Sunday, December 16, 2012

Analog Signal Processing


In the November issue of CQ magazine, there was a great article on an interesting kit. The kit is a regenerative audio filter. The filter, according to the designer, Phil Anderson W0XI, removes or scrubs galactic and man made noise from the audio, leaving only the CW note. At first I thought, interesting, but really??

First, some background. Band noise on some receivers can really get bad, not only bad but teeth grinding, chalkboard scraping annoying. I got rid of a transceiver which was nearly unusable on 40 meters. The noise blanker did nothing to touch the noise. Currently, I am now using a Yaesu FT-817ND which a month or so ago, I was in the backyard with a wire in a tree checking into the NAQCC Rocky Mountain QRS net. It was a rugged contact. The noise level that day was really bad. It started me thinking about different options to deal with the noise level. My two choices were the NEQRP SCAF filter (Temporarily out of stock) or the W4RT installed BHI DSP filter. The SCAF is about $30-35, and the BHI is $169 installed. I was pondering the two when I bought the November CQ magazine to read a review on the Elecraft KX3 and found the article on the CW regenerative filter by Midnight Science.


Meanwhile....

I walked into my wife's sewing room who looked at me and said: “You look bored”. I replied, “I am”. She then said, “You need a kit” First rule of marriage, do not argue with a woman, especially when she is right. Between the CQ article and the need to melt solder, I ordered the regen kit. I went the full meal deal and got the case along with it. It is a basic through hole component kit with 5 chips, resistors, capacitors, all the hardware and a voltage regulator. It is a high quality kit with everything included and integrates nicely in the case.

Now the performance, I was blown away by the ability of this filter to remove noise from a signal. After completing the kit, a random wire was connected to my FT-817 and the filter switched in. You have the option of bypassing the filter, if you wish, by pressing a button. I was amazed at how much static and junk was removed from the band noise. Indoors at the time, when I switched on a fluorescent light, I got a load of extra noise. When the filter was switched in, the lamp noise, along with most of the static, was just......GONE. It was flat amazing. I went to 20 meters and found some CW signals to tune. When you cross the designed frequency (You have the choice of building for 500, 600 or 700 Hz) the signal noticeably peaks. The noise is gone and stronger signals are a pleasure to listen to. I then tuned to a weak signal which was going in and out of the noise. I brought up the regeneration setting until the filter broke into oscillation and then backed it off a skosh. The signal had a slightly hollow, slight echo quality to it at the sweet spot of regeneration. I switched the filter out and listened until the CW started into a deep fade, I then immediately switched in the filter and the signal popped into my headphones. From completely in the noise to easily copyable, the filter is flat amazing. Even if you are not listening to a weak signal, back off the regeneration and use the filter just to clean out the noise, you can listen for longer periods without fatigue. This is one of the best purchases I have made.

72,

Bob

Saturday, October 27, 2012

USBlink Digital Interface

One of my favorite modes is PSK31. I had seen the USBlink project on the fine website of Julian, G4ILO, and the project looked downright useful.
Julian used a cheap USB sound card dongle. Mine cost under 5 dollars US including shipping. The rest of the USBlink is the Skip Teller digital interface circuit for PTT to the transceiver. There are several things I like about this interface project. First is the USB cable. I built the original Skip Teller KH6TY interface from the June 2009 issue of QST. I like the function of the interface, but not the two audio cables hanging out. The USB cable is a nice alternative, no fumbling with which cable is mic and which is phones, just plug in the USB. I built the interface with a six pin din connector. The main reason for the six pin din was my FT817 and Icom IC703 have that connector for digital connections. Interestingly enough, both radios have the same pinout. I can make one cable with straight through connections and not worry which end is plugged into the radio or the interface.
I made only two departures from the USBlink original. First was the the USB connection, I wanted the B type USB connector so I could use a standard B to A cable which you can steal off your USB printer in a pinch. I picked up a female B and a female A connector and wired them together. The dongle plugs into the A connector and the external USB cable plugs into the B connector. The second difference was the green LED. Just like Julian did, I clipped off the green LED from the dongle and soldered wires to a larger LED mounted on the case. I noticed however, the green LED was much brighter than the red Transmit LED. I wanted both LEDs to be about the same intensity so I put a 1K resistor in series with it and now they are visually comparable.
This project is nice, compact, and inexpensive. I got the box and components from my junk box. The purchases were the USB connectors, the sound card dongle and the cable and din connectors. The entire project cost $15 tops. I was in need of a nice 4 conductor cable for the project so I went to RE-PC in Seattle and in the used cable area, got a 15 foot USB cable for one dollar. I clipped the ends off and have enough cable to make five, three foot cables. I don't have that many radio's but I'm sure the cable will come in handy for other projects.
72,
Bob, AD7BP

