WHY MUST I RESCAN ALL THE TIME?

Impossible to answer without 'Make and Model', but we can guess.

Scan for what? Scan for new channels?

How to Scan (or Rescan) For Channels on Your TV

How-To Geek https://www.howtogeek.com > how-to-scan-or-rescan-...
Jun 19, 2019 - Find and select the "Channel Scan" option in your TV's menu. This option is sometimes labeled "Rescan," "Tune," or "Auto-tune."

1. Select Scan or Autotune from your TV or converter box control menu to begin the scanning process.
2. Your TV will do the rest. This process mostly takes about a few minutes to be complete.

go into settings and then rescan for channels

Ok This is what I found out and hopefully found your solution..
Have you heard of Double Rescan?
The Federal Communication Comission Designed a Process called double rescan.
Double Rescanning erases and thenreprograms the channels in the converter box an digital TVs memory.
To Double Rescan, you will first need to disconnect the antenna from the converter box or antenna.
Then disconnect the converter and or digital tv power supplies from the wall. Wait a minute before plugging them back in. The antenna should still be disconnected.
With the antenna disconnected run the channel scan function on the coverter box or digital tv. When the scan completes you will have completely removed any channel data the converter box or digital tv, had in its memory.
Now it's time to rescan for real.
Do this by reconnecting the antenna to the converter box or digital tv and running the channel scan function again.
Thus the double rescan is born.
If the double rescan doesn't work, then try some tips and tricks to get your converter box up and running..I will have to look up the url again that has the tips and tricks...
If the double rescan doesn't work let me know and I will look up more options..
I really hope this works..

The digital to analog converters did not exist when the TV was built and the remote programmed. Thus you will have more luck programming the converter box's remote to control the TV. (At least with my converter box, the included remote could only turn on and off the TV. It would only change channels on the converter.)

Most universal remotes only have codes for devices released 6 months or more before the TV was programmed. So a new universal remote will probably control both the TV and the converter box. (Program the converter box using a code for LG or Zenith set top boxes if Insignia isn't listed. LG makes Insignia video products for Best Buy.) The remotes that are programmable by a USB connection to a computer are the fastest to set up.

A replacement remote for your TV is available here: http://www.mcmelectronics.com/partfinder.aspx?brand=&mdl=NS-LCD27&mode=part . An exact replacement remote for the converter box can be purchased at: http://www.remotes.com/remotes/servlet/rs?a=gmi&uuid=13055197980390&smodel=NSDXA1&brand_pn=INSIGNIA_NSDXA1 . The manual for the converter box (as a PDF) is here: http://cbsdallas.files.wordpress.com/2011/01/insignia-ns-dxa1-manual.pdf .

I hope this helps.

Cindy Wells

Good day,
You should have the instruction guide. If not look below. It's there but look closely for the guide itself and how to increase it's size to readable.

Check on the back of the TV to see if there is a 3 and 4 setting, If so, set to 3.
With nothing connected to the tv, and using the tv's remote, scan for channels. It should come up with only channel 3.
Then using the remote with advanced options, set the the input to either antenna or auto.

Connect the antenna cable to input on the converter box. Using the supplied cable connect the output from the converter box to
the TV. Turn the TV on first, followed by the converter box.
Then follow the instructions.

Not really easy so you'll have to fight your way thru it.
Finding the right setting for the antenna will probably take the most time, requiring a station scan after each adjustment.

http://dtvconverterboxes.blogspot.com/2009/05/rca-dta800b1-owners-manual.html

If you are feeding the signal from your digital converter into the TV antenna input, I would input the converters signal to the TVs video input instead. I am assuming your converter has a video output signal and left & right audio so you will need cables for your audio also. If your converter has only rf output for the TV tuner input it is generally on either channel 3 or 4 and there may be a switch to set this. It is possible that when the TV scanned for channels the converter was off and it did not find a signal on 3 or 4. If you can get the TV to re-scan, be sure the converter is turned on and on an active channel. All your channel selection should be via the converter after that and the TV simply stays on 3 or 4. I would suggest looking in to getting the original remote. Try partstore.com and see if they have one for your model.

The connections stay the same, but you may need to rescan your converter box: http://www.ezdigitaltv.com/Rescanning.html

You should be able to accomplish this. Run the antenna to your converter box. Run the video and audio outputs of the digital converter box to the inputs on your vcr. Your vcr should then be able to record the program (select line-in as the channel when setting up the recording). Hook your vcr audio and video output to your tv.
It's best to use a converter box that has an event timer - this allows the converter box to turn on at a specified time and channel. Otherwise you will need to manually set the channel you wish to record on the converterbox, and leave it turned on.

You have to use the RCA plugs on the back of the converter box and the tv (red,yellow and white). Or you can attach the antenna wire to box and then attach the wire that comes with the converter that is listed as to the tv and instead attach it to the antenna in on the vcr. The converter box will determine which channel your vcr will get a singal to record from. Your VCR for every program will be set to channel 3 or 4 (depending on what your converter box is set to broadcast on). Make sure the power saver on the converter box is turned off as if you want to record a program in say 4 hours, if the converter box turns off in 2, your vcr will have nothing to record.

I ran seperate coaxible cable to the tv from vcr and unplug the tv converter box everytime I want to watch the vcr. You can also use the RCA cord to send the signal from the vcr to the tv and use the input signal to watch your recorded programs. I had static showing up everytime I played it through the second converter box thus I solved it by running a seperate coax line. I don't know if you will have this problem, just wanted you to be aware.