RF (Antenna) plumbing

[Don Y]

Hi Michael,

In CATV it is called a 'Distribution Amplifer'. Here is an example
of a one in, eight out remote powered DA for CATV:

<http://www.ebay.com/itm/8-Output-Po..._EN_Networking_Components&hash=item519c86b06c>

So, this addresses the splitter *and* buffers. Instead of inserting
an amplifier upstream (to compensate for the insertion loss of the
splitter), this gives me unity gain *across* the slit AND buffers
each output (as Joerg has suggested)?

So, the only losses I have to deal with are the ~5dB in the cable
"drops"?

I don't see a power supply with this listing, but new, sealed
packages show up fairly often or you can make your own out of a wallwart
and a chassis mount female F' connector.

Hacking together a small supply is never a problem.

The matching power supply is called 'ARPI-200M power inserter'.

I bought a used set for 99 cents plus shipping in July. I still need
the large plastic junction box to mount it outside, and to replace some
existing coax.

Anything special about the box? Or, will any (suitably sized) box work?

(not a problem for my application)

 

[Don Y]

Hi Gary,

in message news:[email protected]...

Modern digital cable plants top out at somewhere between 850MHz and
1GHz. Most are at 850MHz.

OK, so roughly the same as DTV.

The tricky part is the cable is
bi-directional; the set-tops transmit signals back to the headend for
interactive services (video on demand, for example).

If you're with cable company such as Comcast, the return path is below
100MHz, maybe even below 54MHz (my memory is fuzzy). Cable modems use
this same path for the upstream data.

If you're on FiOS, a technology called MoCA is used (Google it). MoCA
essentially creates an Ethernet type LAN (or LANs) above 1GHz (1.1GHz
isn't unusual, but it does change). It is used for communication between
the set top boxes, the router, and the ONT. MoCA is able to pass through
splitters - it can go in one "out" port and come out all the other
ports. Of course, there is significant loss when it goes through
splitters, but it is designed to work with typical home coax networks.

So, if you want the return path to work, make sure you use the right
splitters and amplifiers that match your service provider. For cable
companies, make sure any amps have a low loss upstream path. For FiOS,
be careful with splitter and amp selection, as they shouldn't block the
high frequency MoCA signals.

If you spend some time with Google and Wikipedia, you should be able to
get a good idea of the frequencies and technologies in use by your
particular service provider.

We don't use cable so its not an issue. I am more concerned to make sure
the wiring scheme *can* accommodate CATV when/if the need arises.

Thanks!
--don

 

[Joerg]

Hi Joerg,


But that's misleading. It actually doesn't include the "computers"
(there are ~22 additional nodes in the office, etc.). Keep in mind, I
intend to serve *everything* over IP. Look around your house and
count the number of televisions, phones, HiFi's, etc. Then, think
about where you could conceivably want to relocate each of those.
I.e., you may not have a TV in (each) bedroom, but, if you were
sick/bedridden, the ability to drag one in that room would be nice!

There is one TV jack. If the TV needs to be in another corner we'd just
run a longer cable to it. After all, it's only for the duration of a
sickness that might possibly strike some day.

What about the front and back *porches*? (the weather here allows
for year round outdoor activities)

Both have TV jacks. The back porch also has CAT-5 but normally unplugged
for security reasons.

Then, think about other "fixtures" that you would have in place:
ceiling/wall mounted speakers (powered and driven over the network),
surveillance cameras, etc. You may not want a TV in the *bathroom*
but might welcome being able to hear the balance of a newscast
while (ahem) "reading"... :>

You must have built the house from scratch. There would be no way to get
CAT-5 to all those places here.

On top of that, imagine places where you would want to "interact"
with your "house":
- I have drops by the front and back doors for "control (touch) panels"
that let you view and set things ("who is at the front door ringing the
doorbell?", "Turn the ACbrrr down a few degrees", etc.)

The real AC is never on anymore because we have an evap cooler now. The
time constant of that cooling is several hours, so we have a totally
revolutionary control concept: Walk over there, reach over, turn big
knob

For some other stuff we have several handheld RF remotes.

- similarly, a panel in the hallway to the bedrooms ("I'm going to
bed, tun the house 'off'")
- and the passageway to the garage
- and *in* the garage, itself
- (I even ran a drop up to the roof so I can control the swamp cooler
*while* servicing it!)

It is astonishing how quickly this list grows! :< (at least *I*
was surprised!)

We used to have X10 for all that, with a central controller that can be
reached via any of the remotes. But the PLC part, comm standard, and the
hardware are all of sub-par quality so I ripped most of it out again.

I haven't worried about things like lighting. I'm more interested
in HVAC, making sure the big freezer doesn't "thaw", ensuring the
yard gets watered appropriately (regardless of weather), etc.
I.e., things that aren't typically readily instrumented. ("Is the
garage door closed?")

And, most of all, being able to tie all the cruft together so
relationships between them can be expoited. ("Someone rang the
doorbell! Let me route the front_door_video to the display(s)
nearest the current occupants...")

I dropped my efforts to do that. It's impossible in an existing house
like this because there is no decent hardware at reasonable prices. Huge
untapped market, the big players simply don't get it.

Of course, the existing CAT5 cable is still *usable* -- just overkill!

[The goal here is to get rid of all the "kit" lying around the house
as well as centralize its maintenance. Let the house know what you
want -- on demand or algorithmically -- and then let *it* get it to
you,
wherever you might be.]

If you ever come across something reasonably priced that can replace
this %#&@!! X10 stuff let me know. Right now it also won't let me put
CFLs on the times lights because it's all triac switched in the wall
switches.

I think the way to do this (for new construction) is with switching
at the electrical panel (one of my uncles built a home like this
50+ years ago -- everything controlled by low voltage switching.
Jeez, what a piece of cake *that* would be to automate!!)

