RADIO HAM: Antenna Autopsy NAGOYA MAG-77-EL teardown and repair.
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- Опубликовано: 29 янв 2023
- After having a High VSWR on my Car antenna last week (other Ham's reported that my signal was down against my normal report) I removed the antenna and replaced it with a new one. This week I want to know what was/is wrong with the old antenna and can I fix it? So in this upload I teardown the antenna to take a look. Antenna Autopsy
Last weeks video: • HAM RADIO: High VSWR o...
Hey why not look it up and see for yourself I'm not an expert on these matters just a guy that is giving it a go and sharing my experiences.
Hope you enjoy...
Just for fun
Please subscribe and like.
Cheers
Mike - M0MSN
P.S. do not take my word for it, give it a go for yourself. 
Развлечения
Always nice to see someone repairing stuff rather that throwing it in the bin and buying new, Top Man !!!
Thanks Keith.😊
Keep up the great work MIKE and get better soon.
Thanks 😊
Thanks for the video, an I hope you're feeling much better soon Mike.
Thanks John
Nice one Mike. Good to see you back in action. Get well soon.
Cheers Paul, how is Exmouth?
Thank you . Really like these technically stimulating mind boggling videos.
Seriously, I like the "why and how" rather than "because".
Thank you.
Get well soon. Thanks for the video 👍
Thanks Ady
I sure hope you bounce back quickly. thanks for the video.
Thanks🍌🍌
This going to be splendid sir
👍🍌🍌
Red is usually the permanent thread locker in the US. But applied on a dirty surface, it won't be. All of them also break down when heated, that's how you get permanent thread locker to let go.
Thanks
I was wondering about the connection to the shield until you mentioned tank circuits. Enjoyed the video. Get well soon.
Thanks Vinnie.
Nice to see a decent radio back in the motor Mike :)
Thanks Dan, well it had to happen.🤪
I wish the best recovery to you.
Thank you
Hope you get over the covid soon Mike, glad to see you got the antenna fixed. Some heatshrink or spray paint should tidy it up.
Hi Mark, no it’s a work of art… 🤣
You sound like you have been hit hard with Covid. A great video, above and beyond the call of the duty; really interesting to see what went wrong with the antenna and how they are constructed.
I hope you and your family are better soon. Best 73
Thank you.
get well soon Mike!!!
Thanks
Great job Mike. You seem to do your best work when you are under the weather. hihi. Hope your feeling better. 73 Joe
It the only time I get away from work..🤧🤧😂😂
Get well soon Mike
Thanks
I have a Chinesium Diamond SG2700 with similar issues and I recalled this video and it inspired me to have a go. It's similar to yours - in my case there is only one capacitor and it's short circuit to DC which is a bad sign! 😀. Trouble is there is no markings and so no idea what the value is, so will have to do some experiments I guess...
Hi Mike sorry to hear you are struck with the covid, get well soon mate. Really interesting looking inside the antenna , I had no idea you could take them apart like that. Yep it's pain trying to open things treated with thread lock, I find adding a little heat helps but I guess you had to consider plastic moulting. really enjoyed the video.
Hi John, tested positive Friday evening so still got a day or two… hope you had fun in /A.
hope you get better soon!!!
Thanks
Colinear antennas are multiple stacked antennas separated with a coil and good use of a stub for a capacitor a lot more robust good to a FM repeater still in operation in the background
Hope your on the mend soon great couple of vids, simple repair also , and we thought you were just full of Jack Daniels lol 😆
😂😂🤪👍
Good job, though the threaded joint looked like liquid ptfe as opposed to loctite for future ref, which make sense to me preventing a Capillary action of rainwater
Well spotted, I never thought of that :)
Hope you feel better soon.
Thanks
As i sayd, fix it! you did, splendid Mike!
73 LB8LG Svein
Glad you got it sorted. I'll send you a good strap wrench for Christmas.
A strap wrench, that a great idea 👍👍🍌🍌
Very nice! It's not every day an autopsy results in the revivification of the 'patient'. It's like Frankenstein's Antenna. Cheers! 🙂
IT’S ALIVE..😂😂
@@mike-M0MSN 🤣
👏👏👏👏👏👏👏
I checked the SWR on my Diamond NR770HB last week and it was in the red. Started to go through the diagnostic process. With a different antenna on the boot mount the SWR is low. Put the diamond antenna on the roof on a magmount , SWR is low. Checked all connections and all are ok. Don’t know if water has got into the antenna which has been on the car for a few years. My set up is very similar to yours in the video on your car.
Get well soon Mike 👍🏻 Thanks for the post-mortem! I wonder if the cause (if not that cap solder) was the inner copper tip? Looked grubby when you pulled it out of the housing.
Hi Ian, Both good possibilities, shame I mashed the housing..
Stay hydrated and get some rest, Covid is no joke...
