++++++++++++++++++++ Date: Tue, 15 Jan 2002 17:27:58 -0800 From: Vic Rosenthal Organization: Transparent Software To: Bill Myers Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] QRO Choices Bill Myers wrote: > > What amplifier brands work, and what > problems are typical with the QSK issue. The TenTec amps, I believe, come with QSK. Some others (QRO Technology, Alpha, e.g.) also have models that include QSK, and other brands may have it as an option. QSK amps tend to be expensive. Basically there are two solutions: PIN diodes and Vacuum relays. Each has its proponents: the PIN diodes are faster, but can be damaged by static electricity or high SWR (read: in the heat of a contest you transmit full power into the wrong antenna). Vacuum relays have a finite life, but are available cheaply as pulls, and are hard to damage. I use a reed/vacuum relay setup which I've built into two miniboxes. I use double male coax adapters to mount them right at the input and output terminals of the amplifier. That way, I can use the system with any amplifier. I key it with the amplifier keying circuit shown on the Elecraft web site at . The QSK circuit itself is described by Rich Measures AG6K, at . Rich sells a kit of all the parts needed (except for vacuum relay, connectors, etc.) quite reasonably. Vacuum relays can be obtained from Allen Bond at . I find that this system works quite smoothly with the K2 and my Henry Radio SS750HF solid state amp. I've removed an attenuator from the amp and cranked up my K2 a bit, and I now get from 400-800 watts from the amp (depending on band) when driving it with the K2 on CW. 73, Vic, K2VCO Fresno CA -------------------------- Date: Tue, 15 Jan 2002 16:46:15 -0800 From: Bill Myers Organization: FOCUS To: elecraft at mailman.qth.net Subject: [Elecraft] QRO Choices I've had my K2 (#1760) now for a year. After many many great QSOs and hours of enjoyment, I have no desire to change anything on the K2 - including being limited to 10 or so watts. During this last year, that has been plenty of power to do what I enjoy most ... ... except I do work with NTS on cw. The K2 is a great rig for traffic work! The receiver is the best, and its QSK is great. Ten watts is fine for district work, but is marginal for regional and area coverage (at least in the West.) So, I have to conclude that I need more power for reliable communications night after night on 80 meters. I'm looking for a way to boost power for that one activity only! I could (and probably will) wait for the K2 PA. Or, I've found a clean Omni V for a reasonable price that would be adequate for 80 meter cw. It would also be workable to drive an external amplifier with the K2 and use it only when needed. I believe the K2 will drive the typical amateur KW amp to 200 or 300 watts, and that's more than enough! The one requirement is that the K2's QSK must be retained. Having never owned an amplifier, I have no experience with high power QSK. I'd be interested in what experience others have had with this approach. What amplifier brands work, and what problems are typical with the QSK issue. Thanks for the inputs, Bill K6IFF ++++++++++++++++++ From: "Stuart Rohre" To: "Bill Myers" , Subject: Re: [Elecraft] QRO Choices Date: Wed, 16 Jan 2002 13:11:40 -0600 Bill, the cheapest way to increase your power is to improve the 80m antenna. We found at several field days that a large (1.25 wave around) horizontal loop was plenty for nation wide coverage with S9 signal at 5 watts if you have the room for such a wire. If you only have a dipole or inverted Vee for 80m, you can add a slant wire director to an inverted vee and achieve some gain that may be enough for your regional/national net. 72, Stuart K5KVH ++++++++++++++++++ Date: Wed, 13 Mar 2002 10:30:04 -0800 From: Eric Swartz WA6HHQ - Elecraft Organization: Elecraft To: Mark Rozmilowski Cc: n6kr at elecraft.com, dbarker at visioncomm.net, elecraft at mailman.qth.net Subject: Re: [Elecraft] Re: QSK K2 Revision 