Okay, I have a problem with hum on my AM-25. I disconnected the audio and there is still hum so it more or less isolates it to the power supply, unless I am picking up some stray hum from the mains power. This does not seem likely. I have heard that the wall wart Ramsey provides tends to produce a hum. Has anyone else had this problem? Is there a better power supply I can use?
Bill Harms
Okay, I have a problem with hum on my AM-25. I disconnected the audio and there is still hum so it more or less isolates it to the power supply, unless I am picking up some stray hum from the mains power. This does not seem likely. I have heard that the wall wart Ramsey provides tends to produce a hum. Has anyone else had this problem? Is there a better power supply I can use?
Bill Harms
Bill. The power supply that comes with the AM25 in plain english stinks. Mine hummed like the dickens. I recommend a Pyramid power supply. Their 3 amp model would do. Pyramid's can be found at bottom prices at www.buyreliant.com under catalog on the home page header. Jim B
Jim:
I just placed one on order. I let you know how it works when it gets here.
PhilcoBill
Old Time Radio
650 KHz
Elkridge, Maryland
Hello,
Me too, i have this problem especially before when the sky went dark while i was far from my transmitter (i.e. more than 100 meters away from my AM25). My power supply is a NexxTech 12 VDC 500 mA.
Regards
Yves
PS: btw, Bill, i'm impressed that you broadcast at the beginning of AM band. How much coverage you broadcast? I guess you have a big loading coil for 650 kHz. Have you ever experienced to broadcast at the end of AM band (> 1500 kHz)?
Bill and all,
There are a couple of gremlins you need to be aware of with the AM-25.
First, take the Ramsey supplied wall wart and see how far you can throw it. If you have a shotgun, before you throw it you can yell, "PULL!" Before you shoot, rememeber to swing through the target.
Second, use a regulated and filtered ~12volt DC power supply to power your transmitter.
Third, make sure the transmitter has a good earth ground.
Fourth, I used shielded audio wire from the audio device to the transmitter audio input. Make sure you connect the ground/shield lead only at the feed input end to ground.
And finally, check your audio device (cd player, computer, mixer, ect.) to make sure the audio levels have been adjusted for the least noise of any kind.
A word to the wise: If your AM-25 continues to hum, do what I did, teach it the words to the song.
Marshall Johnson, Sr.
Rhema Radio - The Word In Worship
http://www.rhemaradio.org
Those of us who live on the East Coast have to suffer with the lack of open frequencies, even the extended band (X-band - 1610-1700) is packed here, so I had to choose a frequency in the lower end of the band. I don't mind building a large coil. In fact, I have had fun doing it. As far as the coverage is concerned, I have gotten out to a 1/4 mile okay, but I am still tweaking it. Regardles, the transmitter serves it purpose of broadcasting old time radio shows so I can hear them on my old Philcos.
PhilcoBill
Old Time Radio
650 KHz
Elkridge, Maryland