Kind of simple question matching impedances/resistances on twin-lead

[Treeline]

I cut in half a twin-lead antenna wire, typical 300 ohm wire.

I inserted a Balun transformer on the first cut end to make it 75 ohms and connect it to an old TV.

So far, so good.

Then I got to thinking and that was bad. How can I reconnect that twin-lead that I cut in half, in
case I wanted to use the other, unused end? And still keep that Balun transformer on that end?

Hmmm, can I use the already terminated 75 ohm Balun transformer and connect it back up to the
second half of the twin-lead antenna wire?

Can I untransform or re-transform the 75 ohm Balun transformer to a 300 ohm thingee?
If the first balun is 4:1, can I get a 1:4? Without too much dB loss.

I found some RCA VH104 Signal Separator/Combiners in a dollar store.

If I connect the balun transformer to the VHF OUT/IN
to the UHF OUT/IN - will this so the trick?

In other words, I am using just the inputs to really do the transformations, not exactly what the
device is set up for.

I am wondering if I can get a schematic of this part somewhere to see what it is doing internally.

Supposedly it, RCA CH104, takes a twinlead 75 antenna and a 300 ohm coaxial cable and combines them
to output into a coax with the single wire, what I might call a male connector but it's call an F
type.

And I assume it can do the opposite, take an input of the coax and separate it into 75 twin-lead
UHF and 300 lhm VHF outputs.

Thanks.

Come to think of it, would it be better just to connect the twin-lead directly to the TV which as
inputs for this for it's inside antenna? It has screws for the two rabbit ears and another set of
screws for a loop antenna.

 

[[email protected]]

I cut in half a twin-lead antenna wire, typical 300 ohm wire.

I inserted a Balun transformer on the first cut end to make it 75

ohms and connect it to an old TV.

So far, so good.

Then I got to thinking and that was bad. How can I reconnect that

twin-lead that I cut in half, in

case I wanted to use the other, unused end? And still keep that Balun

transformer on that end?

<snip>

This has to be a troll.

 

[Treeline]

ohms and connect it to an old TV.
twin-lead that I cut in half, in
transformer on that end?

<snip>

This has to be a troll.

Why is this a troll? In any case, I did a quick test and I would reckon doubling up the
transformers results in a very marginal loss. I noticed one spec of 0.5 dB loss on parts like this,
and that sounds reasonable without measuring.

I'll bet if Newton came to you about an apple falling on his head, you would say, heh, you'll a
troll.

Asking questions which may be obvious to others is not trolling unless I already know the answers.
Here I do not. I could find out the answers if I got my equipment out of storage but it's snowing
again and quite cold in that unheated place. And I really don't mess much with antennas and TVs,
hence asking here since TV appears to be ubiquitous for most.

 

[Ken Taylor]

Why is this a troll? In any case, I did a quick test and I would reckon
doubling up the
transformers results in a very marginal loss. I noticed one spec of 0.5 dB
loss on parts like this,
and that sounds reasonable without measuring.

I'll bet if Newton came to you about an apple falling on his head, you
would say, heh, you'll a
troll.

Asking questions which may be obvious to others is not trolling unless I
already know the answers.
Here I do not. I could find out the answers if I got my equipment out of
storage but it's snowing
again and quite cold in that unheated place. And I really don't mess much
with antennas and TVs,
hence asking here since TV appears to be ubiquitous for most.

The ultimate question you ask was, is it better to not screw about and just
connect directly to the TV. And you wonder why you're considered a troll??
Maybe you are just experimenting (good on yer) but your post was a bit of a
ramble.

And for the other questions, yes, you can use the transformers in 'reverse',
and yes, they can be cascaded.

Ken

 

[Fred Bloggs]

I cut in half a twin-lead antenna wire, typical 300 ohm wire.

I inserted a Balun transformer on the first cut end to make it 75
ohms and connect it to an old TV.

So far, so good.

Then I got to thinking and that was bad. How can I reconnect that
twin-lead that I cut in half, in case I wanted to use the other,
unused end? And still keep that Balun transformer on that end?

Hmmm, can I use the already terminated 75 ohm Balun transformer and
connect it back up to the second half of the twin-lead antenna wire?

Can I untransform or re-transform the 75 ohm Balun transformer to a
300 ohm thingee? If the first balun is 4:1, can I get a 1:4? Without
too much dB loss.

I found some RCA VH104 Signal Separator/Combiners in a dollar store.

If I connect the balun transformer to the VHF OUT/IN to the UHF
OUT/IN - will this so the trick?

In other words, I am using just the inputs to really do the
transformations, not exactly what the device is set up for.

I am wondering if I can get a schematic of this part somewhere to see
what it is doing internally.

Supposedly it, RCA CH104, takes a twinlead 75 antenna and a 300 ohm
coaxial cable and combines them to output into a coax with the single
wire, what I might call a male connector but it's call an F type.

And I assume it can do the opposite, take an input of the coax and
separate it into 75 twin-lead UHF and 300 lhm VHF outputs.

