Sainsonic INF-661 Dual band antenna
Price: 2 for £9 free postage
Manufacturer: Sainsonic
Model: INF-661
Band: UHF 2M / VHF 70cm
Gain: +2.15dBi
Max power: 10W
Connection: SMA female
Impedance: 50 ohms
S.W.R.: < 1.5
Type: 1/4 wave (144Mhz) 1/2 wave (430Mhz) whip antenna
Length: 36cm
Weight: 15g
Construction: Flexible alloy element
First impressions
It's no secret that I have owned this antenna for some time now, It has featured in a few antenna tests and comparisons but has never had a review of its own. There is a good reason for this which will be apparent in due course.
I originally bought this twin pack of INF-661 antennas back in July of 2016 from a seller over on Amazon. I can't remember the name of the seller now, it seems like ages ago.
Nevertheless I paid a little over £9 for the pair including the postage cost which at that time didn't seem too bad a deal.
They arrived in good time and packaged well, everything seemed OK.
Both the Baofeng GT-3MK2 and the GT-3TP MK3 radios ship with the rather fantastic Sainsonic INF-641 which for a stock antenna takes a lot of beating. The 641 does have its limitations though.
I was hoping the INF-661 with its extra length would boost RX/TX on the VHF 2M band where a shorter antenna would normally struggle a bit.
At the time I has the owner of a GT-3MK2 and as other owners will know, the GT-3 series of radios doesn't like antennas with a wide base. They just don't screw down properly.
This INF-661 was just an extended INF-641 really so should fit perfectly to the radio.
The INF-661 measures 39cms long and weighs virtually nothing.
The base coil housing is slim and identicle to the shorter 641.
INF-641 V INF-661
Differences:
INF-641 = 22cm
INF-661 = 39cm
Apart from the obvious length there is a few interesting differences between these two antennas.
First of all the construction.
Unlike the shorter 641, the 661 uses a stiffer piece of wire acting as the antenna. It's really flexible. Maybe too flexible. In fact it takes a fair few seconds for the 661 antenna to settle down and stay still after being moved. It sometimes pulls the radio over as a result of the excessive wackering about. It's bloody annoying to be honest.
The shorter stock 641 is so supple that it can be bent out of shape easily and return to its original position quickly and smoothly.
The longer 661 is likely to have someone's eye out if that were to twang back!
I'm really not sure why Sainsonic chose to use a different metal alloy?
Slight differences in the quality of the printed logo
The GT-3 stock 641 has a bright and vibrant orange logo whilst the longer 661 has a dull orange logo. What does that mean?
Well I think Sainsonic commissioned another company to make the after market INF-661 - Afterall Sainsonic are the designers behind the radios and not necessarily the manufacturer.
Were they made by the same company?
Testing
Having owned this antenna for 6 months now you'd think I would have thoroughly tested it. Well, you'd be wrong, in fact it has spent a good three months in the closet under the stairs.
To be fair it has been on a few trips to the hills and done some home testing so I think I can form a good enough opinion of it now.
Receiving
When it comes to recieving signals this antenna is no better than a stock antenna.
Listening to stations on the 2M band (VHF) was just as scratchy and fuzzy as when a shorter antenna is used.
Good reception on the VHF 2M band is what I bought this antenna for! It's woefully inadequate.
Whatever you do don't move the radio!, The signal comes in and out with every swish of the antenna moving back and forth - this eventually stops when the antenna comes to rest.
Using the INF-661 on UHF 70cm is again no better than the stock antenna. Unlike the slightly longer Nagoya NA-771, the Sainsonic 661 didn't boost the signals as I had hoped.
Where the 661 fails a bit on 70cm is when you move position - it seems very directal. You have to point it in one place. That doesn't happen with the likes of the INF-641 - the GT-3 stock antenna.
Transmitting
Signal reports from other stations have been few and far between. Through the local repeaters the feedback from other operators were mediocre. Certainly no better than my normal stock antenna.
This antenna has been tested radio to radio over a few miles and once again the results were nothing to write home about.
One good thing about the 661 is that it doesn't radiate heat to the base of the antenna. The spec sheet suggests that this antenna is rated up to 10W but you can't always trust the sales hype.
Running the antenna on the GT-3TP at 8W high power was fine. No heat was detected.
The packaging is not bad.
I just don't like it one bit. pity.
What did i do with the other one?
The INF-661 came as a twin pack. The other antenna was chopped down to a more reasonable length (17cm or so) to work on UHF 70cm. This resulted in a total disaster. The new trimmed up 661 was worse than ever. Hissing away like a cage full of vipers. Utter crap.
Suffice to say it found its way to the bin rather quickly.
The rather sexy Sainsonic GT-3TP radio
Designed by sainsburys more like
Rating: ✅✅ 2 out of 5
Those who buy this in the hope it will improve VHF 2M operation will be sorely disappointed.
In a word the INF-661 is shite and offers no improvement over the much shorter and flexible Sainsonic INF-641 or Nagoya NA-701 which are much better antennas. I wouldn't bother.