IMPROVED MINI 9:1 UNUN - When ON-AIR testing gets wrong due to Geomagnetic Storm
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- Опубликовано: 28 июл 2024
- I was measuring and testing my newly improved Mini 9:1 UnUn transformer for the EndFed Random Wire antenna. (www.sk-tech.sk/om0et/mini-9-1-...) In this transformer I have used much thicker wire (1mm) and 8 trifilar turns instead of 5 trifilar turns in my previous version. The SWR measurement was done with MINI 1300 Antenna Analyzer. I've used approx. 16,2m (53ft) long radiator wire and about 17m (56ft) long counterpoise wire. Radiator wire still need's to do a lenght adjustments due to very high SWR on some bands and low SWR peaks located out of the bands.I wanted to do an ON-AIR test, but radio propagations was deeply degraded by running Geomagnetic storm (my wrong timing). I found just 2-3 stations on 20m and some more strong stations on 40m. 80m was still attenuated due to early time. Unfortunately just started raining... :-) I hope for better conditions in the next time ;-) Thank you for watching this video and 73! Paul OM0ET.
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Track: Missing Piece - Broke in Summer [Audio Library Release]
Music provided by Audio Library PlusWatch: • Missing Piece - Broke ... Free Download / Stream: alplus.io/missing-piece
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#mini91UNUNEndFedAntenna #MINI1300AntennaAnalyzer #XIEGUX5105 
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I really like this series of videos. They explain how and why you do things and like that contacts don't always happen, it's real life. Too many videos only show when things go right. More like this please!
Thank you for your multiple nice comments! :) Thank you for your interest an support! :) I am glad that you watched my videos. Have a nice day and 73! Paul.
Your not kidding the bands on Monday were absolutely awful. Even on 15 megs I heard 2 shortwave stations and that was Radio Havana Cuba and and the station down in Florida WRMI....great job and great video...Fred VE3FAL
Hey Fred! Thanks! 👋😊 Yes K-index 4 and SSN 0, I guess I've choosed bad timing 😄 Hope the propagations will improve with the new solar cycle and begin the heaven for us - QRP'rs ☺ 73! Paul.
Great job and great video. Thank you. I hope to hear from you when conditions improve!
73 de 9A3GVD
Thanks! I hope so too 😉 Maybe on 80 or 40m we should 👍 73, Paul.
hello Paul, you are number one . your videos are very very clear and very informative.
Thanks for the nice comment Antonio! :) 73
Try, EFHW 49:1, I love these antennas, I think they're much more efficient too. No need for radials and tuners on the resonant bands.
Propagation is not that bad, I regularly make SSB contacts to North and South America from Ireland with the FT-891 and Chameleon MPAS 2.0 on 20 Meters in the Evenings UTC.
I Enjoying making contacts too on Olivia and PSK31.
Thanks. Yes I plan to try the EFHF 49:1 too and make the video about that ;) This 3 days is minor geomagnetic storm, that's the reason why is the band so flat. Hope that it will improve soon :) 73, Paul.
I just noticed it. If you measure SWR with e.g. a Nano VNA with 1 m cable then e.g. Xiegu G90 through a 20 m cable. These results are quite varied. I suspect that the SWR measurement in Xiegu devices is quite approximate, are there any phenomena in the cable? What do you think? Regards, Marek SP2CG
I cut my long wire to 42.2535 m (138ft.71/2"). That way it is resonant on 3.550 / 7.1 /14.2/ 28.4. The impedance is going to be in the range of 2,450 Ohms +/- a few ohms, so a 49:1 transformer is the ideal way to go. A T240-31 ferrite core is suitable, if you want to use 160m. Use one, two or even three toroids if you are licenced for 1.5KW or, if you are Italian, 20KW.
The transformer will be quite flat (1:1.1) until 12m, then a gentle rise to 1:1.8 at 10m should be expected. You are going to need an ATU for 6m and 4m, especially, but this is expecting a lot from a tuner, so a dedicated antenna for 6m and 4m ought to be used.
Neat design.
Thanks! 😁
Myslím si, že také merania SWR sú nespoľahlivé.
Možno meranie pomocou merača intenzity poľa umiestneného v blízkosti alebo počúvanie blízkej WebSDR by umožnilo lepšie hodnotenie antén.
Obdivujem vaše experimenty a srdečne vás pozdravujem, Paul. 73 SP2CG
Out of interest hat sort of charger do you use for your Xeigu?
I use modified old small lead-acid charger with 13.8V output voltage or my 13.8/30A desk DC power supply.
@@OM0ET Thanks
Ho there, I thought that you needed to calibrate everytime you changed frequency? 73s Kev
hello i like this video please make a test whith an END FEED antenna in QRP mode is very good 73 from Argentina LW4DKI
Bought the mini 1300. It sucked. Got the exact same reading on every band with every antenna whether it was a HT whip or 66’ EFHW.
Your analyzer must be calibrated.
@@OM0ET how many times? More specifically, how many times following the directions to the letter? Picked up a smaller nanoVNA-works perfectly
You don't have to cut the wire, you can fold it back on itself!
Yes Rubbish today I was testing Home brew efhw & 49:1 but not much luck...better luck to us both in the near future ! 73
Yes, but on the other side, would be boring if the propagations was just great every day 😄 is it not? I am sure that better times are waiting for us 😉👍 73 and good luck! Paul.
Never tune on the occupied frequency
❤🤛🏾👍🏾👌🏾😎
Bring a piece of cedar shingle n let it smolder near you, will keep those nasty little buggers away KC3ONO
Good to know Kevin ;) Thanks for advice!
Life is to short for QRP, particularly with rubish antennas.....
Variety is the spice of life. ;-)