Martian Special Radio

[19and41]

The microscopic structure of your whisker may be changing a bit as well.  I had never heard of anyone cleaning or changing the crystal surface, whatever the result.  I agree it is looking like you are getting better in teasing a better result from the crystal.  Bear in mind that any corrosion or oxidation in the structure of your radio acts as an additional detector.  In working with 2-way radio, I have even seen radio towers with corrosion contribute small amounts of harmonic interference in some radio frequencies.

[TelePlay]

Interesting.

When I first got all the parts back together after cleaning, I was using an 81A tracer placed near the antenna "in" post to generate static to find a sweet spot (discovered the 81A had to be hung in air for the vibration is created would vibrate the diode interface creating a false sweet spot. I barely found one or two sweet spots and they were weak. Now, after much usage, I no longer need the 81A. At least 40% of the crystal surface is "sweet" and some spots sweeter than others. Easy to find a spot now and then by increasing the pressure of where the whisker is touching the crystal, the reception increases, gets louder, sometimes much louder. For some reason, the crystal/whisker diode is getting better with use. More spots and increased volume.

And, when cleaning the set, I took everything apart and cleaned all the parts. Only thing I did not take apart were the 6 screws holding the coil to the base. I might try cleaning those one at a time to see if it makes a difference.

After reading up on old Piezo headphones, I was hoping the moisture over time had not destroyed the salt chip in mine and was very happy to see they are working well. I keep them in a zip lock plastic bag with a 2 cubic inch sack of silica gel to keep the moisture to a minimum.

And, yes Dave, it is truly remarkable to say I have a 100 year old radio that still works. And, yes, it does not have fine tuning but that wasn't really needed 100 years ago when there was only one, maybe two, transmitters in the area. Back then the listener would be happy to get that one station, I would guess.

More to check out or do, stay tuned . . .

PS: What the radio is putting out may be a lot better than I hear. My hearing is not what it used to be due to old age and abuse many years ago making that old age thing worse.

[TelePlay]

Was able to pick out a 3rd station this morning. WOKY 920 AM in Milwaukee. Their tower is about 12 miles due east of my location and they broadcast 5,000 watts during the day and drop off to 1,000 watts at night. My antenna is running north, northwest. They come in just below 1640 AM, where it drops off, on the tuning wire.

That 50,000 watt daytime station, 620, still takes up the bottom half of the tuning range on the radio.

[TelePlay]

Was listening to 620 last night and they had about 30 seconds of silence  between the end of a commercial and the start of the next program. During that time, I could hear 2 or 3 other radio stations so I know they are out there, just getting walked over by 620. I must be in a pattern sweet spot (location, height, antenna length and direction) to have that one station come in so well all of the time with the others much weaker.

My wife took this photo of me working with my radio.

[19and41]

 

[DavePEI]

Was listening to 620 last night and they had about 30 seconds of silence  between the end of a commercial and the start of the next program. During that time, I could hear 2 or 3 other radio stations so I know they are out there, just getting walked over by 620. I must be in a pattern sweet spot (location, height, antenna length and direction) to have that one station come in so well all of the time with the others much weaker.

That was advantage I had when I was a kid  the local station, CFJR on 1450 reduced power at night to 250 watts, and aside to it, the closest station was over 50 miles away in Kingston, also a power deduced at night station. This left a pretty clear band to listen to.

The radio I had had capacitive tuning, and therefore was a bit better selectivity wise, but still suffered from splatter when CFJR was broadcasting at full power.

So tons of stations to listen to at night....

Dave

[19and41]

I always liked how the stations quietly and gently would come up to be heard as one tunes, like the words coming up on a upturned magic 8 ball.

[DavePEI]

I always liked how the stations quietly and gently would come up to be heard as one tunes, like the words coming up on a upturned magic 8 ball.

And listening to the stations fading in and out overnight. You would be listening to one station, then all of a sudden propagation would change, and without changing the tuning, you were hearing an entirely different station!

[TelePlay]

I always liked how the stations quietly and gently would come up to be heard as one tunes, like the words coming up on a upturned magic 8 ball.

Yes, I've noticed that with my Martian. It's as if it takes a while for the circuit to load. I've also noticed that my headphones, any of them, each have two ear pieces and I usually get sound out of only one speaker until I get a very good sweet spot, one with a strong current and a lot of audio, and then the other headphone kicks in. I thought it was a bad wire but that does not seem to be the case. I can move the whisker off of the hot spot and loose one headphone speaker.

Now, I hooked my makeshift antenna up to my Frog 7 (analog Yaesu FRG-7) last night and was easily pulling in SW stations from France and Romania (and Canada and Mexico). There is a China Radio station in Romania that broadcasts in English for two hours each night around midnight and it comes in as strong as if listening to a local AM station. The internet and Google is a great tool for finding station location, pattern and power information based on just a bit of information picked up while listening for 10 to 15 minutes.