2 firmware (and later) added the '8R Hold' option to the 'T-R' menu item. When 8R hold is enabled the K2 keeps the external amplifier keying circuit enabled for the same time as the T/R delay set in the T-R menu (up to 2.5 sec.). This is fully described on the 2.01 F/W document on our manual download page at: http://www.elecraft.com/manual/K2_rev_2FW_rev_B.pdf 73, Eric WA6HHQ ==== Mark Rozmilowski wrote: > T-R delay would be fine. However, I'm driving my Mosfet amp with the K2. > In my K2 I have build and installed small board with two transistors > (the one suggested on K2 website) in order to control the amp. > The problem is that no matter what T-R delay I have on my K2, the amp. > doesn't react to it and is always switching very fast QSK reacting to any dot > at CW speed 30 WPM. > Mark WQ7X +++++++++++++++++++ Date: Sun, 23 Jun 2002 20:23:10 -0400 From: Brian Murphy To: Cc: Subject: [Elecraft] Driving (big) linear amps with the K2? Hello Peter, I have had the same thoughts as you, and using the K2 to drive a grid-driven tetrode seems the best way to avoid 'daisy chaining' amps to meet the 50-100 watt input requirements. The other alternative: I have seen several posts to this reflector on using it with an Alpha producing reduced power (500-700 watts I remember), but I still wanted the capability for 1000+ for all my trouble and expense. I had my eye on the QRO brand (I believe) amp with a single tetrode hoping that I could easily modify the input circuitry of the amp to produce 1000-1500 watts with only 5-10 watts from the stock K2. That way, I would preserve the K2 without modifications for QRP and still be able to hook it up to a single amp at home when needed. However, I came across a Harris RF110 amp for sale at less money than a used QRO! And, it required only 100 mW of drive (yes, that's milliwatts!). I now have the amp. It works great with the K2, but I have not used it much partly since propagation conditions have been so good, partly because it has taken me some time to build a tuner, transmission lines, and antennas rated for full power, but mostly because I have been remodeling my house! You may try to keep you eye out for one of these. This can be a good solution if you don't mind trying a 'non-mainstream' solution. By the way, there are apparently many of them available, but the 220vac single phase power supplies are the difficult component to find. Hope this helps, Brian N4YTL ++++++++++++++++++ Date: Thu, 20 Jun 2002 16:56:48 -0500 To: "phoon.usinet" , From: "Timothy A. Raymer" Subject: Re: [Elecraft] Driving (big) linear amps with the K2? At 15:43 06/20/2002 -0600, phoon.usinet wrote: >Has anyone used the K2 either barefoot, or with the KPA100 "cover top" >amplifier to drive a linear amplifier (Alpha, QRO, etc)? The KPA/100 has the capability built in. If you want to use the K2 to drive it, there is a circuit someone(s) here on the list created, along with a circuit board, that plugs into the K2 on a header in the back of the radio, and Keys an amp just fine. As far as the power output, 10 watts is the most you can depend on from the K2 barefoot. While you can squeeze a bit more out, you do it at the expense of distortion. the KPA/100 takes you up to where you can drive it comfortably, and also run 100 watts if that is all you need. I don't know if anyone on the list has a commander, but I know there are many Alphas on here being run by K2s. Tim Raymer Timothy A. Raymer Missouri Department of Health and Senior Services +++++++++++++++++++ Date: Thu, 20 Jun 2002 17:53:36 -0400 To: "phoon.usinet" , From: Hank Kohl K8DD Subject: Re: [Elecraft] Driving (big) linear amps with the K2? At 6/20/02 03:43 PM -0600, phoon.usinet wrote: >Has anyone used the K2 either barefoot, or with the KPA100 "cover top" >amplifier to drive a linear amplifier (Alpha, QRO, etc)? The answer to your question is yes. The keying transistor or mosfet will handle it. I have used it with my Alpha 374A and it worked fine (It did