Pre-tuned vs DIY antenna

[Defender92]

Hey guys, I’m new to radios. Sorry if this is a dumb question. I’m in the process of building my base station. I’m good there. Got a Comet CA-712EFC antenna, LMR400 coax and a Kenwood to-8180 30 watt. I’m getting around 1.2 - 1.4 SWR. 

I just ordered a couple used tk-8180h 45 watt radios on eBay. I want to put one in my jeep and another in my electric Cushman cart (for shits and giggles). 

My question is now that I have an SWR meter I’m thinking about getting a generic antenna for my vehicles and tuning myself. I’d prefer stainless for corrosion resistance. By tuning my own antenna and using stainless am I losing much? Versus getting a pre-tuned GMRS antenna?? 
 

thanks,

Brad

 

also, at the end of the day is it just getting a good SWR reading or is there more? 

[OffRoaderX]

12 minutes ago, Defender92 said:

By tuning my own antenna and using stainless am I losing much? Versus getting a pre-tuned GMRS antenna?? 

also, at the end of the day is it just getting a good SWR reading or is there more? 

No. As long as you do it right/dont screw it up, you lose nothing.. 

The SWR is a good indicator to let you know there are no shorts in your coax/connectors and the antenna is not way out of tune - but yes there is more:  Does it actually work?.. and the answer is probably yes...  

You are already WAY over-thinking all of this. Just install everything, double-check with your SWR meter, then go enjoy your radios.  

[SteveShannon]

5 minutes ago, Defender92 said:

Hey guys, I’m new to radios. Sorry if this is a dumb question. I’m in the process of building my base station. I’m good there. Got a Comet CA-712EFC antenna, LMR400 coax and a Kenwood to-8180 30 watt. I’m getting around 1.2 - 1.4 SWR. 

I just ordered a couple used tk-8180h 45 watt radios on eBay. I want to put one in my jeep and another in my electric Cushman cart (for shits and giggles). 

My question is now that I have an SWR meter I’m thinking about getting a generic antenna for my vehicles and tuning myself. I’d prefer stainless for corrosion resistance. By tuning my own antenna and using stainless am I losing much? Versus getting a pre-tuned GMRS antenna?? 
 

thanks,

Brad

 

also, at the end of the day is it just getting a good SWR reading or is there more? 

Hi Brad,

Antennas are much more than simply a good SWR reading. A dummy load will provide nearly perfect SWR while emitting very little RF.

All antennas have gain, which is a concentration of the emitted RF in a particular pattern, expressed in dBi or dBd.  
If you have time, knowledge, and the right tools it’s possible to make and tune an antenna to perform as well as a commercial antenna.  I wouldn’t advise it for someone who’s eager to get on the air though.  And if your time is valuable it’s unlikely you’ll save money. Most antenna are already made of materials unlikely to corrode although sometimes manufacturers screw up and use set screws that are not stainless.

[Defender92]

Thanks for the responses guys. I think now it is just easier to buy one. I might try to tune one eventually just to get the experience. Looks like there are a couple with good reviews on Amazon. 

[SteveShannon]

41 minutes ago, Defender92 said:

Thanks for the responses guys. I think now it is just easier to buy one. I might try to tune one eventually just to get the experience. Looks like there are a couple with good reviews on Amazon. 

I like making my own wire antennas for ham radio and I have an antenna analyzer and a nanoVNA which both help with tuning (interchangeably-you don’t need both). It’s one of the more rewarding aspects of amateur radio, and tuning an antenna that is designed to cover the range of frequencies to a specific frequency such as for GMRS is straightforward, but there’s a learning curve for the process and the tools. Like many hobby projects it can be very frustrating if you don’t have a mentor close by. 

[WRYZ926]

I would buy a pre tuned antenna if just starting out in radio. It will be much simpler and easier for you.

A good antenna analyzer or NanoVNA is a must if you are going to properly tune any antenna. 

There are plenty of free online calculators and phone apps for figuring out the lengths of different types of antennas.

A friend has a big roll of solid core 75 ohm cable that he uses for making 2m, 70cm, and GMRS j pole antennas. It's not difficult with knowledge and the proper tools to include analyzers/NanoVNAs. I will say that there is a bit of a learning curve with a NanoVNA. A good antenna analyzer won't be cheap.

I have made a few wire antennas for the HF amateur bands but I could not have done it without an analyzer or NanaVNA.