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VHF / UHF Antennas with an SWR of 1.8 or less (1 reply)

M0OER
12 months ago
M0OER 12 months ago

Hi All,

Thought I would highlight a possible issue with the some of the VHF / UHF antennas out there as optional extras for hand held radios.

The SainSonic INF-661 36cm 144Mhz & 430Mhz optional antenna for the Baofeng series radios for example, quotes an SWR of 1.8 or less.

However the Baofeng hand held radios, such as the GT3 Mark 3 Tri Power (1/4/8 W) state in the included instruction / user manual (page 2) that and antenna with an SWR of 1.5:1 or less should be used, to prevent damage to the power amplifier final stage transistors.

This advice in the Baofeng GT3 Mark 3 Tri Power instruction / user manual therefore concurs with the general advice in the RSGB 'Advance' Manual (page 73) which states '...for transistors the maximum SWR is about 1.5:1.

I have concluded from this information that using an optional antenna such as the SainSonic INF-661 which states its SWR as less than 1.8, may cause damage to the radios that it is supposedly recommended for use with, such as the Baofeng GT3 Mark 3 Tri Power.

However having said that, I have used the SainSonic INF-661 optional antenna with the Baofeng GT3 Mark 3 Tri Power radios, so far without causing any noticeable damage to the radios power amplifier.

To be on the safe side though, it is probably best to stick to an antenna with an SWR of less than 1.5:1 - as per the Baofeng instruction / user manual (albeit in very small type admittedly!) and RSGB 'Advance' Licence Manual.

If anyone has any user experience with extended use of antennas with an SWR of 1.8 or less with hand held radios, please let me know...?

Paul M0XMT
12 months ago
Paul M0XMT 12 months ago

I'd take the advice in the instructions with a pinch of salt. 1.5 is 4% reflected and 1.8 is 8.2%. I'd say anything under 2 is fine and to be honest wandering about with it in your hand will probably send it all over the place anyway. Plus Baofengs are plentiful shall we say.....

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