Guy Hooks Modern Consoles and PC to 1970s TV

Megalith

Megalith

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Introduced in 1970, the JVC Videosphere is a CRT television that resembles a space helmet. The display is so old that it doesn’t even feature RF cable inputs, but someone has figured out how to game on it with a mishmash of converters and other hardware.
 
Hooking it up through the antenna was a pretty sweet trick. Though once he got one device working, I am not sure what was gained by showing us the rest of the devices.
 
Reminds me of the time I tried Doom 3 on a Casio TV 400

XTiRrSU.jpg
 
That's awesome, I actually have a very similar setup right now from my 2017 Intel Xeon system to amber monochrome monitor from 1989, and previously green monochrome monitor from 1984.
He did a great way of explaining this, and using the VHS player to do this is a great alternative to a Composite-to-RF adapter as well!

https://hardforum.com/threads/red-falcons-retrocomputing-thread.1841374/page-3#post-1043493050
Red Falcon said:
Magnavox Computer Monitor 80 (1989)

magnavox_computer_monitor_80__1989__by_redfalcon696-dc3l2er.png


Well now, this Magnavox Computer Monitor 80 amber monitor has been featured before, but I figured I would share some info about connecting it to a modern day computer via HDMI or DisplayPort.
This Composite-based amber monitor is currently connected to my Intel Xeon x86_64 system from 2017 (cylinder computer with the Elder-sign on it) above.

If the monitor uses composite:
Active HDMI/DisplayPort-to-VGA adapter (powered by USB) -> active VGA-to-Composite adapter (powered by USB) -> Any Composite-based CRT SDTV since the 1950s-present.

If the monitor uses coax or twin-lead RF:
Active HDMI/DisplayPort-to-VGA adapter (powered by USB) -> active VGA-to-Composite adapter (powered by USB) -> Composite-to-RF adapter (can be 75Ω coax or 300Ω twin-lead) -> Any RF-based CRT SDTV since the 1950s-present.

Most of these adapters will take resolutions up to around 1024x768 (4:3 aspect ratio), but some will take higher resolutions if you go for higher-end models.
These adapters can be purchased at Amazon or eBay for relatively cheap, and are all plug-and-play without requiring any software or drivers, outside of the modern system's GPU drivers.

Since the monitors are basically just SDTVs and don't have a true 1:1 pixel resolution that the computer can detect, it may be a good idea to set the resolution on the computer to either 800x600 or 1024x768 first, before connecting the adapters and composite/RF monitor.
I figured I would share a bit of information in relation to the post on our news page today about "Guy Hooks Modern Consoles and PC to 1970s TV", and while this monitor may not be quite that old, this method should allow anyone to connect their modern systems to any SDTV from the 1950s to present! :D

Stay retro! :cool:
Click to expand...
 
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Seriously, I'm really digging that JVC Videosphere SDTV, and that chain to hold it up is great - it's so 1970s! :D
Thanks again for sharing this Megalith, this is very inspiring!!!
 
That dude is moving the camera around like a crazy person... I made it about 2 minutes before I had to turn it off before my head imploded.

I see what he was going for... the VCR is really just being used as an RF modulator, converting the component cables to 75 ohm coax out.

Having worked at Radio Shack in my youth, what this dork really needs is a 300 ohm to 75 ohm adapter. They still sell these at walmart for like 5 bucks. Instead, he soldered a coax line directly into the 300 ohm input of the antenna. I'm actually surprised this worked as well as it appears to without having to correcting the impedance. I'm sure everyone's parents/grandparents have one of these lying around in a box in the garage somewhere, but not a huge need for them in the last 20 years. Well, unless you were trying to hook up an old OTA antenna to a modern TV. I keep forgetting people still use old antennas for OTA.

https://www.walmart.com/ip/75-to-30...enna-or-television-By-Parts-Express/576994666

1ed826e3-2070-469b-a5ef-724b1d579e5a_1.5e6b22b5f949de6912213ed6fde82753.jpeg
 
realdeadman said:
'minds me of the old days......hooking up a TRS-80, atari, NES to grand ma's TV lol
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Yup yup. Back in my teens / Commodore days, I had an old TV I used as a "monitor" because monitors were actually more expensive than the damn computers. When I got a C128, I made my own RGB to component video adapter from Radio Shack parts... I ran this via a super long cable into the living room, into the VCR, and then coax out of the VCR back into my bedroom to the TV. Why? So I could use the 80 column C128 mode without buying a $300 monitor. It looked like fuzzy ass and it was B&W, but it sort of worked. I could have also used an RF modulator but those were like $50... endless cables strung all over an apartment was free.
 
