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Allowable SWR for Midland MXT400


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#1 RickW

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Posted 04 September 2018 - 03:49 PM

Our family recently purchased a couple of Midland MXT400's. I am trying them out using my GP-9 dual band antenna, but of course the SWR is very high (2.5:1) since it is far from the design frequency. The heat sinks don't get very warm with say a minute or so key down at high power setting, but I wonder if anyone has run this type of rig and damaged the finals at these SWR levels.

 

Although I recently joined the group, I have been reading the mail for the past year or so and I know that there are some very accomplished technical experts here with a lot of practical experience.

 

Thanks for any help or suggestions.

 

Rick W



#2 Elkhunter521

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Posted 04 September 2018 - 04:39 PM

The price of a Mid XMT400 ($200) vrs the price of a proper antenna ($35) I would not deal with it. Browning/ Tram 1170 (magnetic mount) or BR450 (nmo ) mount either one will come ain at 1.2 or less (swr) after trimming to the supplied chart.

Why not just get the right antenna to star with.

The aradio is just a power supply for an antenna.
Be vewy vewy quiet.
I'm listening to my wadio!

#3 WRAK968

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Posted 04 September 2018 - 07:28 PM

After blowing finals on a yaesu 7900 due to an improper ground on a magnetic antenna that sent SWR through the roof, I became very strict about what my SWR was. I test and retest until I get down to about 1.5 or less. Currently all my radios, ham and GMRS, run about 1.05-1.2:1. I am ok with 1.5 but I always feel it can be tweaked that little bit to get better results.

2.5:1 is not very good and is close to infinite [3.0:1 and above] which WILL damage your radio very quickly.



#4 JohnE

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Posted 05 September 2018 - 07:22 AM

as a general rule 10% (2:1) is the pass/fail. most antennas will be ~1.5:1 but you would have to check the manufactures spec there are quite a few 2:1 specs out there.


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