Coping with the heat wave

Hello all, while this isn’t actually a post about amateur radio I wanted to post about how we (my partner and I) decided to deal with the June 2021 heatwave in the Pacific Northwest. While this isn’t directly related to ham radio I think it’s worth discussing as the temperatures in this region don’t typically reach the levels they were at and most homes and people aren’t prepared to cope with those temperatures. Some folks will probably laugh at this post and the situation in its entirety, but you have to remember that homes, businesses, animals, and people in what is typically a fairly temperate climate aren’t used to these sorts of temperature spikes. Some of us will mostly be uncomfortable and maybe inconvenienced but for others this is a deadly situation. There are large numbers of unhoused folks sleeping rough and stuck outdoors during this time. It is easy to die of exposure in situations like this even in a city. In nature you might be better or worse off depending on where you are. When operating in the field it’s important to keep yourself and your equipment cool, and I don’t think this is the last time we will have unseasonably hot weather. Next time it could be during another disaster or trigger secondary problems like power outages. This post is mostly about optimizing a solution for a problem with cheap and easily available materials to decrease misery and help alleviate a situation that could lead to an emergency.

One obvious issue with the house we live in during this specific situation is that it has a very large single-paned south-facing window, which definitely heats the house up during the summer. We were fortunate enough to have a single window-mounted AC unit for the whole house but it was only able to keep the house in the high 80s to low 90s which is definitely better than 110+ degrees, but I wasn’t sure if the power grid would hold up under additional load and the heat itself. My partner and I decided we’d take some steps to cool the house further for our comfort and our dog’s safety. The most obvious thing we could do to limit solar gain would be to cover windows that we could with blankets, etc. which helped, but we didn’t have a big enough blanket to cover the window. I wanted to actually keep the heat outside rather than heating a blanket that was already on the inside of the house and having it radiate that heat into the living space. A cheap reflective shield with an air gap between the shield and the house would be a possible solution to the problem.

Problems to solve:

  • Keeping as much heat out of the house as possible
  • Shielding a large area
  • Keeping it simple
  • Passive cooling (a plus)
  • Temporary mounting
  • Not wanting to put tape on paint
  • Keeping it cheap
View of the outside of a house with a mylar blanket suspended in front of a large window supported by paracord. There are lots of plants.
Hastily constructed mylar “heat shield”

A quick trip to the grocery store yielded the following materials: a roll of duct tape, 50′ of paracord, and 4 mylar blankets (we only needed 3 it turns out). The entire solution cost less than $20, some moderate burns, and sweat. We taped the edges of the mylar blankets on both sides to hold them together and taped across the gap intentionally leaving holes that would be left to ensure the wind loading was lower since this was in part just held up by tape. Our first attempt at the solution was to run paracord from the fence to the gutter, but it required too much paracord and the angle the mylar blanket would be at would be less-than-optimal so I ran the paracord from the ground and weighed the ground ends and center point down with rocks. The end of the paracord attached to the gutter was run between the gutter nails and didn’t require tying or taping. I did, however, end up taping the corner of the mylar blanket to the inside of the rain gutter because there wasn’t a suitable anchor point for paracord near the corner of the house that I wanted to cover. We weighed down one corner with some rocks and were back inside within 35 minutes. Ouch note: ladders get hot in intense sun and gloves are a good idea.

The photos I’m including were taken after day 2. We had to go back out and shore parts of the heat shield up because some of the spots I taped to the paracord slid down. To combat that I just did extra-long wraps of duct tape around the paracord and attached it to the edges of the mylar blankets. I also taped the inside of the shield to the paracord at the bottom to prevent the heat shield from riding up the paracord. The end of the mylar blanket that was weighed down by rocks also tore in the wind/breeze so we coated the corner we stuck the rocks in with duct tape as a protective pad for the mylar. All the photos are this setup are shown below. The air gap between the window and mylar also served as a nice passive cooler. As the breeze and wind blew between the mylar and window it carried some of the heat away. After installing the mylar heat shield the temperature in the house dropped by 10-15 degrees over the next 30 minutes!