I have seen a house like that, probably around 40 years old. Mains home
runs could only be done back in those days, when copper was cheap. Also,
those relays were freaking hot, could barely touch them.

Nowadays, I think the real downside risk is not being able to purchase
replacement parts!

You'd probably have to sit down and rebuild a relay.

But, if it is designed for indoor use, I suspect the components won't
have been chosen with environmental extreme in mind...

Well, yeah, one would never mount those out in the rain. Although
there's cabinets if you had to. But the electrolytic in there would
likely croak soon.

My splitters will pass DC. The problem I worry about is that now I am
putting that "injected DC" on everything connected to that splitter!
I.e., the downstream side of the injector is blocked or DC. But, the
other "drops" just have cables running to them with this DC sitting
on it -- courtesy of the splitter!

That's whar thems condensers were invented for

[...]

Sorry< I wasn't clear. :<

I meant turning that store room into living space would require
opening a *doorway* through that load-bearing wall. We visited
a nearby home with the same (basic) floorplan. On returning home,
chuckled at the realization that the owner had removed a load-bearing
wall in the center of the house. ("Gee, this wall breaks up the view
through the house. Let's remove it!") I've been dying to get back in
there and count the cracks in the ceiling, etc.! :>

One guy in this area had his roof starting to sag after that.

 

[Joerg]

Hi Joerg,

The phone runs are not used and might never be. The LAN is, because
WLAN
is iffy and slow. Then two coaxes each, one for back-feeding.
I ran CAT3 for the phones - mainly because that was cheaper (free!) than
buying a spool of "quad". But, that's there "for future owners" as the
phones here are moving to VoIP -- like everything else!
I ran CAT-5 everywhere because it's so cheap. Got two 1000ft boxes to be
able to do the double pull. I'll never use them up in this earthly life
of mine. Same for the two RG6 spools.
Ah, I've run a fair bit more than that (not counting the CAT3 stuff).
<frown> I'll be needing a third box RSN (there are ~50 CAT5 "drops",
here). ...

Fifty? Wow!

... I've opted to do everything *wired* instead of "wireless".
Even this laptop is currently tethered to the wall with ts wireless
"off".

However, I may want to change much of the automation kit to run a
slower protocol (instead of 10/100BaseT) to save complexity and money
on the network switch. Doing everything PoE -- and having to battery
back much of that -- leads to a horrendously costly switch when
the traffic doesn't really *need* it (and, finding PoE switches
that let you selectively back up certain parts of the fabric makes
this even worse!)

Looks like you went pretty far with home automation. I have dismantled
most of it because this whole X10 stuff is IMHO junk. Plain unreliable.
And the transmission protocol isn't very good to begin with.

Of course, the existing CAT5 cable is still *usable* -- just overkill!

[The goal here is to get rid of all the "kit" lying around the house
as well as centralize its maintenance. Let the house know what you
want -- on demand or algorithmically -- and then let *it* get it to you,
wherever you might be.]
If you ever come across something reasonably priced that can replace
this %#&@!! X10 stuff let me know. Right now it also won't let me put
CFLs on the times lights because it's all triac switched in the wall
switches.
I think the way to do this (for new construction) is with switching
at the electrical panel (one of my uncles built a home like this
50+ years ago -- everything controlled by low voltage switching.
Jeez, what a piece of cake *that* would be to automate!!)

I have seen a house like that, probably around 40 years old. Mains home
runs could only be done back in those days, when copper was cheap. Also,
those relays were freaking hot, could barely touch them.

Of course, "what goes where" can change over time. So, I
want to be able to "rewire"/replace the splitters as the
need arises.
That will make it expensive if you want to do it properly.
Not a big problem. So far I've spent $0 (had 1,000 ft of RG6
plus a collection of splitters, F connectors, etc.). Biggest
issue is the "mechanical" one -- figuring out what needs to
be mounted and how to arrange it in a serviceable manner.
Yeah, but to do it properly that's not going to suffice. You'll need
buffer amps, splitters, filters and other additional hardware. Which
either costs money or time if you roll your own.
So far, it looks like the buffer amps are the missing ingredient.
The bigger issue is making sure it doesn't have to be done over
(or -- GASP -- *relocated*!)
I use this kind, two of them:

http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053

Good luck with those. I used to buy dead ones for 50 cents and
replace the single transistor that died every time there was a nearbly
lightning strike. They dropped like flies in Central Florida.

Beats me why many "RF designers" can't get it into their heads that the
very first component in any RF amp after the coax jacks shall be a choke
to ground.

In our case it's ok since they are inside and behind the preamp. But
IIRC there's five transistors in each.

They are very easy to pry open, and quite often the back doesn't make
good contact so stray RF can get into or out of the cheap stamped steel
case. (Ingression or Radiation)



<http://www.alltronics.com/cgi-bin/item/25A001/35/RF-Preamplifier-Module>
surplus for $1.99.

That's inexpensive indeed.

 

[Don Y]

Hi Joerg,

There is one TV jack. If the TV needs to be in another corner we'd just
run a longer cable to it. After all, it's only for the duration of a
sickness that might possibly strike some day.

Different perspectives. A neighbor was bedridden for several
years before just passing away. Another friend just diagnosed
with ALS. I.e., it's not uncommon for people to spend considerable
time "trapped" in a room.

Plus, a future owner would probably have kids and they would want
media access in those rooms.

"Wire is cheap" :>

Both have TV jacks. The back porch also has CAT-5 but normally unplugged
for security reasons.

I just change the routing tables to prevent them from going anywhere.

You must have built the house from scratch. There would be no way to get
CAT-5 to all those places here.

We re-routed the HVAC supply ducts. At the time, that gave us
easy access to many of the "interior" walls in the house. Birdboards
give us (continued) access to one of the exterior walls. And, the
"end" birdboards give us access to two of the other exterior walls.

