开云体育

Decided to test this SRH805S wide band antenna. They claim it covers 144/430/1200 MHz.
While the nano doesn't cover 1200 MHz, it does handle the lower two bands.

Clearly there is a problem as 144 MHz band is not showing any reasonable SWR.

By the way, my graph shows the SWR (left scale in red) and reflected power in percent (right scale in green).

As for the SRH805S, I must have gotten a bad one. One band missing!

Does it require a ground plane? I would put an SMA connector centered on a plate of PC clad card. Then feed the cable thru back to the VNA.

________________________________
From: [email protected] <[email protected]> on behalf of George <steber@...>
Sent: Thursday, July 11, 2019 7:12 PM
To: [email protected]
Subject: [nanovna-users] SRH508S Antenna SWR with NanoVNA

Decided to test this SRH805S wide band antenna. They claim it covers 144/430/1200 MHz.
While the nano doesn't cover 1200 MHz, it does handle the lower two bands.

Clearly there is a problem as 144 MHz band is not showing any reasonable SWR.

By the way, my graph shows the SWR (left scale in red) and reflected power in percent (right scale in green).

As for the SRH805S, I must have gotten a bad one. One band missing!

It was tested with a small ground plane. Tried other configurations too, but with only very small changes.

This antenna was bought on eBay for US$0.99 with free shipping. So it was probably a poor rip-off.
If someone just needs a 430 MHz band antenna it might work out.

Anyway, it's nice to know that the Nano worked well enough to find the missing band problem.

Makes you wonder how many people buy something like this and just plug it in expecting it to have been tested etc beforehand ... then damage thier TX.

Also perhaps 'Donate@ it to the world and take the duff one apart see what is really in one of them ... obviously nit just a dummy load as i suspected or you would have that nice big dip for 70cms

cheers

Tim M0THM