Burticus said:
Yup yup. Back in my teens / Commodore days, I had an old TV I used as a "monitor" because monitors were actually more expensive than the damn computers. When I got a C128, I made my own RGB to component video adapter from Radio Shack parts... I ran this via a super long cable into the living room, into the VCR, and then coax out of the VCR back into my bedroom to the TV. Why? So I could use the 80 column C128 mode without buying a $300 monitor. It looked like fuzzy ass and it was B&W, but it sort of worked. I could have also used an RF modulator but those were like $50... endless cables strung all over an apartment was free.
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Some of these kids have no idea how good they have it. Seriously. This isn't a get off my lawn joke. I mean the ds and the 3ds would have been mind blowing 20 years ago.
 
viscountalpha said:
Some of these kids have no idea how good they have it. Seriously. This isn't a get off my lawn joke. I mean the ds and the 3ds would have been mind blowing 20 years ago.
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No joke. A $10 Raspberry Pi zero has like 500x the computing power of a C64, NES, SNES etc.

My nephew has like 3 devices on him at all times. Tablet, phone, and a 3DS. When the battery dies on one, he drops it like a brick and moves on to the next device. He's 9. When I was 9... (queue up the "get off my lawn jokes" I had an Atari 2600 with like 4 or 5 cartridges. Hooked up to a B&W TV. Stupid kids have ZERO idea of how good they have it now.

Side note - back then, when I wasn't busy doing free unpaid day care for my baby little brother (seriously, who puts a 9-10 year old in charge of an infant? ) I was working my little ass off doing chores. Never ending dishwashing (no dishwasher... it was all me and a scrub brush), yard work, helping with dinner, laundry, etc.... for $3 a week allowance. Kids nowadays... sheesh.
 
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JVC is barely holding on (in the us) but that set looks like new. What did they do 'yesterday' that was better ?
 
BeavermanA said:
Call me crazy, but I'll stick to my 4k OLED tv and HDMI cables.
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What?!
And miss out on this high definition glory??? :D

compaq_deskpro_8086___benchmarks_and_software_by_redfalcon696-db1sbmq.png


The irony is that I really am using an HDMI cable with this monitor now, haha.
Good times!
 
shspvr said:
He should gotten a HDMI to RF Converter Box
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Most of the ones I've seen are prohibitively expensive ($400+ USD) and only output digital cable, not analog, so yet another adapter would be needed to convert that signal to analog which older SDTVs like this would accept.
If you have one that is cost-effective and outputs in analog out of the box, though, I would really like to see it! :)
 
Burticus said:
That dude is moving the camera around like a crazy person... I made it about 2 minutes before I had to turn it off before my head imploded.

I see what he was going for... the VCR is really just being used as an RF modulator, converting the component cables to 75 ohm coax out.

Having worked at Radio Shack in my youth, what this dork really needs is a 300 ohm to 75 ohm adapter. They still sell these at walmart for like 5 bucks. Instead, he soldered a coax line directly into the 300 ohm input of the antenna. I'm actually surprised this worked as well as it appears to without having to correcting the impedance. I'm sure everyone's parents/grandparents have one of these lying around in a box in the garage somewhere, but not a huge need for them in the last 20 years. Well, unless you were trying to hook up an old OTA antenna to a modern TV. I keep forgetting people still use old antennas for OTA.

https://www.walmart.com/ip/75-to-30...enna-or-television-By-Parts-Express/576994666