In two places, I had to cut small holes in the ceiling to get the drop
*down* into the wall. But, doing so carefully make these easy to
patch.

The drops for the front porch are currently tucked up in the ceiling
*by* the front porch -- waiting for me to get a chance to remove that
paneling and stucco the porch. (No rush for those drops since we
couldnt leave anything *out* (TV, etc.) on that porch as it isn't
"secure".)

The real AC is never on anymore because we have an evap cooler now. The

We stopped using the cooler a few years ago. *I* prefer the moist
air (at least during the dry part of Summer) but I only get one "vote".
<frown>

But, the furnace and cooler are also controlled. I had hoped to
install motorized skylights so the cooler/ACbrrr tradeoff could be
dynamic and automated. But, with only that one vote... :>

time constant of that cooling is several hours, so we have a totally
revolutionary control concept: Walk over there, reach over, turn big
knob

For some other stuff we have several handheld RF remotes.


We used to have X10 for all that, with a central controller that can be
reached via any of the remotes. But the PLC part, comm standard, and the
hardware are all of sub-par quality so I ripped most of it out again.

Ive put reed switches on the floor to detect when the garage door is
fully closed. A long-throw opto-interrupter to detect fully open.
A sensor in the freezer to monitor temperature (and provisions to
monitor the compressor therein -- is it running "a lot" yet failing
to cool, adequately?). The same for the hot water heater (though
waiting to replace it before instrumenting that control).

Other things are much easier to accommodate. E.g., the doorbell.
There are "panic cords" in the bathrooms ("Help! I've fallen and I
can't get up!" :> ). I also ran controls for a motorized
projection screen in the living room (I consider the big TV's to
be an eyesore -- much nicer if the "screen" disappeared into
the ceiling).

Things like the thermostat and irrigation controller are a bit more
involved because they need to operate in the absence of "supervisory
control". I.e., if the automation server crashs, you don't want the
house to heat up *or* cool off extraordinarily. So, (part of) the
control loop has to reside in those "motes" -- not just the I/O's
(as is the case for the garage door, etc.)

I dropped my efforts to do that. It's impossible in an existing house
like this because there is no decent hardware at reasonable prices. Huge
untapped market, the big players simply don't get it.

Again, in our case, we took advantage of the opportunity to run wire
to all of those places. If we had an attic or basement, this would
have been much easier.

Once you have wire in place, it becomes relatively easy to script
many of these things:

for door in doors
if (doorbell[door]) {
announce_visitor();
locations = locate_occupants();
for l in locations
route_video(l, door);
}

Well, yeah, one would never mount those out in the rain. Although
there's cabinets if you had to. But the electrolytic in there would
likely croak soon.

The amplifier I have is intended to be outdoors. Presumably
taking into account the fact that it rains AND the sun shines on it.

One guy in this area had his roof starting to sag after that.

Yes but I wonder if they'd ever *notice*? This (partial) wall supports
(part of) a 25' 4x12 that carries the living room ceiling. It also
acts to psychologically isolate the living room from other arts of the
house (by breaking sight lines). *They* obviously decided the wanted
to *open* those sight lines -- without thinking about other reasons for
the wall's presence! :-/

[I was lucky to come across a set of prints for this house so know
where the footers are poured. "Gee, look at this footer in the center
of the house... right under this funky little wall..."]

 

[mike]

Hi,

[hoping this is the right place to ask]

I'm trying to organize the antenna feeds at home. There are
two separate antenna -- TV + FM. And, two CATV feeds (one
acting as a spare). These will, in some combination, feed up
to ~15 drops throughout the house through a set of splitters.

Of course, "what goes where" can change over time. So, I
want to be able to "rewire"/replace the splitters as the
need arises.

My current plans are to terminate the source feeds and one
end of *each* drop in male F-connectors at a "patch panel" (of
sorts) consisting of double threaded (female) F-connectors.

Then, connect the sources to splitters (i.e. for each source)
using male-male "patch cords" and the splitters to the drops
with similar patch cables.

It is unlikely that every drop will ever be driven from any
single splitter. Worst case would probably be an 8-way.
In practice, probably 3 or 4 -ways.

I'm using RG6 and the longest drop is probably ~70 feet.
So, I figure roughly 5dB in the cable and ~10-12dB in the
(8-way) splitter(s).

I figure I can insert a small wideband, in-line amplifier
ahead of each splitter to compensate. And, a power injector
*immediately* downstream of that (no mains power available
nearby).

Schematically (fixed width font), something like this:

How are you combining the multiple sources at V?
I'd pay some attention to dynamic range. If you have weak
signals and strong signals, you may run out of it.
I had a situation where I cascaded so many splitters that
there wasn't enough signal. Adding an amplifier at the front
end made the whole system worse cause it overloaded the front end
of the less attenuated stuff.
Using a distribution amplifier designed for the job and ditching
most of the splitters helped a lot.

Having quality stuff everywhere helps, but I don't have any of that.

_
V (antenna, CATV, etc)
|
|
|
+-> >< <====> >AMP< <====> >INJ< <=+
|
|
--> >< <==============> >-S |
: : : P |
--> >< <==============> >-L-< <====+
: : : I
--> >< <==============> >-T


where "<===>" are patch cords terminated in male connections
and "><" are the double female connectors.

My questions:

Is it *worthwhile* to use female F-connectors on each cable
instead of a male connector screwed into the double female?
(the male+female+path approach is a bit easier to assemble)

Are there practical consequences of using the various (short)
lengths of "patch-cords"? (i.e., instead of tying feeds/drops
directly to the splitters/amps)

I assume the double female connectors should be mounted on an
insulated plate so that the grounding is dictated by the
particular splitters/drops?

If the splitter passes DC (i.e., power), I imagine it is still
not advisable to locate the injector on one of the drops? (i.e.,
pushing power back *through* the splitter to the amplifier)

As the amplifier is relatively low power, I assume I can just run
a (long... ~50 ft) length of zip cord to get power to the injector?

