I am extremely impressed by your
162 kHz operation.
God, I wish I had your ability.
Do you have any data on the coverage
area? I realize this is difficult
to do, because most LW portables are
not very sensitive.
Wow is all I can say.
Bruce, DOGGRADIO STUDIO 2
"What are you transmitting on it?"
My LW station carries the same programs that air on the AM CC station, the FM station and the 3 streams.
Sometimes..depending upon the program content on the primary SAM, the LW/AM and FM break away via the 2nd SAM to other programs or for localized programs.
RFB
"Do you have any data on the coverage
area?"
Not anything accurate. Just driving around with a battery operated portable, about 2.5 miles to the south and about the same to the east and west, about 1 mile to the north.
The antenna and ground are not a great setup, just a quick throw together thing. This coming summer I plan to put up a much better system with a vertical mast and better ground radial system....that is if there is room!
RFB
RFB, that's coverage is a lot, as
far as I am concerned.
I'm impressed again.
I have to go to job #2, so I will
check in later.
Best Wishes,
Bruce, DOGGRADIO STUDIO 2
Hi RFB
I am tansmitting on 170Khz in ASCII ,or packacket radio that most hams
radio opperators do. I am a ham radio opperator and also kept up Large AM
Broadcast stations as well. I am a retired engineer for Ratheon ,and Advance
technolgies research Labs. Which was a part of NASA. I also retired from the US
Military.
I like running on 8Khz also ,and found that data streaming could be
done on those frequencies. AS well voice communications. It a really hard thing
to do since voice takes up alot of band space. Here what you need to do to
get voice communications in that band. First you need to change your voice
in digital files. These digital files carry a much smaller bandwidth,and then
you can transmitt the digital file and your receiver connected to a computer
can open these files. For instant comunication I just change the voice patterns
over to a 16 bit digital word that can be transmitted. This can be then
converted back from a Digital to analog converter chip. It really easy to
do.
My transmitter at 8Khz run between 20 to 25 watts output,and I also transmitt
at 170Khz using digital,and SSB since SSB will travel much further than
AM A3E. I use a Sageon ATS803A receiver that can have an out door antenna
hooked up to it. I have designed an antenna tunner so I could match a 210ft
Inverted L antenna up to the receiver it work quit well. This is for the 160Khz to 190Khz range. I have a homemade receiver for the 8Khz band.
The 8Khz receiver consist of on RF stage , Local ocsilator,,mixer, three stage IF Amp at 25 Khz and beat frequency to give CW or SSB reception,detector stage
for AM use only, Audio amp stage.
My Rf stage is a LM741 chip set at the gain of 50 this alows this amp to go to
20Khz cut off frequency. I could have use the Cmos 555 chip but square wave
gives off to many harmonics. The best chip again was the LM741 for the local
oscilator. Th oscilator will go up to 40 Khz then mininus the 25Khz IF strip.
This will alow me to receive up to 15 Khz. I also have the lowest frequency on
the local oscilator set to 30Khz which allows me to tune down to a 5 Khz signal.
Please keep in mind you want you Local oscilator and If strip above the audio
range since if you start mixing frequencies in the audio range you will be able
to hear your local oscilator tone. That in return will cover up the signal
you are trying to receive.
Now let use the 8Khz I like working at. First off my Local oscilator is set at
33Khz above the human hearing range. My IF strip is set at 25 Khz still above
the hearing range of a human. Now when that 8 khz signal come in it is
coverted down to the 25Khz IF frequency. 33Khz-25Khz= 8khz being received
on the front end of the receiver. Now you need to detect the 8 Khz sigal that
in the 25 Khz IF stage the easiet way is to use a simple 1N34A Diode. Then run
to your audio satge.
For CW reception I just mix a 26Khz single with the 25khz IF which is easy.
26Khz-25Khz= 1 Khz an audible tone to the ear. This was CW can be received.
The other way is to Receive A3E AM signal..
Uyou can also use a varible osicalator that goes from 22.5Khz to 27.5 Khz and
mix this and it will allow you to receive SSB singles on LSB and USB.
Anyays my receicer receives from 5 Khz to 15 Khz, on AM,CW,USB,LSB.
I have not put the FM stages in it yet,but can be done fairly easy.
I hope this make some sense to you RFB ,and that I did not get to technical
Thanks
Sean
Dear seanwk40
Your description of your LW project was very clear, I thought, and super interesting. I am very glad you posted that here and it is a wonderful project.