Sunday, September 16, 2012

Low Noise End Fed Half Wave Antenna


This afternoon I grabbed my ATS-4 to hop on 20 meters and do some operating. My ATS-4 had 5-6 bars lit on the S meter display, which translates to NOISY, but not sure what the corresponding S reading is. I wish I had my FT-817 so I could have looked at a regular S meter. I tuned around and heard some signals, some were copyable, but it was just too noisy to really operate. This is obviously not the first time the noise was just too high to operate. I was, by the way, in the backyard with one of my end fed wires in a tree. I pulled the wire out of the tree and strung it across the ground and the S indication dropped from 5-6 bars down to 1-2 bars!!! So, I decided to FINALLY change one of my tuners to allow switching between two different wires. 
Most of my tuners are very small and compact to throw it in a pack and go into the woods. I have one large tuner with a real capacitor and added a switch and a second terminal for the “low noise” wire which lays across the ground. I guess the only downside to this arrangement is having to flip the switch going between transmit and receive. But, if I can knock down the noise by two thirds, it is more than worth the hassle. Since I mostly operate on 20 meters, I only have to cut a single wire.

72,
Bob, AD7BP

Sunday, September 2, 2012

Summer Tomatoes


It is about time I made another food post, seems that ham radio is taking more of the bandwidth than food.
I love summer, my favorite part is the crop of produce which is available. My two favorites are fresh figs, which are past and gone. They were delicious though! And tomatoes. I was at the local Costco and there was a 25 pound case of California Roma tomatoes calling my name.
We like a simple pasta sauce of olive oil, garlic, basil and tomatoes. Being a fan of putanesca, I toss in capers and Greek olives with my serving. With sauce in mind, it took me nearly 3 ½ hours to cut up the tomatoes. The cut tomatoes were put into a 2 cup measure and poured into a food storage bag for freezing.
25 pounds of tomatoes yielded about 25 bags of tomatoes for the freezer. At $11.65 for the case, the tomatoes for each meal is roughly 47 cents. Considering one pasta meal a week, this one purchase gives 6 months of nice tomatoes for pasta night. I did have a thought. We normally grow basil to make pesto to freeze. Since we are stocked in the pesto department, no basil was planted. Major mistake! Though I like the flavor of dried basil, 4 or 5 leaves roughly torn and tossed into the tomato sauce right before serving gives the sauce a bright, fresh flavor. That mistake will not happen next summer.

Life is way too short not to make a meal which puts a smile on your face. Cooking need not be complex to be satisfying. Make something good this week!
Bob

Saturday, August 11, 2012

Radio in the great outdoors


I finally got the week off I have wanted all summer. OK, truth be told, I got sucked into work Wednesday and a couple hours Thursday in the morning. But..... My friend Eldon, WA0UWH and I had a radio trip planned for Thursday. I hit home long enough to change into some proper outdoor clothes, lit off the espresso machine and back on the road. My radio gear was already packed and waiting. We went to Mt. Pilchuck, which is northeast of the Seattle area and drove up a forest service road to a nice vista looking west to Puget Sound.

