[Amps] SB-220 HV Transformer Wanted ; thread stolen for bias question

Wed Nov 6 04:32:54 EST 2019

Many computer accessories and USB drives use 3 to 5A power supplies. I 
have a 5A Netgear router PS plugged into a remote, 10 TB USB
hard drive. It's a switcher, but absolutely silent.  There's no such 
thing as a standard connector so you might need to modify, or replace 
the one on the PS. Then, again you might get lucky.

73, Roger (K8RI)

On 11/4/2019 1:52 AM, Roger (K8RI) wrote:
> My opinion:
> In the  "old days" we were expected to tune into a dummy load and 
> match the antenna with a tuner using low power as we are today
>
> The big Henry amps were usually run well beyond the legal limit, so 
> tuning beyond a KW was no different than running 3 to 5 KW SSB, or CW. 
> The difference in "those days" was the FCC enforced the rules so you 
> generally needed to be much more careful when running your California KW.
> Of course with today's VNAs it's quite easy to get the SWR right down 
> to 1:1 so tuning into a DL and then switching to the antenna requires 
> no peaking. If everything is matched and the signal is clean, 
> "GENERALLY" no one bothers you unless the signal is obnoxiously strong 
> and creates problems.for others. I don't believe the FCC has the 
> manpower now days to go after anyone except the really bad apples.  If 
> you read the FCC actions, they typically are for hams who are causing 
> malicious interference.  In those cases power may be mentioned..
>
> The knowledge level on the bands is abysmal. It reminds me of when 
> working as a GA for my masters. I was teaching the intro to Computer 
> Science to 5 classes with a max of 40 per class. I had a total of 195 
> students.  This was for non CS students. Mostly business majors.
> I had around 5 ot 10 who weren't going to make it.  I had another 5 or 
> 10 who were at, or above my level. IOW, for them it was a "blow off" 
> class, but in general the knowledgeable level in there was abysmal too.
>
> I spend a lot of time on FB, helping new hams.  With the new testing, 
> they have no technical knowledge.  Virtually none!
> Typically the old timers are merciless and when they do try to help, 
> the new hams knowing nothing get angry because they think they are 
> being talked down to.
>
> The gap in technical knowledge is tremendous so explaining to these 
> new hams using the technical language is a lost cause and having 
> taught to this level, I can understand why they feel snowed under and 
> talked down to.and why there is so much animosity.
>
> 73, Roger (K8RI)
>
> On 10/31/2019 9:30 AM, Mark Bitterlich wrote:
>> Hi Gary, thanks for your reply.
>>
>> Yes, I was around when regulations were based on input power (1968) 
>> and have
>> heard your explanation before but I tend to question it simply 
>> because the
>> Henry 3K and 8K series of amps also came stock with the CW/SSB 
>> selection and
>> either of those two could easily exceed 1000 watts DC input in the CW
>> position.  FSK and AM modes were also advised to use CW and not SSB 
>> modes
>> possibly with plate dissipation limits in mind as well as legal 
>> issues of
>> input power.
>>
>> But based on the typical pair of 3-500's say in the 3K original 
>> designs, in
>> CW mode idling current was 90-120 ma, and in the higher plate voltage 
>> SSB
>> position  170-220 ma.
>>
>> My logic was simply:
>>
>> Bias controls the class of amplifier.
>> A change in bias means the class of amplification must have also 
>> changed.
>> Switching from CW to SSB causes an indicated bias change from 120 ma 
>> to 220
>> ma.
>> The impact of a bias change of  120 to 220 ma would lead me to 
>> believe that
>> the class of amplifier shifted slightly in a more linear direction 
>> with also
>> the result of slightly lower efficiency.
>>
>> Right or wrong or maybe just trivial ...  if wrong could you please 
>> explain
>> your logic?
>>
>> Mark
>> Wa3jpy
>>
>> -----Original Message-----
>> From: Gary Schafer [mailto:garyschafer at largeriver.net]
>> Sent: Wednesday, October 30, 2019 10:13 PM
>> To: 'mark bitterlich'; 'Joe Subich, W4TV'; 'Joe'; amps at contesting.com
>> Subject: RE: [Amps] SB-220 HV Transformer Wanted
>>
>> No. The amp runs AB2 meaning it draws grid current.
>>
>> The reason for the CW/SSB switch was to allow tune up at 1 KW DC 
>> input on
>> CW.
>> This was the regulation at the time the amp was designed. You were not
>> allowed to ever exceed 1 KW DC input, even during tune up.
>> Switching to SSB after CW tune up allowed higher PEP input by 
>> maintaining
>> the same plate load impedance (where the amp was tuned)for the higher 
>> power.
>> In other words the voltage to current ratio remained the same when the
>> higher voltage was selected.
>>
>> 73
>> Gary  K4FMX
>>
>>> -----Original Message-----
>>> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of mark
>>> bitterlich
>>> Sent: Wednesday, October 30, 2019 4:23 PM
>>> To: Joe Subich, W4TV; Joe; amps at contesting.com
>>> Subject: Re: [Amps] SB-220 HV Transformer Wanted
>>>
>>> Ok, this brings up a technical question that pertains to the topic
>>> amazingly enough. When you shift from single sideband to CW on this amp
>>> are you or are you not moving the class of operation from AB1 towards
>>> AB2 and thus  improving efficiency?MarkWA3JPY
>>
>>
>>> -------- Original message --------From: "Joe Subich, W4TV"
>>> <lists at subich.com> Date: 10/30/19  16:36  (GMT-05:00) To: Joe
>>> <nss at mwt.net>, amps at contesting.com Subject: Re: [Amps] SB-220 HV
>>> Transformer Wanted On 2019-10-30 3:12 PM, Joe wrote: > Why need
>>> them?Some people prefer to keep their equipment "stock" or at
>>> leastfunctionally stock.  The SB-200 was never designed for 1500Woutput
>>> on CW - it was designed to operate at 1 KW DC input (ca.700 W CW or 
>>> 1500
>>> W PEP SSB output).Pushing the SB-220 to 1500 W CW output (or worse,
>>> running RTTYon the high taps) is a quick way to fry something.  Even
>>> thetoroidal transformer you recommend is only rated for 800 W!73,    
>>> ...
>>> Joe, W4TVOn 2019-10-30 3:12 PM, Joe wrote:> Why need them?> > Run it at
>>> the HV side and use less drive and less currents all around.> > The
>>> CW/SSB switch I converted into a stand-by switch.> > Joe WB9SBD> Sig>
>>> The Original Rolling Ball Clock> Idle Tyme> Idle-Tyme.com>
>>> http://www.idle-tyme.com> On 10/30/2019 1:38 PM, Joe Subich, W4TV
>>> wrote:>>>> >> https://www.antekinc.com/as-8t800-800va-transformer/>>>>
>>> Unfortunately, this transformer lacks the primary taps for CW/SSB>>
>>> operation of the OEM device.>>>> 73,>>>>    ... Joe, W4TV>>>>>> On 
>>> 2019-
>>> 10-30 10:23 AM, Joe wrote:>>>>>> On 10/30/2019 8:56 AM, Joe wrote:>>>>
>>> Morning Dick,>>>> If you are not afraid of making a few electrical and
>>> mechanical >>>> modifications, I would go with this transformer.>>>>
>>> https://www.antekinc.com/as-8t800-800va-transformer/>>>>>>>> I'm glad I
>>> did! 1/4 the cost of most drop in replacements. yet MUCH >>>> better
>>> performance!>>>> Joe WB9SBD>>>>>>
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>
>

-- 
Roger (K8RI)