Jim makes a good point, if I'm going to use a solid-state relay it had best be
a mosfet one...this train of thought all started when I found this old crydom
ssr in my junk box...as I was moving stuff from the old QTH to the new QTH...
Sent from my iPhone, still learning to use it
> On Dec 28, 2016, at 08:40, amps-request@contesting.com wrote:
>
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> Today's Topics:
>
> 1. Re: FCC Denies Expert Linears' Request for Waiver of 15 dB
> Rule (Paul Christensen)
> 2. Re: FCC Denies Expert Linears' Request for Waiver of 15 dB
> Rule (Kim Elmore)
> 3. keying issue resolved (ka9egw@ka9egw.com)
> 4. Re: keying issue resolved (Jim Garland)
> 5. Re: FCC Denies Expert Linears' Request for Waiver of 15 dB
> Rule (Manfred Mornhinweg)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 28 Dec 2016 08:38:34 -0500
> From: "Paul Christensen" <w9ac@arrl.net>
> To: "'Amps group'" <amps@contesting.com>
> Subject: Re: [Amps] FCC Denies Expert Linears' Request for Waiver of
> 15 dB Rule
> Message-ID: <008201d2610f$b00866b0$10193410$@arrl.net>
> Content-Type: text/plain; charset="us-ascii"
>
>> "Moreover, we agree with FlexRadio that granting Expert's waiver request
> while the rulemaking petition remains pending would provide an unfair market
> advantage for one equipment model over other manufacturers' RF power
> amplifiers that would still be limited by [the existing rules]."
>
> First, there are two proceedings relating to the elimination of the 15 dB
> amplification gain restriction: (1) the Petition for Rulemaking filed in
> April; and (2) Expert's Waiver Request filed in June. The PRM that
> permanently amends the 15 dB gain restriction is still pending with the
> Commission. Flex's rationale for the objection to Expert's Waiver Request
> is probably reasonable -- although Flex doesn't even have an amplifier
> that's ready for certification and thus Flex would not be financially
> disadvantaged if the waiver request was granted. So, Flex has no current
> standing on the issue but that doesn't diminish the Commission's concerns
> while it assesses comments.
>
> A grant of Expert's waiver also creates a potential conundrum: what if the
> FCC denies the petition after granting the waiver request to Expert? If the
> grant of the petition was merely a short-term formality, then I see no
> problem with a waiver grant. In essence, Expert prematurely requested its
> waiver. Why would the FCC want to see a quick proliferation of high-gain
> amps into the U.S. market, only to later deny the formal petition on the
> same issue after full consideration?
>
> Paul, W9AC
> ps
>
>
>
> ------------------------------
>
> Message: 2
> Date: Wed, 28 Dec 2016 08:12:13 -0600
> From: Kim Elmore <cw_de_n5op@sbcglobal.net>
> To: Amps group <amps@contesting.com>
> Subject: Re: [Amps] FCC Denies Expert Linears' Request for Waiver of
> 15 dB Rule
> Message-ID: <0432B9D1-EAAA-4848-ABA2-DF21A571FEAE@sbcglobal.net>
> Content-Type: text/plain; charset=us-ascii
>
> I think the idea that the commercialization of ham radio is a bad thing is
> misguided. Yes, I can -- or in principle should be able to -- make everything
> that sits on my operating desk, including SDR radios. But I can't do it as
> cheaply as I can buy it, both in time and materials.
>
> The tube-based amps are by far the most amenable to amateur fabrication. Some
> examples don't even bother with metal chassis! Solid-state amps are a bit
> tougher. But I don't think there's anything intrinsically wrong with making
> prefabricated amps available for purchase nor is there anything wrong with
> someone making a few bucks off of selling them.
>
> With all that, Paul's observations are spot on. This isn't about money as
> much as it's about the ramifications of granting a waiver without changing
> the regulatory structure.
>
> Kim N5OP
>
> "People that make music together cannot be enemies, at least as long as the
> music lasts." -- Paul Hindemith
>
> ------------------------------
>
> Message: 3
> Date: Wed, 28 Dec 2016 08:17:31 -0600
> From: <ka9egw@ka9egw.com>
> To: <amps@contesting.com>
> Subject: [Amps] keying issue resolved
> Message-ID: <02d201d26115$27229130$7567b390$@ka9egw.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> My sincere thanks to all who responded. After serious consideration I got
> inspired to keep it simple-a 240VAC 30A solid state relay with the low side
> of the 3-32VDC input pulled to ground by any of several radios will
> facilitate keying the +160VDC-keyed-line 30L-1, and also the
> 6.3VAC-keyed-line Hunter 2000C [which some say is the amp the 30L-1 could
> have and should have been], and also the Dow-Key relays on the Heath
> Warrior.
>
> Thanks to all who responded!
