Re: fan timer circuit
I've seen a number of fan delay, time on, time off circuits
posted on web. The neat'o web page url I just posted here
on the group has one and it might be the one you're looking
for.
http://www.w1ghz.org/small_proj/small_proj.htm
and the fan controller
Maybe it's just me, but I've never understood the need for a special circuit
to run cooling fans.
I run my fans from the PTT line using a relay. I have also used a simple
chassis thermostat, but prefer using PTT. I suppose you could easily use
both methods so that in the event that the
At 12/21/2008 09:24, you wrote:
Some of our local start-up radio clubs throwing repeater
packages in place often start out using and stay with an
external RF amplifier designed for mobile operation. Sometimes
the amp runs so hot you can't keep your hand on the heat sink
but I've yet to see one
Is there a point inside the Mitrek that one can take the
audio out to the controller (in this case a Link-Comm RLC-2A)?
A low band Mitrek (33Mhz)
Depends on what type of audio you want. The high side of the
volume control is often a great place to take de-emphasized
audio. However, some
I mostly agree. My thinking is that a fan that runs continuously
wastes power and draws dust and dirt into the equipment. I also
believe that a fan that runs only during PTT is not doing much good
except on very long transmissions- when the heat of the PA has made
it to the fins. It may
I moved over to utilizing the PTT instead of the thermostat disks after I'd
had a few thermostats fail. But I agree with your thinking.
In my mind the slight inefficiency of running my fans earlier than the heat
builds up is not significant to me. I like to think it slows the heat
buildup.
The thermal switches sold for attic fans should work great. I bought one rated
at 119ºF at a surplus store.
My S-COM controllers all had start-of-activity and end-of-activity macro
triggers, which would be a more elegant way to do the timer-based function than
a separate board with a 555 IC.
One Summer's day in Los Angeles I had a service
call on a microwave repeater (vacuum tube).
It was located in a warehouse, near the roof.
In the heat I lugged my stuff up the stairs.
As I set down the service monitor I leaned
my other arm against the cabinet. I jerked
it away because it was
There you go Joe! The man with all the answers! That sounds like the exact
situation you have!
Good work on that info!
Now I'll have to go back and see what the deal was with the duplexer we had
here!
Bill - W6CBS
_
From: Repeater-Builder@yahoogroups.com
Joe, Sent you an email off list and it bounced.
Shoot me an email. Commconinc @ Gmail.com
Thanks
Peter
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Joe
Sent: Tuesday, December 02, 2008 8:11 PM
To:
Arthur,
I don't have a copy of the manual, but I can advise you that the manual part
number is 68-81061A75, which may help you find a copy. Unfortunately, it is
NLA from Motorola Parts.
73, Eric Lemmon WB6FLY
-Original Message-
From: Repeater-Builder@yahoogroups.com
Hello group.
Not specifically repeater questions, but thought this group might hold the
folks who have the answers...
I have a Motorola Spectra VHF High Power (110 watts) that I am converting
for packet use, as an APRS digi-peater.
It will be a high-profile machine...probably running around
Sounds like the best thing to do is a combination of both the PTT and
Thermodisk versions together.
That way the fan starts blowing when users start using the repeater.
Then the thermodisk takes over after it heats up until all traffic quits and
the tx'er cools down.
Just my 2c worth.
Merry
GOOD AFTERNOON kEVIN
This last response is my thinking about the Mitrek and is why I asked the
question earlier. If the Mitrek coils are the same as the Micor coils what
factor would prohibit this being done. There is considerable work to change
the coils but if the Micor coils are the
Hello Kevin
I did not see where you gave a price of a set of Micor receiver coils.
Where might I find this info? Thanks. 73 de Tom Manning, AF4UG
- Original Message -
From: Eric Lemmon
To: Repeater-Builder@yahoogroups.com
Sent: Saturday, December 20, 2008 9:37 PM
On Sun, 21 Dec 2008, Christopher K. Greenhalgh wrote:
It will be a high-profile machine...probably running around 30-40% TX
duty cycle...possibly more during certain times.
Well, you're out of what the manual specifies the duty cycle of the
radio to be. Accordingly, you should look at turning
Tom,
The Mitrek coils are not the same as Micor coils. Not even close.
