic sounding radio Chris . The coil packs remind me of an over sized RJ11 . 🤣🤣
Nice quality old radio 🙂 👍
Thanks Bob. Best regards Chris
I still have one of those.....and all the plug-in band coils.
Do you have the power supply?
@@allthegearnoidea6752 yes, I have the original National Power supply. Still a great receiver, and more fun to use than my FT747. Takes me back to my childhood, sitting in front of a Westinghouse tube (valve) short-wave receiver, listening to the world. Tubes are warm, transistors are 'cold'...lol
@@airborne63 you are so right. 90% is nostalgic trying to catch a wiff of those happy bygone days. I was saying to the wife over the dinner that it’s sad the bands are just dead compared to what they were.
Much enjoyed, Chris, looking forwards to when you do some work on it.
Thanks Theo. I need to sort out the power supply it’s severely overheating.
I recently gave one of these away, it appeared to be painted gold from new. The chap I gave it to is something of an expert on these but he had never seen a gold one before. Your is in much nicer condition, thanks for sharing Chris 👍
Did you give a try before parting with it. Just wondering how you thought it performed compared to some of your other receivers. Thanks for watching regards Chris
@@allthegearnoidea6752 No, it was heavily modified to use B9 valves and they were all missing.
@@IrishvintageTVRadio funny I had one that was modified for B9 valve but it was trashed.
Outstanding and interesting video, America used to manufacture quality products.
Thanks 😊
HRO now = "Hell of a Rush Order". In the Doghouse power supply the transformer and choke were encased in black pitch for thermal stability. This made the transformer run rather hot so, over the years, it would eventually fail. The pitch is very hard to remove so not many Doghouses are renovated as its much easier to just make a complete replacement P.S.U.
Just bought bought a dog house on eBay but haven’t had the opportunity of testing in yet. I will perhaps make a video on it
@@allthegearnoidea6752If yours is working, don't do what I did. Mine worked fine for some years until I stupidly forgot to switch it off one day. When I remembered about it, some hours later, it was too late! I have a National rack mounted P.S.U. now which has been re transformered. No pitch so runs nice and cool.
Second try. The fact you have a working HRO and the parts needed to receive different bands makes this a jewel of a
radio to your collection Chris. Also if you had bought it at the 1939 price I see from the second website mentioned it
had a whopper of a price tag that in todays dollar's would be around $5950 US. Thanks for the show and tell on it.
That second website with the word crypto in it has a pdf link that is very information filled. Steve
I think this feature again in a future video as I would like to check over the radio in more detail regards the previous electrical work. Yes the price is remarkable but the engineering is very good. The mechanicals would have been expensive. Thanks for the comments for some reason a lot of comments disappear for no reason I can understand.
@@allthegearnoidea6752 Possibly mentioning said websites in comments sections makes angry the YT algorithm god?
Most things makes YT angry they lose and delete comments all the time
Enjoyable video - thanks. Buying an HRO introduced me to radio, electronics and subsequently computers. I realised that much of the traffic was RTTY. I got one of the very early microprocessor developments systems (SC/MP) in iirc 1976 and started playing about decoding 5 figure groups and telegram traffic. It was relating this experience in interview when I left college that got me my first 'real' job with Ferranti, ending up doing quite a bit with FCO and occasionally Blechley Park!
Thanks Andrew for watching and leaving such an interesting comment. Out of interest which branch of ferranti did you work for. A lot out of my friends worked out of Oldham
@@allthegearnoidea6752 I was Wythenshawe Division but based in London looking after (theoretically) the industrial process control computers (Argus 400 / 500 / 600 /700) but many were in none industrial settings with Government departments and the military. Had quite a bit to do with Cairo Mill in Oldham as many of our module repairs were done there.
Yes my friend worked at the mill David Bray. I’m from Ashton under Lyne original so know the Area. Don’t know why but YT keep deleting the comments. My best regards chris
I’m also a fan of data modes but it’s mainly PSK31 and hellscriber for me, although I dabbled in slow scan tv
@@allthegearnoidea6752 Although I still have an excellent condition RA17 my interest in Radio waned a bit as life / family / houses etc took over. I always regretted disposing of the HRO - it was an excellent introduction to electronics (although I'd been building crystal sets with a gas ring heated soldering iron from age 8 !!) I never got past RTTY & morse and it was amusing to recognise CQ CQ calls on your video!