What sort of bandwidth should I plan on for the CATV feed and
its amplifier? (I figure ~1GHz for DTV+FM)


[Apologies for any delay in my replies as end-of-the-year equipment
upgrades have me working without full news feeds, etc]

Thx,
--don

 

[Don Y]

Hi Mike,

How are you combining the multiple sources at V?

"V" is actually intended to be an antenna symbol:
_
V
|

There are two. Plus two CATV feeds. So, to answer your
question: I'm *not* combining anything! The DTV antenna
feeds a splitter that drives the drops intended for OTA
reception. The FM antenna feeds a splitter that drives
the drops that feed HiFi's. The CATV lines feed a splitter
that ...

I'd pay some attention to dynamic range. If you have weak
signals and strong signals, you may run out of it.
I had a situation where I cascaded so many splitters that
there wasn't enough signal. Adding an amplifier at the front
end made the whole system worse cause it overloaded the front end
of the less attenuated stuff.

I'm more concerned about the way I've routed the cables
and where I've decided (schematically and physically) o
locate the various "components" involved. E.g., amp
ahead of splitter -- instead of at the load end of a drop...

Using a distribution amplifier designed for the job and ditching
most of the splitters helped a lot.

Having quality stuff everywhere helps, but I don't have any of that.

Well, I'm not breaking the bank with this (I had to buy some RG6Q
F connectors is my biggest out-of-pocket) but don;t want to make
any obvious mistakes. Opening up the ceiling again to fix something
would be painful. OTOH, I could very easily convince myself to just
*ignore* any problems! :>

 

[Joerg]

Hi Joerg,



Different perspectives. A neighbor was bedridden for several
years before just passing away. Another friend just diagnosed
with ALS. I.e., it's not uncommon for people to spend considerable
time "trapped" in a room.

Ok, but that warrants a lot more changes and you might then throw in
another wire drop. For example right now our master bedroom has no LAN.
But it'll be easy to run if the need would arise.

Plus, a future owner would probably have kids and they would want
media access in those rooms.

That's what causes problems in a lot of kids these days. I am glad my
parents did not allow that.

"Wire is cheap" :>

If it's a new house, yes, otherwise it can be a pain in the neck to fish
it through. Fire stops are special fun.

I just change the routing tables to prevent them from going anywhere.

Oh, I just hop into the basement. And while down there, I grab a nice
bottle of Belgian Trappiste ale

[...]

We stopped using the cooler a few years ago. *I* prefer the moist
air (at least during the dry part of Summer) but I only get one "vote".
<frown>

But, the furnace and cooler are also controlled. I had hoped to
install motorized skylights so the cooler/ACbrrr tradeoff could be
dynamic and automated. But, with only that one vote... :>

I was lucky. At frst my wife said "But I don't want an ugly monster like
So-and-so has", referring to a friend who generally just kludges such
stuff. So I promised her I'd do a really nice and clean install and now
she loves it. I even made a winter cover that matches the wall. Beats me
why the mfgs do not sell any, they are literally leaving money on the table.

Ive put reed switches on the floor to detect when the garage door is
fully closed. A long-throw opto-interrupter to detect fully open.
A sensor in the freezer to monitor temperature (and provisions to
monitor the compressor therein -- is it running "a lot" yet failing
to cool, adequately?). The same for the hot water heater (though
waiting to replace it before instrumenting that control).

Other things are much easier to accommodate. E.g., the doorbell.
There are "panic cords" in the bathrooms ("Help! I've fallen and I
can't get up!" :> ). I also ran controls for a motorized
projection screen in the living room (I consider the big TV's to
be an eyesore -- much nicer if the "screen" disappeared into
the ceiling).

Things like the thermostat and irrigation controller are a bit more
involved because they need to operate in the absence of "supervisory
control". I.e., if the automation server crashs, you don't want the
house to heat up *or* cool off extraordinarily. So, (part of) the
control loop has to reside in those "motes" -- not just the I/O's
(as is the case for the garage door, etc.)

Pretty impressive. Most stuff is automated here as well but it is not
networked. Because I haven't found any reliable comms method that is
reasonably priced. But I do not really central servers too much.

Again, in our case, we took advantage of the opportunity to run wire
to all of those places. If we had an attic or basement, this would
have been much easier.

We have a Frank Lloyd Wright style house and retrofit runs are painful
to impossible in most areas. You push into a ceiling and 4-5ft later ...
thwock ... full impenetrable stop.

Once you have wire in place, it becomes relatively easy to script
many of these things:

for door in doors
if (doorbell[door]) {
announce_visitor();
locations = locate_occupants();
for l in locations
route_video(l, door);
}

I'd do it without scripting. Plus 99.xx% of buyers are not programmers.

The amplifier I have is intended to be outdoors. Presumably
taking into account the fact that it rains AND the sun shines on it.


Yes but I wonder if they'd ever *notice*? This (partial) wall supports
(part of) a 25' 4x12 that carries the living room ceiling. ...

Ouch! That sounds like they wrecked the static integrity of their house.

... It also
acts to psychologically isolate the living room from other arts of the
house (by breaking sight lines). *They* obviously decided the wanted
to *open* those sight lines -- without thinking about other reasons for
the wall's presence! :-/

[I was lucky to come across a set of prints for this house so know
where the footers are poured. "Gee, look at this footer in the center
of the house... right under this funky little wall..."]

I can crawl underneath ours and actually see where they are.

 

[Don Y]

Hi Joerg,

Ok, but that warrants a lot more changes and you might then throw in
another wire drop. For example right now our master bedroom has no LAN.
But it'll be easy to run if the need would arise.

Adding ANY wiring (e.g. drops) here would typically be done on the
*outside* of the house OR by carefully boring through the roof
HOPING to it the interior of a wall (*insane*!). So, when you have
he chance to string wire, you string everything imaginable!