Does the "voice" embedded in your carrier signal say anything in particular ---- like weather or identification information? Is it your voice?
"I hope this make some sense to you RFB ,and that I did not get to technical"
Oh...I think there is A LOT you might want to catch up on within the last couple of years in the forum.
However, I am quite sure it got "too" technical for some others and has them thinking! 😀
Not to offend but I just about spewed coffee all over my screen reading that last line! LOL!!!
"To" and "Too"...can become a bit complex eh! 😉
RFB
Well, I still am amazed by what you guys are
doing.
But, as I have said before, I'm not an engineer,
I'm just a dude.
Best Wishes,
Bruce, DOGGRADIO STUDIO 2
It is strange that electronic technicians are called "engineers." We do not operate locomotives.
Airplane pilots are not called engineers, even though they run jet engines.
Bus drivers are not called engineers even though they drive diesel engines.
Bicycle riders...... skip them.
What is the "eer" extension that we add to the word "engine"?
Are we announcineers? Producineers? Blogineers
Am I an over-thinkineer?
I'm a DUDEINEER. And because I made up the
word, I can spell it any way I want!
Right now, the above spelling looks OK.
Actually, I'm a bicyclistineer, too, but a
very slow one. Top speed, 7 MPH.
Bruce, DOGGRADIO STUDIO 2
Hi RFB
Ok I am guessing that I did not get to technical for you. I did not
know your background in electronics. Anyways I am have been told many times
this statement. Please now say it in English.
Anyways I wanted to go in some detail but not super detail how the
tuning is done through low and high pass filters using RC networks.
As well LC circuits. Also I have a dual conversion set I designed
to keep out imaging frequencies. That was a single conversion set
I first design,but I added a one stage IF that work at 50Khz to just
kill imaging frequencies showing up in the receiver.
That changes the Local osicalator frequency,but it all was a very simple change.
I also added circuit to kill Noise. I placed noise filters in the receiver
also.
What do I broadcast down on that frequency. I can place my voice over the air.
again remember that I have to change it in to a digital form. This allows
me to place audio voice into a very narrow band width. At 8Khz
bandwidth is very tight. I try to work in a band spread of +/- 500hz
Which would be 7.5Khz to 8.5Khz for a 1 Khz bandpass. This is still pretty wide
but normal voice communications would never work. So place a voice into a
digital form you can get it to work nice in this band width.
Even digital communications will work in this band width. do not expect
anything fast and high speed. Remember let just say 300 baud.
Well that take up a band width of 300hz. Now printers in the 1980's and early
1990 had a baud rate of 600 baud ASCII. This would still place you into a
band width of 600hz. So you can transmitt digital comunications in this
band but just remember that it will be much slower that any dial up
connection found today. Now still it good enough to set up a BBS over the
air. You can easly talk to each other at these slow rates.
Old ham equipment ran at 110 baud for ASCII and these can still be found.
MFJ and other ham manufactures made these units for digital communications.
So there is alot that can be done on those super low frequencies.
Here is the best deal of all. There is no antenna limitation or power limitation.
This is all experimental and the FCC has now rules on what you can do in
that band. So if you want to run 10,000 watts no one going to stop you.
There is several transisters that can produce 250 watts that are fairly
easy to get. I just happen to make my first transmitter run at 20 to 25 watts.
The antenna is the tricky part. Big loading coil even when my antenna is over
280 ft in length. Now I have had electronic people show me how to make a
huge attenna loop.It almost looks like the Ferrite antenna's you see in
AM radio. Just imagine one in 4 ft diameter,and about 12 to 16 ft long.
Save alot of room. this will work for a transmitt and receive.
Very directional also,so a good rotar is needed to point your signal.
Anyways this is other stuff I mess with
SeanKW40
I have always considered myself as a Pioneer...always creating and always solving and always observant.
It might surprise everyone..but all of us are a Pioneer of one form or another.
RFB
A pioneer tracks pie in the sky ideas.
Radio-Pie and the Eer-ie Tones.
Na...won't work.
RFB
I don't know about the rest, but I prefer "Engineer" than "Technician". Technician sounds too green behind the ears whereas Engineer has a distinctive sound, catchy and solid, wisdom and strength.
Anything else simply does no justice to the skill.
RFB