1ed826e3-2070-469b-a5ef-724b1d579e5a_1.5e6b22b5f949de6912213ed6fde82753.jpeg
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This had me slightly curious as well. From Wiki:

As a transmission line, transmission efficiency will be maximum when the impedance of the antenna, the characteristic impedance of the twin-lead line and the impedance of the equipment are the same. For this reason, when attaching a twin-lead line to a coaxial cable connection, such as the 300 ohm twin-lead from a domestic television antenna to the television's 75 ohm coax antenna input, a balun with a 4:1 ratio is commonly used. Its purpose is double: first, it transforms twin-lead's 300 ohm impedance to match the 75 ohm coaxial cable impedance; and second, it transforms the balanced, symmetric transmission line to the unbalanced coax input. In general, when used as a feedline, twin-lead (especially ladder line versions) has a higher efficiency than coaxial cable when there is an impedance mismatch between the feedline and the source (or sink). For receive-only use this merely implies that the system can communicate under slightly less optimal conditions; for transmit use, this can often result in significantly less energy lost as heat in the transmission line.

Twin-lead also can serve as a convenient material with which to build a simple folded dipole antenna. Such antennas may be fed either by using a 300 ohm twin-lead feeder or by using a 300-to-75-ohm balun and using coaxial feedline and will usually handle moderate power loads without overheating.
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https://en.wikipedia.org/wiki/Twin-lead


Basically it sounds like what it comes down to is that it's just changing how the energy is being delivered to the other end. Because this is on the receiving end it's already really low power, and the amount of cable involved is so small that the losses being incurred from switching to one or the other isn't a big deal. I would expect that a lower ohm rating = more amperage, so the direction that it's going (75 to 300ohm) probably just means you'd be more likely to over drive the signal. But I don't think that would actually happen because it's usually down to the load side to determine the power draw, so if the resistance is higher on the load than source, it's going to limit current automatically. So best I can gather is that in the direction this is going, it should work exactly as expected since the TV is limiting the current, much like you don't draw 15A from a wall outlet if you only plug in a device that only draws 1A.


Outside of butchering the antenna design, there really isn't anything special about this. I have an HDMI > composite box, and I might even have a stand alone composite to RF converter from back in the day. (Obviously the VCR handles this fine as well) I would have thrown in a proper converter like you mentioned, but it's obviously not a critical component to making this work. From the comments I was thinking he was transmitting to the antenna somehow, which would have been cool. In this case it would be better if he had removed the antenna portion from this as it's just causing massive amounts of interference in both ingress and egress. The signal from the VCR is more or less broadcasting on whatever channel it's on, and the antenna is also picking up anything that's operating on that channel. Channel 3 - 4 which is used on everything in the US will soon be used by cellular, so I can only imagine the noise that setup would pickup once they light up their towers.
 
Red Falcon said:
Most of the ones I've seen are prohibitively expensive ($400+ USD) and only output digital cable, not analog, so yet another adapter would be needed to convert that signal to analog which older SDTVs like this would accept.
If you have one that is cost-effective and outputs in analog out of the box, though, I would really like to see it! :)
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The HDMI to digital is an interesting proposition, I'm guessing it's a niche product so that you can hook a satellite box to a PC tv tuner card and still get HD.

It looks like radioshack made what you're asking about at one point, but it's no longer being sold.

https://www.amazon.com/Radio-SHack-HDMI-RF-Converter/dp/B06XWZMFD8



But I don't think it's a big deal to get one of these:

https://www.radioshack.com/products/radioshack-hdmi-to-composite-converter

And plug it into one of these:

https://www.radioshack.com/products...MIy670jpW22QIVR7bACh080wUWEAQYASABEgL9nvD_BwE

For $50 you can make it happen, and then you can not only watch the video on one screen, but throw a splitter on there and watch it on a few more.

I've used that second device before way back in the day to hook a computer up via the S video port to a TV to run powerpoint slides. (Probably 15 years ago) As long as you used a big enough font it wasn't really a big deal for slides. But I've used s video to composite to try to use a TV as a display before and that is just awful. Even if my CRT monitor was only 1024 x 768 that's still a heck of a lot better than 480i.
 