however weld the relay in my IC-746!) I think the K2 is good for over an amp to key your amp. 73 Hank K8DD */ Hank Kohl K8DD k8dd at arrl.net */ ARRL TS http://www.qsl.net/k8dd */ MI-QRP - Vice Pres. QRP-ARCI - Director */ If God intended you to be on single sideband, he would have given you only one nostril. - Steve, K2PTS ++++++++++++++++ Date: Thu, 20 Jun 2002 15:27:09 -0700 From: Vic Rosenthal Organization: Transparent Software To: "phoon.usinet" , Elecraft Subject: Re: [Elecraft] Driving (big) linear amps with the K2? "phoon.usinet" wrote: > > Has anyone used the K2 either barefoot, or with the KPA100 "cover top" > amplifier to drive a linear amplifier (Alpha, QRO, etc)? I've done both! > The QRO HF 2500 linear amp can put out healthy RF with surprisingly low > drive levels, as low as 5, 10 or 15 watts (1000 watts out with 20 watts of > drive on 40 - 80 meters). Whether the KPA100 is necessary to drive the QRO > HF 2500 Linear, is open to debate. Not to 1500 watts, but to a quite respectable output level. > In addition to RF drive, the QRO HF 2500 amplifier requires keying output > from the K2 transmitter, in a shielded audio cable connection, in one of two > possible ways: > > Key XMT: Relay contacts of xmtr must be open during receive, closed during > transmit, and must "sink" +12VDC to ground at 80 MA for CW. The KPA100 includes an output that would work fine. For the K2 without the KPA, it's easy to add. See > 1) Does the keyer circuit of the K2 have such a capability? I know that > the K2 has diode switching, but can it handle 80 Ma? The circuit at the link above will work fine. > Is there an external "keyer out" jack on the back of the K2 with a phono > female jack? You can use one of the 'xverter' holes. > 2) I assume that if the above keyer out put connection to the QRO HF 2500 > can be made, that VOX SSB operation from the K2 to the vacuum QSK relay > inside the QRO HF 2500 is also doable. Comments welcomed on this point. Does the KEY XMT input also operate this relay? If so, yes it will work. The K2 amp keying circuit is activated on transmit, regardless of mode. > 3) The power output of the K2 is 12 to 15 watts "barefoot". Has anyone > been able to increase the output to 20 or even 30 watts, perhaps by changing > the final amplifier transistors, and/or their biasing? Or, by altering the > driver circuit that drives the final transistors? That is, with out the > KPA100 "cover top" amplifier? Yes, I went up to 20 watts on most bands. I do not recommend it, for various reasons. I'll send you details off list. 73 Vic, K2VCO Fresno CA +++++++++++++++++ Date: Sat, 19 Apr 2003 02:00:14 -0400 (EDT) From: k4wtf at enterzone.net To: n3drk Cc: elecraft Subject: Re: [Elecraft] k2 with ameritron al-811 On Thu, 17 Apr 2003, n3drk wrote: > I posted this question before but must have deleted the responces. I just > received the Amp Keying Kit for my k2 and want to know if there are any > other considerations which need to be taken when using the al-811 amp. > > john John, prior to building the KPA100, I used the amp keying kit with my AL-811H with no problems at all. I think I was able to get something like 200-300w peak with the K2 running wide-open driving the 811H. Good luck! 73 de John - K4WTF K2/100 #2490 +++++++++++++++++++ From: "Dave" To: Cc: Subject: Re: [Elecraft] (no subject) Date: Sat, 31 May 2003 06:54:40 +0100 Dan I used to own a Heathkit SB200, long before I bought my K2. I used it with several solid state rigs, but in order to keep the high keying voltage out of the solid state transceiver(s) I used an external keying relay. As the K2 will only switch a few milliamps, an external relay will need a transistor to drive it. An opto isolator is a more elegant solution... but a relay and transistor will work fine. If you don't want to modify the K2 to bring out a switching line, the KIO2 will be needed (probably a better idea as it keeps stray RF from the inside of the K2). Dave, G4AON K2 #1892 ----- Original