MFJ-949E Arcing!

A clip of my MFJ-949E arcing with 70w into a bad antenna at 1850KHz. It flashes on and off because when the radio detects a high vswr, it cuts the power, so the flashes are not continuous. This tuner is fine with normal tuning, but this antenna is way too small for 160m :)

Category:

Science & Technology

Tags:

• MFJ
• MFJ-949E
• Tuner
• ATU
• Antenna
• Unit
• Matching
• Doublet
• Topband
• Arc
• Arcing
• Flashover
• Amatuer
• Radio
• Ham
• M0UKD

[TheZeke1974]

I have a 949E as well as a 941, tuner and they both work great!! I think the reason a lot of hams down the MFJ tuners is because they try to load up antennas for frequencys they are not tuned for. I.e. trying to tune a 40 meter dipole on 160 meters, lol. Heck it even says in the manual not to tune an antenna that is way out of resonance on a frequency the antenna isnt tuned for.,

[sparkie21]

@TheZeke1974 Hi. I think the 949 is a great tuner. Here, it's trying to match an antenna that's possibly 5kΩ to 50Ω! Cant blame it. I just took the video. I was not suggesting the tuners are rubbish. I have 4 MFJ tuners and I am happy with them all ;)

73

[sonick808]

is that bad for your finals ?

[sparkie21]

@sonick808 I should think so

[K9FON]

Try lenthening the antenna. Thats the reason your tuner is sparking. The tuner can only do so much. Your antenna is only 66 feet long and you are trying to use it on 1850. The antenna needs to be at least 250' long. A lot of people bash MFJ stuff, but they use the tuners on antennas that are way to short and expect them to work, then blame the tuner.

[sparkie21]

@K9FON - I wasnt blaming the tuner. In the description I do say "a bad antenna".

I think the tuner is great I have no problems with it. Thanks!

[petchharrison]

THAT WILL WRECK THE CAPACITOR PLATES NOT THE BEST THING TO DO.

JEFF... 66 FT THAT WONT LOAD A UP ON MW FULL STOP...

[grant2053]

Lol looks like your antenna has turned into a dead short XD Good luck with fixing it.

I also have the 949E and i also this is a great tuner

73 KF5CNU

[uploadJ]

Cool ...

[kaboooom2000uk]

the trouble is the air gap spacings are just too small on the caps.

At resonance the Q is so high that there may be over 5000V on the caps. Very common problem on most ATUs. I mostly use homemade PI's but still is noticeable.

nice to see somones filmed it.