For discussion of television hardware.

27 responses total.

I want to set up a satellite (ancient) TV to show tapes or television
programs played on a master(new)  TV/VCR connected to cable. There are
several ways of doing this: 

1. Put a "Y" tap on the RG-59 cable from the VCR to the TV, and hard
wire it. Are taps a problem? Cheapest - just the cable.

2. Buy a UHF Modulator/xmitter that broadcasts on UHF channel 19 and feed
it with the audio/video from the VCR. I think this will only give me tape,
however. (The unit costs ca. $50). 

3. Buy a Recoton 900 MHz wireless video sender, which I *think* will work
from the tap on the VCR-TV cable, as in #1. (Most expensive - ca. $80)

What are the relative merits or demerits of these options - and are there
any other? (The remote TV is *very* old and has only 300 ohm VHF and UHF
antenna terminals, so the usual matching will also be required.) 

r.e. option 1:  Don't use a tap.  Use a signal splitter / amplifier
-splitter.  Otherwise you muddy up the impedance waters.
 
If you have audio and video sources for all the things you want to send
to your satellite TV, the satellite is not going to move around much and
it is not difficult to run the coax to it, I'd go with option 2.
Modulators are pretty cheap and work pretty well.  Otherwise there is
always option 3.  I have also seen TV signal X-mitters that operate
on channel ~14 and can X-mit a couple hundred feet.

Thanks! By "Y" I did mean "splitter" (since I worry about that
impedance stuff in other contexts) - I'm picking up the jargon! 
I have run coax, but using a switch rather than a splitter. I'll
try the latter to see if there is a signal level problem.
I am concluding that option 2 does not feed through the cable TV signal
but only the 'line level" stuff to do with playback and recording (at
least, on my VCR). I may have to go to option 3 as the annoyance of
a cable snaking around the house starts to get under someone's skin.. :)
(though I am checking out places to run ports through the wall, for
the cable). 

As I have the Jameco catalog in fron of me, I see they have a "Video
Transmitter Station" that X-mits on channel 7-13.  It includes the audio
and video input cables, has a F-connector on the back should you want
to X-mit to the entire neighborhood, a telescoping antenna for local
X-mitting, a built-in test pattern switch, etc. all for $45.  Home Auto-
mation catalog also has such devices in it, I'm sure.

That device does not appear to accept a VHF input, which I need it to do.

There is a "High quality Popular Mechanics" 900 MHz X/R system listed
by Electronic Goldmine and the blurb suggests it will broadcast a cable
signal, which would be fine *if* the receiver output is also a VHF signal
(my satellite TV does not have line-level audio/video input jacks). The
transmitter also accepts line-level. Do these units usually output VHF too?

I'm confused than.  Your option 2 said something about feeding audio/video
(I assumed that you meant line-level audio/video signals here, not RF)
from the VCR to a modulator.  That is what this is, except this A/V
modulator has a much higher RF output such that you can forgo the coax
connection between the modulator and the satellite TV and use their
antennas instead.

BTW, the little $5 Jameco A/V modulator will allow you to feed line-level
A/V signals into your satellite TV that doesn't have line-level inputs.

My option 2 fails my purpose because the VCR audio-video line level output
is not of the TV signal except when recording (if I understood correctly).
The device in #5 will apparently accept a VHF signal, broadcast it near
900 mz, and then yield *at least* line-level audio-video. However I need
TV band output (VHF) to feed the TV. Do these devices also have that output?

If your new TV has line-level inputs, it may be worth your while to 
connect those to your VCR and experiment with what comes out of the
VCR line-level outputs.  My experience has been that whatever is on
the the F-connector is also on the the line-level jacks when in play-
back, record and when you are using the VCRs tuner to display TV on
a monitor.  When the VCR is off, rewinding or in playback, the RF in-
put is connected to the RF output.  This way you can insert a VCR into
the the coax that feeds your TV without it interfering with the
operation of the TV when it is off. Yet you to play tapes to the
TV simply by pressing the play button on the VCR and switching to
channel 3/4 on your TV.
 