One of my favorite terms is: “This is not my first rodeo” When it comes to outdoor ops, this is certainly not Eldon's first rodeo. As you can see below, we had a nice table, mast for the end fed antenna and shelter to keep the sun off of us.
Being in the Seattle area, I take trees for granted. There is always a tree that is much too high to throw an antenna wire into by hand. On Mt. Pilchuck, the tallest tree was 12-15 feet. Needless to say, my antenna paled in comparison to Eldon's 36' mast which elevated his wire, but shockingly enough mine worked well.
Propagation was not happening like we would have wanted, but we did get a few QSO's in the log, including a 40-45 minute PSK31 chat with a California ham at 5 watts using the internal battery (W4RT) in my FT817. Shortly after we signed, I looked at the voltage display on my radio, smiled at Eldon, went key down on CW, which shut off the rig. About 6 hours of operation, including the 5 Watt PSK contact, on one charge. Not too shabby.

Finally: Mountains, radio and man's best friend. (Eldon's dog Tess.) Who could want more?
72,
Bob, AD7BP

Monday, July 30, 2012

Pounding Brass


I really like CW keys, and I own a few of them, but a couple of things bother me. First is the cost, I have shelled out a few bucks for some keys and only one had the best ratio of cost to performance and that is my Czech Army key, it is the best key I own.
 Last week, I was using an old key that I got a when I got back into ham radio 9 years ago which is the brass key made by Ameco. I picked that one up because it was what I had as a Novice back in High School. I was using it the other day and it was horrible. At the contact point I could hear in my headphones the start of a dit or dah and it dropped out then in when I mashed the key contacts together. It sounded like a 600 Hz static right before the dit or dah. Enter my homebrew key. It is small, built in a 1.4 x 1.4 x 0.6 inch Hammond case. The heart of the key is a small microswitch. The microswitch makes a good, solid, clean, make and break giving me nice clean sounding sidetones in my ear, and hopefully nice clean CW out of my rig.
I built it intentionally small to go with my ATS-4 and MTR, Steve Weber KD1JV radios. Did I mention price? The switch and case are just over five dollars total for both. The rest of the hardware is in my junkbox. The rubber feet are from my favorite antenna store, Home Depot. All in all, it makes a great key for portable use. I have parts to make a couple more and am tempted to put a real CW key knob on the key, which will make it look even sillier than it looks now, but what the heck, it works well. Isn't that what matters?

72,
Bob

Monday, June 11, 2012

End Fed Half Wave Antenna


OK, call me an antenna snob, but in my opinion the End Fed Half Wave antenna is about as good as it gets for an easy to put up, great performing antenna. I am a coffee snob too, but that is another story. I came across EFHW antennas a while back when I was just starting to figure out antennas. My best and favorite source for end fed information is Steve Yates, AA5TB's great site http://aa5tb.com/efha.html The tuner is “Stupid simple” to assemble, but an antenna analyzer is really helpful in tuning the antenna wires. The only downside to EFHW antennas is the need to cut a different wire for each band. The upside to EFHW antennas is no long counterpoise. The antenna tuner needs a 0.05 wavelength counterpoise to work properly. Three turn primary from the radio and 24 turn secondary with a capacitor across it. That is it.

Lets take 20 meters, 468/Frequency = Half wavelength: 468 / 14.0 = 33.42 feet for the half wave wire.
Move the decimal point over one to get the 0.05 wavelength counterpoise of 3.34 feet.

