Foxhole Radio Modifications

I played around with the foxhole radio we made earlier to try to increase the signal.  In a traditional foxhole radio a single diode is used, which cuts off half of the AC from the signal and converts it to a useable audio wave.  This is a half wave rectifier, which does not make use of all the power potentially available in the signal.

I used four LEDs hooked together in a diode bridge to make a full wave rectifier where current flowing in both directions in the signal are converted to an audio wave. 

Here is the actual setup.

And a closeup of the LED diode bridge.

Before with the single diode I was able to tune in stations from 10 to 15 miles away.  I was able to find the same stations again, so it is not worse, and I also found three more stations, the tower of one of these is just over 20 miles away!  Below is a map of the station locations I tuned in using this setup (click for a larger image).

So there seems to be some improvement.  I searched for mention of this online and in forums I read that using a full wave rectifier in an unamplified radio wouldn't help because of the voltage loss from the signal going through two diodes instead of just one (these types of radios work with very low power so any loss is bad).  However, my results suggest is does help.  For much beyond 20 miles I am going to run out of island.  I need to bring in signals from over 50 miles away to reach the next island, Moloka'i.  Perhaps next I will try to increase the size of the antenna.

Christmas

We had our first Christmas in Hawai'i; it was also F's first Christmas anywhere!

The night before M made some snickerdoodle cookies, and each of the older kids read a short Christmas book to the family (M read Merry Christmas, Merry Crow and T read Who's That Knocking on Christmas Eve?), which has become something of a family tradition. 

Sprinkling cinnamon on top of the cookies before baking.

The kids had a lot of fun opening all of their presents.  Thanks to everyone for the presents!

Christmas Loot

F didn't understand what was going on at first, but she quickly learned.  She got a lot of blocks, stuffed animals and soft toys.  She was playing with the older kids, they would stack up the blocks then she would excitedly knock them down.  She also got a large new toybox to store them in.  She is starting to figure out how to drop the blocks in the box. 

T got lots of legos and construction sets, and books (he is an avid reader).  He quickly set up his new magnetic dart board and was enticing us to contest with him. 

M got some craft sets and a kindle!  We registered the kindle and set it to charge up.  Then she broke out a ceramic painting set and started to paint her own bowls. 

I surprised V with tickets in her stocking for her and the older kids to go to a live radio show that will be broadcasting from Honolulu on Christmas eve.  (I will stay home with F; children under six are not allowed to the show.)

M made a gift for me within the minecraft game we have been playing.  It is a house filled with gold and diamond blocks, which are valuable in the game. She was very thoughtful and left a special pick inside the house to use to mine them.  She made the outside of the house in a present pattern using blue and yellow dyed wool.  She also put a sign next to the door saying it was to me and from her. 

A gift house in Minecraft

It was a warm day, a high of 83 F, and the weather was perfect so we decided to have a picnic.  We ran to the store to pick up bread and meat for sandwiches.  I let F hold on to the steering wheel for a minute just before we left and pretend to drive.  She let out two sharp high pitched squeaks as a laugh in her excitement.

We drove up to the north shore and had the beach to ourselves.  We played on the beach, ate sandwiches, and played on the beach some more before heading back.  Then we all relaxed around the house and later V fixed one of my favorites, chicken and dumplings for supper. 

Looking for sea creatures in the rock pools.

The beach to ourselves.  The people in the distance are T and M.

F in her pink wetsuit playing in the sand. 

Drive to Waianae

It is still Christmas Eve here.  We took a drive this afternoon up the west side of Oahu to Waianae.  We haven't been up that way yet so we did some exploring for a bit.  We stopped at a place that had lava formations at the beach.  It is riddeled with holes that the surf moves through. 

There are crabs that hang onto the rocks as the waves beat down over them; they remain in exactly the same place between waves. 

Here is the view back towards Honolulu from Makakilo.  In the foreground is a lot of construction for new houses.  In the distance Perl City is to the left and the towers of Honolulu are in the distance to the right.  Diamond head is the peak on the horizon that sticks out in the ocean on the right.

In a completely unrelated point.  We planted some hibiscus plants in the back yard.  The one M picked out had two nice blooms on it today. 

Waiting for Christmas

Hawai'i is close to the international date line and on the "wrong" side of it.  It is now Christmas over most of the world but we will be one of the last places for it to arrive.  Along with our neighbors to the north the Aleutian Islands and French Polynesia to the south we are at UTC-10:00.  Our closer neighbors to the south, Kiribati, moved to the other side of the date line in 1995 and have been celebrating Christmas all day now.  The only ones behind us are one hour later in UTC-11:00, they are American Samoa and Niue. 

While we are waiting, below is a short video clip T pointed out to me.  (Don't worry, everyone is OK.)