25W transmitter nearby; overload concern

[sgnlsekr]

My setup is a discone on the roof, feeding into a unity gain drop amp, then a line going to my SDS200. I want to add a 25W UHF transmitting antenna on the roof. It would only be about 30 feet away from the discone. Will it likely cause any damage to the scanner or the amp?

 

[mmckenna]

My setup is a discone on the roof, feeding into a unity gain drop amp, then a line going to my SDS200. I want to add a 25W UHF transmitting antenna on the roof. It would only be about 30 feet away from the discone. Will it likely cause any damage to the scanner or the amp?

Probably not. Depends on your antenna on the UHF side, though. If you are running a high gain yagi and it's pointed right at your discone, you'd want to test things. But if it's just an omni and with 25' spacing, you'll be fine.

Mobile, I used to run a ham dual band and a separate UHF commercial radio for GMRS. With a few feet spacing, it was just fine. Your discone has zero gain and there will be more loss in the feed line.

 

[sgnlsekr]

Probably not. Depends on your antenna on the UHF side, though. If you are running a high gain yagi and it's pointed right at your discone, you'd want to test things. But if it's just an omni and with 25' spacing, you'll be fine.

Mobile, I used to run a ham dual band and a separate UHF commercial radio for GMRS. With a few feet spacing, it was just fine. Your discone has zero gain and there will be more loss in the feed line.

The UHF antenna will probably be a 5db GMRS Ed Fong antenna. I'm optimistic that nothing will be affected. Thanks for the input as always!

 

[KevinC]

Put a 50 ohm load terminated wattmeter on the end of the discone coax, then key up the transmitter and see what it shows.

 

[prcguy]

I calculate close to 1mw off the receive Discone with 25w into a 0dB gain antenna 30ft away at 462MHz. That will not hurt anything but will overload the drop amp and scanner and interrupt reception.

 

[sgnlsekr]

Put a 50 ohm load terminated wattmeter on the end of the discone coax, then key up the transmitter and see what it shows.

I don't have access to one. The only test equip. I have is a nano-VNA.