Using TV as second monitor picture blurry

Most TVs do tend to look a little blurry for the most part compared to a monitor, but in this case the problem is compounded by the HDMI to RCA connector. If I remember correctly, a TV's RCA input is at best 480p, maaaaybe 720p if you are really lucky and the TV isn't that old.

The problem is that the TV is trying to upscale a signal which has less information in it than the image it is trying to display. The result is a blurry picture.

Get yourself a decent monitor and avoid all of that eye strain.

Is the flatscreen monitor a true HD? i.e. 1920 x 1080?
what's the refresh rate you're running? TV usually get away with 25 f/sec.
Lastly most blurring can be due to a dampening effect caused by capacity or in inductivity.
Buy a high-end HDMI 2.1 cable to connect and check. You might be surprised*
lastly what type of of converter do you have?

What's the brand and features/specs off the monitor?
From the specs you gave on your laptop, you note the resolution is1280X780.
If the TV is a 1980 x 1080 either the video card in the laptop or the TV cannot adapt to a needed resolution.
Any scaling, especially upscaling (making more out of less) will look fuzzy[ier].

You also mentioned "...So I bought an HDMI to RCA adapter/convertor..."
That to can be the problem. the conversion electronics is too slow or qualitatively not laid out for higher resolutions you'll get a fuzzy image as well.

Keep in mind the HDMI 2.0 specs layout for 4K format and 60 frames a data rate of around 18 GB per sec!
In a crude calculation, a 25f/sec of 1920 x 1080 [~2.07MB] is 51.84 MB per second just for the 25 image frames without any overhead data. For 60 f/sec you're up to 224.2 MB/sec.
Just imagine at UHD (4K) 8.3 MB and 60 f/sec you would be "shoving" half a gigabyte per second through the wires! and all that without any overhead! Just a crude "5th grade school level" approximation.

My hunch is the HDMI to RCA adapter/convertor adapter you use as well as HDMI cable are to "slow" to handle this.
I HDMI 2.1 cable first and see what happens. The 2nd step would be to get a higher end/speed converter.
(You can put a Porsche engine into a Volkswagen beetle, but it's still is and drives like a Volkswagen beetle!)
By that time you might as well spend the money and by a brand-new even larger monitor who will deliver!

*I use as a computer screen an UHD (4K) 55 inch Samsung Q7 TV. to be useful as a computer screen you need at least 4K (3840x2160) at this screen size as well as 60 f/sec or higher rate.

In the very beginning I didn't get a sharp crisp computer desktop image as I had hoped for. It was slightly fuzzy.
the next thing was that from time to time I had a sudden screen blackout for about a second while working or watching.
I bought a quality HDMI 2.1 cable and all the problems vanished never to appear again.

RobbyK said:

When I posted, I kind of guessed I would end up just buying a monitor, and finding another use for the TV. I just wanted to get a second opinion before I went and spent money when I didn't have to.

Thanks for the help, I do appreciate it.

This is kinda difficult for me to chew on.........................................

1. Digital video works by sending actual data between devices. You literally have devices that could send HDMI to HDMi on a wireless scale that is legal to own and buy ( because it is digital and not analog which you would be running a television station and would have to paint your walls with Aluminum to get by using that ).

2. All HDMI cables are no different then RJ45 cables ( you know those Yellow/Blue cables for internet ??? ) In fact the RJ45 cables
are just the same as phone-wire but has more lanes and carries more power. You can use a Phone wire in a RJ45 and vice versa to some extent. This is DSL actually had more speeds then Cable based on network traffic. You have HDMI to RJ45 adapters and vice-versa. So you do not even need to buy a fancy HDMI cable.

3. HDMI as with USB 2 v. USB 3 also comes in various sizes delivering HQ based on speed rates.

4. Your TV ( the display your friend gave you ) most likely could output pre-DVI ( Analog signals ). Meaning RGB + BW to give you the bet image possible. Same reason why a Playstation2 can also use HDMI adapter and give the best possible image outside using any emulator.

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I give up on digital displays. They are useless outisde of playing duck-hunt.

Get a "Short-throw-projector" with a matted frame for it to shoot on. This will set you back - 2000 to 4000 bucks. It will give you the best picture on your wall, without mounting anything. You will just have a projector on a table where the TV should be. Super sharp image.

OLED is the best but because it is organic can fail over time.
They even have paper-thin displays where the light comes from the bottom of the unit and looks like something out of a space movie. Even that is not new.

Another thing to consider is the type of HDMI --> RGB you are using. Some of them are plug in pass-through devices while others are no-power pass-through devices. You could save money and the picture still looks terrible because of the method the adapter is using.

Daymin said:

This is kinda difficult for me to chew on.........................................

1. Digital video works by sending actual data between devices. You literally have devices that could send HDMI to HDMi on a wireless scale that is legal to own and buy ( because it is digital and not analog which you would be running a television station and would have to paint your walls with Aluminum to get by using that ).

2. All HDMI cables are no different then RJ45 cables ( you know those Yellow/Blue cables for internet ??? ) In fact the RJ45 cables
are just the same as phone-wire but has more lanes and carries more power. You can use a Phone wire in a RJ45 and vice versa to some extent. This is DSL actually had more speeds then Cable based on network traffic. You have HDMI to RJ45 adapters and vice-versa. So you do not even need to buy a fancy HDMI cable.
A: Wrong! There are 8 different grades of HDMI cable standards

3. HDMI as with USB 2 v. USB 3 also comes in various sizes delivering HQ based on speed rates.
A: Higher demands request different cables!

4. Your TV ( the display your friend gave you ) most likely could output pre-DVI ( Analog signals ). Meaning RGB + BW to give you the bet image possible. Same reason why a Playstation2 can also use HDMI adapter and give the best possible image outside using any emulator.

.................................................................................................... .................................................................................................... ....................................

I give up on digital displays. They are useless outisde of playing duck-hunt.
A: Wrong! Today all displays are digital displays unless you have some ancient CRT monitor.

Get a "Short-throw-projector" with a matted frame for it to shoot on. This will set you back - 2000 to 4000 bucks. It will give you the best picture on your wall, without mounting anything. You will just have a projector on a table where the TV should be. Super sharp image.
A: You can get almost pocketsized HD short throw projectors for under $500

OLED is the best but because it is organic can fail over time.
They even have paper-thin displays where the light comes from the bottom of the unit and looks like something out of a space movie. Even that is not new.
A: Wrong! OLED can last well over 10 years! OLEDs are not backlit as each pixel creates/is its own light source. As a general rule, if you run your TV for approximately 8-10 hours a day, the OLED screens last approximately 8-10 years.

Another thing to consider is the type of HDMI --> RGB you are using. Some of them are plug in pass-through devices while others are no-power pass-through devices. You could save money and the picture still looks terrible because of the method the adapter is using.
A: You get what you pay for! Quality low capacitance cables rated for high data transfer rates deliver perfect images all the way to UHD

My answers embedded in bold