Guess I should have signed that previous post.
73
Roger (K8RI)
Roger wrote:
> Bill W5WVO wrote:
>
>> After reading all the suggestions (serious and otherwise), I am
>> left with only one really appropriate and practical option: Leave
>> it the way it is.
>>
>> (a) The tubes ARE graphite anode 3-500Zs, and (b) I do operate
>> mostly WSJT digital modes, full carrier 30 seconds on/off, or in
>> the case of EME, one minute on/off. So maximum cooling is
>> required. I'm not comfortable with slowing down the fan given
>> these two realities. I will just have to live with the noise.
>>
>>
>>
> You might want to look at 140mm computer fans. Noise varies from a
> whisper to sounding like a turboprop starting up. Surprisingly the
> airflow is not proportional to the noise. The 140's are lower RPM, many
> are 3 speed, and most move a lot of air. They are all 12VDC and much
> quieter than the 120VAC variety. I'm currently sitting within 3 feet of
> 12 of the things, and although quite audible they are no more noisy than
> our forced air furnace/air conditioner.
> http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010090573%201372726540&name=140mm
> These tend to run 1000 to 1500 RPM. I'm looking at one that delivers
> 63.5CFM @ <16dBA and another that delivers 27.2 - 47.8 CFM @ 18 to 22 dBA.
>
> One multi speed the
>
>
> Noctua NF-P14 FLX 140mm Case Fan - Retail
> <http://www.newegg.com/Product/Product.aspx?Item=N82E16835608017>
> has particularly good figures at:
>
>
> * *Air Flow:* Airflow: 64.96 CFM Airflow with L.N.A.: 49.29 CFM
> Airflow with U.L.N.A.: 41.93 CFM
> * *Noise Level:* Acoustical Noise: 19.6 dBA Acoustical Noise with
> L.N.A.: 13.2 dBA Acoustical Noise with U.L.N.A.: 10.1 dBA for
> about $30
>
> On some of them you might want to disable the LEDs <:-)), but the one
> above is just a multi speed, many blade fan.
>
>> Thanks for all the feedback, guys, both on and off the reflector.
>>
>> Bill W5WVO
>>
>>
>> ----- Original Message -----
>> From: "Bill K2OWR" <k2owr@comcast.net>
>> To: "Carl" <km1h@jeremy.mv.com>
>> Cc: <amps@contesting.com>
>> Sent: Thursday, December 17, 2009 1:09 PM
>> Subject: Re: [Amps] Alternative cooling strategies for SB-220?
>>
>>
>>
>>
>>> :::: I'm very thankful someone finally called this discussion,
>>>
>>>
>> particularly
>>
>>
>>> relating to possibly water cooling an SB220 amplifier,
>>>
>>>
>> "impractical"....
>>
>>
>>> I can think of other words, but I'm new here, so I wouldn't want
>>>
>>>
>> to be
>>
>>
>>> obscene.
>>> BILL
>>>
>>>
>>>
>>> ----- Original Message -----
>>> From: "Carl" <km1h@jeremy.mv.com>
>>> To: "Rob Atkinson" <ranchorobbo@gmail.com>;
>>>
>>>
>> <amps@contesting.com>
>>
>>
>>> Sent: Thursday, December 17, 2009 15:03
>>> Subject: Re: [Amps] Alternative cooling strategies for SB-220?
>>>
>>>
>>>
>>>
>>>> The SB-220 fan draws air in from the rear and the output is
>>>>
>>>>
>> split by the
>>
>>
>>>> chassis to pass over the socket pins and the glass envelope.
>>>>
>>>>
>> It exhausts
>>
>>
>>>> thru the top and side perforations.
>>>>
>>>> Remoting a fan is impratical due to the friction loss and a
>>>>
>>>>
>> big blower
>>
>>
>>>> would
>>>> be needed.
>>>>
>>>> Nice to talk about for 3 days but not very practical.
>>>>
>>>> As I said before, add a resistor or as another said, go back
>>>>
>>>>
>> to the stock
>>
>>
>>>> fan. However graphite anode tubes need the extra air if those
>>>>
>>>>
>> are being
>>
>>
>>>> used.
>>>>
>>>> Carl
>>>> KM1H
>>>>
>>>>
>>>>
>>>> ----- Original Message -----
>>>> From: "Rob Atkinson" <ranchorobbo@gmail.com>
>>>> To: <amps@contesting.com>
>>>> Sent: Thursday, December 17, 2009 2:09 PM
>>>> Subject: Re: [Amps] Alternative cooling strategies for SB-220?
>>>>
>>>>
>>>>
>>>>
>>>>> Not sure what mode you want to operate (i.e. what duty cycle)
>>>>>
>>>>>
>> but if
>>
>>
>>>>> high d/c the duct trick with the blower remoted may have this
>>>>>
>>>>>
>> problem:
>>
>>
>>>>> the 220 fan is normally placed in the cabinet in such a way
>>>>>
>>>>>
>> that air
>>
>>
>>>>> is drawn in through the p.s. from what I remember of it. If
>>>>>
>>>>>
>> you run
>>
>>
>>>>> duct direct to the rear hole next to the RF deck, you loose
>>>>>
>>>>>
>> that p.s.
>>
>>
>>>>> cooling through the v.doubler and B+ transformer. But I have
>>>>>
>>>>>
>> no idea
>>
>>
>>>>> how hot the p.s. gets under normal condx or if it gets hot at
>>>>>
>>>>>
>> all.
>>
>>
>>>>> Another thing you can try is a tx keyed relay switch on the
>>>>>
>>>>>
>> power line
>>
>>
>>>>> to the fan that bypasses a resistor on tx but is n.o. so the
>>>>>
>>>>>
>> fan power
>>
>>
>>>>> goes through a voltage dropping resistor to slow it down so
>>>>>
>>>>>
>> it is only
>>
>>
>>>>> full speed and noisy when you are transmitting. You have to
>>>>>
>>>>>
>> wire it
>>
>>
>>>>> so the fan is not powered in series with one side of the B+
>>>>>
>>>>>
>> primary
>>
>>
>>>>> (if that is the stock SB220 arrangement). If you make a
>>>>>
>>>>>
>> long RTTY or
>>
>>
>>>>> SSTV tx and the tubes get real hot you will need to use a
>>>>>
>>>>>
>> timer relay
>>
>>
>>>>> with a set delay time so the fan speed drops around 30
>>>>>
>>>>>
>> seconds after
>>
>>
>>>>> you switch to rx.
>>>>>
>>>>> Just some ideas.
>>>>>
>>>>> 73
>>>>>
>>>>> Rob
>>>>> K5UJ
>>>>> _______________________________________________
>>>>> Amps mailing list
>>>>> Amps@contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>>
>>>>>
>>>> _______________________________________________
>>>> Amps mailing list
>>>> Amps@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>
>>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
>>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|