Next month (August) will mark 10 years since I built my little Sproutie HF Regen Receiver. I recently received an email from Bob W3BBO. A few years ago, he built a Sproutie, and he has just built another one – more on that later. Bob’s first Sproutie is shown in this post, along with a few of his other projects. Take a look – there’s some good ones there. His email got me thinking about my Sproutie. I looked up my post on it, and realized that it has now been in the world for 10 years. This seemed like a good time to haul it down from the shelf and see how it has fared. From time to time, I see comments on Manhattan construction, questioning what the copper-clad boards look like after a few years. What a good time to find out! To be fair, I drag The Sproutie out every few months and give it a whirl, so I knew what to expect. It looks essentially the same as it did when built, with the exception of some Dymo labeling that I recently added, and some light dust. I live in an old house, built in 1908, that is very dusty. Comparing the National N dial to how it looked 10 years ago, there does appear to be some light corrosion breaking through the plating, but nothing serious –

All is looking good on the outside, but what about those boards? Well, it turns out they’re looking pretty good too –

These boards were sprayed with clear lacquer before use, and it has protected them from oxidation quite well. In a few of my projects, I didn’t lacquer the boards at all, and they went dark with oxidation after a while. They are still perfectly functional; just not quite as attractive. Over the course of a few years and a few different projects, I learned that how the lacquer is applied makes a difference as well. Very light coats result in a somewhat stippled appearance and, if you don’t apply enough coats, can result in light oxidation with the passage of time. Applying the lacquer more heavily creates a smoother finish, but care is required here – too heavily, and the lacquer pools. If I remember correctly, it will also wrinkle as it sets if multiple thick layers are applied. Both the distance between the spray can and the board makes a difference, as does the length of time you spend spraying. Experimentation is key.

My WBR receiver was built in a case made out of double-sided copper-clad. After 13 years, the circuit board inside still looks good. The outside of the case hasn’t fared as well though. The lacquer was applied quite lightly. In the areas where the receiver was handled a lot, the lacquer must have worn thin, as the board has oxidized in those areas. From the outside, it doesn’t look as bright and shiny as it did when it was built in 2011. This is one of the reasons why, with subsequent projects that I built a case for out of copper-clad, I used single-sided board, and kept the copper side on the inside.

Anyway, The Sproutie still looks presentable, and it sounds just as good as it did when built. Occasionally, the AF and RF gain, and LPF bandwidth pots are a little scratchy, but rotating them a few times cures that. It is still a fun receiver to travel around the HF bands on, though I wish there were more SW AM BC stations to listen to. This receiver would have been a real hoot in the 70’s and 80’s. If I could have built and used this when I was 16, I would have felt as if I’d died and gone to heaven!

The coil box was made from an old cigar case, and some basswood for the compartment divisions. I made this coil box 10 years ago and these, like the Sproutie pictures in this post, are current photos –

Building things is fun, and it’s even better when the project you’ve built remains very usable year after year. If I was building any iteration of The Sproutie again, I’d leave out the fine tune control, as I found it unnecessary. Not sure how I’d make the front panel look balanced without that knob on the right side though. That would have to be given some thought.

As I mentioned at the beginning of this post, Bob W3BBO just finished building his second Sproutie. He didn’t have an AD820AN on hand for the variable bandwidth audio LPF, so he used half of an NE5532 op-amp as a preamp with 6dB of gain and a cut-off at 20KHz, which is essentially just an audio amp with a little gain. See the post on my Sproutie MK II for details on those active filters. With the coil he had, shortly after switching it on, he was able to hear the CHU time signals at 7850 KHz –

These are the two boards that Bob mounted underneath the chassis, and which comprise most of the circuitry for his Sproutie regen –

Congratulations Bob, on bringing another HF regen receiver into the world, and thank you for sharing details of your FB project!

Next month (August) will mark 10 years since I built my little Sproutie HF Regen Receiver. I recently received an email from Bob W3BBO. A few years ago, he built a Sproutie, and he has just built another one – more on that later. Bob’s first Sproutie is shown in this post, along with a few of his other projects. Take a look – there’s some good ones there. His email got me thinking about my Sproutie. I looked up my post on it, and realized that it has now been in the world for 10 years. This seemed like a good time to haul it down from the shelf and see how it has fared. From time to time, I see comments on Manhattan construction, questioning what the copper-clad boards look like after a few years. What a good time to find out! To be fair, I drag The Sproutie out every few months and give it a whirl, so I knew what to expect. It looks essentially the same as it did when built, with the exception of some Dymo labeling that I recently added, and some light dust. I live in an old house, built in 1908, that is very dusty. Comparing the National N dial to how it looked 10 years ago, there does appear to be some light corrosion breaking through the plating, but nothing serious –

All is looking good on the outside, but what about those boards? Well, it turns out they’re looking pretty good too –

These boards were sprayed with clear lacquer before use, and it has protected them from oxidation quite well. In a few of my projects, I didn’t lacquer the boards at all, and they went dark with oxidation after a while. They are still perfectly functional; just not quite as attractive. Over the course of a few years and a few different projects, I learned that how the lacquer is applied makes a difference as well. Very light coats result in a somewhat stippled appearance and, if you don’t apply enough coats, can result in light oxidation with the passage of time. Applying the lacquer more heavily creates a smoother finish, but care is required here – too heavily, and the lacquer pools. If I remember correctly, it will also wrinkle as it sets if multiple thick layers are applied. Both the distance between the spray can and the board makes a difference, as does the length of time you spend spraying. Experimentation is key.

My WBR receiver was built in a case made out of double-sided copper-clad. After 13 years, the circuit board inside still looks good. The outside of the case hasn’t fared as well though. The lacquer was applied quite lightly. In the areas where the receiver was handled a lot, the lacquer must have worn thin, as the board has oxidized in those areas. From the outside, it doesn’t look as bright and shiny as it did when it was built in 2011. This is one of the reasons why, with subsequent projects that I built a case for out of copper-clad, I used single-sided board, and kept the copper side on the inside.

Anyway, The Sproutie still looks presentable, and it sounds just as good as it did when built. Occasionally, the AF and RF gain, and LPF bandwidth pots are a little scratchy, but rotating them a few times cures that. It is still a fun receiver to travel around the HF bands on, though I wish there were more SW AM BC stations to listen to. This receiver would have been a real hoot in the 70’s and 80’s. If I could have built and used this when I was 16, I would have felt as if I’d died and gone to heaven!

The coil box was made from an old cigar case, and some basswood for the compartment divisions. I made this coil box 10 years ago and these, like the Sproutie pictures in this post, are current photos –

Building things is fun, and it’s even better when the project you’ve built remains very usable year after year. If I was building any iteration of The Sproutie again, I’d leave out the fine tune control, as I found it unnecessary. Not sure how I’d make the front panel look balanced without that knob on the right side though. That would have to be given some thought.

As I mentioned at the beginning of this post, Bob W3BBO just finished building his second Sproutie. He didn’t have an AD820AN on hand for the variable bandwidth audio LPF, so he used half of an NE5532 op-amp as a preamp with 6dB of gain and a cut-off at 20KHz, which is essentially just an audio amp with a little gain. See the post on my Sproutie MK II for details on those active filters. With the coil he had, shortly after switching it on, he was able to hear the CHU time signals at 7850 KHz –

These are the two boards that Bob mounted underneath the chassis, and which comprise most of the circuitry for his Sproutie regen –

Congratulations Bob, on bringing another HF regen receiver into the world, and thank you for sharing details of your FB project!