I thought it odd at the time that a 3.34 foot counterpoise was necessary to make the antenna work, but when I disconnected it, the antenna would not tune very well. When I connected it back up, I could tune to 1.0:1. Below is the small version I built for my MTR radio. I typically use T50-2 toroids for most of my QRP tuners, but I did not have any of the T50-2's handy, so I substituted a T30-2 from the junkbox. Since the bandpass filters on the MTR use T30-2's, I figured the antenna tuner would be fine with that small a toroid. It did work! I used the tuner on 20 meters for the first time, for the first QSO, and made a nice contact with Gary, K5ON in NM at just over 1,200 miles. Nice!
Tuning the wire is an interesting process. AA5TB has you connect a 4.7K resistor across the tuner antenna connections and tune the analyzer to the band portion to which you want to center the antenna. Tune the capacitor on the tuner to get the lowest SWR. Leave the antenna tuner alone and start pruning the antenna wire until the SWR drops to the value with the resistor connected. One quick comment about that. Even though I tune for the CW portion of the band, the antenna SWR up in the phone portion is still very low.

I tune the the wire a tad different than AA5TB. (For 20 meters) The length of 468/14.0 drops you to around 13.8 MHz. What I do is fiddle with the analyzer and antenna tuner to get 1.0:1. Once I find the sweet spot on the tuner, I nibble a quarter inch at a time off the antenna wire and slowly walk the wire resonant frequency up to where I want it to be. You typically need to tweak the tuner a little bit (less capacitance) as you walk the analyzer up. Again, I tune the 20 meter wire for 14.050 MHz, but up in the SSB portion of the band, the tuner still tunes 1.2:1. Nice bandwidth too. One last thought, you can tune the EFHW by ear for max band noise. I know some of the QRP tuners have a resistive bridge LED SWR indicator gizmo attached, but you really do not need it.

Give an EFHW antenna a try. You will become a believer too!

72, Bob

Monday, May 21, 2012

The MTR station is ready to put on the air!


The Mountain Topper Radio is done and ready to go. The last two pieces needing completion was an end fed half wave antenna tuner and paddles. I have an end fed tuner for each of my portable radios. An order of polyvaricons from Doug Hendricks at QRPkits.com gave me what I needed to make several. In this instance the 20 meter wire alone tunes 20 meters and connected with the 40 meter wire gets you to the 40 meter half wave length. I had to connect both sets of plates together on the PV to get the capacitance I needed to tune 40 meters.
The paddles are homebrew. I was at my favorite electronics place in Bellevue, WA, a stones throw from Icom. I found a couple of small micro switches (that was sort of redundant) and a small Hammond box to put mount the switches in. The actuator levers are brass. Brass, because that is what I had handy. The radio is now ready to put on the air. After that is designing the bag the setup is going into. The wife sews my radio bags, the only question is whether it be in urban cammo or blue digital cammo....

72, Bob 

Saturday, May 12, 2012

The MTR lives!


The Mountain Topper Radio lives! This was a fun build, the latest from Steve Weber, KD1JV. The radio is a dual bander designed for life in an Altoids tin. Mine was built for 20/40 meters. I thought long and hard about what kind of box the MTR was going to be put into. I had taken an Altoids tin and was getting it ready for the MTR when I found a Hammond 1591BTBU transparent blue case that is a little longer and a little deeper than an Altoids tin. This allowed me to swap the RCA jack that came with the rig for a BNC connector, which is standard fare for a QRP radio.
20 meters was pretty much dead here on the west coast this morning after the rig was finished so I did not even try a contact. Typically, I can get a signal into California virtually any day. But today it was different. I wanted to make an SSB contact with the USS Midway in San Diego, but I could not even hear them. I heard a few, obviously KW, stations calling them, but I could not hear any response. I hope to put the MTR on the air tomorrow.

72, Bob 


Monday, April 23, 2012

MTR build, day three


I think this is day three of my build. Thus far I have hit no real snags, only a couple of recalcitrant SMT capacitors that refused to stay where I soldered them. This kit has been a load of fun to put together. I have finished all of the SMT parts and started the through hole parts this evening with crystals and switches. I looked at the time, looked at the board and looked at the capacitors and decided to hang it up for the night. I think one more evening and I will be ready to power up the radio. Tomorrow morning, I am going to wander into downtown Seattle and stop at Specialty Bottle and pick up an Altoids tin or two for the project. Yes, I need a few for when I trash one drilling the holes.