View from the inside of the window showing hanging plants, art work, and the mylar heat shield. Paracord is duct taped to the blakent to keep it off of the window and in position.
View of the back of the heat shield through the window.
One corner of a mylar blanket duct taped to the inside of a rain gutter. The tape is coming off the gutter in spots and the blanket is precariously attached.
Duct taped corner two days after installation. This is the weakest part of the installation.
Paracord tied around two rocks being used as a center point anchor with two "wings" going two directions. Mint and raspberry plants are behind the rocks.
Rocks anchoring the center point of the paracord running from the ground to the gutter. Both ends of the paracord were held down by rocks as well.
One corner of a mylar blanket being covered in duct tape and weighed down by three pieces of broken concrete sitting on a piece of wood in front of some siding.
The duct tape re-enforced corner of the mylar blanket is held down with broken concrete.

Pros:

  • Cheap materials that are readily available
  • Relatively fast to set up on the fly
  • Minimal tooling required to put it up
  • Removable
  • No tape used where it could remove paint
  • Effective at reducing temperature and quickly

Cons:

  • One-time use
  • Will require cutting to get it down
  • Required some maintenance after a day of being up
  • Needs a ladder to set up
  • Required two people to be outside in the heat on the south face of the house for 35 minutes
  • Kinda ugly
  • Dealing with duct tape on top of a ladder in wind wearing gloves is a PITA

Lessons learned

  • I burned myself on the ladder before getting gloves. Don’t get burned.
  • I got sunburned, but when I sweat it dissolves sunscreen so that was expected.
  • I should build something prettier ahead of time that’s easy to take up and down but also cheap to build.
  • Putting a ladder in the middle of a garden bed without absolutely destroying the (very thorny) plants is hard but doable.
  • The mylar blankets in this configuration worked very well!

Cold weather backpack setup test

So, the weather in Portland has been pretty snowy which is a touch unusual! As most folks have been inside and not out attempting to drive on icy and snowy roads which are not plowed I decided I’d take my HT for a walk in the cold weather and test methods of keeping it warm enough to not have the battery fail as the temperature is dropping to ~18F with wind chill. My partner and I have been walking to the grocery store and taking our dog out so I decided to test an external antenna I’d built to mount on my backpack a year ago in the gnarly weather. I did some tests with APRS and some 5w FM phone as well. The theory here is that keeping the HT inside the fairly sealed bag would preserve some amount of air that’s warmer than the bag’s surroundings. It seemed to work as I was out with this setup for a few hours at a time and battery performance was within expectations.

Snow and ice covered backpack set on a snow-covered sidewalk with counterpoise extending down and antenna extending up.
Setup covered in ice and snow.

In order to not go stir crazy I’ve been taking walks with my partner and we’re close enough to a grocery store to just walk and pack our food in our bags which is very fortunate. I’ve taken the opportunity to test different ways of carrying the HT so it doesn’t get too cold, and to test a MOLLE antenna holder with a simple antenna and counterpoise setup. During the grocery store run pictured below I was able to reach stations in SE and NE Portland with a strong signal. I was between 2 and 9 S units into a station in Battelground, WA as well depending on structures around me. The antenna I’m using in this picture is a Nagoya NA-771. I used that instead of my Signal Stick because the signal stick doesn’t stay rigid in cold temperatures and will curve and lay over giving poorer performance. The speaker mic was used as both a speaker that I could hear outside the bag and as a sacrificial component in the event something gets too wet. A $30 speaker mic is much cheaper than a new HT. I did test the SWR on this setup and 2m performed very well near 1.2, but 70cm performance was poor with the SWR being near 2.8.

The small bit of orange paracord is used to secure the speaker mic for cable routing purposes. When the mic comes un-clipped intentionally or on accident this cord makes it easier to grab and replace or remove and use. The longer orange paracord holds the weight of the HT in side the bag so the antenna cable and speaker mic don’t hold it up. It’s also necessary to hold it up in the bag to make sure there’s enough speaker mic cable to reach outside the bag and to my shoulder.

HT in the bag suspended by paracord.

The HT holder inside the bag is suspended by the longer bit of paracord that runs through a loop on the HT holder. This suspension system also makes it easy to load the bottom of the bag with heavier items that might otherwise crush the HT or damage connectors.

The above gallery shows the antenna assembly set up but not mounted to the webbing on the backpack.