Touring the Rochester MN “Cave House”

May 11, 2021

A Minnesota real estate listing went viral recently due to the artificial sandstone caves connected to the house. Since I’m involved in digging sandstone caves of my own, I thought it would be fun to take a look! We investigated the cave layout and design, as well as some of the history of the property and surroundings. I have a video tour of the property below:

And here’s the quick map I made of the caves and house (it’s not 100% accurate, especially with regards to the house layout, but I did my best to do the caves to scale!).

And a few more photos of the property:

DIY Duck Pond Filter

April 28, 2021

A while ago I posted about our garden pond and homemade filter swamp. Prior to building the fish pond, we did a smaller pond for our pet ducks & goose. This one is basically just a buried stock tank next to the bird coop.

Since water birds produce a lot of umm… “dirt” in the water, we wanted a pretty beefy filter to keep the water clean. The pond includes a submerged pump (Tetrapond 1000) with plumbing that runs up to an external barrel. The barrel drops water into the bottom, then filters it upwards through progressively smaller layers of stones, pumice, gravel, and composite filter media. The filtered water runs off the top of the barrel and back into the pond.

That thing in the center of the barrel is an aerator tower. Water is pumped into the side of the large plastic pipe, which has an opening at the top for air. The water then drops down inside the large pipe, ideally pulling some air along with it and mixing the air in with some nice splashing.

Here’s what the aeration tower looks like before it went into the barrel. The “legs” at the bottom hold up the first layer of filter media (larger rocks / gravel on plastic grating) and maintain an open space at the bottom where solids can settle out. Water comes in near the top of the tower through a small pipe with a 90-degree fitting inside. This makes sure it drops straight down the center of the tower to maximize splashing.

Below shows the tower inserted into the barrel. At the bottom you can see angled pipes with 90s that inject the new water in a circular pattern into the bottom of the tank. This helps stir the bottom chamber to avoid clogs and let the sediment settle out.

Here are a couple rough sketches I made while planning this out. Neither of these shows exactly what we did with the filter media. Some websites suggested things like floor scrubber pads, but we ended up using layers of large rocks, gravel, and pumice, then topped it off with some filter mat rolls intended for koi ponds. The idea is not only to filter out solids, but to create a lot of different-size crevices and surfaces for beneficial bacteria to grow. The bacteria does the bulk of the cleaning by removing dissolved nutrients from the water.

The final setup is seen below. We have water-loving plants growing in the top of the filter barrel. The red thing in the pond is a float valve that tops off the pond from a rain barrel on the bird coop. The other white pipe coming in from behind the coop is an overflow from the rain barrel, so when it’s full the extra rain water also goes to the pond.

So far the filter has worked great through several years of use. Without filtering, the duck pond would grow mats of stringy slimy algae. With the filter, any green stuff grows inside the filter media and the pond water stays crystal clear! In fact, one year we accidentally raised goldfish in the bird pond!

In the winter we shut all this down and drain the whole system so it doesn’t freeze. The barrel filter has a large cleanout valve at the bottom, it’s large enough to stick a hose in and wash out all the sand that builds up. For the winter the birds get a smaller shallow pond (kid’s sandbox) that’s small enough for a submerged heater to keep liquid.

Here’s the video tour of the finished pond system:

Trains Made From Trash

April 7, 2021

I’ve dabbled in railroad bikes or “velocipedes” before, but recently I’ve been trying to create an improved design. The following set of videos are my early model, I’m currently working on an even better one!

Stay tuned for the future adventures of this silly hobby, as I add… MORE POWER!

Funter Bay History: 1990

April 7, 2021

Yes, I know it’s a little more modern than my usual Funter Bay History posts, but this is some personal history! I found an old tape from my grandparents that shows my family and some friends and relatives, our house, and the “neighborhood” of Crab Cove in 1990. There’s even an early saveitforparts invention!

Listening to Geostationary Satellites… with Trash!

April 7, 2021

In the further adventures of my dumpster-dived satellite dish, I aimed it at the GOES-16 weather satellite, about 22,000 miles away in geosynchronous orbit. It turns out that a commercial TV dish is a little too small for this particular use (TV sats are the same distance away but have much more powerful transmitters). I couldn’t find a big antique dish and didn’t want to pay money for a GOES-rated Wifi dish (which you can buy on Amazon), so I made mine bigger!

I extended my dish in every direction with cardboard, then covered it in metal foil tape. And it really works… somehow. The signal and error rates are a bit marginal, but I can still download nice pretty pictures of the earth! A few examples are in the video, and below.

For more of the technical stuff, I’m using an RTL-SDR Blog v3 software defined radio, a SAWbird+GOES LNA from Nooelec, a cantenna feedhorn, and a Raspberry Pi computer for processing. I found that other Linux distibutions don’t quite work with the collection of code and drivers needed for this.

The cardboard won’t last long-term, so I’m looking for an antique C-band dish that I can set up as a more permanent solution. However, for a cheap and expedient ground station, this worked pretty well!

A step-by-step guide to receiving GOES satellites can be found here:

More information here:

Both of these guides assume you’ll be using a re-purposed Wifi Grid dish. You can get the entire “kit” of dish, SDR receiver, and LNA amp/filter here:

You can piece this together with other parts and antennas, but you will at minimum need the SAWbird LNA and an SDR that can handle 1700mhz. The ability to power the filter via Bias-Tee from the SDR is optional, however the Sawbird will back-feed power if using a usb cable, so in that case you’ll also want a DC filter. If you don’t want to buy the Wifi dish, any LARGE satellite dish should work with the cantenna design I used.

