|
#1
|
|||
|
|||
Quote:
My CCII from 1976 has 75 ohm coax as well. |
#2
|
||||
|
||||
Quote:
I have a mid to late 60's Setchell-Carlson school/industrial 23" monochrome TV/video monitor that uses if I recall the name correctly a PL-259 75ohm coax connector for the VHF...Oldest set I've seen with coax RF in.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#3
|
|||
|
|||
Those must be quite rare (tvs that old with coax input) There used to be a wide variety of antenna inputs on tvs without any real apparent rhyme or reason. At first there were just screw terminals, then you had sets with screw terminals and a coax. Sometimes the VHF signal was a coax input and the UHf was a 300 Ohm twin lead. Some sets have 4 screw terminals and a jumper that went into the 75 ohm input all of this with no apparent rhyme or reason. I grew up in the 90s and 00s, so by then, the singular 75 ohm coax was standard.
__________________
Game Room TV's: 1997 RCA Colortrak 27" Console 1987 Zenith 19" V3912W |
#4
|
|||
|
|||
Quote:
I'd love to see pics. Just out of curiosity. It used to annoy me when I would bring home a small set and all it would have is the screw terminals. Now that I am older, I wish I had been able to keep my 13" Color GE and my 13" B&W Goldstar - both from the 80s, knob Tuned and 300 ohm twin lead only.
__________________
Game Room TV's: 1997 RCA Colortrak 27" Console 1987 Zenith 19" V3912W |
#5
|
||||
|
||||
This is an almost all !
VHF tuners had 75 ohm inputs. then a balun mounted on the tuner & off to the term board at 300 ohms. Coax was a rarity in the olden days for a down lead. You could have 2 matching transformers & the balun all giving losses. So in the mid 70's coax VHF inputs became common usually with a 300 ohm input that could be switched in for ears etc. UHF tuners had 300 ohm inputs. They kept that for good reason. If you compare RG59 with quality foam 300 ohm at UHF freqs the loss of coax is much higher. So in a fringe UHF area you could need an amp for UHF using coax. Other way is to run separate antennas with coax for VHF & 300 ohm for UHF. Remember every time you add something EVEN a connector there are losses especially at higher freqs ! Some combo antennas could run separate outputs also. Dont remember but probably Wineguard & maybe Jerrold (GI), they were the premier antennas then. 73 Zeno |
Audiokarma |
#6
|
||||
|
||||
Quote:
The S-C don't have a thread, but there is a picture or two out there. I don't have time to take pictures of it now with the ETF meet on the way.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#7
|
|||
|
|||
makes me wonder how long twin lead connectors lasted.
Newest I saw were on a VCR from 1991 |
#8
|
||||
|
||||
Quote:
I dont know. Latest 300ohm U/V were probably on low end Korean jobs & 1st gen Chi-Com junk. Must have gone away with knob-job tuners. I do remember some RCA sets kept 75 & 300 ohm late. Not the stuff I remember as it really didnt effect my job. 75 only simplified service. No need for clothes pins, just stick on a push on connector. Fast but we did go through them by the bag after being stepped on etc. 73 Zeno |
#9
|
|||
|
|||
Quote:
I have seldom seen them on anything but a knob tuned set. Is there any particular reason for that? Digital tuned tvs (usually bpc's) usually have only coax.
__________________
Game Room TV's: 1997 RCA Colortrak 27" Console 1987 Zenith 19" V3912W |
#10
|
||||
|
||||
Quote:
Early varactors & digitals started with 2 TNR's. Then they put it all in one pkg with 2 inputs. To make things cheaper, smaller & better eventually built the matching & splitting into the single U/V tuner. |
Audiokarma |
|
|