You can also use your VCR as a tuner as well as a VCR if you use your
new TV (The one with line-level inputs) as only a monitor.  The RF
signal would go to the VCR RF input and the VCR line-level outputs
would go to the line-level inputs of both your new TV and your video
modulator which X-mits the signal to your satellite TV.  A line-level
output is capable of driving at least two line-level inputs so you can
use a simple Y adapter to split the signals.  This would allow you to get
by with only one remote too.  (I have used a similar setup at home for
years.  I could have saved some money by getting a TV without a tuner ;-)
With this setup you can play tapes to both TVs or show a given program,
tuned by the VCRs tuner, on both TVs.

I'll take a closer look at what is on the VCR line-level outputs, in
various VCR modes. I already have both the VCR RF (F) output and the
line-level (RCA) outputs connected to the TV, and can run a tape with the
VCR in VCR mode and watch that or the TV channel selected on the TV, with
the VCR/TV choice on the TV remote. [I'm going to have to diagram all
this, as it is more confusing than VCR programming instructions!]

You are correct. The VCR tuner signal is on the line-level output if one
is not running a tape. I disconnected the RF VCR output, and could play
both TV and tapes (as expected) from just the line-level input to the
TV. So, a modulator-xmitter would do just fine. Would it be better to
use the Jameco unit that xmits to ch 7-13, or the one that xmits to
UHF channels? The satellite TV has the usual discrete tuning for VHF
ch 2-13 (with 'rabbit-ears'), and continuous tuning for UHF (with the loop).

I tried lots of combinations last night, including disconnecting the RF
feed to the TV, and learned a lot, but also got myself rather confused,
what with VCR options of off, on with choice of "TV/VCR", and tape, and
TV options of TV/VCR, and the choice of control of either the VCR or the
TV from the same remote....I often didn't know where I was! 8^{

[Is anyone else following this thread - and getting confused too?]

I suspect that getting a good  modulator-transmitter would be far more
important than if it transmits on VHF or UHF.  I bought a $35 x-mitter
at Dayton several years ago.  It operated around channel 14 to 14, was
not crystal controlled and was able to x-mit about 200' with the built
in antenna.  (~Ideal conditions: Mounted 7' up on a hill and x-mitting
to a loop antenna on the back of and old color TV  inside a house.)  I
got a second one last winter for about the same $s but it doesn't work
quite as well.  Having an "analog" tuner is of an advantage as you can
tune to the x-mitter instead of tuning the x-mitter to the TV.  Few of
the x-mitters seem to be crystal controlled

I've ordered the Jameco unit. Will report.....

The Jameco unit - made by "Oarsman" of Taiwan - works. It has screwdriver
adjustments of channels (7-13 for this unit), audio volume and 'brightness',
and a choice between transmitting or modulating RF on a cable connection.
As far as I can tell there is no significant signal distortion, but my
satellite TV is very old and has lost it green gun, so it is hard to tell.
One problem is "tuning" the system with the satellite TV in another room
in the house. I checked for a channel on the satellite TV that received
no noticeable signal, which turned out to be 12, and am transmitting on
that. (The range is supposed to be ca. 100 feet, and all neighbors are
further than that, so I am probably not interfering....maybe.)

TV REPAIR - Help needed
I've got a late model TV that has lost the lower half of the picture and
displays it as a 1/4 inch bright band across the center screen, while the
upper portion is displayed as a few dozen lines expanded vertically filling
the rest of the screen.
Can someone recognize this problem and give me direction.  It's not worth
taking to a repair shop, but if an inexpensive part is the cause I'd like
to fix it.  Adjusting the height pot had no effect.  
Its a 1990 Toshiba CF2044J....any ideas?

It sounds like your vertical sweep oscillator has a minor problem.  A bad
capacitor, resistor or minor active component.  Should be inexpensive to
repair.  Finding it, however, may not be easy.  Be cautious poking around
on a live chassis too.  Some high voltages run around on TV circuit 
boards.