If it's a new house, yes, otherwise it can be a pain in the neck to fish
it through. Fire stops are special fun.

That's why having access to the HVAC soffits was such a blessing!
Can't run cable *in* the ductwork but you can run it *along* the
ducts!

Oh, I just hop into the basement. And while down there, I grab a nice
bottle of Belgian Trappiste ale

Hard to automate "run into basement"! :>

I was lucky. At frst my wife said "But I don't want an ugly monster like
So-and-so has", referring to a friend who generally just kludges such
stuff. So I promised her I'd do a really nice and clean install and now
she loves it. I even made a winter cover that matches the wall. Beats me
why the mfgs do not sell any, they are literally leaving money on the table.

Our cooler shares the same distribution ductwork as the furnace and
ACbrrr. So, switching among them is relatively easy -- *except* heat
and AC typically happen with windows *closed* (while the cooler needs
a vent)

Pretty impressive. Most stuff is automated here as well but it is not
networked. Because I haven't found any reliable comms method that is
reasonably priced. But I do not really central servers too much.

My first pass just used wiring to bring the field *to* the controllers.
Then, I redesigned t move the controllers out *to* the field. Since I
was using PoE for the telecom and multimedia stuff, this seemed a
natural extension: run everything over ethernet and use the PoE
feature to get power to the various motes.

But, I now wnt to go back to a slower technology to cut down on
the size/complexity of the PoE switch. ($$) This is unfotunate
as t means I will need to have a second system of power management
instead of just treating the automation nodes/motes as "yet another
powered device/peripheral" (e.g. a second battery backup scheme
and an independent set of management criteria)

Once you have wire in place, it becomes relatively easy to script
many of these things:

for door in doors
if (doorbell[door]) {
announce_visitor();
locations = locate_occupants();
for l in locations
route_video(l, door);
}

I'd do it without scripting. Plus 99.xx% of buyers are not programmers.

I'm not interested in buyers! :>

Ouch! That sounds like they wrecked the static integrity of their house.

Yup. I figure the footer and support wall were put there for a reason!
So, I wonder when his sh*t will hit the proverbial fan! :-/

 

[Joerg]

Don Y wrote:

[...]

Our cooler shares the same distribution ductwork as the furnace and
ACbrrr. ...

How did you do that? A giant "cold air SPDT relay"?

... So, switching among them is relatively easy -- *except* heat
and AC typically happen with windows *closed* (while the cooler needs
a vent)

One company makes ceiling vents for that. Forgot the brand but they open
into the attic when pressure from the cooler builds but close through a
temp fuse when there is a fire. Not sure how well they hold up in winter.

[...]

Once you have wire in place, it becomes relatively easy to script
many of these things:

for door in doors
if (doorbell[door]) {
announce_visitor();
locations = locate_occupants();
for l in locations
route_video(l, door);
}

I'd do it without scripting. Plus 99.xx% of buyers are not programmers.

I'm not interested in buyers! :>

Hmm, but don't we have some moral obligations for after when we leave
this earth? Paying for assisted living would also require fetching a
pretty penny for the house. Unless you'be been a state employee with a
super-fat pension plan. It'll be tough to sell if the installation is
deemed "weird". If the home inspector doesn't understand or doesn't
approve of it people usually nix the deal.

Yup. I figure the footer and support wall were put there for a reason!
So, I wonder when his sh*t will hit the proverbial fan! :-/

Probably when he sells and the buyer comes in with a smart home
inspector. Not sure about the law but I assume they'd have to report an
unsafe structure, and then all hell would break loose.

 

[Don Y]

Hi Joerg,

How did you do that? A giant "cold air SPDT relay"?

[Of course, the ACbrrr shares the furnace ductwork due to the location
of the Acoil on the top (exhaust) side of the furnace.]

The supply ducts are located high in the rooms. So, it is convenient
for a roof mounted, downdraft cooler to push chilled air *down* into
the ducts. Barometric dampers are located below the cooler (yet above
the ducts) and above the A-coil (yet below the ducts) acting as one
way valves, of a sort.

<http://www.indoorcomfortsupply.com/cgi-bin/commerce.exe?preadd=action&key=2091>

But, these leak. So, when I *know* the heating/cooling season is
over, I install baffles below/above the ducts alongside the dampers
for a tighter seal.

One company makes ceiling vents for that. Forgot the brand but they open
into the attic when pressure from the cooler builds but close through a
temp fuse when there is a fire. Not sure how well they hold up in winter.

I wanted to just install motorized skylights -- and vent them when the
cooler needed to run. This would have the added benefit of bringing
light into rooms. (we like *lots* of daylight in the house)

Once you have wire in place, it becomes relatively easy to script
many of these things:

for door in doors
if (doorbell[door]) {
announce_visitor();
locations = locate_occupants();
for l in locations
route_video(l, door);
}


I'd do it without scripting. Plus 99.xx% of buyers are not programmers.

I'm not interested in buyers! :>

Hmm, but don't we have some moral obligations for after when we leave
this earth? Paying for assisted living would also require fetching a
pretty penny for the house. Unless you'be been a state employee with a
super-fat pension plan. It'll be tough to sell if the installation is
deemed "weird". If the home inspector doesn't understand or doesn't
approve of it people usually nix the deal.

You will note that I said *remove* the kit when leaving the house! (in
an earlier post) That's the reason that I'm going to the effort of
installing more conventional infrastructure (regular telco wiring,
CATV drops, etc.).

Probably when he sells and the buyer comes in with a smart home
inspector. Not sure about the law but I assume they'd have to report an
unsafe structure, and then all hell would break loose.

No doubt! If not sometime *before* that! ("Bob, why is the living room
ceiling sagging?")

 

[Joerg]

Hi Joerg,

How did you do that? A giant "cold air SPDT relay"?