73, Eric Lemmon WB6FLY
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tom Manning
Sent: Sunday, December 21, 2008 3:40 PM
To:
I was wondering if anyone had links to any websites that talk about
radios used in TV and Movies.
What got me thinking about this was that I had been watching the old
TV show Emergency on Netflix. (remember squad 51, rampart hospital, etc.)
I know some of the stuff is just props but I thought
You can start here...
http://www.emergencyfans.com/
Eric,
VA3EAM
Albert wrote:
I was wondering if anyone had links to any websites that talk about
radios used in TV and Movies.
What got me thinking about this was that I had been watching the old
TV show Emergency on Netflix. (remember squad
Albert,
If you do find such a site, let me know! I was watching the Bruce Willis
flick Live Free or Die Hard and noticed that every government agency and
the DC Police used an ADI AR-147 2m mobile radio in their cars. I guess
interoperability has finally taken hold, because every radio in the
Tom Manning wrote:
GOOD AFTERNOON kEVIN
This last response is my thinking about the Mitrek and is why I
asked the question earlier. If the Mitrek coils are the same as the
Micor coils what factor would prohibit this being done.
The coils are not the same, but I believe there is no
At 12/21/2008 14:01, you wrote:
I moved over to utilizing the PTT instead of the thermostat disks after I'd
had a few thermostats fail. But I agree with your thinking.
My thoughts as well: the thermostat is an elegant solution, but if it
fails, your repeater fails in a rather expensive way. One
At 12/21/2008 14:15, you wrote:
Personal opinion, but I'd never put up a repeater that relied on a fan to
keep temps within spec.
Yes, fans are not as reliable as 100% passive cooling. Unfortunately, the
latter method requires a lot more rack real estate which sometimes ( in my
case, always)
n...@no6b.com wrote:
One reason why I've dismissed using any switching on my 110 V cooling fans
let them spin 24/7.
I have used 220 V muffin fans on 110 V and they last for years. I put
one in service in 1997, and it's still turning.
Kevin
Kevin, another method of slowing down an AC fan is to put a capacitor
in series with the AC leads as a voltage dropping element.
A local Ham played with this idea many years ago and as I recall he started
with a 1 Mfd paper capacitor.
In his case he dropped the voltage to around 90 volts to
Jordan,
The RLC-MOT works very well since it is an exact copy of the squelch circuit
found in the Micor. The only problem is it is now VERY expensive.
Kevin had done some extensive testing on the dual squelch modues some time
ago. Maybe he can chime in here... Kev??
Scott
Scott Zimmerman
One more thing to be careful of when using fans on remote equipment.
Make sure there are guards on both sides of the fan. We had a muffin
fan on a 100wt 220 amp that failed when a mouse tried to get closer to
the warm heatsink. His carcass jammed the fan blades and got dessicated
with the
m...
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Burt Lang
Sent: Sunday, December 21, 2008 10:39 PM
To: Repeater-Builder@yahoogroups.com
Subject: Re: [Repeater-Builder] Re: fan timer circuit
One more thing to be careful of when
Hello All
I said OK to an invitation to fix a repeater that suddenly quit after years of
trouble free service. Found a critical wire chewed in two and several more
almosts. The fixes were easy but a problem remains in the cleanup.
Rat trash and droppings (OK to read as a common four letter
a mouse tried to get closer to
the warm heatsink. His carcass jammed the fan blades and got dessicated
with the heat.
Burt Lang VE2BMQ
Yes I guess that could Happen , I live in a City and My 6 Month old
Fridge quit working , Well of Course bring a Ham Some of us including
Me thing We can
Pretty hard to remove , I have in the past had some success with crc inox
and several other derusting thread lubricants ( sorry don't know the local
names in your part of the world)
Most of them contain mineral turpentine and some other oils which offer the
chance of at least softening that
Whatever you do, use caution in cleaning that stuff up. Rodent droppings,
especially when they become dried over time, are a major threat to carry some
really vicious diseases into your body if the dust gets airborne.
http://www.cdc.gov/rodents/diseases/direct_rodents.htm
73,
Paul, AE4KR
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