I'll put the antenna back up next Friday night and see how good it really is doing some DX listening.

This is starting to be fun, stay tuned for more . . .

[19and41]

One thing I wanted to mention that was brought home here this evening here is that it would be wise to install lightning protection on your antennae.  It isn't that hard nor expensive and can become very important very fast.

[DavePEI]

I'll put the antenna back up next Friday night and see how good it really is doing some DX listening.

This is starting to be fun, stay tuned for more . . .

I knew it would be. My crystal radio got me into SWL'ing back when I was a kid, then abut 30 years ago, into Ham Radio. I loved working DX, especially after I got my advanced certificate and could use SSB. In the next few years after I got my license, I worked over 350 DXCC countries. Even before I got my advanced certificate in 1984, I had regular skeds with fellows in Australia and New Zealand.

Then came Hurricane Juan, dropping my beam through my roof. I haven't really been active since then, occasionally listening, but almost never getting on the air.

One fun note. We had a Contest group here, and we used to set up stations in the CQWW and WPX contests on my properties in my barn, electronics shop, and in my house. We played around with all sorts of antennas in addition to the beams - one year we set up a huge 40 metre wire quad in the West field of our property, supported by trees.

I had a homebrew linear amplifier made with a 4-1000 broadcasting tube which we used to feed the quad. It let us run at the full 2kw limit. We got punchy one night, and during a break while others operated the station, Darrell MacArthur and I each took 48 inch fluorescent tubes out into the field and anywhere under the quad, they would light with the RF.  We spent our break playing light swords under the antenna. The neighbours thought we were nuts, perhaps alien!

Another funny thing. Once we both thought we had seen kids at our mailbox looking at our mail. Well years later, we were at a Dutch wedding of one of the kids next door, and they played a fun game where they confessed things they did as kids. They confessed that they often checked my mail. They saw QSL cards coming from around the world, including communist countries. They were convinced because of this that we were spies  Of course when they grew up, they knew otherwise, but it must have been great fun for them spying on the spies!

Ahh, the good old days!

Dave

[TelePlay]

One thing I wanted to mention that was brought home here this evening here is that it would be wise to install lightning protection on your antennae.

That is very good advice. Very good advice indeed. That is why I use the best lightning protection available, I don't hang the antenna if there are storms in the area and if they do come within half a state, I pull it down. Took it down tonight for the week in about 3 minutes total time. Released it from the attachment to my upstairs window, the weight hanging down in the tree pulled the wire down to the street and all I had to do was wrap it up.

Living on the top of the highest spot around, I am very conscious of lightning anytime. We had a bolt hit the brick chimney two houses down a few years ago. Not much left of the chimney but no other damage. We had an electrical storm here last Wednesday night and just as I lookout out my window to see how hard it was raining, a very thick, white and wide bolt came straight down and hit about 300 yards away. I've been a lot closer to a strike than that (you know you are close when all you get is a bang and no thunder) but this one was something I had never seen in my many years of life. After the blinding white light disappeared, I could see a green dome of light about 200 feet high around wherever the bolt stuck and it lasted for about 10 seconds. It was a light lime green fluorescent light that looked like something out of a science fiction movie. Must have hit a copper roof.   

[19and41]

A few years back, I saw when a stroke hit a white stick antenna on a tower water tank.  It atomized all the water on the surface of it, making a momentary cloud around it.  It might've been something like that you saw.

[TelePlay]

A bit of an experiment today. Stopped by a local Science and Surplus store yesterday and discovered that they had a box full of piezo disks with two wires already attached. Bought two 1" diameter disks. Dropped a 20' wire out the window as a temporary temporary antenna just to get a signal.

The straight down vertical was alongside the brick exterior on the north side of the building effectively shielding the antenna from the blowtorch 620 AM tower to the south. Easily picked up the 1640 tower to the north, no 620 at all. So, antenna design/direction will affect my crystal radio reception - no surprise there.

Anyway, after getting loud reception through my piezo headphones, I hooked up one disk in parallel and series to the headphones. I lost some volume on the headphones but could weakly hear the station on the disk. With just the disk alone, same volume on it. So the impedance of the disk reduced that of the headphones - no surprise there.

Hooked a piezo disk directly to the headphones and wow, talk about sensitive. Just touching the disk or sliding it along the surface provided a loud volume in the headphones. I could hear spoken word but it was a lot lower in level than physical contact. I have a couple of piezo surface microphones, the kind used to attach to large surfaces to capture big noise like jets, explosions, thunder, etc., and they do that job quite well.

Going to stop by the store a get a variety of sizes in those disks. The smallest was a 1/4 inch. Maybe those will be louder with the passive voltage generated by my radio.

More to come, stay tuned . . .

[19and41]

I saw a thread on another site I frequent that might be of some interest with these projects going on.

http://www.tuberadioforum.com/t4464-a-neat-little-widget-homemade-solid-state-amplifying-device