[TenTec] Power supply types

[Bob McGraw - K4TAX]

I would never pilot an airplane unless I performed a proper and complete 
ground inspection while using a check-list.

I would never buy a power supply unless I perfromed a proper evaluation but 
first knowing the needed power requirements.

73
Bob, K4TAX




----- Original Message ----- 
From: "Ken Brown" <ken.d.brown at hawaiiantel.net>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Monday, January 20, 2014 8:19 PM
Subject: Re: [TenTec] Power supply types


> They are both commonly available and they can both be used to power 
> typical HF transceivers. I think it is a reasonable comparison to make.
>
> Here is another question: What kind of power supply did you first see 
> reviews in QST in which the subject of RF noise generation was even 
> mentioned?
>
> Yes, switched mode power supplies CAN be made that do not generate (and 
> radiate) RF noise. And switched mode power supplies are generally more 
> energy efficient.:
>
> How about we state the question this way:
>
> Suppose you're on vacation and you brought your mobile rig along with you, 
> which runs on 12 VDC. You planned on only operating from your vehicle, so 
> you did not bring a power supply for use from 120 VAC. You are offered an 
> opportunity to stay for free in a nice vacation rental cabin for a week. 
> The cabin has all the conveniences, including grid power. There are tall 
> trees and you have a spool of skinny copper wire and an antenna tuner in 
> your vehicle. You think it will be a great opportunity to get on the air 
> from a remote location, with hopefully not a lot of RF noise. Before you 
> head up into the mountains to the go to the cabin you see a store which 
> sells two kinds of power supplies that have the right voltage and current 
> rating to power your rig. One of the power supplies is very lightweight 
> and the label say it is super efficient and uses switching mode 
> technology. The other power supply is heavier, and you can see it has a 
> laminated iron core transformer and a big electrolytic capacitor in it. 
> The prices of the two power supplies are identical and they both appear to 
> be well constructed. You cannot find any other data about these power 
> supplies. The drive to the cabin is long, and you don't intend to drive 
> back to town until you have finished your stay at the cabin. If you buy 
> both power supplies, you won't have enough money left to buy the wrist 
> rocket slingshot you intend to use to send the skinny wire up into the 
> tall trees.
>
> Which power supply would you buy?
>
> DE N6KB
>
> On 1/20/2014 3:41 PM, Kim Elmore wrote:
>> This is an apples vs pecans question.
>>
>> Better-stated questions:
>>
>> What's the probability that a properly-designed and engineered linear 
>> power supply will radiate  RF noise of sufficient amplitude to be 
>> bothersome?
>>
>> What's the probability that a properly-designed and engineered switching 
>> power supply will radiate  RF noise of sufficient amplitude to be 
>> bothersome?
>>
>> Answer: unknown. likely small but equal.
>>
>> Kim N5OP
>>
>>
>> On 1/20/2014 7:13 PM, Ken Brown wrote:
>>> What is the probability that a transformer/rectifier/capacitor 
>>> filter/linear regulated power supply will generate and radiate (through 
>>> AC power input or DC power output leads) RF noise of sufficient 
>>> amplitude to be bothersome? That probability may not be zero.
>>>
>>> What is that probability that a switched mode regulated power supply 
>>> will be not "properly engineered" and generate and radiate RF noise of 
>>> sufficient amplitude to be bothersome?
>>>
>>> How do those two probabilities compare?
>>>
>>>
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>>
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