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YouKits HB-1B (and a bonus wG0AT chase video)

I’ve had this YouKits HB-1B for a while but have not used it much. Picked it up for $100 USD from a local ham. It is the older version in the steel case with bands: 20/30/40/80

I have been making some QSOs with it over the past few days and I notice that I have to turn the audio down to almost nothing or else the signals sound very ‘thumpy’ and harsh / overdriven. I have the attenuator turned on, and I only use about the first 1/000th of the range of the AF Gain control. I have tried with different headphones and external speaker and it’s the same.

Here is a good example that I recorded this morning:

Any other HB-1B users care to comment? I can live with it, but none of my other QRP rigs have this problem. Almost like the audio amp gain is way too high… maybe there is a modification to correct this?

Thanks!

-Josh WU7H

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Mine doesn’t have enough gain. Same with the HB-1A. I used one owned by DF3MC, and it also had low gain. Did your local ham install a little amp?

Elliott, K6EL

I have never seen a circuit diagram of this rig to see if any components can be “turned down”. I have the same model as you and yes I often have to adjust the volume of different stations I hear. I think they are a great QRP radio and I should use it more for SOTA but a lot of my faithful chasers only use SSB so its more of a portable yard radio. I always park the rig with volume setting low.
Regards.
Ian vk5cz …

2 Likes

I’m not familiar with the rig but it occurs to me there’s no AGC circuit?

GL/73

Hey El, I looked inside and there don’t appear to be any modifications. I did get a schematic for an HB-1B from KL7KN - not the exact same revision as mine but close enough. Mine is HB-1B8c/2014 board.

It does have AGC according to the schematic I got from KL7KN. And the audio amp is LM386.

I’ve never had that issue. I think that mine is the mk3 version.
Peter KD0YOB

Hi Peter! Yes, I think the newer ones in the aluminum case are improved. I do like this rig and it’s very usable for SOTA. Been a while since we had a QSO… hope to catch you out there soon.

Oh, and here is a shout out to @KN6EZE for his awesome HB-1B side rail and cover design:

I did a ‘remix’ of his project to make something similar for the steel cased HB-1B. I haven’t posted it on Thingiverse yet, but I will soon. Here is a pic:


The top cover (for transport) is held on by magnets and works very well. It also replaces 1/2 of the steel case so reduces the weight quite a bit!

-Josh

3 Likes

Maybe a wrong value volume pot or wrong resistor in the LM386 circuit. Sounds like it is running pretty Hot, as in extremely high gain. I ain’t no expert, I just know enough to be dangerous. Hi Hi.
73’s
Tim

1 Like

Thanks Tim. I’m going to bust out my magnifying glass and have a look at that LM386 circuit and AF gain pot.

Hi Josh -

I have an older version HB-1B I bought around 10 years ago - it’s my main SOTA rig and the same one I have worked you on many times :slight_smile: I think I might have experienced that phenomenon, but never found it bothersome. So, I tried it at home with another rig locally to really hit the AGC and it seems to do it only on very strong signals. Sounds like yours does it on less-strong ones, compared to mine. Well, there will be unit to unit differences… My hunch is that it’s related to the AGC circuitry. You said you already use the radio’s attenuator - if you can experiment with an additional outboard attenuator (if you have one) that might help you narrow things down. On the other hand, if you’re pretty sure it’s on the audio section, you’ll need to look there of course. The audio on mine seems good - I usually use earphones/earbuds, and usually don’t have to run the volume at more than halfway - maybe a bit higher if there’s ambient noise (wind) at the summit. I just copied a strong 40M station, and varied both the IF and volume control and could not get it to thump, regardless of the volume setting (it’s a pretty strong signal) - both with atten on and off, or with earbuds and an amplified speaker.

I don’t know the specific circuitry or have a schematic of the HB-1B, so I’m probably not much help. If you need me to try something on my end with my HB-1B, send me an email.

If you figure it out, let us all know!

73, Dave, N0DET

2 Likes

Thanks Dave - I think mine is about the same vintage as yours. I do think it’s something in the audio section because I can only turn the volume up a TEENY TINY bit or it is way too loud. If I turn the volume down low enough those strong signals sound clean - otherwise they THUMP. If I turned mine up to 1/2 volume it would blow out my ear drums!

Perhaps I could get you to take a high-res photo of your board? Interested to see what value parts they used in the AGC and audio amp circuits on yours. I’m thinking mine may have a wrong value part - either an assembly mistake or something they changed in a later rev. Mine is HB-1B8c/2014.

Thanks,

-Josh WU7H

1 Like

I can do that - I’m having a key jack issue (was messing with my SOTA activation yesterday) and I plan to open it up and check it out anyway - while I’m there I’ll take some pics and email them to you.

I’ll try to do that today - I’m at work today but I’ll see if I can get that done.

Dave

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Thanks for the fun video, Josh!!
Hah! Wow can’t believe I didn’t hear you early on but till near the end of pile? Although QSB was playing our signals! This is a good example of if you hand in there till end of pile you’ll eventually get through and make the contact! Your newly acquired HB-1B has good ears just need to adjust than audio/AGC or ?? …GL-73, Steve/wGØAT

1 Like