72, Bob

Saturday, April 21, 2012

A few hours of build time


I started the MTR rig yesterday and continued again today. I have gotten all of the semiconductors down on the back side along with the resistors. Next come the capacitors. I am taking my time on this as I tend to make mistakes when I move along either too fast or work too long. This is my third kit which has SMT components in it. The first two were the Softrock Ensemble RX, followed by the ATS-4b. I expected this kit to be similar to the ATS-4, and it is, schematic wise, but most of the components seem smaller on the MTR. Or maybe I just had amnesia set in since I built the ATS-4. As long as work does not mess up my evenings this week, I should have the MTR built and on the air by next Saturday.

72, Bob

Here is the MTR shot through a magnifier.

Friday, April 20, 2012

The MTR is here!


A couple of days ago, the latest Steve Weber, KD1JV, kit landed on my doorstep. It is the MTR, the Mountain Topper Radio. The MTR is mostly SMT and will fit into an Altoids tin. The rig itself is a lot like his ATS series radios, a separate up and down button for frequency. I actually like using that style of tuning as I have one of Steve's ATS-4 radios. It is kind of like using RPN (Reverse Polish Notation) on an HP scientific calculator, once you get comfortable with RPN, it becomes preferable.  Steve's style of tuning is pretty darn easy to use and is rapidly becoming a preferable tuning method for me.

The rig is a two bander where you can choose two of your favorites from 40/30/20 meters. I have decided to build a 40/20 meter radio. Though it fits into an Altoids tin, it has a blistering 5 watts of power. Incredible for a radio of this size. Thus far I have installed 10 chips/transistors on the board. I had to hijack a magnifier from the XYL to see what I was doing as the chips are really small. More posts coming as I put this bad boy together.

72, Bob

Wednesday, April 11, 2012

Low Fidelity


Another one of those ham experiences that take you a long time to notice that the “Obvious Meter” is pegged to the far right. I was outside on the porch a week ago with a wire in a tree. I did not have that much time before dinner to spend on the radio so I started on 20 meter SSB. I had a quick trade of information with a QRO ham in LA and went over to CW, again on 20 meters. I worked a CW QRO station in Cupertino California. No problem. So on Tuesday, I decided to try the NAQCC sprint and had a horrible time with all the QRP stations, I could barely pull them out of the noise with my FT-817. I decided to go inside a grab my Weber ATS-4b to try that. I was amazed at how well that rig worked pulling the signals out of the mud. I looked suspiciously at my FT-817. The only difference was a pair of Koss earbuds that I found on sale at Radio Shack plugged into the ATS-4. With the Yaesu, I was using a pair of earbuds that I got with some AM/FM radio, at some point in the past. I moved the Koss over to the FT-817 and amazing!   I could actually understand the CW. Even though the Koss earbuds were less than 5 bucks, they had much better fidelity than the generic ones. Looks like a trip to Radio Shack tomorrow, I hope they still have the earbuds on sale.  The moral of the story?  The earphones/earbuds are nearly as important as a good antenna.  

72, Bob

Saturday, March 31, 2012

What time is it? GMT!


GMT stands for Garlic, Mushroom and Tomato.... Pizza. Saturday, at the AD7BP QTH, has become pizza night. We have been making all of our bread for many, many years, but had not made the jump to pizza. I have no clue as to why. So, about a year ago, we went out and bought a pizza stone. A pizza stone is a great thing to have, it ensures that crust is nice and crisp from edge to edge of your pie. I am thinking maybe the reason we never made pizza on a regular basis is because the few pizza's we did make had a soggy, doughy center. Nothing is worse.
The dough is a simple dough. Being health conscious, we are making it with half white flour and half whole wheat flour. I like the extra chewiness and flavor the whole wheat provides, but I do like white flour pizza crust too.
Speaking of healthy, we only do vegetable toppings to cut down on the fat and chemicals associated with cured meats. The recipe that makes enough dough for two people is as follows:

1 ½ cups of flour. Half whole wheat and half unbleached white flour
3/4 tsp dry yeast
½ tsp salt
2/3 cup of water warmed 30 seconds in the microwave on high.

