Have Jensen jtc2421dc TV on my boat. Do not have WI-FI. Want to stream from my iPhone. Did the connections Apple says to use but only get a prompt of NO SIGNAL.

Do not have WI-Fi.

1. You still need an internet connection (on the phone) at playback time to authorize the content to be mirrored.

2. Some content may not work with HDMI adapters. Some content may not work with mirroring of any kind. What were you trying to watch?

Using hdmi cable.

Do you have the Apple Lightning Digital AV Adapter? Or a different adapter?

NO SIGNAL prompt in a rectangular box.

That is indicative for a non-functional HDMI connection. Content, DRM, or source device have no influence over that. Did you set the TV to take input from the connected HDMI port?

I’m hearing that I should have the Apple TV box.

That is still designed to use Wi-Fi. Any use of it without Wi-Fi has hurdles.

Hello tbears19,

It sounds as though you're wanting to connect your iPhone using an HDMI cable to your TV to watch video content. To do this, you would need to ensure you have an appropriate adapter. You can verify the compatible adapters in the "Find out which adapter you need" section of the following article. After confirming you have the correct adapter, follow the steps listed below.

"Get connected"

"Connect your iPhone, iPad, or iPod touch to a display:

1. Plug your Digital AV or VGA adapter into the charging port on the bottom of your iOS device.
2. Connect an HDMI or VGA cable to your adapter.
3. Connect the other end of your HDMI or VGA cable to your secondary display (TV, monitor, or projector).
4. Turn on your secondary display. 
5. If necessary, switch to the correct video source on your secondary display. If you need help, use your display's manual."

"Now the screen on your iPhone, iPad, or iPod touch should appear2 on your TV, display, or projector."

About Apple Digital AV Adapters for iPhone, iPad, and iPod touch - Apple Support

If you need additional assistance, you may need to reference the steps in the "Get help" section of the same article.

Take care!

Jensen JTV2421DC doesn’t list HDCP protected content (DRM) support, so—if that feature is indeed omitted—what rented or purchased content can be played will be limited.

Specs and manual:

https://asasupportdocs.blob.core.windows.net/docs/Literature/lit-JTV2421DC.pdf

https://asasupportdocs.blob.core.windows.net/docs/Owners%20Manual/Owner's%20Manual%20JTV2421DC.pdf

If this display lacks HDCP, your options for rented/purchased media playback will be limited. Regardless of source. Check with the vendor. This TV might have HDCP support and simply omit it from the specs.

Yes I have the Apple AV DIGITAL ADAPTER and the new HI SPEED HDMI cable. What I’m reading on the web is if I have these two things I don’t need WI-FI., hence it’s cable connections.

You should be able to at least mirror the home screen of your iPhone with that connection, and let you know that the connection is working. “No signal” means that the connection isn’t right yet. That is different from the other mentioned possible issues.

So if I do add a Apple TV Box, the Box needs a WI-FI to work. Am I correct?

The Apple TV box is intended to connect to a home network that has internet connectivity. Wi-Fi is very suitable for that. Alternatively, a wired ethernet cable is also a possibility. There is offline peer-to-peer connectivity possible, but that is not suitable for DRM’ed content that wants to verify with online servers. More for home videos.

So what of the Google tv, or these Fire Sticks, still need WI-FI?

Those too are intended to connect to a home network that has internet connectivity. Wi-Fi is very suitable for that, and for some models the only method. This is not the forum that is expected to have expertise on detailing the limits in trying to use these third party streaming devices offline.