Thursday, July 30, 2009
Sunday, July 26, 2009
IOTA Contest - July 24, 25
This weekend was the IOTA contest and it was fun. A little aggravating at times with pile-ups on some of the more "exotic" calls, but still a good time.
I only made 15 contacts, but these included two Hawaii stations, one New Zealand, and two Australia stations plus several states ranging from TX to MT, MA, NY, and OH. There were also a couple of Canadian stations included.
Most were on 20 meters but I had one HI, MA, and OH on 40 meters. The antenna I used was my G5RV JR mounted about 20 feet high on the roof. I used my Yaesu FT-840 most of the time running about 75 watts.
I should have made more contacts, but time was limited ... come on Sunspot Cycle 24!
...AR
I only made 15 contacts, but these included two Hawaii stations, one New Zealand, and two Australia stations plus several states ranging from TX to MT, MA, NY, and OH. There were also a couple of Canadian stations included.
Most were on 20 meters but I had one HI, MA, and OH on 40 meters. The antenna I used was my G5RV JR mounted about 20 feet high on the roof. I used my Yaesu FT-840 most of the time running about 75 watts.
I should have made more contacts, but time was limited ... come on Sunspot Cycle 24!
...AR
Sunday, July 12, 2009
Vertical Antenna Ground System
When I come across really useful information, I just have to pass it along. Rudy Severns, N6LF, did an incredible amount of work during the spring of 2008 to evaluate the effect of radials on the effectiveness of 1/4 wave vertical antennas.
For the whole set of articles, click here:
In his Vertical Antenna Ground System Experiment No. 4, he makes the following observations:
1. If you are limited to 4 radials for whatever reason, you can SHORTEN the radials (from a 1/4 wave) by up to 40 percent and improve your gain by 2.9 dB. Or you can add a ground rod (4 ft.) and improve your signal gain by almost 3 dB. But doing both does not seem to improve things any more than doing either one. I know, read it for yourself.
2. If at all possible, use at least 8 radials. With the 8 radials you improve your signal gain by about 2.5 dB over the 4 radials and the gain can be improved to 3.9 dB by shortening your radials by about 40%.
3. If you can get to 16 radials, then you have overcome most of the ground losses and shortening the radials is no longer a major factor. He says, "I would think that with 32 or more radials, you wouldn't worry about resonances in the radial screen. The problem is only important when fewer than 16 radials are deployed over average or better soil."
There is a lot more information at his web site and I have not made it through all of it yet. Very good stuff!
... AR
For the whole set of articles, click here:
In his Vertical Antenna Ground System Experiment No. 4, he makes the following observations:
1. If you are limited to 4 radials for whatever reason, you can SHORTEN the radials (from a 1/4 wave) by up to 40 percent and improve your gain by 2.9 dB. Or you can add a ground rod (4 ft.) and improve your signal gain by almost 3 dB. But doing both does not seem to improve things any more than doing either one. I know, read it for yourself.
2. If at all possible, use at least 8 radials. With the 8 radials you improve your signal gain by about 2.5 dB over the 4 radials and the gain can be improved to 3.9 dB by shortening your radials by about 40%.
3. If you can get to 16 radials, then you have overcome most of the ground losses and shortening the radials is no longer a major factor. He says, "I would think that with 32 or more radials, you wouldn't worry about resonances in the radial screen. The problem is only important when fewer than 16 radials are deployed over average or better soil."
There is a lot more information at his web site and I have not made it through all of it yet. Very good stuff!
... AR
Thursday, July 09, 2009
NTS Message Example #2
Mike, KE5YOO, submitted this example of message handling. He copied special Field Day Message #4 that I sent on the June 25 Tulsa Amateur Radio Club Thursday Night Net.
This message was sent to "Your Station" as a traffic-handling practice exercise. My goal here was to involve everyone listening to the net.
Mike used an on-line form and sent it to me. This form has some great information right on the radiogram message form itself.
Click Here for ARRL Version of Radiogram Form .
You can find on-line information and training at the ARRL website or click on the following link: The National Traffic System .
Thanks Mike and very nicely done!
... AR
Wednesday, July 08, 2009
NTS Message Example #1
This example is from Gerry, KC5JKU. He copied the special Field Day message I sent on the June 11 Tulsa Amateur Radio Club Thursday Night Net.
This message was sent to "Your Station" as a traffic-handling practice exercise. My goal here was to involve everyone listening to the net.
Gerry used an ARRL Message Pad to record the message as sent. You don't have to have a radiogram form, but it is handy: Radiogram
You can find on-line information and training at the ARRL website or click on the following link: The National Traffic System
Anyway, Thanks to Gerry for sending this in. Click on the form to enlarge it.
...AR
Tuesday, July 07, 2009
Healthy Hams Smoothie
Of course we are supposed to eat fruits and veggies. Most of us don't get enough of either of these in our diet and we know it. So if there's an easy way to improve our diets, maybe that will be something we can do to make a change we already know we should make - right?
One 12 ounce glass is about 3 1/2 servings of fruit. So, here's a way to get your fruit for the day and it is almost painless!
The Fruit Smoothie (and, yes, my wife gets the credit here):
This recipe makes about two 12 ounce servings (or you can drink the whole thing if you want.)
Make ahead and freeze these ingredients...
1. A medium-sized banana sliced into fairly thin slices (don't go crazy). Put into a ziploc bag or just wrap in saran wrap and place in freezer overnight.
2. 1 cup of strawberries. Use fresh or frozen. Either way, slice into smallish pieces. Again, ziploc bag or saran wrap one cup portions and freeze.
3. 1/2 cup of blueberries. We buy frozen and that works great. If you want to try fresh, then see the strawberry prep but you should not have to slice a blueberry.