Mix the ingredients and knead for 10 minutes with 1/3 cup extra white flour. Try to keep the dough on the wetter side. Leave in a cooler environment for 4 hours to slowly rise. The slower rise enhances the flavor of the dough.

Pizza Sauce

2 tsp olive oil
8 oz of crushed tomatoes
1 heaping tsp of dried basil
1 head of garlic, Thats right I said head of garlic

The trick to using an entire head of garlic is to treat the garlic gently. Do not smash, or cook on high heat. The rougher you treat garlic, the more pungent and sharp it becomes. Husk the garlic and thinly slice. Heat oil on medium heat and add garlic. When the garlic starts to cook, turn down the heat to warm and cook slowly, stirring until it is translucent. Add crushed tomatoes, (Crushed make a great pizza sauce compared to using regular tomato sauce) Add dried basil and cook on low for 10 minutes.

Heat oven to 450 degrees with pizza stone already in the oven. Spread the dough on parchment paper and top with sauce, tomatoes and mushrooms. Slide the parchment onto the stone and check pizza at 15 minutes, and bake up to 20 depending on your preference as to how brown you like your cheese.

The following two books arrived this last week. Father Dominic's books got my hands back in the dough many years ago with his PBS television show: “Breaking Bread with Father Dominic”

The second book, “Artisan Pizza in Five Minutes a Day” is the third in the series of Artisan Bread in Five minutes a day books that have revolutionized home baking. Take a look at the following video.  How much easier can real bread at home be?  http://www.youtube.com/watch?v=vcG4PpG1LcQ

























73, Bob

Friday, March 23, 2012

Homebrew Transceiver project


This is my first foray into building a transceiver from scratch. I wanted a simple radio which would cover several bands and not be rockbound. I settled on an interesting radio from the October 1989 QST, “The QRP Three-Bander” by Zack Lau, W1VT (KH6CP). It looked like an interesting project as I have not built a direct conversion receiver, nor a VXO transmitter. To make this project more challenging and fun, I decided to convert as many components as I can to surface mount. Next is to create a printed circuit board and etch it myself. Thus far I have gotten the schematic put into Diptrace, a really nice program.   http://www.diptrace.com/ Diptrace is a full featured software package with a free version which has several upgrades to larger schematic capability. Thus far, the project has moved along fairly quickly. Right now, I need to create some new components that are not in the standard library. The components I need to model are toroid based inductors and transformers. I cannot forget to mention the bandpass filters need to be be redesigned to take into account the harmonic suppression requirements have changed since this article was written.

I wish I had some pictures, but the article is a black and white scanned PDF from the ARRL. QRP Tri-Bander You have to be an ARRL member to view this, but I like the design. In an upcoming post, I will provide some more details and pictures also.

Bob

Thursday, March 15, 2012

My first post

My friends have been bugging me to start a blog for a while now.  Thanks to John, NG0R and Eldon, WA0UWH, I am posting this.  Eldon and I were chatting on Google Talk and he talked me into starting the blog "real time" as it were.

The blog is going to mainly be about ham radio, I am a QRP guy who likes to tinker with accessories for the ham shack and with antennas.  More on that in future posts.  The eggs portion of the blog is devoted to good food.   I like to cook and work in the kitchen, with the caveat that anything made is not in, how shall I say this?   Not in the fatal food group.  I like that term.  In a later post, will be the origin of the term. The meaning is of course, food that will not make you fat or kill you.

73,

Bob