Usb spe-2kfa

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I just got around to hooking up my Flex 6700 and SPE-2KFA amp with SSDR 1.10 (beta). I was pleasantly suprised at how easy it was. I had some FTDI USB to serial adapters that I got off of Amazon a few years back. I wasn't sure if they were genuine FTDI, but I tried anyways. The Flex recognized it right away. Once I got the baud rate set up the SPE recognized the Flex as well and the SPE controls the RF power setting when the amp is in operate mode and resets it when the amp is in standby.

As I understand it, the ALC input on the Flex doesn't really work so we have to manually set the max power out using the feature of the amp.
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Mark Erbaugh

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Posted 2 years ago

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Joe WD5Y

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Mark,
I believe the alc function works on the flex. I use it with my amp and it seems ok. Somebody else may need to elaborate on this as well. The meter on smartsdr shows alc indication for sure. I know many operators do not prefer alc but I chose it's use as further protection.

73's
WD5Y
Joe
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Tim - W4TME, Customer Experience Manager

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The ALC does work on the FLEX-6000.  The max power setting was for the FLEX Series radios that do not have ALC.  However, the use of ALC in general, has been in debate because the delay between setting the ALC voltage and the power reduction of the exciter may be too long to prevent damage to some amps.  If the amp has internal protection mechanisms, those should be your first line of defense.
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Mark Erbaugh

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I ran a quick test. The ALC meter does indicate activity, but I didn't want to overdrive the amp, so I was afraid to crank the Flex power to full and see if the SPE ALC limits the power out. The SPE manual recommends running the drive level at full and letting the amp control the ALC. I like the extra protection of setting the max power out, so I'll use both.
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Gary

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Ah - OK.... I hadn't seen that in the documentation. I was visiting someone else that has a 6500 yesterday and in the course of showing his station he did show me that if he set his amp in standby (an Elecraft KPA500) the 6500 changed the power level to 100W ... however he is using DDUtil for this. He agreed, although we're both still not 100%, or weren't, that it can or can't be done in SSDR. So you're saying SSDR alone will know when the amp is in standby and change the power back to some other setable level - correct?

If that is the case then indeed the ALC is not needed... HOWEVER - again - as a last resort protection method, knowing fair well that things can and do go wrong - if its there - I WOULD/WILL USE IT! Although the SPE amps are (almost) bullet proof I'd never want to hit them with high power without an ALC. So once again - I'd still say install the ALC line which brings us back to - why did they not design the input to allow a wider range of ALC levels!? A simple resistive divider with a clamp would not have created any delays to speak of and would still provide full protection. [and yes - I know that some people will indeed turn their exciter to max and rely on the ALC - and would agree that is just dumb ... ]

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Ria - N2RJ, Elmer

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The details about CAT power control is on page 39.

http://www.expertlinears.com/pdfs/expert_1-3K_manual.pdf
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Gary

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thank you .... I'll still keep an ALC as its purpose isn't for 'routine' power control but rather "stuff happens" (cleaned up the phrase) control... but I stand corrected - thanks again.

g.

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Mark Erbaugh

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Aren't you concerned that the -11v could damage the flex?
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Gary

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its a simple voltage divider and a zener clamp ... I wouldn't connect them without having done this first nor would I recommend anyone doing that. Since I don't know whether or not the 6700 will be damaged, as the their manual seems to suggest ... I'll protect (the protection circuit).
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John - K3MA

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Does PTT also work thru the Flex to USB to SPE interface?  If so how is this enabled?
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Ria - N2RJ, Elmer

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Ptt needs a relay connection as you would normally do for any amplifier (except power genius XL i heard)
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Mark Erbaugh

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My oversight. I did have a phono cable set between TX1 out on the flex and the Relay input on the amp.
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Matt NQ6N

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FWIW there was a thread on the Elecraft reflector about this, and Wayne recommended not using ALC as the primary method of controlling amplifier output with a K3. His response was based on the characteristics of the K3's ALC circuit.  Seemingly the K3's ALC circuit is slow and will result in a fair bit of overdrive (and splatter) when connected to an amp.  

http://elecraft.365791.n2.nabble.com/Question-K3-ALC-w-SPE-Expert-1-3K-FA-amp-tp7600955p7600957.html