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When I was in my teens my buddy had a smaller tv that we would put on his bigger tv and the RF would feed through the antenna and we would play mp NES games mostly world cup soccer. Was fun and pretty cool when we discovered it.
 
bman212121 said:
The HDMI to digital is an interesting proposition, I'm guessing it's a niche product so that you can hook a satellite box to a PC tv tuner card and still get HD.

It looks like radioshack made what you're asking about at one point, but it's no longer being sold.

https://www.amazon.com/Radio-SHack-HDMI-RF-Converter/dp/B06XWZMFD8
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Ah shoot, that's too bad.
Radio Shack did have some good products at one time; nice find, though.

But I don't think it's a big deal to get one of these:

https://www.radioshack.com/products/radioshack-hdmi-to-composite-converter

And plug it into one of these:

https://www.radioshack.com/products...MIy670jpW22QIVR7bACh080wUWEAQYASABEgL9nvD_BwE

For $50 you can make it happen, and then you can not only watch the video on one screen, but throw a splitter on there and watch it on a few more.

I've used that second device before way back in the day to hook a computer up via the S video port to a TV to run powerpoint slides. (Probably 15 years ago) As long as you used a big enough font it wasn't really a big deal for slides. But I've used s video to composite to try to use a TV as a display before and that is just awful. Even if my CRT monitor was only 1024 x 768 that's still a heck of a lot better than 480i.
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You know, I used to have the earlier black-case version of the adapter in the bottom link, and it worked great.
Not sure how much I would trust the HDMI-to-Composite adapter in the top link, though, especially when it isn't an active adapter.

The only reason I say that is because passive adapters tend to behave really flaky at times, depending on the resolution or device it is connected to, resulting in compatibility issues more often than not.
I don't think passive adapters are bad or anything, just a bit of a gamble unless you officially know it is going to work. :)

At $35 USD as well, that HDMI-to-Composite adapter is a bit above the cost of an active HDMI-to-VGA adapter plus an active VGA-to-Composite adapter, which they themselves are both around $15 USD, each.
It does help to simplify cables and cable management, and if it works, it would certainly be a much cleaner setup, though!
 
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Red Falcon said:
Most of the ones I've seen are prohibitively expensive ($400+ USD) and only output digital cable, not analog, so yet another adapter would be needed to convert that signal to analog which older SDTVs like this would accept.
If you have one that is cost-effective and outputs in analog out of the box, though, I would really like to see it! :)
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The don't cost that much a as all you need is one RF Converter Box and one HDMI to Composite Converter Box.
 
shspvr said:
The don't cost that much a as all you need is one RF Converter Box and one HDMI to Composite Converter Box.
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Yeah, I talked about that already, as did bman212121 right above my last post.
Also, yes, a single straight HDMI-to-RF adapter does indeed cost that much, at least from what I've seen.
 
shspvr said:
I'm not ware of any cost $400 got a link that one costing $400 ?
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Cha-ching! http://www.provideoinstruments.com/MINI-RF-Modulators_c_49.html

In mean time will this do it only $40
https://www.radioshack.com/products/radioshack-hdmi-to-coax-adapter
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Oh man, that's awesome, and would have simplified the heck out of the video in the OP.
Very nice find, thanks for sharing!!

The only slight inconvenience on this adapter is the following:
The source device such as Blu-ray, Set-top box, and gaming console that is connected to the HDMI input on this product. Must be able to output a 480i/480P signal.

Using all of the other adapters, it should be able to output up to 1024x768, but if the source can be 480p, then it should work great.
Either way, for less than $40 USD, that's a pretty good deal which would allow for a very clean setup.
 
shspvr said:
That is not an RF Analog Modulator Red Falcon just a hint on what it dose it just take the incoming video signal and encode in to MPEG2 + Stereo or it embedded DD 5.1 in to ts container for Digital TV Tuner to see over Digital ATSC / QAM / DVBT / ISDBT / DMBT / DVBC
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Yep, as I stated above. ;)
 
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