Power adjustable FM transmiiter gets hot when RF power reduced

[Alcyone]

I bought a 10 watt fm transmitter that's power adustable from 1 mw to 10 watts. However, when I turn the RF power down to any degree the transformer heats up to the point where you can't touch the bottom of transmitter without burning yourself. Is this normal and is this something to be concerned about?

Thanks

 

[audioguru]

We cannot read your mind!
Since you didn't post a schematic and point to the transformer that gets hot then nobody will answer you.

 

[Alcyone]

Well like I said I bought it. I didn't build it. And therefore don't have a schematic...

 

[KJ6EAD]

The reasonable alternative to a schematic is a set of sharp photographs of the circuit and all brand, model and specification information.

I am now reading your mind and can see that you have a transmitter designed for 10W but that uses a crude linear regulator to reduce the supply voltage as a means of limiting output power.

~KJ6EAD, Electronic Psychic

 

[alec_t]

Do you really mean 'transformer', or should it be 'power supply'? Is the 'transformer' (/power supply) original kit designed to supply the Tx specifically? What markings does it have on it?

 

[Alcyone]

I'm sure this pic doesn't help much. The model is an ELE 10w transmitter. It's an off brand so I'm sure no information can be found on it.

Regarding the transformer vs. power supply. I don't know. It uses a power adaptor with the supply built in, like what you have with a laptop.

Thanks

**broken link removed**

 

[alec_t]

The letters/numbers at the top of the picture are unclear. Can you confirm what they are?
Does the power adaptor have any markings? If so, what are they?

 

[Ziddik]

We cannot read your mind!
Since you didn't post a schematic and point to the transformer that gets hot then nobody will answer you.

why can't the ignorant audioguru post a solution without reading a schematic? I thought he was really a good expert! Now i got it!!

 

[audioguru]

why can't the ignorant audioguru post a solution without reading a schematic? I thought he was really a good expert! Now i got it!!

If you insult me again then I will have you banned from here.
Stop being rude. Please go back to your foreign country.

The OP never showed which transformer gets hot. He said it has a "power adapter" which probably has a transformer but he never said it gets hot.

 

[Ziddik]

If you insult me again then I will have you banned from here.
Stop being rude. Please go back to your foreign country.

The OP never showed which transformer gets hot. He said it has a "power adapter" which probably has a transformer but he never said it gets hot.

banning me will not be a solution for the above problem and i am not being rude and u can't do ban me urself!! U knw that i really thought you know everything..and I really scared now.. U prefer to ban a person who talks truth?

 

[audioguru]

banning me will not be a solution for the above problem and i am not being rude and u can't do ban me urself!! U knw that i really thought you know everything..and I really scared now.. U prefer to ban a person who talks truth?

We speak English in this forum. You can't speak in clear and proper English.

 

[Alcyone]

I appreciate the help. I operated the tansmitter on reduced power for about 4 hours. It got really hot, but doesn't appear to have any damage. The seller claims the case is used to release heat and the heat is normal. I think it's ok. I was thinking there was a generic answer as to why it might heat up when the RF power is reduced. In the end, I guess it doesn't matter.

 

[Ziddik]

We speak English in this forum. You can't speak in clear and proper English.

english is not my first language so the problem when spell is natural! Don't read my post If u cant understand it :lol:

 

[carbonzit]

I appreciate the help. I operated the tansmitter on reduced power for about 4 hours. It got really hot, but doesn't appear to have any damage.

The question is, how hot is too hot? Kinda hard for us to tell, not having any temperature readings and having to go by your description.

As you probably know, heat is not a friend of electronic devices. If something gets too hot to put your hand or finger on it, it's probably too hot for something in there.

Any way to take a temperature reading?

 

[mbarazeen]

i have one of the same transmitter, if you dont connect a propper antenna, the out put transistor gets very hot, even chances to get damaged, but the point you mentioned, it only gets very hot when operated at 1W is not clear.

you better conform you use a propper antenna or a dummy load, then see the range with both 1W and 10W out puts.

about power supply getting hot... are you sure it only happens when operated at 1W? may be some thing wrong on the display control in the front.
also keep in your mind operating such transmitters are illegal in most of the countries..

 

[Alcyone]

Do you have an ELE transmitter? A ground plane antenna is connected. I've also tried a dummy load with a non-inductive, 10 watt resistor strapped to a heat sink. It still gets hot when the power is reduced. I know it's not a defective transmitter because the seller accidentally sent me another one and it does the same thing when the power is reduced, and only when the power is reduced. If the signal only goes several houses down the street I don't see it as being a big issue.

 

[carbonzit]

If the signal only goes several houses down the street I don't see it as being a big issue.

Even if it causes interference with their radios, TVs and other electronic devices? Really?

 

[Alcyone]

A lecture? Really? Using a band pass filter so spare me the lecture. Not that it would interfere anyway.