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Balun One Nine: cutting R1
Posted: Sat Sep 02, 2023 7:55 pm
by rjzastaury
I'm finally getting around to building a SULA. I have my Balun One Nine in hand, but I'm not clear on what cutting the R1 jumper/resistor entails. Can someone please tell me how exactly to do it? Pardon my ignorance...
Thanks,
Ron
Re: Balun One Nine: cutting R1
Posted: Mon Sep 04, 2023 9:44 am
by Egil - LA2PJ
It is done to obtain galvanic isolation between the antenna and radio.
See here:
https://swling.com/blog/2019/10/the-noo ... lun-19-v2/
73's
Egil - LA2PJ
Re: Balun One Nine: cutting R1
Posted: Mon Sep 04, 2023 4:24 pm
by rjzastaury
Thank you, Egil. I guess I should clarify my question: How do I physically cut the resistor? Score across it with a knife?
Re: Balun One Nine: cutting R1
Posted: Mon Sep 04, 2023 5:05 pm
by Egil - LA2PJ
Just scrape it off whith a knife... Carefully!
Good luck!
73's
Egil - LA2PJ
Re: Balun One Nine: cutting R1
Posted: Mon Sep 04, 2023 10:24 pm
by rjzastaury
Thanks!
Re: Balun One Nine: cutting R1
Posted: Tue Sep 05, 2023 12:00 pm
by Andrew (grayhat)
rjzastaury wrote: ↑Mon Sep 04, 2023 4:24 pm
Thank you, Egil. I guess I should clarify my question: How do I physically cut the resistor? Score across it with a knife?
see here
you just use a cutting blade to cut the circuit trace, then use a multimeter to check if the two sides are disconnected; to rejoin the connection, use a soldering iron and put a drop of tin to reconnect the sides
Re: Balun One Nine: cutting R1
Posted: Tue Sep 05, 2023 3:12 pm
by rjzastaury
Thanks, Andrew!
Re: Balun One Nine: cutting R1
Posted: Tue Sep 05, 2023 4:16 pm
by Andrew (grayhat)
notice that the V1 has the central tap, while the V2 doesn't so with the V2 there's nothing to cut
Re: Balun One Nine: cutting R1
Posted: Tue Sep 05, 2023 8:10 pm
by rjzastaury
It's the V2 that I have. How is it done for the V2?
Re: Balun One Nine: cutting R1
Posted: Tue Sep 05, 2023 8:20 pm
by rjzastaury
Do I scrape it here?