Message ----- From: To: Sent: Saturday, May 31, 2003 5:59 AM Subject: [Elecraft] (no subject) > I have a Heathkit SB200 amplifier, and I have been told that you cannot use > it with modern rigs. First, is this true, and why? Can some modifications be > made so that I could use it with my K2? > > Thanks for any advice > > Dan Flores WB6PKB +++++++++++++++ Reply-To: "Bob Lewis (AA4PB)" From: "Bob Lewis (AA4PB)" To: Subject: Re: [Elecraft] (no subject) Date: Sat, 31 May 2003 08:22:11 -0400 The only issue with using the SB200 with modern rigs like the K2 is that the T/R keying voltage on the SB200 is somewhere around a -120 VDC. You need to provide a relay or some other circuit to isolate the K2 from this high voltage. ++++++++++++++++ Date: Sat, 31 May 2003 06:59:14 -0700 (PDT) From: Harry Yingst Subject: Re: [Elecraft] (no subject) To: DFlor788 at aol.com, elecraft at mailman.qth.net What you want is a Soft-Key module $23.00 from: http://www.harbachelectronics.com/ --- DFlor788 at aol.com wrote: > I have a Heathkit SB200 amplifier, and I have been told that you > cannot use > it with modern rigs. First, is this true, and why? Can some > modifications be > made so that I could use it with my K2? > > Thanks for any advice > > Dan Flores WB6PKB +++++++++++++++++ Date: Sat, 31 May 2003 20:30:35 -0400 To: elecraft at mailman.qth.net From: "Clark L. Stewart" Subject: Re: [Elecraft] SB-200 Amplifier Keying At 12:59 AM 5/31/03 -0400, WB6PKB wrote: >I have a Heathkit SB200 amplifier, and I have been told that you cannot use >it with modern rigs. First, is this true, and why? Can some >modifications be >made so that I could use it with my K2? > >Dan Flores WB6PKB Dan, Your SB-200 amplifier's keying relay requires that the transceiver key 135 volts at about 3 AMPS. This is WAY more than most modern rigs with solid-state keying circuits can handle. Here is a company called Harbach Electronics that sells a mod kit for your SB-200 that lets the transceiver only key ONE volt at 1.4 MILLIAMPS! The kit you need is the SK-201 module and sells for $23. From the home page above, click on SB-200 in the left hand frame and scroll down the new page. However, the guy who runs this company now, W8CQ, is moving to Michigan. So, I would make the order ASAP in hopes he can get it out to you before he moves. There are probably other companies who make a similar product but this is the only one I am familiar with. Hope this helps. 73, Clark, W8TN +++++++++++++++++ Date: Sat, 31 May 2003 17:58:49 -0700 From: Vic Rosenthal Organization: Transparent Software To: Elecraft Subject: Re: [Elecraft] External Amp QSK Operation with K2 Clark L. Stewart wrote: > I was recently asked a question by a potential K-2 purchaser. He wants > to know: > > "Is there a digital signal available from the K-2 to allow QSK operation > with an external amplifier?" > > Some amplifiers apparently have special provisions for not allowing > themselves to be hot-switched during QSK operations. The barefoot K2 needs a small (single transistor) circuit added to provide an amplifier keying output. This is built into the KPA100. This circuit is driven from the K2 8R line, which is is sequenced so that it keys the amplifier significantly before RF output appears from the K2 and holds until after RF output has stopped. I've successfully used this method to directly key several different amplifiers from the K2, some with vacuum-relay QSK and one (Alpha 86) with PIN diode QSK. In all cases it's been quite adequate to key the amplifier at high speeds (40 wpm) without hot switching. -- 73, Vic, K2VCO Fresno CA +++++++++++++++ Reply-To: "Mike" From: "Mike" To: Cc: , "Elecraft Reflector" Date: Mon, 2 Jun 2003 06:05:42 +1200 Subject: [Elecraft] SB200 amp/soft key I can confirm the Harbach Soft-Key module is a VERY worthwhile addition to the old SB200, allowing it to be keyed by the K2-100 etc. Been using one in my SB200 for 10 years or so with no problems. 73 de Mike, zl1mh. ++++++++++++++++