Info on cantenna design here:

You have to be connected to a network for goesrecv / goesproc scripts to run, otherwise it can’t find localhost (because… reasons?). I had to be within wifi range to get this to work, even setting a local static IP didn’t help. There’s probably another way around this if you want to run this setup off-grid or remote where theres’ no network.

If your dish is made of reflective foil and the sun lines up just right, you might cook your feedhorn / LNA!

Some Experiments in Smelting

February 12, 2021

I built a small aluminum smelter and have been experimenting with melting down old cans and scrap metal. so far it’s not the easiest process, I still need to work out some kinks and issues. Here are a couple videos on the project so far, I plan on doing more soon.

Listening to Space

February 10, 2021

I’ve been playing around with radio astronomy and satellite stuff lately. As usual, this is with the cheapest / free-est (is that a word?) gear I can build or scavenge. So far I’ve made a very very basic “radio telescope” out of an old TV dish and security camera mount. I’ve also managed to listen to passing weather satellites with some bits of wire. This is another project I’ll be working on more in the near future. I’d like to be able to do more with the dish (maybe pick up free NASA TV), and more with the weather satellites (maybe geostationary next). Stay tuned for updates!

Some weather images I received from NOAA satellites using the V-dipole antenna:

Listening to NOAA weather satellites as they pass overhead is relatively simple! Actually getting imagery decoded from the transmissions took a little more effort, as I learned in the process of making this video. Below are some of the resources and guides I found helpful for this project:

Basic intro to satellite reception:

The antenna design I used:

Website for tracking satellites and determining upcoming overhead passes (As of early 2021, the ones to watch are NOAA 18, 19, and 15):

Info on the NanoVNA I used for antenna tuning:

This is a decent Software Defined Radio that’s capable of hearing these satellites. You can get them with or without lots of extras like antennas and amplifiers:

The software I used to interface with the SDR and record audio files (for Linux / Raspberry Pi): (I have heard SDR# is good for Windows, but have not tried it:

The software I used for decoding images:

Some “gotchas” I ran into when working with saved audio files (not always obvious from online guides):

-WXtoIMG is ancient abandonware and barely works on modern computers. The Linux version has some display issues and freezes when trying to update Keplers, at least on my system. On Windows I found that the beta version works better, the “stable” release won’t install at all). It also doesn’t like modern sound drivers, so if you can’t decode live signals you may have to record and decode later (see below for even more tricks with this!)

-Gqrx saves recordings in stereo at the wrong sample rate. You’ll need to open the saved audio file in Audacity (or some other audio editor), collapse the file to mono and change the sample rate to 11025. You’ll probably also want to Normalize the file after each step. See here for more details:

-WXtoIMG It is very finicky about date/time stamps and you may need to fiddle around a lot to get your recording to match a known satellite pass. I had no luck using the filename to specify recording time as the faq recommends. I had to download a file attribute editor (Or this software can change timestamps: ). You need to change the “Modified” date and time (not the “created” attribute) to the time when the recording started (because once you process the file through Audacity, the timestamp will be different). I then had to manually adjust the map overlay in WXtoIMG (fortunately I had a visible reference point, if it’s all clouds you might be out of luck!) See for some info on this.

Hopefully all that helps! There are a lot of guides online for how to do this, some are more complete than others. There are problably also plenty of videos better at explaining this than mine, I was just trying everything out for the first time.

More Garden Pond / Backyard Fish Stuff

February 9, 2021

Here are a couple videos expanding on our DIY backyard garden pond. Earlier this year we discovered that goldfish eggs or fry had mysteriously migrated across the yard to the duck pond! We were able to catch and relocate the new goldfish before the ducks ate them, and they seem to be doing well.

The second video is a follow-up on our inverted “fishdome” in the pond. It’s a cool fish observation bubble and works on the same principle as lifting an upside down glass in the sink. The only downside to these things is they need to be cleaned of algae frequently.

Cheap Backyard Railroading

February 9, 2021

I’ve always wanted an outdoor railroad, but it turns out the “real” equipment is expensive! Fortunately I found an alternative in cheap 1980s Christmas tree trains! Made by “New Bright” under a variety of product names, these can often be found at thrift stores and garage sales in the $5-$10 range.

While New Bright does G Scale trains as well, the ones I’ve been collecting are closer to “S scale”. I don’t know if they actually have an official scale or gauge, as they’re just cheap-o plastic products with no real attempt to be detail-accurate. I still enjoy them, and the battery-powered locomotives mean I don’t have to mess with wiring up track.

These won’t last long-term outdoors, so I did put them away before winter. Maybe next year I’ll actually find some outdoor-rated brass track and upgrade to more legitimate G scale!

Taking apart & moving a fast food playland

February 6, 2021

This was one of the bigger projects I’ve been involved in recently! My friend Carl (link to his website) got this massive playland for free from a defunct Burger King. A few friends got together and helped take it apart in the three days we were given before the building was boarded up. We moved the whole thing out to Sandland where it’s stored for the winter. Next spring we’ll start re-assembling it outside (we checked and the manufacturer says it’s UV-resistant).