This webpage shows equipment for my FCC licensed radio station in the Amateur Radio Service in the USA. I've received emails requesting information on starting college radio stations as well as radio stations in foreign countries. Here are commercial websites with FREE information which should answer all of your questions:
Mulcher FM
The Federal Communications Commission
IBS Intercollegiate Broadcasting System
1
2
1: Transceivers, audio chain and receivers inside the shack.
2: Linear amplifiers in the garage.
1
2
3
4
5
1: Audio chain overview.
2: Electro-Voice RE27N/D dynamic microphone, 150 ohm balanced output, 45 Hz to 20 kHz response.
Click HERE to see my homebrew, no vibration mike "boom".
3: Mackie 1202-VLZ 12 channel mic/line Pro Mixer. Bullet-proof design for RF rejection. Very low noise and enough gain for low impedance microphones. Current settings: HI-EQ 0 DB, MID-EQ 0 DB, LO-EQ -3 DB.
4 Top: Behringer DEQ2496 digital audio processor. My modified Viking II is flat from 20 hz to 5 kHz but I bought the Behringer anyway. When the DEQ2496 arrived, I started having fun with the Viking II into a dummy load with an RF sampler and a scope, a separate wide band receiver with good quality headphones and the many, many audio menus. After a while I discovered, by listening to my audio from on the air playbacks from other amateurs, that I was overprocessing my audio so I turned off all the menus on the Behringer except the compressor which is set at 8 DB. I ended up with a slight tweak of the 3 band EQ on the Mackie mixer. If my transmitter were not flat, I'm sure, from testing, that the Behringer would overcome any audio fidelity problems.
4 Bottom: Alesis RA500 250 watts per channel power amplifier (10 Hz to 70 kHz).
5: Hammond 1642SE single ended audio transformer, 20 Hz to 20 kHz, 75 watts, 300 ma, 5000 ohms to 4/8/16 ohms.
1
2
3
1: The modified Viking II is the RF exciter transmitter for Amplitude Modulation. Modifications include: An outboard modulator (see audio chain overview above), variable power (0-100 watts) and flat audio response from 20 Hz to 6 kHz. Click HERE to see my the hi-fi Viking II mods.
2: The Viking II VFO is an ICOM IC-718 which is menu adjusted down to flea power. The IC-718 feeds the buffer stage of the Viking II.
3: The Kenwood TS-870S is primarily used on SSB, which excellent audio, although it can also operate on AM with fairly decent audio. The 870 will not modulate greater than 70% in the AM mode no matter what external audio level you put in. Audio for the TS-870S is taken from a special mixer port on the Mackie which is 30 db down from line level.
1
2
3
1: Overview of the linear amplifiers in the garage. They were moved out of the shack to eliminate blower noise and heat.
2: Homebrew 3CX3000F7 linear built inside a Gates transmitter box and the accompaning homebrew high voltage supply in the black Bud cabinet.
Click HERE to see the single 3CX3000F7 linear amplifier.
3: Homebrew 3CX3000F7 monobander and three Ameritron linears, (AL-1200,AL-1200 and AL-1500).
Click HERE to see the linear amplifier with a pair of 3CX3000F7's.
1
2
3
4
5
1: Drake R8B tuning from 10 kHz to 30,000 kHz for LSB, USB, RTTY, CW, AM and FM. One of the really nice features of the Drake is that if there is an interfering carrier above or below the AM station you are listening to, you can put the receiver in "sync detect" and select either upper or lower sideband and the interfering carrier is eliminated.
2. Collins R-388 tuning from 500 kHz to 30,500 kHz for AM and CW. Receiver was modified to take audio right at the detector.
3. The ICOM IC-PCR1000 computer controlled receiver. 10kHz to 1300 mHz, AM, FM, CW, WFM, SSB).
4. Computer screen showing Ham Radio Deluxe software controlling the PCR-1000.
5: Optimus mixer to enhance audio and match output levels from the Collins R-388, the Drake R8B and the PCR-1000 recievers to a HI-FI amplifier and speaker.
1
2
3
4
5
1: Lodestar AG-2601A, Audio signal generator. Provides both sine wave and square wave output from 10 HZ thru 1 MHZ. This generator is plugged into the station audio mixer and is used for tuning up the linear amplifiers in AM service. It is also used to "sweep" the AM driver transmitter to find out its "HI-FI" capability.
2: Homebrew RF sampler made from an A-B coax switch: The A-B switch is removed, the "A" strap carries the RF from transmitter to antenna and the "B" strap, in parallel, grounded at one end, is the RF pickup and feeds my oscilloscope. Off-the-air RF envelope examination is a must for operation of Linear Amplifiers in AM service.
3: Elenco S-1325, dual trace, 30 Mhz Oscilloscope. This scope is invaluable for tuning up the linear amplifiers in Amplitude Modulation service.
4: The Bird 43 wattmeter (left) is measuring AM carrier input power to the AL-1500 linear amplifier and the Bird 43 meter (right, with 4300-400 peak reading kit) is reading the peak envelope power output of the AL-1500. (Note: I replaced the batteries with two 9 volt power modules ("wall warts") and I now leave the PEP kit on all the time).
5: The dummy load (background) with the external RF sampler is the Bird Termaline RF Load-Coupler, model 6411 rated at 500 watts at 50 ohms. The Bird dummy load plus RF sampler weights 23.5 pounds. The dummy load (foreground), is a US Navy DA-75/U, rated at 1000 Watts average at 51.5 ohms nominal in the range of 1.3 to over 1000 mHz. The DA-75/U while looking similar in size to the Bird 6411 is actually 3 inches longer, has much thicker radiators and it weights 33 pounds (10 pounds more than the 500 watt Bird 6411).
1
2
3
4
5
1: Alpha Delta antenna coax switches to amplifiers, antennas and dummy load. All antennas are fed with LMR 400 coax.
2: Antenna selection switch (160 METERS: Coax fed dipole with center at 60 feet and ends somewhat lower. 40 METERS: inverted V, sharing the same coax as the 160 meter dipole. 75 METERS: Coax fed dipole with center at 60 feet).
3: Transmitter/transceiver selection switch.
4: Linear Input Switch.
5: Linear Output Switch.
1
2
3
4
Measurements by an MFJ-259B at the shack end of the coax:
1: 75 meter dipole: 124 feet long of #10 copperweld, fed at the center with LMR 600 Coax, 60 feet high running north-east to south-west.
2: 160 meter dipole: 225 feet long of #10 copperweld, fed at the center with LMR 400 Coax, 60 feet high at one end, 15 feet at the other end running north-east to south-west.
3: 40 meter inverted V: 67 feet long of #12 flexwire, fed at the center with the same LMR 400 Coax that feeds the 160 meter dipole, 60 feet high running north-east to south-west. I found that the length was critical. I had to chop and test, chop and test to get it to the desired range.
4: Common feed point for 160 meter dipole and 40 meter inverted V. SO-238 is covered with GE-silicon rubber. The LMR 400 is fastened to the center insulator with two UV tie raps.