Big antenna on portable VHF

[ariesss]

Hello,

I have a big VHF antenna that goes on boat and I would like to plug it, with different adaptors on my COBRA VHF HH330 or 500. I only use it for reception, but is there a risk for the coax port or electronics components to have a big antenna like that ? The signal may be stronger !

Thank you,

 

[RFI-EMI-GUY]

It depends on the design of the portable and the specifications. If EIA/TIA603D specs you might be fine. Otherwise you may have signal overload when in port in some urban areas. If you hear NOAA weather bleeding in, that is probably what will happen.

 

[kb5udf]

Experiment at your own risk, but you should be fine in terms of damage, unless you are changing antenna connections on a portable radio often (you may wear out the connector). As RFI-EMI-GUY said, it is possible you will have receiver overload in some areas, but unless you have another radio transmitting high power very close (like under 5 feet) you will probably be fine. I would add another sign of overload is hearing vhf paging (been there done that) on a marine radio.

 

[RFI-EMI-GUY]

For the price of these radios, you would be better off with a good fixed marine radio, especially if you are wandering off coast, intentionally or not. Keep the portable for back up.

 

[mmckenna]

Hello,

I have a big VHF antenna that goes on boat and I would like to plug it, with different adaptors on my COBRA VHF HH330 or 500. I only use it for reception, but is there a risk for the coax port or electronics components to have a big antenna like that ? The signal may be stronger !

Thank you,

It's not going to damage the radio to connect it to a larger antenna.
The larger antenna will improve performance in most cases, but as noted above, strong adjacent signals can overload the receiver.

However, many do keep an adapter so they can hook up the radio in the even the larger radio fails. Cobra even has a webpage that shows you what parts you need to do it:

Connecting an External Antenna to Your Handheld Marine Radio

The following applies to the models listed below. Read further for other models. MR HH300 MR HH325 MR HH400 MR HH415 MR HH425 The antenna connector on your radio is a type “SMA female”. External antennas typically have a UHF connec...

support.cobra.com

An adapter cable like this would be what you would need:

https://www.amazon.com/Superbat-Adapter-Extension-Baofeng-Handheld/dp/B08BNQGTK9/ref=sr_1_3?crid=1JZLC5PWD5Y39&keywords=uhf%2Bfemale%2Bto%2Bsma%2Bfemale&qid=1698848496&sprefix=uhf%2Bfemale%2Bto%2Bsma%2Bfemale%2Caps%2C159&sr=8-3&th=1