# If I touched to antenna of 500 Watt or 10 KW FM transmitter, will it shocked me?

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#### Willen

##### Well-Known Member

Another question-
If I made 5 watt FM Tx and used 2db gain dipole, will it double the power into 10watt in radiation? Then will it work this 5watt Tx as a 10 watt Tx? And if use 15db gain Yagi-Uda, then will it work as a 75watt Tx (5 watt X 15 gain)?? If yes wow!

#### Willen

##### Well-Known Member
Will it shocked me it I touched to antenna of 1 KW or 1 KW FM transmitter?

Main question is:-

If I made a 5 watt FM Tx and used dipole antenna of 2dB gain, Can I transmit double radiation power of 10 watt?
And can I use my 5watt Tx as a 75 watt Tx using 15 dB gain Yagi antenna (5W x 15dB=75)? If yes, wow how great antannas!!!

#### MikeMl

##### Well-Known Member
If you touch the antenna of 500W transmitter with your finger, you will get a nasty RF burn in the end of your finger. A hole a couple of mm in diameter and several mm deep. It will be very painful and take a long time to heal, because the surrounding flesh is cauterized. Ask me how I know!

If you touch the antenna of 10kW transmitter, you will be lucky if you do not lose your arm!

If you use an antenna that exhibits gain, the gain occurs only in certain directions, and you get a signal loss in other directions. Yagis are used only in point-to-point transmission. Vertical co-linear antennas are omnidirectional and get gain by directing signal towards the horizon that would otherwise go upwards.

Power gain stated in decibels (db) is 10 log (Pout/Pin), or Pout = Pin χ 10^(db/10), so for a gain of 2db, the effective Power out from a 5W transmitter is Pout = 5% χ 10^(2/10) = 5W χ 1.5849 = 7.92W

Pout = 5W χ 10^(15/10) = 5 χ 31.62 = 158W

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#### MikeMl

##### Well-Known Member
Why the duplicate post?

#### Sangoma

##### Member

Main question is:-

If I made a 5 watt FM Tx and used dipole antenna of 2dB gain, Can I transmit double radiation power of 10 watt?
And can I use my 5watt Tx as a 75 watt Tx using 15 dB gain Yagi antenna (5W x 15dB=75)? If yes, wow how great antannas!!!

If it was a 5W transmitter with a high gain antenna, maybe not.

Don't expect it to make a huge difference at the receiver in all cases. It will make more difference than the same gains on HF over a long distance however.

Remember the Yagi is also directive, not much help if you want 360degree coverage.

Is it legal in your country?

#### Willen

##### Well-Known Member
Why the duplicate post?

sorry, the browser was encountered during submitting the thread due to the network and I thought it is not posted. Then I reopened and posted again. There is no option to delete my own thread!

#### Willen

##### Well-Known Member
Is it really different type of shocking you are talking about?

#### Willen

##### Well-Known Member
Is it legal in your country?

It is really Legal to make. But illegal to transmit without license hehe

#### Nigel Goodwin

##### Super Moderator
Yes, a RF Burn is different than a "shock"

Yes, we used to have a guy who did aerials for us (he's sadly dead now) and he had a 'dead spot' on his arm about 2cm in diameter. It was caused working on radar in WWII, where he had to reach in to a machine (I'm not sure if it was transmitter, aerial, or what) to make adjustments. Doing this subjected your forearm to an RF burn in the same place every time, hence all the guys who did the job had the same burns.

#### Willen

##### Well-Known Member
OH MY GOD!!!

Such small spot might kill us??????

I thought antenna has no shocking capacity! Once I visited 10KW FM repeater station. I saw all the machines! If I got chance to climb to the tower (if tower manager would be my causin ) I would really touched the antenna (If nobody had rejected me). I thought I am jocking asking such question! How fool I am!

Small power is not harmful. How much minimum power (W) starts to shock? Is it current or voltage shocking? Can't visualize the RF Burns.

If I am 5 cm far from 10KW Tx's antenna, will it shock me too?

#### kubeek

##### Well-Known Member
A tiny 4mm bullet can kill you too. You can get infection into the wound an then bad things start to happen.

#### ronsimpson

##### Well-Known Member
RF (AC) is not like DC or low frequency 60hz. It conducts much better. I have worked with 100khz and it will bite you.

#### crutschow

##### Well-Known Member
You do not feel a shock from high frequency RF since it mainly travels over the surface of you body (like the current from a Tesla coil). But for high power RF the power density is so high where it enters the body at a small point that it will cause a burn. You can minimize the localized burn effect if you hold a piece of metal and let the RF enter your body through the larger area of the metal.

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