Everybody Staze...

Nobody leavz...

TSI DP-Calc 8705

By

8705-DPCalcI recently had a complaint from someone staying at my house that the guest room stayed too warm when the door was closed. Knowing there was no air return vent in that room, I figured the door being closed was preventing good air flow. But, sadly, there was no good way to test this (with the tools I had). So, I went hunting on eBay for the proper tools, and found the TSI DP-Calc 8705 (a Micro-manometer) with no bids, for $15! Sure, it was listed as broken, but they admitted they just didn’t have the means/knowledge to test it. And the sticker had shown it was calibrated in 2012. So, I bought it. Even if it was broken, it would probably be a decent source of parts, or a good teardown to send to the EEVblog. =)

Unit arrived a couple weeks later, and was in amazing condition. Sure, it didn’t come with the RS-232 cable, or tubing, or static/pilot tubes, but I didn’t really need any of that for my purpose. It seems to register perfect, and I was able to go around my house and measure the pressure differentials with the door closed (sticking the more positive “sensor” tube under the door from the main part of the house into the room with the HVAC running). With that, I got the following results:

Bedroom 5.72 pascals (high)
Son’s room: 9.2 pascals (very high)
Bathroom: .747 pascals (great!)
Office: 3.48 pascals (high)

The US Department of Energy Energy Star homes standards for closed door pressure differentials at ≤3 pascals (0.01″wc) (undercutting doors), but using those numbers, it does seem like the gap under all my doors (except possibly the bathroom) is too small. I say possibly with the bathroom because excess pressure would just push out the bathroom fan exhaust. So my next quest will be to cut the door openings a bit larger and see how that changes things.

I also made a nice serial interface cable for the unit using an old DB-9 cable, and some RJ-45 ends. To figure out the pinout, I emailed TSI, and they sent me the whole schematic for the unit! The pinout is “backward” from right to left looking at an RJ-45 connector, but making the cable was pretty painless, and seems to work. The unit literally sends the measurement to the computer when you hit “Print” (just plain old ASCII). If you type “V” on the computer, it’ll echo back the current reading. Pretty simple, and could make for some fun experiments.

Overall, while the unit is pretty old relative to more modern units, it still does an amazing job, and is more than capable of doing what I need. Also, for reference, the tubing is 3/16″ ID and 5/16″ OD. I purchased some Tygon tubing from work and use that. I may buy some silicone tubing in the future…

[xrr rating=5/5]

HAM for the man that doesn’t eat Pork

By

International_amateur_radio_symbolAnyone who reads my blog, at all, knows I’ve been repairing a lot of gear for the last while. But, I’ve wanted to take it up another notch, and repair some radio equipment… mainly HF/VHF/UHF transceivers. Now, while there’s nothing against doing that and being unlicensed for Amateur Radio, I thought it would be more responsible to actually have a license so I could test said gear rather than just pumping it into a dummy load.

So, I spent a couple weeks studying, and took the Amateur License Exam 2 weeks ago, and passed Technician with no problem at all. Sadly, I was able to take the General exam right after for free, and missed it by one question! So, I have my license, and right now, have a call sign of KG7VJC, which is fine, but I have applied for a Vanity Call Sign. That takes a while, so I’m holding off on saying what that call sign may end up being.

As for a radio, I initially planned on just buying a Baofeng radio, but after never hearing anything overly great about them (other than cheap), I started watching eBay and Craigslist for used Yaesu/Icom/Kenwood HTs (Handheld Transmitters). I quickly found one, in Portland, for a Yaesu VX-8DR, a pretty high end HT that looked awesome. So, I saved up a bit, and just last week bought it while up in PDX for a bit more than I’d have liked, but I’m sure it will serve me well, and radios really seem to hold their value (I can always resell if I need to).

Anyway, I’m now a ham. I’ll post a review of the radio (and probably other radio gear as acquired), as well as be adding some repairs of transceivers once I have some to repair. I’ll also be joining a local club… as that was suggested by the person I bought the radio from (lamenting he hadn’t joined one earlier). Joining the ARRL, though, may not happen anytime soon. It’s kind of spendy.

Spiders, spiders everywhere!

By

Weather-StationI recently was out in my back yard when it was breezy, and when I glanced up at my weather station, I noticed the anemometer cups weren’t spinning. They’d twitch just a bit, but not spin. I had a feeling I knew what was up (A spider had “tied” them down), but it required a trip to the roof to check.

Once on the roof, I took the station down (my 10ft mast detaches at the half way point so I can work on the station). And indeed, an industrious spider had managed to put a web in each cup, and then linked each cup to the ISS (Integrated Sensor Station). Impressive. I cleaned the station up with some paper towels (including the solar panel), and got the spider down to the ground (attached him to the roof line, and let him lower himself down). Then put the station back up.

Checking my submitted weather data, at first, I thought I had lost a month worth of wind data, but checking again, showed about 12-16 hours of it missing (can’t really tell when the wind was zero MPH vs when the anemometer was stuck). Then the question became, how do I keep this from happening again, and me losing a week+.

First, software. I submitted a request for Weathercat to notify me when wind data remains at zero for a long time. Others on the forum also suggested I sign up for AWEKAS, which apparently WILL notify if sensors stop making sense (no wind for days/weeks). So, here’s my station on AWEKAS.

Second, how do I keep spiders off the station. I’ve thought about putting “Tanglefoot” on the mast, but that seems like a pain. I’ve also heard flea collars will repel them, so I think I’m going to try that up by the station next time I’m on the roof. For now, though, if you own a weather station, you may want to check your station in the summer to make sure a spider hasn’t made a home and wrapped up the whole thing disabling any of the moving parts. =)