Avoid the SainSonic INF-661 Antenna

Feb 16, 2014
Europe, Czech Republic
Hi, just warning for others.

I recently bought the SainSonic INF-661 (36cm dual band antenna) for better performance of my Yaesu FT-65 HT. The antenna cost about USD 12 (incl. shipping).

I performed some test of this antenna using the KVE520 vector analyzer and the results were terrible. The antenna is complete crap. The SWR on 145MHz is 6,3 and on 438MHz it is even 12.5. On VHF, the antenna tunes a bit to SWR on 2.9 on VHF 152MHz and does not tune on UHF at all (all frequencies from 400 to 500MHz over SWR 10).

Don't buy this antenna, it is a complete crap, it will not work and you may burn your radio.


Apr 28, 2016
Making good contact?

Looking at Amazon, 20 out of 22 reviews are 5 stars.
Just to throw it out there, are you sure the connector on the bottom of the antenna is "deep" enough to make a good connection to the radio? SMA's can get funny about that. An SMA antenna for one brand won't quite mate right with another brand radio.
Aug 15, 2008
Sainsonic GREAT on VHF, not even close on UHF.

Tested 2 on a Bird SiteHawk and they tune <1.1:1 at 146 Mhz! However on UHF the lowest SWR was 3.5:1 at 435 Mhz and at 440 it was over 5:1 SWR!

You can cut them down at the top a bit and adjust them to the 150-160Mhz band for commercial or marine transmit use, but you will need to glue another end cap to the top.

Better VHF SWR than on genuine Nagoya NA771 antennas on VHF which had lowest SWR at 152 Mhz with a 1.3:1 SWR, but at least the Nagoya antennas had <2.0:1 at 440 Mhz while these are too high for transmit...

Wish they made these with SMA-Male connector for VHF marine and commercial portables...

(***Remember all VHF antennas are 1/4 wave on VHF so you need to hold the radio or meter when testing SWR to provide a ground plane on VHF, UHF is 1/2 Wave so no ground plane is required***)
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Feb 11, 2017
My general policy is that I don't buy anything ham related unless its listed in the eham reviews and has at least 4.5 stars with at least 10 reviewers.

I took a chance on a Signal Stuff Signal Stick, it had a 5 rating but only 6 reviews and it works great on my HT on both 2m and 440.