G4NSJ - National HRO 5TA1 5A1 R106 mk1 mk2 comms receiver - part seven

In this HRO receiver video, part seven, I talk about the US Navy and the 175KHz IF frequency plus different coil packs for the Navy. I've got the crystal filter working, which I demonstrate. I've added a BFO switch and have a quick listen to SSB to the 40m band.

[@Paddy_Roche]

Well done on finding these elusive articles Ray. You are like a Super-sleuth tracking down this information to allow you to make progress. Fascinating series. Thank you.

[@g4nsj]

It's taken hours but it's been worth while. A super-sleuth! I like that! Cheers, Ray.

[@Zerosho]

Ray, I have a National NC-2D that has the same three position switch you removed. Position 1 allows the receiver to heat up so there is no drift i.e. reception is cut off. Position 2 is "manual" with no AGC. Position 3 is AGC. A friend of mine sent the radio to me as we both worked in SIGINT in the 80's. He found it at a radio convention, abused and left for dead. I refurbished it. It's a boat anchor! I named her "Natalie" for National Radio. She was made in 1947. Also, really enjoy your videos. You remind me of the gentlemen who introduced me to radio when I was 16. Keep making videos, Old Man. Cheers -- Buzz

[@g4nsj]

Hi Buzz, my switch wasn't wired that way but tjhat's interesting. Natalie... I like that. I'll have to think of a name for my HRO. More videos on the way! Cheers, Ray.

[@WECB640]

Ray, I believe people "gronch" the adjustable components because they're desperate to learn how the unit works. It's also a result of far too few mentors available to satisfy the next generation. I too did a few gronches as a lad and worked my way up to 50Kw with great success as a broadcast engineer. Your channel is very important as it teaches and mentors that new breed that wants to walk in your footsteps. Be patient with them. Show them the correct way and the proper tools to use. That's what I try to do now with my peeps. PS. I wish I had an answer to the crystal question. Only thing I can come up with it that it's lightly loaded by capacitance coupling and without the spacers we have an impedance mismatch (heavy loading) on the crystal and thus a low Q. That's my best guess. 73 OM Looking forward to the next video.

[@g4nsj]

Yes, I agree that people might want to learn how the unit works. As you say, there are far too few mentors around these days. I shall be patient. That's a good point about the crystal and lightly loaded by capacitance coupling. More videos coming soon! Cheers, Ray.

[@kc8aro66]

Hi Ray, the GOLDEN SCREWDRIVER!! Glad you got it sorted out, been great progress, thanks for sharing.73

[@g4nsj]

A, yes! The GOLDEN SCREWDRIVER! Haha!

[@mmwaashumslowww7167]

I had to laugh when you said "Graunch". That was a favourite saying of my dad when he heard someone doing a bad gear change. Turns out that it was a popular saying amongst motorcyclists too in the mid 70s as I remember.

[@g4nsj]

Graunch... it is an old word! I remember it being used in the 1960s.

[@coroamanicolai4527]

Great video! Looking forward to the next part :)

[@g4nsj]

Thanks!

[@G4WTV]

Fantastic, Ray. Surprised that SSB resolution works so well, as I thought these old radios were for just CW and AM. Keep up the good work with getting the radio in top working condition.

[@Mike-H_UK]

Hi Ray, Great video, many thanks. Perhaps during a future video or in one of the weekly videos you could explain why the US navy needed to change the IF to 175kHz in order to receive 400-500kHz. I gather there is some problem with receiving broadcasts at the same frequency as the IF.

[@g4nsj]

Yes, good point. I'll make a video as soon as I can. Cheers, Ray.

[@Mike-H_UK]

@@g4nsj Thanks. I guess on thinking about this a bit more, if the incoming frequency and IF are too close there will be a tendency for them to lock together in the mixer resulting in dead zones in the receive band.

[@g4nsj]

@@Mike-H_UK That's right. I will make a video about it.

[@MM0IMC]

13:00 I recognise that voice, it's 2E0KKA, Chris from Exeter.

[@g4nsj]

Excellent!

[@ChuckKirchner-se6ib]

Is the Navy coil pack the one you had to drill a hole in to get the receiver to accept it? Perhaps that's why there was no hole, as the IF was different. This receiver is a fun journey, as long as it doesn't make you mad. I'll be here for any amount of episodes. Cheers, Ray.

[@g4nsj]

Hi Chuck, yes you're right, it's the Navy one. Good point! I don't think I've gone mad just yet. Well, not quite! Cheers, Ray.

[@callumtew2693]

Hello Ray really good video I am loving the content anything coming up at Halloween on your 2nd channel

[@g4nsj]

Good to hear from you. I'm working on something for Halloween... Cheers, Ray.

[@callumtew2693]

@@g4nsj ok cool xx

[@itsonlyme9938]

I have a class d wave meter it has a 1 meg and 100khz crystal reference and it does also rattle around in side its holder

[@g4nsj]

That's interesting, thanks.

[@bilbp41]

Right try contacting Mr Carlson’s labs. I’m sure he’s done a HRO radio on KZbin.

[@g4nsj]

@@bilbp41 thanks, I’ll do that.

[@paulswift700]

Hi Ray. Have you seen the guy from the states videos he is working on this type of radio as well. 73 Paul G0MIH, HS0ZLQ

[@g4nsj]

Hi Paul, I'll take a look. I have seen a few videos but I'm not sure about that one. 73 Ray.

[@stelthtrekker9445]

I understand none of this.