The Isotron Antenna has been proposed as a viable approach to short length Medium Wave radio transmitting antennas. Now some intrepid souls are trying home brew versions.
The Isotron Antenna has been proposed as a viable approach to short length Medium Wave radio transmitting antennas. Now some intrepid souls are trying home brew versions. Read more on the PCS-Eletronics forum, here on the Home Brew Isotron thread.
Real Community Radio, a part 15 radio group, took part in the Ozark Area Communty Congress (OACC) October 7-9, 2005…
Real Community Radio, a part 15 radio group, took part in the Ozark Area Communty Congress (OACC) October 7-9, 2005…
Real Community Radio was a co-sponsor of the event.
RCR had an information table complete with maps, brochures, and CD samplers of programming. Many visited the booth during the event. In addition we had two scheduled presentations about using Part 15 for community broadcasting.
Several participants signed up as volunteers and for workshops to be offered by Real Community Radio. Several expressed interest in part 15 broadcasting and references were given to www.part15.us
Real Community Radio hopes to expand coverage to several towns in Southern Missouri. There was a great deal of interest in creating new programming by attendees. Workshops will be set up to help those interested.
This was the first participation by Real Community Radio in OACC. This was the 26th year for OACC. At any given OACC there has been and will be variously people strongly involved in, for instance, organic gardening and agriculture, appropriate technology, alternative health, communities, land trusts, ecological protection, forestry, home schooling, conservation, responsible media, sustainable businesses, biodiversity preservation, ecological restoration, culture, music, arts, eco-villages, and the list goes on indefinitely.
A picture of one of the presentations can be seen at
http://www.realcommunityradio.com/pix/oaccmeet.jpg
12vman writes I have a thought.. “Could a low powered FM xmtr (Part-15) be used to transmit audio to a Part-15 AM xmtr?”
12vman writes I have a thought.. “Could a low powered FM xmtr (Part-15) be used to transmit audio to a Part-15 AM xmtr?”
I mounted the SSTRAN and an F.M. pocket radio (mono) in a weatherproof box at the base of the antenna. I use a Velleman kit F.M. xmtr to get sound to the SSTRAN. I had the most trouble with getting the Velleman to sound good. After that, everything was fine..
I find that the A.M. doesn’t bother the F.M. at all! Actually, the highs are better than going through cables. Much cleaner! The bass response is great! Holds togather very well! The compression on the SSTRAN is touchy but once it’s set, it almost sounds as good as the F.M. direct. I could adjust the antenna better without the audio cables running up there. I got a better (higher) voltage easier without them. Everytime I connected the audio cables to the SSTRAN with the V.O.M. on the test points, the voltage would drop 2 volts. Now the only cable going up there is power. I can get a great peak as high as 15 volts. I couldn’t do that before. Also I believe that some of the R.F. from the SSTRAN was going down the audio lines to my mixer making it sound somewhat “Softer” than it is now. Much less background noise also..
I operate the SSTRAN and the pocket radio from a 24 volt D.C. supply. I decided to convert the 12 volts to 24 volts in the house and send it up to the top because of less loses through the wiring. I have around 26 V.D.C. at the xmtr and connected that directly to the xmtr. I used a 7805 regulator to operate the pocket radio. I contacted SSTRAN about this and Phil said it would be ok but approaching the high limit of the 15 volt on board regulator. I let it run for 3 days constant with no issues..
Here are some spec’s to keep in mind when designing kits and type accepted transmitters…
Here are some spec’s to keep in mind when designing kits and type accepted transmitters…
1) Transmitter should employ a PWM Modulator and a Class “E” Final.
2) Modulator Deck and RF Deck should be seperate from each other.
3) The RF Deck should employ a PLL using a TCXO reference.
4) The output tuning network should employ a High Voltage / High
Impedance output like the Rangemaster and have a bypass circuit for users who
would like to use a base loaded vertical such as Carl Van Orden”s or
the Magnum. I”d like to see more EH antenna designs and documentation
and notes make it into the library as well as some transmitter designs
based around these parameters laid out here.
5) The Design should offer the option of either unbalanced RCA Line
level inputs or a +4db balanced 600 ohm input to match pro broadcast
equipment.
6) The transmitter should not have extra built-in limiters or at a
minimum the ability to bypass built-in limiting when using outboard
limiting.
7) Transmitter should be capable of -99%/+150% modulation for that big
station sound.
8) RF/Modulator decks should use metal boxes for sheilding.
9) RF Deck should feature a tuning meter to aid in tuning antenna and
setting power output.
10) The final should be 100mw DC input in unmodulated state with the
ability to be Adjusted to 1watt.
11) Please publish complete manual in PDF complete with schematics.
Manual should be well written like the SSTRAN manual.
12) Transmitter should be marketed and sold as a kit only to cut down
on costs and would idealy cost in the $200.00 range. Maybe a Type
Accepted Fully Assembled Version as well
I think these ideas should offer a good starting point to a quality
transmitter design for somebody thinking about designing a new kit or type
accepted transmitter.
Written By
Rev. Robert P. Chrysafis
XRQK/Radio Brandy completes new studio…
XRQK/Radio Brandy completes new studio…
provides two independant feeds for our part 15 AM & FM stations.
The entire studio lives on a five foot table and cost less than $800 bucks to build.
Steve
www.XRQK.com
scwis stole this story from the www.ramseyelectronics.com forums
We were recently contacted by the designer of a new transmitter schematic. The August 23rd update even included component values for the AM MW BCB…
We were recently contacted by the designer of a new transmitter schematic. The August 23rd update even included component values for the AM MW BCB…
Dave Martin, the designer, says “The CORSAIR Shortwave transmitter design grew from the COMMANDO which itself was a development of the old classic by the Radio Animal.
I had been helping members of a Yahoo group to build their own transmitters and noticed that many were struggling with making the modulation transformer, so I designed a circuit that didn’t need a modulation transformer.”
Very interesting stuff, some of which might be adaptable for use at lower power levels, or something.
http://www.geocities.com/thecorsairtx/Circuit.html
Whew!
