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?
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 …
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.
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:
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
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 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.
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.
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.
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
Josh - did you ever figure out your problem with that HB-1B? My volume potentiometer is getting a bit scratchy, so I might look for a replacement part - and it made me wonder if the problem you are experiencing is as simple as a bad volume pot. That might explain why you barely touch it and it seems to go to max volume. Just a thought - it might be as simple as that.
I won the same rig as yours in the 2022 SOTA auction. It has been very reliable and I really like the minimal number of controls and functions with the clear display. Yes the steel case is a titch heavy but on the other hand it is rugged.
I do notice some minor loss of tone and a slight thump on strong signals but maybe I’m not getting signals as strong as yours. And there is always the attenuator. The gain control works fine.
I’ve used it both as a primary SOTA rig and a back up rig and it’s done the job perfectly. It is a bit like the MTR4 I have but with a full digital display and in a bigger case. Heavier too of course. And more sensitive and more gain.
The only suggestion I have is to check the bottom end of the volume control. If there is a dry joint there it would lead to apparent high gain and poor volume control.
Hi David. No, I looked at all the components (and the pot) and didn’t find any problems or obvious wrong value parts. I think this is normal for this particular version of the HB-1B. I have not done anything further to try to improve it. It is totally usable as-is, I just keep the attenuator turned on all the time. I honestly don’t use the rig very often since I have a few (ok, more than a few!) QRP radios to choose from. Now that the higher bands are so good I mostly only use my KX2 anyway. I wish this HB-1B had 17 or 15 instead of 80!
Thanks. It is a fine rig and I do keep the attenuator on 99% of the time. I did check over the PCB and all controls carefully and didn’t find any problems. I do typically have a lot of VERY strong signals here - we are blessed with a strong pool of chasers who have exceptional stations. I may experiment with an inline attenuator that can be switched in/out easily - could be useful for the start of an activation when the big guns are calling =) The RX is very hot on this thing, which is great for hearing those weak S2S stations.
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.