I would suggest opening it up.  DON'T TOUCH ANYTHING.  Besides the high
voltages during operation the inside of the tube acts as a capacitor that
holds eough energy to really hurt you or even kill you if you discharge it
the rwrong way.  Now under bright light and maybe with a magnifying glass look
at every detail of the board to see if you can spot where a component failed
by making a lot of heat and burning itself up.  This will give you a good idea
what area to look for the real problem.  I'll guess that it's a cap that lost
it's open circuitness.  You can then carefully unsolder it and replace it with
an equivalent.  I did this with a monochrome monitor for a leading edge XT.
It is now perfectly fixed, still worthless, and the medium through which I
am typing this very message.  If there is interest, ask about what parts hold
that big charge and we'll try to describe what not to touch.  :)

Thanks to you both.  I've had my share of high voltage encounters from TVs and
the CRT terminals I used to sell.  Since it looks as though an inexpensive
repair is possible I will try to find a technician or some *time* to make the
repair.  I have so many repair projects already that I almost wished for advice
not to repair it.  But REuse, REpair, REcycle, and REsell are the words I live
by and so the TV *will* live again. ;')

Thought I'd post this on the odd chance it might help someone else out:

I recently got an RCA X100 19" TV for $3.  It had a slightly shrunken
picture that refused to sync up.  Whacking the side of the set would bring
changes in the pattern and bring the sound in and out -- classic symptoms of
the dreaded RCA Crappy Solder Joint Syndrome.  I took it apart and prodded
at the board with a plastic pen (with the set running) until I found the
'sensitive' area, then resoldered all the joints around it that looked bad. 
Powered the set up, and the picture still wouldn't sync.  Tapping it no
longer changed things, though.  Hmm.  Gee, those joints I resoldered were on
the controller IC, I wonder....put it in service mode, and the picture
suddenly synced up.  A little tweaking of the rather confused service mode
settings soon got me a beautiful picture. :) The TV works perfectly now and
is almost new.  Not bad for $3. ;)

...and ???? hours?

What are the differences between the bands and modes for cable and broadcasts
television? 

Since cable TV is a closed media. it is not subject to the frequency
allocation rules of the FCC.  Therefore, on cable, TV channels can be
spaced evenly, and spread right across things like FM broadcast, aircraft,
Ham bands, Police, Commercial two-way, etc.  Even the 'normal' channels
2-13 are slightly shifted from the on-air broadcast frequencies.  There
are two different styles of channel spacing in use on cable TV (that I
know of): HRC and IRC.  Unfortunately, I've forgotten the specifics of the
distinction.

I have obtained an ALPS QBBT452 video-RF modulator (for converting a
composite TV signal so I can watch it on a portable LCD TV that has no
composite input). It has a phono-jack for "to VTR TU". What is that?
It also has three (3) pins, ostensibly for video in, something called
"MD. +B", and Control. I guess "MD. +B" is the power supply line (case
ground). But which pin is which (before I fry something....)? 

VTR usually means "video tape recorder" (older acronym), probably TU means
"tuner"?  +B may mean power suppy positive ("Battery +", olde tube era term).

That what I thought (being from the "olde tube era" - but I didn't
expect to see it on a solid-state rf unit. Your suggestions for VTR and TU
are reasonable - that's what that jack is for. Now...what about "MD",
"Control", and...which pin is which?

I found ALPS on the web, but not for components - just for computer interface
devices. I have inquired of All Electronics (maybe they sent me the
wrong spec sheet). 

Incidentally, "B" in the olde tube era didn't mean "battery". Battery
suuply was divided into "A" for filament batteries, "B" for plate batteries,
and "C" for grid batteries. One doesn't find "B" batteries any more. You
can still find "A" style batteries, even though there are no "filaments",
and it is possible that the "C" battery notation got carried over to the
C *size* battery. 

Actually, I have seen "B+" on other solid state devices.

I also meant to mention in #24 that these devices are not even operated
on batteries in VCR (or VTRs). I can see the convention being carried
over from "B" being the anode (plate) supply to the anode (collector)
supply for solid state.

Re #19:  I'm a college student.  My time is worth, at best, $6 an hour.

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