Thanks.

Come to think of it, would it be better just to connect the twin-lead
directly to the TV which as inputs for this for it's inside antenna?
It has screws for the two rabbit ears and another set of screws for a
loop antenna.

The "separator/combiner" does its thing by frequency band, it separates
out the combined UHF/VHF into separate UHF and VHF channels for older
receivers with two antenna inputs- usually with 300 ohm twin lead for
VHF and 75 ohm coax for UHF, or it can be used to combine the 300 ohm
twin lead from a VHF antenna with a 75 ohm coax input from a UHF antenna
to produce a combined VHF/UHF 75 ohm feed to a modern receiver with a
single antenna input. Your application is different, you're not going to
get combined VHF/UHF back onto that 300 ohm remnant without a splitter.
I am not sure there is a more asinine approach, you lose a lot of signal
no matter what you do trying to re-use the twin lead without a
preamplifier at the antenna to overcome substantial balun and splitter
loss.

 

[Fred Bloggs]

ohms and connect it to an old TV.


twin-lead that I cut in half, in


transformer on that end?

<snip>

This has to be a troll.

You missed the part about frequenting a "dollar store"- this indicates a
certain level of socio-economic development that is fairly basic.

 

[Spehro Pefhany]

You missed the part about frequenting a "dollar store"- this indicates a
certain level of socio-economic development that is fairly basic.

I go into those places just to marvel at all the crap they can sell
for such a low price. There are even companies that specialize in
making *electronics* (of a sort) that can be sold in dollar stores.
Not that you'd want to own any of it yourself, but it mostly even
functions.


Best regards,
Spehro Pefhany

 

[Treeline]

If you recall, the part I purchased, an RCA VH104, just happens to be
the very same part sold in all the stores around here. This is not a typical
dollar store part since it's actually a name brand.

 

[Treeline]

The ultimate question you ask was, is it better to not screw about and just
connect directly to the TV. And you wonder why you're considered a troll??
Maybe you are just experimenting (good on yer) but your post was a bit of a
ramble.

That's true. I do tend to ramble while exploring what is for me, something
I do not know about. If I had been working on this problem for a while,
then I can use parsimony which is the goal of science or fewer words.

And for the other questions, yes, you can use the transformers in 'reverse',
and yes, they can be cascaded.

Ken

Thanks, this I discovered. And in my "ramble" I was actually extremely accurate
when I reckoned a -0.50 dB loss if they are reversed. One web site,
dealing with antennas, reckoned around -0.46 dB loss.

 

[Treeline]

The "separator/combiner" does its thing by frequency band, it separates
out the combined UHF/VHF into separate UHF and VHF channels for older
receivers with two antenna inputs- usually with 300 ohm twin lead for
VHF and 75 ohm coax for UHF, or it can be used to combine the 300 ohm
twin lead from a VHF antenna with a 75 ohm coax input from a UHF antenna
to produce a combined VHF/UHF 75 ohm feed to a modern receiver with a
single antenna input. Your application is different, you're not going to
get combined VHF/UHF back onto that 300 ohm remnant without a splitter.
I am not sure there is a more asinine approach, you lose a lot of signal
no matter what you do trying to re-use the twin lead without a
preamplifier at the antenna to overcome substantial balun and splitter
loss.

You're the one that made an ad hominem argument and your explanation
above is neither relevant nor accurate. Figures.

You did not read carefully what I was asking. I am using a splitter but
I am not splitting the signal. That may be difficult for your brain to grasp
because you obviously think only inside the box. And you used the word,
"asinine" - pot, kettle, black.

In any event, the dollar store sold an RCA part, VH104, that was the same
part, exact same part, sold in other stores in my area. The same dollar store
also had parts when the ubiquitous Radio Shack did not have them in
stock.

 

[Treeline]

You missed the part about frequenting a "dollar store"- this indicates a
certain level of socio-economic development that is fairly basic.

That's funny. Of all the replies I have had, yours was the only one that
was not only ad hominem and crude, but your other technical reply
was just plain wrong.

So tell me, what is your socio-economic development? Do you have any at all?

 

[Fred Bloggs]

You're the one that made an ad hominem argument and your explanation
above is neither relevant nor accurate. Figures.

If you say that part is a "signal separator/combiner" with ports labeled
UHF IN/OUT and VHF IN/OUT, then YOU ARE A LIAR! It will be a cold day in
hell before the likes of LOW TRASH like *you* tells me *anything*.

You did not read carefully what I was asking. I am using a splitter but
I am not splitting the signal. That may be difficult for your brain to grasp
because you obviously think only inside the box. And you used the word,
"asinine" - pot, kettle, black.

O shut the F_ up and GFOAD... low life p.o.s. trying to appear clever...

 

[Fred Bloggs]

That's funny. Of all the replies I have had, yours was the only one that
was not only ad hominem and crude, but your other technical reply
was just plain wrong.

So tell me, what is your socio-economic development? Do you have any at all?

