View Full Version : Little Help
07-31-2004, 10:46 AM
I have a 1wtt transmitter that I use for sporting events(foreign made),nice little dipole antenna I use with it.So last night I broadcast a soccer game,works great,plug it in this morning and now my signal goes about 20ft.What went wrong here?
07-31-2004, 11:04 AM
07-31-2004, 11:33 AM
So what should I do to correct it?Not really electrical put opened the cas nothing seems loose,everything was working fine last night now today no go?Thanks in advance for any imput
07-31-2004, 01:34 PM
Sounds like a blown rf amp stage, (my Zen troubleshooting), but it actually could be anything. First inspect the board with an eye loupe. Check for solder splashes that could wedge under pins or wire fragments that could roll around. Look for broken, weak or damaged components and connections.
Best to sit down with a DMM and check your supply voltages first. Next I'd power off and check resistances across the amp stages. If you have a diode function on you DMM, it can help bias some transistors, not all RF amps work with this method.
Some designs don't protect the RF output if your antenna is not loaded correctly. Others just run balls to the wall without heatsinking for extended use. Then there are those without isolation on the final amp stage, so a simple electrostatic spark on the antenna can blow the final amp as well.
The only bad experiment is the one where you learn nothing.
08-01-2004, 02:38 AM
You say,It still works okay,but has much shorter range all of a sudden?
Yep,I'd agree.Sounds like the RF final is toasted.
Check your antenna,connections,etc aswell.
08-01-2004, 03:26 AM
I dont really know what your problem is. Like stated earler check the solders, resistance, and connections.
89.5 fm radio
08-01-2004, 12:57 PM
hello fellow microbroadcasters, I have the same problem as WAR EAGLE. I checked everything ,did exstensive test measurements and came up with no problems in the circuitry.I have a question for WAR EAGLE, do you also have the problem of suddenly your frequency suddenly changing and showing up all over the bandwidth?I use a simple dipole antenna also.I hear they have all kinds strange radio activity in your neck of the woods. 89.5 fm radio
08-02-2004, 02:22 AM
Originally posted by 89.5 fm radio:
do you also have the problem of suddenly your frequency suddenly changing and showing up all over the bandwidth?Just my 2 cents! ;) It sounds like you have a RF Final problem and also a PLL Circuit problem. If your freq is allover the bandwidth, your PLL is failing. :( Please keep us updated!
Wish You The Best!
08-02-2004, 12:18 PM
Ok,First of all,thanks for all the input.But this is what happened.I used this transmitter on Friday evening at a sporting event.Worked fine,Single Dipole,good connection.Brought it to a trade show,hooked it up,,get 20 feet away signal dies.it is switchable from 25mw to 1watt stereo,all it does is get louder,and the range is gone.I did not get any schematic with it(not that it would matter-might as well be trying to read Latin for me)so,I guess all I can do is try and look for someone who knows what there doing to take a look at it,any suggestions?
08-02-2004, 12:23 PM
Oh,and no,I am not getting any freguency drift at all it is staying locked on .Checked my antenna connection,I am using the same antenna with a fm25b(it is A tuned Veronica Unit brand Neww)and it works fine with the 25b,so I really like this little foreign transmitter it reall reaches out and Touches" well,hope I can save it.Thanks Guys
08-02-2004, 01:43 PM
I have this problem before,I find out the connectors of music input to FM25 and output to antenna,they need to be tide very close.
08-03-2004, 07:19 PM
I've got an above average parts stock. If you want to take a blind gamble and change out the final amp stages, just tell me the part number(s) of the tranies-FETs etc.. and if I have 'em I'll drop 'em in the mail.
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