K3MRI

This was AI’s response. 

Hi Tim.
Great question.
Impedance is always the name of the game. Any two feed lines, no matter their type, can be connected in series if their impedance matches. In your case, both are 50 ohms so you're absolutely fine. Where you will have a problem, not really a problem but a slight impact, is in loss. If we use 10 Mhz, RG-8X will have 1 db loss per 100-feet. Your 213 will only have 0.6 db loss (obviously, the higher the frequency, the greater the loss). Another issue is always the connector. Connectors are weak points in so many ways. Make sure that if you connection is intended to be permanent, you choose the best possible connectors and properly grease them and protect them from water/humidity. Of course, try to keep the number of connectors to a minimum. An approximate loss for most barrel-type connectors is approximately 0.5 db, so if you introduce two connectors, for example, you're losing an additional 1.0 db. Depending on the frequency, that can hurt.
Because you asked, let me give you a slightly more in-depth answer as regards any type of connection, including two coax cables. There is something called PIM - Passive Intermodulation. You really do not need to worry about it in HF frequencies. It only becomes an issue in very very high frequencies such as EHF/SHF or LTE, HSPA and CDMA cellular networks. Again, not your concern, but the reality is that any connection introduces a slight signal distortion. The higher the frequency, the greater the consequence.
Finally, make sure you choose a 'good' connector. Remember, if it's a permanent installation, it does not have to be the same as your other connectors. If you tend to use the 259/239 combo, you can still use N-connectors for this particular junction. Also, you have metals options to think about. But connectors were not your question so we'll stick to coax for now 😁
I hope this was helpful and maybe another Elmer will weigh in with their better answer 😇
Jim
 

Hi Tim.
I'm running out the door so I'll give you the really short answer: bad idea. Why? Simply because there is a golden rule with ladder line, keep it away from anything conductive. Most will give you a formula of two times the width. In other words, keep any conductive element, yes, even carbon fiber 🤫 away. My father had a far better rule, nothing metal parallel to the line at arms length. He was a physicist and engineer so his explanation was very lengthy, and if you'd like, I might bore you with it later. For now, as I run out the door, just don't do it. Find another solution. 

So, that's also a really good question and one which other Elmers might answer better, but I'll give it a shot.
First of all, a coiled choke has a purpose, to reduce common-mode current that may bring RF into the shack. As such, in all cases, you would rather have the choke nearer to the tuner than to the connection. Secondly, I will point you to an interesting, albeit technical paper on chokes: 
I will add that you should only use a choke if you experience noise - generally speaking. One reason is a loss of power through heat. When he common mode signal hits the choke and creates a magnetic flux inside, lots of energy is lost (hysteresis and perhaps other effects) as heat. You're reducing energy.
Another thing to consider is whether or not there is a likelihood of common mode noise in your environment. Bad full-bridge power inverters can be one source. Grounding issues are another.
If I were you, I would avoid the choke initially, you can always wind the coax later.
Let's see how many disagree with me? 😎

Hi Larry. Sorry I took so long to reply, this one slipped through.
These DIN plugs, I've used them for years having grown up in Europe where they were the absolute norm for decades, are hard to come by in 90-degree angles. I spent a little while looking for properly wired DIN plugs online, as you must've, and could not find any. However, and this is a long stretch, if you're willing to take the time to look for 'MIDI' plugs/cables, you may find a solution. The problem with out of the box MIDI cables is their pin wiring; it's different than the Yaesu ones. But with a little creativity, and even a custom job at a music store, you might be able to get a wire cut precisely. I had the same problem with my 891 when I had the FC-30 (which I then sold).
Hope this helps, albeit late...

The common mode choke on the antenna feedline will help the radio, not the LED. To be effective, you have to put chokes on the LED side, which you can't because it's all hidden wiring.
Just to do a final debug, do the LED bulbs go off if they are installed in a socket that is not controlled by a dimmer? Let's just make sure it is not the bulbs (90% sure it's not). As for a really good explanation of chokes on the 'appliance' side, vs. the radio side, https://www.coilcraft.com/en-us/edu/series/a-guide-to-understanding-common-mode-chokes/ - They actually make the chokes that are installed in appliances, hifi, TVs, etc. Of course they are more focussed on high frequencies, which is not your issue. But the explanation is one of the better ones.
My instinct tells me that if you want to keep your antenna where it is, if you want to continue feeding it the current power level (and maybe some day more), you are indeed better off going the on/off route (not as pretty, I know).
Last note... In re-reading your original post, I would try one more thing. I would look for any electrical wires near the antenna in the attic. Those are the ones most likely to be feeding the hf into your house power lines. If you do find some that are there, as a test, kill the breaker on those lines and see if the interference stops. If it does, then you might want to put chokes on those lines only, thus preventing the signal from propagating throughout the house. Just a thought.

Nope, that won't work. I'll give you some short answers and then point you to some concepts and reading.
First the drawing implies a ground plane but only on side at a time. You're going to have directionality issues. Also, your drawing shows no lengths so no idea which band you're tuned for. Finally, you're creating a relationship between active elements and passive ones that will create a rather bizarre signal.
I love antenna design. It is my personal favorite aspect of amateur radio. I also love experimentation and I did notice that you built your own first antenna. But, as with most arts and skills, think martial arts, think fighter jet flying, think surgery; any of those require the basics first. Even if you have already built one, and especially if you are keen on building more, I would first study up on, and practice with, simple, basic, true and tried designs. I'm not saying you have to buy them, you absolutely can, and there are some amazing ready-to-use designs out there, but think about it. Right now you want to get on the air and have fun. Why not do it with the best possible equipment first? Then, once you're on the air and loving it, you experiment, but you do so after having read some of the antenna books, some of which are masterpieces. There are some that are geared towards theory, others are more DIY oriented. There are VHF/UHF books vs. HF ones. There are specific apartment dweller books, vs. the large arrays or super-high towers. Take your pick based on your personal interests and start experimenting away.
Here is a simple, available, not too expensive option on the, ready-to-use antenna front: https://amzn.to/3OXMEkB. There are many others. Just Google 2m 6m combo antennas and you'll have them at your fingertips. As far as books are concerned, if you are an antenna nut like me, the reference is: https://www.arrl.org/arrl-antenna-book. Again, many many others, some maybe even better, but this is a go-to, must-have-in-your-library book.
As with all advice, I may be completely off the mark and if I am, apologies, but hopefully some of this response will get you closer to getting on the air actively and with great success.
73
Jim

Totally agree. Will change them later today. Thanks so much for the input. That’s how we improve.

Fixed, especially 130 that was awful. I think I have to rethink those horizontal bar graphs a little... Thanks again.