[Of course, the ACbrrr shares the furnace ductwork due to the location
of the Acoil on the top (exhaust) side of the furnace.]

The supply ducts are located high in the rooms. So, it is convenient
for a roof mounted, downdraft cooler to push chilled air *down* into
the ducts. Barometric dampers are located below the cooler (yet above
the ducts) and above the A-coil (yet below the ducts) acting as one
way valves, of a sort.

<http://www.indoorcomfortsupply.com/cgi-bin/commerce.exe?preadd=action&key=2091>

I thought I had understood it but this throws me off guard. That kind of
damper is usually mounted under where a rood-mounted the evap cooler
pushes it's cool air inside, isn't it? Also, doesn't code require a
fire-shutoff function?

But, these leak. So, when I *know* the heating/cooling season is
over, I install baffles below/above the ducts alongside the dampers
for a tighter seal.

Yeah, the leaks is what I am concerned about. Usually manufacturers do
not understand this and homeowners are on their won, and must kludge.
Took me a couple of hours to make a decent looking cover box for the
evap cooler inlet. SWMBO wanted one that blends into the textured wall.

I wanted to just install motorized skylights -- and vent them when the
cooler needed to run. This would have the added benefit of bringing
light into rooms. (we like *lots* of daylight in the house)

And brings wasps and other nice guests inside

Once you have wire in place, it becomes relatively easy to script
many of these things:

for door in doors
if (doorbell[door]) {
announce_visitor();
locations = locate_occupants();
for l in locations
route_video(l, door);
}


I'd do it without scripting. Plus 99.xx% of buyers are not programmers.

I'm not interested in buyers! :>

Hmm, but don't we have some moral obligations for after when we leave
this earth? Paying for assisted living would also require fetching a
pretty penny for the house. Unless you'be been a state employee with a
super-fat pension plan. It'll be tough to sell if the installation is
deemed "weird". If the home inspector doesn't understand or doesn't
approve of it people usually nix the deal.

You will note that I said *remove* the kit when leaving the house! (in
an earlier post) That's the reason that I'm going to the effort of
installing more conventional infrastructure (regular telco wiring,
CATV drops, etc.).

That I never do. I want it to be so that I can essentially drop the keys
and move out. Of course, it'll never be that way but I try to strive for
that.

No doubt! If not sometime *before* that! ("Bob, why is the living room
ceiling sagging?")

I wonder when the first homes with "engineered beams" show such
problems. Probably all it takes is a leaky toilet or bathtub.

 

[Don Y]

Hi Joerg,

How did you do that? A giant "cold air SPDT relay"?

[Of course, the ACbrrr shares the furnace ductwork due to the location
of the Acoil on the top (exhaust) side of the furnace.]

The supply ducts are located high in the rooms. So, it is convenient
for a roof mounted, downdraft cooler to push chilled air *down* into
the ducts. Barometric dampers are located below the cooler (yet above
the ducts) and above the A-coil (yet below the ducts) acting as one
way valves, of a sort.

<http://www.indoorcomfortsupply.com/cgi-bin/commerce.exe?preadd=action&key=2091>

I thought I had understood it but this throws me off guard. That kind of
damper is usually mounted under where a rood-mounted the evap cooler
pushes it's cool air inside, isn't it?

One is located "above the roofline" (to be accessible AND above the
ductwork) but *below* the cooler (to place it in the outlet air flow).
This is what make it troublesome to "baffle", manually (i.e., you have
to climb onto the roof)

The other is located in the outlet duct of the furnace -- just above the
A-coil (thereby blocking airflow BACK into the furnace from the cooler).

AFAICT, they are identical devices.

Of course, the one in the furnace is very readily accessed.

Also, doesn't code require a fire-shutoff function?

Apparently not. Note that it (rooftop) only opens when air wants to
be blown DOWN through it. As soon as the cooler shuts off, it snaps
closed (annoying to hear the louvers slap shut).

Yeah, the leaks is what I am concerned about. Usually manufacturers do
not understand this

Oh, I'm *sure* they "understand it"... they just don't *care*! :>

Coolers are often covered (weatherized) in the winter so someone is
up there to cover the cooler -- and can insert the baffle.

The biggest appeal to the dampers is NOT the heating vs. cooling
switch but, rather, the ACbrrr vs. swamp cooler switch. Previously,
we would use the cooler for most of the Summer (hot, dry) and just
resort to the ACbrrr during Monsoon. The automatic dampers made this
really easy (though switching to AC from cooler has to be done with a
bit of care as the moisture content of the air -- from the cooler
plus the fact that RH is rising, in general, when we want to make
that switch -- can be a chore for the AC to address).

and homeowners are on their won, and must kludge.
Took me a couple of hours to make a decent looking cover box for the
evap cooler inlet. SWMBO wanted one that blends into the textured wall.


And brings wasps and other nice guests inside

No, you put a screen on the window.

We are debating a 46" square skylight for the kitchen (anything larger
starts to present significant structural challenges). But, are worried
about the thermal load it will place on the cooling system.

(It's amazing how hard it is to get concrete data that you can *relate*
to for things like this!)

That I never do. I want it to be so that I can essentially drop the keys
and move out. Of course, it'll never be that way but I try to strive for
that.

I'm not willing to live with what "normal" folks would consider
acceptable! :> E.g., most folk see nothing wrong with lots of
"equipment" (hifi, dvd, cd, tv, etc) cluttering up the place.
I don't want to see *any* of that, here! So, the burden falls
on me to come up with ways of *hiding* it.

The bigger worry is, "what happens if some ill befalls *me*!" :>

I wonder when the first homes with "engineered beams" show such
problems. Probably all it takes is a leaky toilet or bathtub.

Yeah, each time I look at that stuff, I (intellectually) understand how
it works. But, it doesn't leave me with a warm, fuzzy feeling thinking
something as "flimsy" as that might be keeping the roof up over my head!