You can do the prep and make enough ahead for several smoothies. That makes the actual smoothie preparation go pretty easy. It goes something like this:
1. Get out your blender and put in 2 cups of orange juice (not frozen)
2. Add the packets you've made using the frozen banana, frozen strawberries, and frozen blueberries to the blender.
3. Let set for a few minutes before blending. Sometimes the fruit is hard to blend.
4. Start blender on slow, then increase the speed until the sound is smooth (get it?) and everything is blended.
5. Pour into glasses and enjoy a very refreshing drink.
You can get as creative as you want with this recipe, but this is as basic as you can get. If you want to make it thicker, you can add some yogurt. OR, you can freeze 1/2 cup of pineapple and add that in the mix.
Anyway, this is an easy way to get your daily servings of fruit. I guess the cleanup is the hardest part, but even that goes fairly smooth.
Although I haven't tried it, you could buy one of the frozen fruit packages at the store and measure out equivalent amounts for the berries. You'll still need the bananas, tho.
Give it a try and let me know how it goes!
...AR
One 12 ounce glass is about 3 1/2 servings of fruit. So, here's a way to get your fruit for the day and it is almost painless!
The Fruit Smoothie (and, yes, my wife gets the credit here):
This recipe makes about two 12 ounce servings (or you can drink the whole thing if you want.)
Make ahead and freeze these ingredients...
1. A medium-sized banana sliced into fairly thin slices (don't go crazy). Put into a ziploc bag or just wrap in saran wrap and place in freezer overnight.
2. 1 cup of strawberries. Use fresh or frozen. Either way, slice into smallish pieces. Again, ziploc bag or saran wrap one cup portions and freeze.
3. 1/2 cup of blueberries. We buy frozen and that works great. If you want to try fresh, then see the strawberry prep but you should not have to slice a blueberry.
You can do the prep and make enough ahead for several smoothies. That makes the actual smoothie preparation go pretty easy. It goes something like this:
1. Get out your blender and put in 2 cups of orange juice (not frozen)
2. Add the packets you've made using the frozen banana, frozen strawberries, and frozen blueberries to the blender.
3. Let set for a few minutes before blending. Sometimes the fruit is hard to blend.
4. Start blender on slow, then increase the speed until the sound is smooth (get it?) and everything is blended.
5. Pour into glasses and enjoy a very refreshing drink.
You can get as creative as you want with this recipe, but this is as basic as you can get. If you want to make it thicker, you can add some yogurt. OR, you can freeze 1/2 cup of pineapple and add that in the mix.
Anyway, this is an easy way to get your daily servings of fruit. I guess the cleanup is the hardest part, but even that goes fairly smooth.
Although I haven't tried it, you could buy one of the frozen fruit packages at the store and measure out equivalent amounts for the berries. You'll still need the bananas, tho.
Give it a try and let me know how it goes!
...AR
Sunday, July 05, 2009
Something You Already Knew - Maybe?
"My Feed Line Tunes My Antenna"... This article was written in the March 1956 issue of QST by Byron Goodman, W1DX. It has been reprinted twice since then - once in 1977 and once in 1991 so it has some good insight that has lasted with time.
Here are my excerpts from this ... basically, main points for me to remember. I hope these bits are useful reminders. I have to read this about once a day to keep it fresh in my mind ...
Here are my excerpts from this ... basically, main points for me to remember. I hope these bits are useful reminders. I have to read this about once a day to keep it fresh in my mind ...
When we say 50 ohm coax or 300 ohm twin-lead, we are talking about the characteristic impedance of the line. "Characteristic impedance of a transmission line is the value of resistance that when used as a termination for the line, makes the input impedance of the line independant of the electrical length of the line."
The simple view of this: A 50 ohm load (antenna or other resistance) on one end of your 50 ohm coax feed line will measure as a 50 ohm load at the other end of the line regardless of the actual length of the line. No tuner needed here because the load matches the characteristic impedance.
SO: The system is resonant and the whole load is resistance only.
SO: The system is resonant and the whole load is resistance only.
But what if your antenna is measured as a 100 ohm load and you are using a 50 ohm feedline? You no longer match the characteristic impedance of the line. The impedance you measure at the end of the line will vary depending on the electrical length of the line.
The electrical length of the feedline is measured in wavelengths. To calculate the electrical length of the feed line, you must know the frequency, the actual length (in feet) and the velocity factor. So your physical feed line might be 75 feet but the electrical length changes as you change frequencies.
When the antenna load is different from the feed line characteristic impedance then the impedance we measure changes as we move down the line.
The Half Wave Rule to remember:
Every 1/2 wavelength down the line, the impedance we measure equals the antenna load and, obviously, this changes with frequency. And this load is resistance only.
The Quarter Wave Rule to remeber:
Every quarter wavelength, the impedance we measure is resistance only but the value is not equal to the antenna load.
Who Cares? Well, I guess I do. The reminder here is that the antenna load is really a reactive load. The antenna load is a combination of resistance plus capacitance (capacitor) OR resistance plus inductance (coil). The tuners we use help to bring the reactance of the load to pure resistance.
The Half Wave Rule to remember:
Every 1/2 wavelength down the line, the impedance we measure equals the antenna load and, obviously, this changes with frequency. And this load is resistance only.
The Quarter Wave Rule to remeber:
Every quarter wavelength, the impedance we measure is resistance only but the value is not equal to the antenna load.
Who Cares? Well, I guess I do. The reminder here is that the antenna load is really a reactive load. The antenna load is a combination of resistance plus capacitance (capacitor) OR resistance plus inductance (coil). The tuners we use help to bring the reactance of the load to pure resistance.
Subscribe to:
Posts (Atom)
