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@largeriver.net]
Sent: Wednesday, October 30, 2019 10:13 PM
To: 'mark bitterlich'; 'Joe Subich, W4TV'; 'Joe'; amps@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@contesting.com] On Behalf Of mark
bitterlich
Sent: Wednesday, October 30, 2019 4:23 PM
To: Joe Subich, W4TV; Joe; amps@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@subich.com> Date: 10/30/19 16:36 (GMT-05:00) To: Joe
<nss@mwt.net>, amps@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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