pmr antenna measurements

[concretesnail]

afternoon. ive tried the search function but had no successes but it might be that a im looking for the wrong term, i just dont know. 

 

what id liek to know are the measurements for making up an antenna for the pmr frequncies as id like to make up a flexible antenna to weave through molle loops. 

I already have a sma to bnc connector to use, so it coax and the lengths for the active and ground.

 

 

[Tommikka]

4 hours ago, concretesnail said:

afternoon. ive tried the search function but had no successes but it might be that a im looking for the wrong term, i just dont know. 

 

what id liek to know are the measurements for making up an antenna for the pmr frequncies as id like to make up a flexible antenna to weave through molle loops. 

I already have a sma to bnc connector to use, so it coax and the lengths for the active and ground.

 

 

Note that for legitimate PMR the antenna should be fixed and not replaced.

 

In doing so this can increase the power and enable the handset to work outside of PMR specifications.

 

You can however work on licenced handsets - which should be operated on licenced frequencies instead of PMR

[concretesnail]

I am aware that the baofeng radios are not pmr built spec radios. However the site I attend uses them and and gives permission, i just want to change how I carry it. as I have the parts to make an antenna, and the tools to do so, I am just looking for the measurements to do so rather than ripping apart perfectly functional antennas or having to purchase prebuilt units.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[The Waco Kid]

I think there is a hint above about not using them due to legality.
 

The site may or may not have a licence for a professional band and a different antenna may not comply with that either. They should not be in pmr frequencies.

 

You cannot transmit legally on PMR frequency with an output of more than  0.5 Watts. The antenna must be fixed. A license doesn’t change that.

 

You can get an amateur licence for specific non-pmr bands however.

Edited January 4, 2023 by The Waco Kid

[concretesnail]

i have already started the ofcom registration and process for amateur registration and will be looking to go down that path. For the time being i just wanted to find out the measurements for a whip style dipole antenna for the baofeng kit. I ask here as i thought that somebody may have done the maths or know the lengths already. 

[Emergencychimps]

The antenna that baofengs come with works on PMR frequencies, doing so even with a license and the power set to 0.5w still technically isn't legal with a baofeng. 

 

The standard antennas provided aren't bad actually and cover a lot of frequencies, probably wider than you'd need. 

 

Great that you're getting the license, if the site already has a license then you don't need an extra one unless you go somewhere else. The license gives you the permission to go up to 5.0w and use a bigger antenna etc on the specific frequencies that the license allows. It doesn't change what you're allowed to do on the PMR frequencies.

 

If you break these rules....well nothing is likely to happen unless you're very silly with it.  

[The Waco Kid]

I am sure there are people on here who have that information.

 

But there is probably a certain reticence due to the regulations and forum rules.

 

Like advising someone who asks how to “make am aeg shot 2j plz helpz”.

[concretesnail]

i apprecaite that some people may be reticent due to laws, but knowing how to break the law doesnt always mean you have broken it. Knowing hwo to make a bike do 200mph doesnt mean you will or have broken the law with it. I suppose there is an element of trust involved, trusting people to make up their own minds on what actions to take with any given information. 

[Tommikka]

6 hours ago, concretesnail said:

i apprecaite that some people may be reticent due to laws, but knowing how to break the law doesnt always mean you have broken it. Knowing hwo to make a bike do 200mph doesnt mean you will or have broken the law with it. I suppose there is an element of trust involved, trusting people to make up their own minds on what actions to take with any given information. 

On trust of course, once preceded by an intent to do what may be illegal then the education of theoretical skills turns its direction.

 

But you have covered the matter that you intend to be a licenced Baofeng user, and could therefore operate outside of the PMR restrictions.

 

I’d still veer towards just buying a Baofeng antenna which would be easier and cheaper than the parts to self assemble.

But as you have the parts then that’s of course in effect free, and can be a fun project and learning experience 

 

If you Google ‘baofeng antenna upgrade’ and/or ‘baofeng antenna length’ then you ought to find all the answers 

 

[mightyjebus]

PMR radios work in the 446Mhz range. Lambda length for 446Mhz is around 62cm however an antenna can be 1/4 lambda so around 15/16cm would work in theory. That's for the TX side for the receive side the longer the better is my experience (I once managed to talk to a ship anchored in Cyprus from Brize using the worlds longest slopping V HF antenna which was a bit of a surprise.).

The TX/RX will probably be shit to be honest as you are working with 0.5W output power so the range is always going to be a bit pants. factor in the site you play at having trees, buildings, etc then the range will drop significantly. 

Thinking into it a bit more the best chance would be to thread 16cm lengths up and down and across the full molle on a chestrig would in theory give you multiple 16cm antennas which might work better.