 

[Joerg]

Hi Joerg,

How did you do that? A giant "cold air SPDT relay"?

[Of course, the ACbrrr shares the furnace ductwork due to the location
of the Acoil on the top (exhaust) side of the furnace.]

The supply ducts are located high in the rooms. So, it is convenient
for a roof mounted, downdraft cooler to push chilled air *down* into
the ducts. Barometric dampers are located below the cooler (yet above
the ducts) and above the A-coil (yet below the ducts) acting as one
way valves, of a sort.

<http://www.indoorcomfortsupply.com/cgi-bin/commerce.exe?preadd=action&key=2091>

I thought I had understood it but this throws me off guard. That kind of
damper is usually mounted under where a rood-mounted the evap cooler
pushes it's cool air inside, isn't it?

One is located "above the roofline" (to be accessible AND above the
ductwork) but *below* the cooler (to place it in the outlet air flow).
This is what make it troublesome to "baffle", manually (i.e., you have
to climb onto the roof)

The other is located in the outlet duct of the furnace -- just above the
A-coil (thereby blocking airflow BACK into the furnace from the cooler).

AFAICT, they are identical devices.

Of course, the one in the furnace is very readily accessed.

Ah, so you made yourself a "poor man's SPDT switch for air flow".

Apparently not. Note that it (rooftop) only opens when air wants to
be blown DOWN through it. As soon as the cooler shuts off, it snaps
closed (annoying to hear the louvers slap shut).

I do not believe that passes muster WRT the code.

Oh, I'm *sure* they "understand it"... they just don't *care*! :>

Ever since I discovered a major boo-boo in the design (!) of our pellet
stove and I as an EE had to tell those MEs how to do it right, my
confidence in the "understanding" part has been shaken.

Oh, and when the cooler arrived and was unpacked, guess who had to
balance the squirrel cage?

Coolers are often covered (weatherized) in the winter so someone is
up there to cover the cooler -- and can insert the baffle.

For our small one they don't even make a jacket. Plus those jackets can
be a perfect recipe for mold because warm moist air from inside hits a
very cold surface.

The biggest appeal to the dampers is NOT the heating vs. cooling
switch but, rather, the ACbrrr vs. swamp cooler switch. Previously,
we would use the cooler for most of the Summer (hot, dry) and just
resort to the ACbrrr during Monsoon. The automatic dampers made this
really easy (though switching to AC from cooler has to be done with a
bit of care as the moisture content of the air -- from the cooler
plus the fact that RH is rising, in general, when we want to make
that switch -- can be a chore for the AC to address).


No, you put a screen on the window.

On our roof that wouldn't last a long time. Some of the birds out here
have several feet of wing span and corrspondingly powerful beeks.
Sometimes you'd think a roofing contractor was up there.

We are debating a 46" square skylight for the kitchen (anything larger
starts to present significant structural challenges). But, are worried
about the thermal load it will place on the cooling system.

(It's amazing how hard it is to get concrete data that you can *relate*
to for things like this!)

Why? It's basically just a window, and I am sure you can get automatic
shutters for it to avoid being pelted by a scorching sun.

I'm not willing to live with what "normal" folks would consider
acceptable! :> E.g., most folk see nothing wrong with lots of
"equipment" (hifi, dvd, cd, tv, etc) cluttering up the place.
I don't want to see *any* of that, here! So, the burden falls
on me to come up with ways of *hiding* it.

The bigger worry is, "what happens if some ill befalls *me*!" :>

Exactly. And that can happen faster than we think.

Yeah, each time I look at that stuff, I (intellectually) understand how
it works. But, it doesn't leave me with a warm, fuzzy feeling thinking
something as "flimsy" as that might be keeping the roof up over my head!

IME, if I don't have a warm and fuzzy about something it is mostly
indeed junk over the long term

 

[Don Y]

Hi Joerg,

Ah, so you made yourself a "poor man's SPDT switch for air flow".

Moe like a "diode switch" :>

I do not believe that passes muster WRT the code.

It is apparently accepted practice, here. I.e., *we* didn't
do it, the HVAC installer did. The previous system used
removable baffles (present on *every* house that has a swamp
cooler). I.e., anyone with a swamp cooler has an *opening*
through the roof that is "open" throughout the cooling season
(i.e., the damper *closes* ours when the cooler is not blowing
air)

Ever since I discovered a major boo-boo in the design (!) of our pellet
stove and I as an EE had to tell those MEs how to do it right, my
confidence in the "understanding" part has been shaken.

Oh, and when the cooler arrived and was unpacked, guess who had to
balance the squirrel cage?


For our small one they don't even make a jacket. Plus those jackets can
be a perfect recipe for mold because warm moist air from inside hits a
very cold surface.

I suspect the covers are effectively "decoration". Hard to imagine
they do much/anything to improve thermal efficiency.

One of my pending improvements is to install a spiral staircase to
make it easier to get onto the roof (think: getting OLDer! :> )
so I can just stuff the cooler with a thermal block/insulation
in the heating season. I've already replaced the fasteners for the
access doors so that they can be removed without tools...

On our roof that wouldn't last a long time. Some of the birds out here
have several feet of wing span and corrspondingly powerful beeks.
Sometimes you'd think a roofing contractor was up there.

The window "looks up", not "out". And, the vent position usually only
"cracks" the skylight. So, it's a relatively small target -- and,
"uninteresting". E.g., we've never had any problems with the Harris'
Hawks, etc. in the neighborhood. OTOH, the little "critters" can't
say likewise! :>

Why? It's basically just a window, and I am sure you can get automatic
shutters for it to avoid being pelted by a scorching sun.

But we *want* it unshuttered during the daylight hours. Shutters/blinds
would actually only be useful at night to trap the heat in the winter.