The HRO psu for my HRO was made in the UK to military spec it has two smothing chocks
and the box is square .
I just acquired a power supply last week that has previously been rebuilt by the previous own. I’m not certain it’s the correct one for this radio but it has a National hro badge and it was very cheap so worth a punt. Thanks for watching and comments regards chris
@@allthegearnoidea6752 Interesting about your PSU, the badge, it might be from a proper HRO PSU,? mine was made by P.S.E.I, LTD , the story I heard is that the dog house PSU was not liked by the military mine has three smothing caps and two smothing chokes to give a sweeter sound on c.w and a RF choke in the HT+
Nice video. I have one of these made in late '35 with its matching power supply and coils. The only essential differences between mine and yours is that mine has a metal dial plated in "German silver" (nickel), round IF cans, 2.5 volt tubes and a slightly different signal strength meter. I disagree with the other commenters who state the power supply runs hot because the transformer is buried in pitch. Whether buried in pitch or not, they should be only slightly warm to the touch. If running hot, then that tells me the decades-old electrolytics are begging for replacement due to internal shorts which the transformer is fighting against. Plates that are glowing red on the type '80 are also a sure sign this is so. With tube gear I make it a practice to swap out old electrolytics about every 15-20 years. Cheap insurance as opposed to the expense of having a now unobtanium transformer rewound. Your coil sets should all have serial numbers marked on them that should match the serial number on your radio (found stamped around the antenna/ ground posts) as they were all match-aligned with your radio before leaving the factory. If you have a few that are mismatched, they can be aligned to your set, so, no worries. You'll find more than you'll ever need to know about these on Henry Roger's site here: radioblvd.com/National%20HRO.htm. On a side note, as a testament to their frequency stability an article in Electric Radio once referenced a ham radio club at Yale or Harvard in the late 50s that was running current day Hammarlund receivers. A pre-war HRO was pulled out, powered up and both receivers dropped repeatedly from a height of one foot to see which would remain on frequency. The HRO only remained dead-on which inspired its tester, decades later, to purchase and restore one. -- 73, Chris KJ6OFC
I suspect for military use, only a few frequencies were in use for a particular unit. So the weird tuning system wouldn't have been an issue. Maybe.
Yes I think the would have had to work out those dial numbers in advance. I do find the tuning a real pain put it’s not such a bad set to operate. I think it needs some work although it may just be a bit crap. Sometimes it’s hard to tell the difference. Thanks for watching and comments regards Chris
I hadn't heard of these before - it looks like a well made item and was likely expensive when new. That smooth tuning is classy! A nice thing. Thanks for an interesting video
Yes these sets would have been very expensive back in the day the tuning and gearbox arrangement wouldn’t have been cheap. It’s nice operating this gear like driving a vintage car.
Just found you video, enjoyed it as I too have an HRO with a 'home brew' power supply. One point, the 2 coil sets for LW (100khz -400khz) are meant to be used with a different model HRO with a lower IF freq. than the standard 455 kHz. I believe it was 176 kHz, but my memory could misfire (☺️). The "secret squirrels " on our side of the pond also used these heavily leading into WW2. I think they were viable until SSB came along.
The frequency conversion chart wasn't a big deal since they didn't know where the evil jerries were transmitting.
Nice story tell Chris. I remember seeing many of the later generation HRO receivers for sale at the Lafayette Electronics store I worked at as a teen. Presumably they came from SK estates. One thing that I noticed, all the topside electrical adjustments are easily available, but the individual coil pack adjustments?
I don’t know the answer on the coil packs I was thinking just the same myself regards adjustment. I haven’t had the chance yet to service the receiver so will take a more detailed look in the future. I think HRO did have good reputation and they certainly built a lot with many finding their way to radio amateurs and SWLs.