Old bicycle inner tubes make great grips for spannering stuff like that, just clean the talc off first.
Another great idea 👍👍👍
@Mike-M0MSN Old leather belt sections make for some pretty good grips, too. Get well soon.
thank you
No thank you.
@@mike-M0MSN now i might dive into a couple of11meter antenas and see why they perform not at all
Hope you get to feeling better soon. Wife and I both had covid a bit over a month ago.
Mike KC5UEA
On the mend now cheers
Hi Mike your antenna looks electrically similar to the NL-770R
( which is on the fundamental band a ,[ Voltage Feed Centre Loaded 1/2 Wave Vertical ] )
Antenna feed using this method is ideal for operation where the ground isn't optimal ( for example on a mag mount )
Being presently under £20 each, ( even thou twice the length of my present antenna) I intend to try out one on my Truck :-)
de John (: licensee G4XJC )
You and Callum clearly went to the same school of brutism. I've got a know-it-all on the internet without actually having done it, hunch, that a bit of bike innertube would have given the required purchase without the burr. Maybe. Was it THAT tight? Really cool you revived it though - that's the bit that matters. Good job.
So here is the funny thing, before I turned the camera on I had the antenna in a plastic rubberised sleeve and it just would not come undone, I also tried a leather strap wrench, nope no movement. I was about to give up and simply trash it. Then I said to myself if I’m going to bin it why not just use metal to metal and open it, guess what it started to move and the rest is on RUclips. Sometimes the only way is brute force and yes it was that tight! The things we do or show on YT are sometimes/most of the time only a fraction of the process. Thanks for the comment BTW Callum was 3 years ahead of me, we had torque wrenches. 😂😂👍
Nice job Mike now that's a good name for a ham, just a thought though, I think I would have thrown a coat of paint on the bottom section all the same but I assume you're all over that in time? Good video keep up the good work it is appreciated.
Dave vk3aif
Cheers Dave.
the reason why the coil is soldered to the "shield" side is for DC grounding. that's why there's the 2 caps there across the center and ground and is also the reason why the first 3 turns are shorted
Ok interesting, please expand.👍👍
I’m sure that a capacitor would ground AC, but it would be a DC block !!
@@Cardassiaprime other way around. it blocks ac but lets dc through
A nube cuestion: On the long antenna bit there is also a ”spring”-sort-of-looking feature. Is that mainly there as a way of making the antenna more flexible/bendable, or does it have any influence on the transmitted radio signal as well?
A 5/8 wave requires a matching coil at the bottom, there may also be something like a coil in the middle of the antenna, this may be a loading coil ( to shorten the height) or a phasing coil to allow for a secondary radiator..
Vy gud job! 73, Mauri Iz2mgn
Thanks
Urban legends say it was shoddy solder joints that sunk the Titanic. And I hear on the grapevine that Noah used sub standard flux core solder on the ark wiring. It seems a common fault.
😂😂
Hope you get better soon, it's only been this later stage of catching it and I've had worse man flu TBH, aha.
I've seen a dual bander on ebay for around £10, do you recommend these?
Sorry didn't see they have a letter after each model; the cheaper one was a 770.
I have the 770 as my standby, watch out for copies the Nagoya Mag-77-el as around £38.
Mike I stripped a 770 down today thinking the same as you top of coil interference fit, it’s not your supposed to disassemble from top it’s soldered 👍 under the piece above the black Tony G7ETT I would assume yours the same😮
Oh ok, I will have to look at this again, how did you get pass the lift and fold mechanism?
@@mike-M0MSN the hinge is an Allen grub screw,fold it over and undo pre loaded spring from below, the brass passes through the plastic with a m10x1 thread out the other side good luck 🤞
I’ve sent you pic on qrz😊
@@tonymoore6395 it’s not quite the same, but fixed now thanks. Ps no video doh 🙄
Great fix! Maybe paint it black to look better and to stop rust if it's steel.👍
It’s chrome plated brass, I kinda like the warn look…🤪
@@mike-M0MSN ah ok, nice. My old eyes couldn't tell on my small phone screen.🥸👍
Can you put a link as to where this antenna is sold?
Most suppliers however I purchased this one from ML&S
In the future use rubber gloves under the grips to get a cleaner finish
Thanks for the tip👍
First
First Reply! Feel better Mike. Thanks for the vid!
🤣
Eighth
Lol 😂
Thanks for this video. I use the Diamond NR 770 H which probably is about the same build. On 2m it gives me a SWR of 1. On 70cm I only get an SWR of 1.6. But in your video I can’t see what your specific problem was and you don’t really show what you fixed. Please be a bit more precise before I crack my Diamond NR770 open.
I will try, the issue was the bottom capacitor had become unsoldered, BTW 1.6 is perfectly good you do not need to adjust it. Cheers
I woulda used a wire wheel to smooth the base instead of grinding it 😖
It was emory cloth/ glass paper.