I've heard horror stories that the space under these can be
significantly warmer. And, seeing that this would be the meal
prep area (i.e., where we spend a fair amount of time), increasing
light at the expense of added *heat* isn't appealing (I'd rather
just add more light fixtures).

Exactly. And that can happen faster than we think.

Yup. But, then again, it wouldn't be *my* problem! :>

IME, if I don't have a warm and fuzzy about something it is mostly
indeed junk over the long term

Well, I don't get that feeling from "metal studs". Yet, I have grown
accustomed to using them liberally! OTOH, I don't use them for the
same sort of structural support that I might use dimensioned lumber.

<shrug>

 

[Joerg]

Don Y wrote:

[...]

It is apparently accepted practice, here. I.e., *we* didn't
do it, the HVAC installer did. The previous system used
removable baffles (present on *every* house that has a swamp
cooler). I.e., anyone with a swamp cooler has an *opening*
through the roof that is "open" throughout the cooling season
(i.e., the damper *closes* ours when the cooler is not blowing
air)

Amazing that the code allows that in your area. Out here the fire
marshall would probably have a hissy fit.

[...]

The window "looks up", not "out". And, the vent position usually only
"cracks" the skylight. So, it's a relatively small target -- and,
"uninteresting". E.g., we've never had any problems with the Harris'
Hawks, etc. in the neighborhood. OTOH, the little "critters" can't
say likewise! :>

That is what neighbors thought, too. Until the day when they heard a
commotion in the kitchen and a racoon was duking it out with their cats,
over who gets to eat the stuff in the bowls and who does not. He had
made a hole in the screen and was rather unimpressed by our neighbor
showing up in the kitchen.

But we *want* it unshuttered during the daylight hours. Shutters/blinds
would actually only be useful at night to trap the heat in the winter.

I've heard horror stories that the space under these can be
significantly warmer. And, seeing that this would be the meal
prep area (i.e., where we spend a fair amount of time), increasing
light at the expense of added *heat* isn't appealing (I'd rather
just add more light fixtures).

I think they make modern IR-repelling glass or something like that. It
ain't grampa's old skylight no more.

Yup. But, then again, it wouldn't be *my* problem! :>

Not guaranteed either. My wife and I visit Alzheimer's places as
volunteers. Some people live there for years or decades. Some
permanently in wheelchairs.

Well, I don't get that feeling from "metal studs". Yet, I have grown
accustomed to using them liberally! OTOH, I don't use them for the
same sort of structural support that I might use dimensioned lumber.

I would _much_ prefer metal over wood. Not this flimsy coke can strength
stuff but real posts and such. Unfortunately those are unobtanium in the
US and importing costs too much in freight. So we'll be forever forced
to fix rot on decks and such.

 

[Don Y]

Hi Joerg,

That is what neighbors thought, too. Until the day when they heard a
commotion in the kitchen and a racoon was duking it out with their cats,
over who gets to eat the stuff in the bowls and who does not. He had
made a hole in the screen and was rather unimpressed by our neighbor
showing up in the kitchen.

Never saw a racoon, here. Bobcats and bears, yes. Racoons, no.

I think they make modern IR-repelling glass or something like that. It
ain't grampa's old skylight no more.

But you can't *relate* to the number on a spec sheet! Just like you
(meaning some *real* person) can't quantify how much warmer you feel
standing in the sunlight than in the shade.

I can look up the specs for a window (skylight) but can't, from that
number, decide how comfortable/uncomfortable it would be to stand under
it for any length of time.

Not guaranteed either. My wife and I visit Alzheimer's places as
volunteers. Some people live there for years or decades. Some
permanently in wheelchairs.

If *I'm* in that state, then it's still "not my problem" :>

I would _much_ prefer metal over wood. Not this flimsy coke can strength
stuff but real posts and such. Unfortunately those are unobtanium in the
US and importing costs too much in freight. So we'll be forever forced
to fix rot on decks and such.

You can buy steel buildings, etc. It's just too expensive to be
practical. (A house I had in Illinois used a steel I-beam as the main
carrying beam)

The metal studs are more convenient than dimensioned lumber for
non-load-bearing framing -- it is *really* nice to be able to trim
things with a pair of tin snips instead of a saw (electric or hand).
But, I wouldn't count on such framing to support anything (perhaps
other than a simple drywall partition).

 

[Joerg]

Don Y wrote:

[...]

You can buy steel buildings, etc. It's just too expensive to be
practical. (A house I had in Illinois used a steel I-beam as the main
carrying beam)

The metal studs are more convenient than dimensioned lumber for
non-load-bearing framing -- it is *really* nice to be able to trim
things with a pair of tin snips instead of a saw (electric or hand).
But, I wouldn't count on such framing to support anything (perhaps
other than a simple drywall partition).

They are junk, IMHO. Once during an EMC debug job I had trouble getting
a panel off a large machine. So I pulled some more, then even more ...
*CRUNCH*

The panel suddenly gave up and I flew backwards into a wall. My shoulder
made a major hole in a wall and bent some of those coke can strength
"studs". The guys from production (on the other side of this wall) came
running out to see if I was ok. I did not feel any pain whatsoever, the
wall just went like that, as if if was cardboard.

 

[Joerg]

Are you forgetting that most of this stuff is low end Asian designs?
Whay would they want it to lst very long?

Much of it was US-engineered and US-manufactured. More industrial stuff,
not low end gear. Some European ones, too.

All of the units I repaired only had a single transistor. Maybe
BFR96?

I think the BRF92 and BFR93 are at the core of most designs. Almost
impossible to beat in price.

[...]

 

[Joerg]

The only marked transistors were all BFR96, so I bought them 10 or 25
at a time for about 35 cents each.

That must have been back in the days of the Pilgrims

It's a really old TO-50 can and nobody carries it these days. Well,
Arrow lists them but there is no stock.