[TowerTalk] LED replacement for incandescent light

[Patrick Greenlee]

A constant current source in series would make every in-line series lamp 
a separate single point of failure which would make the MTBF 1/n times 
the MTBF of one lamp where n is the number of lamps.  Not a high 
reliability approach.

Patrick   NJ5G


On 1/14/2015 1:59 PM, Jim Lux wrote:
> On 1/14/15 11:52 AM, Jack Brindle wrote:
>> LED bulbs have power supplies which convert 120/240VAC down to the DC 
>> level needed by the LEDs. These components are the major failure 
>> point (for CFLs as well). These are high current power supplies that 
>> generate quite a bit of heat and thus require at least some of that 
>> heat sink capacity as well.
>>
>
> True for replacement bulbs for replacing standard Edison base 
> incandescent, like the ones you get at home depot.
>
> Not necessarily true for a specialized application.  If you were 
> replacing ALL the bulbs in a tower, there's nothing stopping you from 
> having a big constant current source at the base, like they do with 
> streetlights.
>
> It's sort of like replacing incandescents with strobes..
>
>
>
>> So what kind of climbing harness is required when changing the 
>> external aircraft bulb at altitude??? :-)
>>
>> - Jack B, W6FB
>>
>>> On Jan 14, 2015, at 10:55 AM, Hans Hammarquist via TowerTalk 
>>> <towertalk at contesting.com> wrote:
>>>
>>> Replacing a bulb on an aircraft is 'slightly" easier than climbing 
>>> 1500 feet.
>>>
>>>
>>> Regarding temperature; the LED do not suffer as for example the 
>>> florescent lights. If I remember it right LE-s work better at lower 
>>> temperatures, the light output goes down as the temperature 
>>> increases. You notice that LED bulbs are equipped with rather large 
>>> heat sinks, needed to keep the LED diodes to work properly.
>>>
>>>
>>> Hans - N2JFS
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Roger (K8RI) on TT <K8RI-on-TowerTalk at tm.net>
>>> To: towertalk <towertalk at contesting.com>
>>> Sent: Tue, Jan 13, 2015 5:16 pm
>>> Subject: Re: [TowerTalk] Fwd:  Now THIS is a tower climb!
>>>
>>>
>>> There already are, very bright LED strobes in use on aircraft.  All the
>>> exterior lights on mine were solid state, except for the landing light.
>>> There are LEDs that could have replaced that, but I never saw any that
>>> had been approved.
>>> I don't know at how low a temperature they will still function, but I
>>> flew in temperatures a lot colder than most towers would see.
>>>
>>> I would think the new LED strobes would be ideal for towers and
>>> replacements would be few and far between.
>>>
>>> 73
>>>
>>> Roger (K8RI)
>>>
>>> On 1/13/2015 12:25 PM, Hans Hammarquist via TowerTalk wrote:
>>>> I think the problem is to introduce a "new", long-life, light bulb. 
>>>> Any,
>>> modern LED bulb would do lifetime wise. I believe, though, there are 
>>> several
>>> light bulbs in the assembly that automatically replace the bulbs as 
>>> they burn
>>> out. That is used in lighthouses to insure there is a light on all 
>>> the time. To
>>> design an assembly that could automatically replace burnt-out LED 
>>> bulbs might
>>> not be that simple. You know, everything there has to be approved by
>>> authorities.
>>>>
>>>>
>>>> Hans - N2JFS
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Richard Solomon <dickw1ksz at gmail.com>
>>>> To: Tower Talk <towertalk at contesting.com>
>>>> Sent: Mon, Jan 12, 2015 6:39 pm
>>>> Subject: Re: [TowerTalk] Now THIS is a tower climb!
>>>>
>>>>
>>>> Repairs ??
>>>>
>>>> Looks like he's changing a light bulb !!
>>>>
>>>> Now, invent a really long life bulb and you will sell at least a 
>>>> hundred !!
>>>>
>>>> 73, Dick, W1KSZ
>>>>
>>>> On Mon, Jan 12, 2015 at 4:33 PM, Mike via TowerTalk <
>>>> towertalk at contesting.com> wrote:
>>>>
>>>>> This is video of a technician climbing 1768 feet to the top of a
>>>>> transmissions tower for repairs.
>>>>>
>>>>> It also shows him free climbing and some dialog to go along with  it.
>>>>>
>>>>> Its a helmet cam so if anyone gets dizzy or has anything that can 
>>>>> give  out
>>>>> watching this stuff while sitting in your chair....be warned!...DO 
>>>>> NOT
>>>>> WATCH IT!!
>>>>>
>>>>>
>>>>>
>>>>> https://www.youtube.com/watch?v=INbKYq0G9nU
>>>>>
>>>>> Mike W2GR
>>>>> _______________________________________________
>>
>> _______________________________________________
>>
>>
>>
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