Swapping ELT's; need antenna help

This is on my '41 Interstate Cadet, a tube & fabric plane that has an internally mounted ELT antenna.

I'm replacing my ELT (Artex 110-4) with an Ameri-king 450, a 121.5 model that uses the Duracells rather than the $89 battery pack that the Artex uses.

Anyway, the instructions for the new one say using anyone else's antenna is not recommended, but when I called the company the tech guy said it would work.

The existing antenna is almost inaccessible; replacement would be very difficult and time consuming.

Now for the question: How can I check the old antenna to verify it would work with the new ELT?

I have a friend who has an SWR meter. Can we use that to compare the 2 antennas? If not, how can we compare the old and new antennas? Do I have to mount the new antenna on the ground plane just to be able to test it? If so, there is no point in trying to use the old antenna.

Yes, I know there are those who advocate the newer ELT's, but I just putt putt around the valley and I can take a PLB with me in the plane or out in the woods.

Thanks for your help.

To verify the current antenna to be compatible with your elt, you would need information regarding this antenna... It's frequency range and Impedance...
Since it is an Antenna that was already used for an ELT, I would say the guy is right to tell you that it will work because those parameters should be the same!
Also, you can do an activation test to make sure that your system work... I don't know how it works at your place, but over here, you can activate your ELT during the 5 first minutes of every hour and make sure you hear your own ELT alarm on your radio or a friend's radio when you do it...

You could also use the SWR meter to test the percentage of power your antenna is forwarding and how much it is reflecting back in the transmitter, but again, to do the test you would need to activate the ELT....

CMBAero said:

.....
You could also use the SWR meter to test the percentage of power your antenna is forwarding and how much it is reflecting back in the transmitter, but again, to do the test you would need to activate the ELT....

Click to expand...

Or just use the SWR meter and transmit on a close to 121.5 frequency.

It will be accurate enough to determine that the antena is really connected to the cable...

az_gila said:

Or just use the SWR meter and transmit on a close to 121.5 frequency.

It will be accurate enough to determine that the antena is really connected to the cable...

Click to expand...

Yepp! Sounds easier!
Now, whyyy dind't I think about that one... looll

Thanks Gil!