If you are talking about a standard run-of-the-mill halfwave doublet, the center should be relatively close together IM (not so) HO. There is an EMF minimum at the center of a .5 Lambda antenna and a current maxima. This holds true whether the antenna is center fed (Voltage Feed)or end fed or...
I would guess the resistive load of the electric heater is sufficient to cause the transformer to humm.
There are several reasons that a transformer will humm,
1) loose laminations in the core
2) loose windings or winding bobbins
3) it likes the tune but never learned the words to "It's too...
What about an LED flasher. Have the flasher turn on after dark. If your Frisbee is lost, wait until sunset, then look for the flashing high intensity LED.
OTOH, you could imbed a tiny GPS engine along with a small transmitter which could transmit the exact location of your frisbee in the...
Wow! I agree, Analog is dead on.
I thought the device would be placed on the Bull so you could go cow-tipping whithout the needless worry of accidently bothering the bull far from the pasture fence!
I remain,
The Old Soldering Gunslinger
A halfwave at 915 MHz is 6.454". The ground plane would be approx. 7" in diameter. The quarer wave monopole would be 3.227" tall.
I remain,
The Old Soldering Gunslinger
Receiver sensitivity generally is rated in terms of a voltage present at the antenna terminals across whatever impedence the receiver presents.
What make and model spectrum analyzer do you have?
I remain,
The Old Soldering Gunslinger
Such a system was described by Hugo Gernsback in 1912 in his book Ralph 24C41+
It was developed for practical use in the late 1930s
It's called RADAR.
Now, you can get a GPS engine a whole lot less expensively than a radar unit and you can adapt APRS (Check on ARRL.ORG about APRS) to have the...
Consider a revolving door concept for input and output from your industrial sized nuke...for some resaon, the though of purchasing microwaved chicken, convection browned or not, isn't appetizing to me...then again, the I can go to the local costco and buy a freshly flame broiled whol bird for a...
Hmmm...one time, you spell color the way we Yanks do, then you spell colour the way the Brits (and former colonials in many parts of the world) would.
Are you, perhaps Canadian?
There have been indications that the earth's magnetic field is becoming unsettled and will switch polarities...
Shakespeare used to make a CB (11 meter band) antenna called "The Big Stick" which was indeed a coaxial or sleeve dipole. The antenna was an aluminum tube wrapped in the same color fiberglass as their 102" whip antenna. it had a 3/8-24 threaded socket at one end and an so-239 (PL259 socket at...
Hmmm...That is an interesting thought...capillary tubes in the exhaust manifold(s).
IIRC, the refrigerant used in the absorption type refrigerators used to be ammonia...I don't think it would be very nice if the evaporator coil sprung a leak while traveling 75MPH on I-10...
When I was a kid, a...
Omaha, $1560/yr reserved space, open lot, 200' to office
Tucson, $560/yr, hunting license in parking garage under cover, 800 yds to office.
Both parking permits were paid in pre-tax dollars.
I remain,
The Old Soldering Gunslinger
What the Comcokid said and one more thing.
At 45 MHz, the skin effect comes into play in a relatively large way. Silver plating will increase the Q of the inductor because of the lower resistance of the silver (or silver oxide).
For example: at 60 HZ, the skin depth in copper is 8.57mm.
At 10...
Alas, RF engineering isn't as "Sexy" as it once was. Instead of mundane sinewaves, the allure of ones and zeros has enticed potential RF engineers to "The Dark Side" :-D.
I might suggest that you advertise your position in periodicals read almost exclusively by RF professionals and (dare I say...
The nicest (in good weather) and strangest commute was a 105-mile (on the road) 70-mile (in the air) commute I had for one Summer. When the weather was good, I hand propped the old J-3 and flew to the site, landed on the property in rural Nebraska, taxied up to the building and tied down. It...
Again, the answer would be yes...or perhaps depends.
For instance, you have one receiver and you wish to couple that receiver to two different antennas, two ports would go to antennas, one to the receiver and one would receive a reject load.
Two transmitters into one antenna the transmitters...
I have several friends (not in Engineering) who commute from Tucson to Phoenix and back every day. From the North edge of the Tucson Metro area ( Marana) to the South edge of the Phoenix metro (Chandler)is about 95 miles.
Pardon me, but that is totally nuts.
I remain,
The Old Soldering...
I guess this ought to be in the "Best Engineering Advice..." thread, however it is a piece of advice I recedived and am no passing on to you.
An old friend who was going through Med School passed this along:
If it isn't written down, it never happened.
Take notes on everything. Save those...
EGAD! That was a third of a century ago or more!
I do remember that the calculator which fit in my (albeit oversized) shirtpocket cost me only slightly less than my first car, a 1966 Mustang Hardtop (purchased used in 1973) which got 20 MPG gasoline and 100 miles/ quart motoroil.
I still have...