What an interesting receiver. I thought, though, that Bletchley didn't receive the signals themselves, rather they relied on feeds from remote "Y stations" which operated the receivers. They didn't want Bletchley to attract attention to itself by having antenna arrays that could be spotted from the air, I guess. What coil packs do you have, Chris?
The pictures I posted did come as Bletchley park but I’m not certain just going off the history. Have a look at the links in the show notes it contains more information about the HRO usage during the war. I will have to have a look at the coil packs I’m not sure what I have. 8 in total but I could have some duplicates.
Great stuff Chris, thanks.
Thanks for watching regards Chris
What an unusual design, plug and play lol :-D
Now i know where microshaft got that idea :)
The very obvious question is: Is there any way a frequency counter could be connected via a high impedence buffer to the 1st local?
It would make the frequency finding a lot faster.
Sorry obvious thought.
Smashing video chris :-D
I did this with my 9R59DS, but that has a spare triode section just waiting to be used for the purpose of buffering. A cheap Chinesium frequency counter finishes the job. It's mesmerizing just watching the drift...
@@oldblokeh Yes it would have some drift, i imagine the radio would be left on for an hour before use.
if the room temprature was regulated by the heating system it would be a bit better.
Yes as you say it does have some drift but it isn’t as bad as many are. Could fit a frequency counter but I think really you need to just put the effort in a work the dial. It’s like a vintage car I like to keep them original but other people may have a different opinion etc.
@@zx8401ztv I was referring to the 9R's drift which is, shall we say, substantial even with the regulator. I doubt that the HRO is nearly as bad. At the higher frequencies you have to use the counter, especially if using the bandspread. But then the Trio was designed to be customised.
I was going to say the regulator helps. Amazing it wasn’t fitted as standard but the drift even when fitted. Still it gives you something to do
Reception was undertaken by the Y Service alongside the volantery interceptors or V.I s who were pre war amateurs ,ex or swls
I’ve seen a few of the coils at ham swap meets some years ago. Impressive set despite the tuning system, seems like there’s a good space between stations on AM. Nice. Quite a bit of RTTY there. Don’t hear a lot here. Wish I didn’t find CW hard to receive, oddly I can key 10WPM
Funny some of the the coil packs have considerably more range than others and those are a bit squeezed. It’s not a bad performer given it’s age original design around 1935. The tuning arrangement is really a pain in the bum. These sets were also manufactured in Australia and they were a popular set. Yes I can also send with a straight key much faster than I received but I think that’s normal. Thanks regards Chris
Might be cool to make a set of coils to tune the am all in 1 band. Would be alot of work though, because wouldn't want to mess up an original coil unit.
I think people have modified existing coil packs but I suspect it is a lot of work trial and error. It appears that for the coil packs I have two coil packs are required but most of the activity is still covered by just one pack so it isn’t so bad in operation. Thanks for watching and comments regards Chris
Hello Chris! Daggumn awesome! Thanks for posting! I have a 1954 NC 300, any relation? Cheers!
Sorry I don’t know about the NC300 but did just watch one being restored by Dlab. They look very impressive haven’t ever seen one here in the U.K. I guess they came out the same company. Thanks regards Chris
@@allthegearnoidea6752 They are HEAVY. Gravity is their brother. But yours is cooler. Cheers!
interesting radio that cap may have been left to preserve originality seeing as it can be easily seen maybe its been stuffed? you gotta love that indicator lamp ! I like to choose something interesting to fit on anything I build !
I it’s one of those cut glass jewel lamps very pretty. I haven’t had a detailed look at the capacitor or the radio in general but it will probably come in bits and be looked at in a future video. We missed you at Goldborne today it’s a shame you couldn’t make it.
@@allthegearnoidea6752 very popular on a lot of equipment mainly vintage guitar amplifiers I think you can still get modern equivalent's
There is several a frequency charts published on A4 paper which I downloaded from the internet some time ago its like the BC221 frequency chart. same idea.
Very interesting.
Thanks for watching and leaving a comment I always appreciated it. My best regards chris
@@allthegearnoidea6752 Your most welcome sir.