You're a typical little sneak and ignorant low life- you are a liar and
incompetent. Here's hoping you fall off that roof and break your neck.
In the future, keep your lying trash off this NG, it has nothing to do
with electronics and you are uneducable. GFOAD

 

[Fred Bloggs]

You did not read carefully what I was asking. I am using a splitter but
I am not splitting the signal. That may be difficult for your brain to grasp
because you obviously think only inside the box. And you used the word,
"asinine" - pot, kettle, black.

Really? Then how in hell do you get to two loads without a split, you
f___g moron. So some days you watch TV on the twin lead and others you
watch the other TV on the coax- hmmm- so ingenious!- aren't you
exceptional. Like I said- in the future keep your lying trash of this
NG. And you don't fool anyway- we know you are a regular pest posting
under a multitude of names to get out of most killfiles.

 

[Rich Grise]

I go into those places just to marvel at all the crap they can sell
for such a low price. There are even companies that specialize in
making *electronics* (of a sort) that can be sold in dollar stores.
Not that you'd want to own any of it yourself, but it mostly even
functions.

I needed some spring-type clothespins not too long ago. I found a
100-pack at the dollar store for 99 cents.

They are pretty amazing, sometimes. Flea markets can be fun too,
especially if your date doesn't insist on extravagance. ;-)

Cheers!
Rich

 

[Fred Bloggs]

I go into those places just to marvel at all the crap they can sell
for such a low price. There are even companies that specialize in
making *electronics* (of a sort) that can be sold in dollar stores.
Not that you'd want to own any of it yourself, but it mostly even
functions.

All that RCA antenna accessory stuff like the VH104 is manufactured in
China- that would make it cheap. It turns out this VH104 is a "push-on"
band combiner, it is for interior use, it pushes on to the single F-jack
for the TV RF input. This push-on has two inputs, an F-jack for VHF and
screw terminals for a twin lead UHF. This "treeline" moron pushes his
antenna fed 300:75 push-on onto the VHF VH104 jack and connects a
300-ohm twin lead to the UHF terminals and possibly onto a second
receiver. Then the idiot has the goddammed nerve to make statements like:

"That's funny. Of all the replies I have had, yours was the only one that
was not only ad hominem and crude, but your other technical reply
was just plain wrong."

"You're the one that made an ad hominem argument and your explanation
above is neither relevant nor accurate. Figures."

"You did not read carefully what I was asking. I am using a splitter but
I am not splitting the signal. That may be difficult for your brain to grasp
because you obviously think only inside the box. And you used the word,
"asinine" - pot, kettle, black."

And to think the goddammed moron is making these connections because
wires go on screws and plugs go on jacks- oblivious to little things
like VHF and UHF terminal labels. Like I said, you have your certain
clientele for dollar stores, and this ignorant and opinionated p.o.s.
"treeline" sounds most typical.

OP:

"I found some RCA VH104 Signal Separator/Combiners in a dollar store.

If I connect the balun transformer to the VHF OUT/IN [and second half of
the twin-lead antenna wire]
to the UHF OUT/IN - will this so the trick?"

-JUST UN-F___KING BELIEVABLE....

 

[Rich Grise]

That's funny. Of all the replies I have had, yours was the only one that
was not only ad hominem and crude, but your other technical reply
was just plain wrong.

So tell me, what is your socio-economic development? Do you have any at all?

That's just Fred. You'll get used to him being around, or at least learn
to ignore him.

Cheers!
Rich

 

[Treeline]

You're a typical little sneak and ignorant low life- you are a liar and
incompetent. Here's hoping you fall off that roof and break your neck.
In the future, keep your lying trash off this NG, it has nothing to do
with electronics and you are uneducable. GFOAD

Somehow you don't strike me as an Ivy League grad. Have you tried Alcoholic Anonymous?

 

[Treeline]

If you say that part is a "signal separator/combiner" with ports labeled
UHF IN/OUT and VHF IN/OUT, then YOU ARE A LIAR! It will be a cold day in
hell before the likes of LOW TRASH like *you* tells me *anything*.

It's fairly obvious that you are not able to assimilate learning.
Funny, you called me "uneducable" and insinuated I was of low SES.
And here you are acting like a Jerry Springer trailer trash. Tsk. Tsk.
Are you bipolar and currently in your manic phase?

O shut the F_ up and GFOAD... low life p.o.s. trying to appear clever...

I was simply pointing out the obvious. Now simmer down or I'll have
to point out that you cannot think in the box or out of the box.

 

[Treeline]

Treeline wrote:

Really? Then how in hell do you get to two loads without a split, you
f___g moron. So some days you watch TV on the twin lead and others you
watch the other TV on the coax- hmmm- so ingenious!- aren't you
exceptional. Like I said- in the future keep your lying trash of this
NG. And you don't fool anyway- we know you are a regular pest posting
under a multitude of names to get out of most killfiles.

So vulgar and you called me low SES. Do you have any education at all?