Distance from VHF radio to antenna

djpeters

Lieutenant Commander
Joined
Jun 9, 2010
Messages
1,824
Hi guys, I'm trial fitting everything in my boat before it gets painted. My question is how important is it to keep the VHF radio at least 3' from the antenna? Here is my dash.

10FC5F67-D87C-4573-88BF-1E8A2DD3899A-5581-0000056DEBF6E195.jpg


You can see where the antenna will mount on the gunnel. I am planning on the VHF radio and stereo head unit to hang under the dash. If I put the VHF left it leves no good place to hang the mic. Probably should follow the 3' rule? Any other helpful observations anyone has please let me know. Thanks.
 

djpeters

Lieutenant Commander
Joined
Jun 9, 2010
Messages
1,824
I'll bring this back up as i'll be getting to installing things here this summer.....

Would it be OK to put the VHF under the dash on the right, or is it too close to the antenna?

Thanks.
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
I do not know of any reason that the antenna has to be away from the radio except that the operator is usually located near the radio while operating it (Capt. Obvious!), and standing next to the antenna is generally not to be recommended.
That said, you will be listening to the radio 99.99% of the time and rarely transmitting, and only for very short periods.
In the last 3 years, my transmitter has been used less than 60 seconds.
Then, consider the location of the antenna relative to the transmitter in a hand held radio or your cell phone.

Is there the option to move the antenna farther back on the gunnel toward the stern, out of your line of sight?.
If Not, Go for what you plan!
 

JoLin

Vice Admiral
Joined
Aug 18, 2007
Messages
5,146
Believe that the '3 foot rule' applies to the minimum length of the antenna lead, not the physical distance between the antenna and VHF. Re-read your installation manual. I could be wrong but I think you're misinterpreting it.

My .02
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
Some Radio Installation Manuals just specify that the Radio needs to be 3 feet from the Antenna.
Other instructions elaborate on the reasons. See Page 12. Section 6.1 and 6.2 ... HERE.
 

waterinthefuel

Commander
Joined
Nov 15, 2003
Messages
2,726
I'm a licensed Ham radio operator. There is no real good reason to have the radio 3 feet physically from the antenna. My dad's bass boat is no more than 2 feet, as is my bass boat. It's not necessary. You only need a 3 foot lead between the radio and antenna. It's fine. Install the radio and enjoy it.
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
The reason stated by the radio's manufacturer, Standard Horizon, is in the link in post #5.
It has nothing to do with the antenna interfering with the radio itself.

This radio is restricted to occupational use, work related operations only, where the radio operator must have the knowledge to control the exposure conditions of its passengers and bystanders by maintaining the minimum separation distance of 3 feet (1m). Failure to observe these restrictions will result in exceeding the FCC RF Exposure limits.

The antenna must be located at least 3 feet (1m) from passengers to comply with the RF exposure requirement.
Choose a mounting location that is at least 3 feet (1m) away from the Radio?s Antenna.

It is assumed that If the Radio is within 3 feet of the Antenna, the Operator will also be within 3 feet of the Antenna.

All Licensed Amateur Radio operators are intimately aware of the requirements to install their equipment so that they will not exceed the Maximum Permissible Exposure (MPE) Level established by the FCC, to limit RF Exposure to themselves, and to others who may not be aware of the hazards. The standards have been in place since the 1990's.

Standard Horizon has already done the RF Safety Study for you, and determined that, at the Radios Maximum Power, and at the Frequencies used, 3 feet is a safe distance.
Touching the antenna while transmitting can produce nasty RF burns that do not heal. It is possible to "Cook" fingers in a few seconds with direct contact.
It all seems like innocent fun and games, until some one looses an Eye ... or Finger!

There is no reason to be afraid of the Antenna if you just respect it.
 
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