Bob Cavalcante from Manassas, VA


#5

Thanks Archie!


#6

Thanks Jack! It’s been an experience, that’s for sure! I could probably write a book. But as you know, Navy port visits aren’t that long so you get a little of everything, not enough of anything. The fun will be after retirement going back to some of those great places with my wife!


#7

Much appreciated, Wendell! And thanks, I’ll need it! lol…


#8

Congratulations Bob and welcome!


#9

Bob,
You have a very interesting life story. The radio stuff was very intriguing. I myself am a very technical person that loves to know how stuff works. I can diagnose most plumbing HVAC and Electrical problems on very large commercial and industrial buildings, but for the life of me I just can’t understand how the radio works. :joy:


#10

Good old Bull Run. Nice.


#11

Thanks Brandon! Interesting is a good word for it. I usually call it a complete mess! :joy:

Radio is actually simple and if you know basic electricity, you’ll understand this. First thing first, how antennas work: Here’s a very simple video explanation of how a simple dipole antenna works. Basically, all antennas are a derivative of this basic design and theory.

Since the two wires don’t touch, there’s no path for direct current flow. But at the high frequency that we transmit in radio, the electrons in the wire itself will still oscillate back and forth at the frequency we selected, creating the current and voltage we need to send a radio wave! This oscillation creates an oscillating magnetic field, which in turn creates an oscillating electric field and thus an electromagnetic field is created and is radiated through the air!

A transmitter is simply a device that turns low power audio voice waves into high powered radio waves. There’s a section of circuits in every radio that takes our voice waves from the microphone and use it to modulate either the amplitude (Amplitude Modulation - AM) or the frequency (Frequency Modulation) of a high powered carrier signal at our selected frequency that is then sent to the antenna.

A receiver is a device that basically electrically tunes the antenna to receive only one frequency (resonance). When a receiving antenna is tuned to the same radio frequency as a transmitting antenna, it detects the signals of that same frequency that are then sent to a smaller audio amplifier circuit creating an exactly duplicated smaller version of the transmitted signal. That’s then converted to an audio frequency that your ears are capable of hearing and sent to the speaker.

Very basic… That help?


#12

Well that’s more than anyone has ever tried to explain to me! Thanks for the crash course. It seems to me that the voltage source would have to be AC instead of DC to have the “oscillating” current at a given frequency. Is this the case or just “fuzzy logic”?


#13

Yes sir! I cross the Occoquan River twice a day to and from work in DC. Not many people know that “Bull Run” is actually the name of the stream that feeds into the Occoquan River further up river. Beautiful place!manassas_ts11
canon_at_manassas_battlefield
Manassas08071101


#14

Glad to help! Love sharing this hobby. Nope. All electronics use DC as to all radios. My radio and most ham radios use a large separate DC power supply. We have our own highly controlled and very accurate oscillator circuits that are super accurate and controlled. Otherwise every time the power grid frequency fluctuated, so would our transmitter!

Couple pics I found that will help explain:
Receiver:
Superhet-Block-Diagram

Transmitter:
transmitter


#15

No so Gary many military radios work on DC, Your mobile phone has it’s roots in military radio technology


#16

Very cool. Great area to live in if you like American history.


#17

That it is and I Love it! Mount Vernon, Monticello, Appomattox Courthouse, Fredricksburg, Antietam, Williamsburg, Yorktown, not to mention all the free museums in D.C.!


#18

hey Bob,
Love the radio talk. I only got as far as a crystal set and Allied Radio walkie talkie kits, but fascinating stuff! And nice to see another 03 C&R here. :wink:


#19

Hey Dan! Glad you enjoyed it! I enjoy the radio, though I need to put up another antenna now that I lost the one in the yard and now have solar panels covering my roof and screwing up my stealth attic antenna!

Yes, another Cruffler. Not a big collection here, but a few keepers!


#20

Hiya Bob! Great write up.

We’re neighbors - I’m just out in Gainesville and pass the Stone Bridge every day…twice.

We should get a local Banjo Ben Get Together lined up - I think there are a few of us from northern VA on here…


#21

You’re welcome Bob. I also am a licensed amateur radio operator, callsign N3TUN, although I haven’t done anything with it for quite a few years…


#22

Hey Harry, that’s a great idea, I like it! I can barely play in front of my wife, but it would still be great to get together and learn from one another.


#23

Hey Wendell! Very cool… You should think about picking it back up. It’s always fun, even in low sunspot cycles.

I see you’re in Bedford, small world! I used to visit our contractor up there outside of the airport, MDL Manufacturing. The owner used to work for my old company - VSE Corporation. I was QA checking their manufacturing and paint process for our government contract. Visited there 5 or 6 times. The best Calzone in the WORLD was at that pizza shop in town… Original Italian Pizza. That thing was HUGE! Easily a pizza folded in half and STUFFED! LOL!


#24

Wow, that’s cool. Not too many people are familiar with Bedford… I live about 3 miles from MDL. I have about enough projects going right now, not sure when I’d do ham radio. We’ll see.