>
> 73, Brian KA9EGW
>
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 28 Dec 2016 07:36:45 -0700
> From: Jim Garland <4cx250b@miamioh.edu>
> To: ka9egw@ka9egw.com, amps@contesting.com
> Subject: Re: [Amps] keying issue resolved
> Message-ID: <5863CDFD.6050802@miamioh.edu>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> Better be careful, Brian! Most AC solid state relays use thyristors for
> switching and depend on the zero crossing of the AC load to switch off.
> In other words, if you try to use one of those relays to key a DC
> voltage, such as in the 30L1, it will key up the amplifier but won't
> turn it off when the control voltage is removed. Also, if I recall
> correctly, some solid state relays have minimum load requirements, which
> you might not reach with a big 30A power relay. Personally, I think you
> need a better solution than what you're intending.
> 73,
>
> Jim W8ZR
>
>
>
>> On 12/28/2016 7:17 AM, ka9egw@ka9egw.com wrote:
>> My sincere thanks to all who responded. After serious consideration I got
>> inspired to keep it simple-a 240VAC 30A solid state relay with the low side
>> of the 3-32VDC input pulled to ground by any of several radios will
>> facilitate keying the +160VDC-keyed-line 30L-1, and also the
>> 6.3VAC-keyed-line Hunter 2000C [which some say is the amp the 30L-1 could
>> have and should have been], and also the Dow-Key relays on the Heath
>> Warrior.
>>
>> Thanks to all who responded!
>>
>> 73, Brian KA9EGW
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> ------------------------------
>
> Message: 5
> Date: Wed, 28 Dec 2016 14:40:15 +0000
> From: Manfred Mornhinweg <manfred@ludens.cl>
> To: amps@contesting.com
> Subject: Re: [Amps] FCC Denies Expert Linears' Request for Waiver of
> 15 dB Rule
> Message-ID: <5863CECF.4050406@ludens.cl>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Hi Jim, and all,
>
>> When you see an SDR receiver selling for a few hundred bucks, it's
>> pretty simple to add a low power transmitter.
>
>> So adding a high gain amplifier makes for a cheap SDR radio capable
>> of medium to high power a fairly cheap option.
>
> Exactly!
>
> At this moment I'm VERY tempted to brew a concoction from these ingredients:
>
> - A Red Pitaya board, for around $300;
>
> - A homemade board containing a low noise preamplifier, attenuator, and
> band pass filters for RX, along with a 10W or so driver amplifier for
> TX. The whole board should't cost more than $150 in parts;
>
> - A high efficiency, high gain, deliberately non-linear, legal-limit
> final stage. This might take the shape of a simple overdriven broadband
> class AB stage, or perhaps a class E stage with tuned, band-switched
> output tanks. It might use a single BLF188XR for about $150, or several
> small switchmode MOSFETs for far less money.
>
> To these hardware ingredients I would add some freely available
> software, such as Pavel Denim's software for the Red Pitaya, plus
> PowerSDR, using closed-loop, RF-feedback amplitude and phase
> predistortion to linearize the amplifier. The software has this already
> implemented.
>
> The result would be a legal-limit, high efficiency, high performance,
> compact, black-box HF transceiver to be used with a PC, for under $1000
> total cost, if you are good at ordering surplus power supplies on eBay,
> and such.
>
> And those who prefer integrated transceivers, can of course add an
> embedded PC motherboard plus small monitor, for a few hundred dollars.
>
> It would just take some tinkering with the final stage. The rest is
> pretty simple to do.
>
> Some more development in the RF power device scenery would be welcome.
> The BLF188XR has the necessary capability at least for the saturated
> class AB version of this idea, in terms of gain, voltage, current and
> thermal characteristics), but it's quite hard (or more bluntly: close to
> impossible) to achieve the desirable 85% or higher efficiency on a
> broadband basis, due to the very low drain impedance and the ensuing
> trouble in properly coupling the drains together and to the output
> filters. Switchmode MOSFETs instead are available with voltage ratings
> that allow operation at convenient impedance levels, but they have less
> gain, higher capacitances, more variation between 1.8 and 30MHz, and
> require the use of several (or many) in parallel. It would be great to
> have true RF power devices that can operate from a few hundred volts,
> and have low enough output capacitance to allow broadband use to 30MHz.
> Along with good gain and convenient price, of course...
>
> As usual, I'm asking too much. But I'm confident enough in this concept
> that I intend to buy a Red Pitaya board and start experimenting in that
> direction, using a class-E output stage based on ARF449 MOSFETs, which I
> happen to have in my "selection junk box". That would make a few hundred
> watts only, but serve as proof of concept. I want to test, hands-on, if
> it is really possible to achieve adequate spectral purity by linearizing
> a deliberately non-linear amp via SDR. Normally the predistortion system
> included in SDR software is intended to make a run-of-the-mill linear
> amplifier extra clean, and not to make a dirty-and-ugly but highly
> efficient amplifier clean enough!
>
> Manfred
>
>
> ========================
> Visit my hobby homepage!
> http://ludens.cl
> ========================
>
>
> ------------------------------
>
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> ------------------------------
>
> End of Amps Digest, Vol 168, Issue 103
> **************************************
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