K3 and linear amp
Locked
12
12
 
|
RTTY works even with Class C finals!
Cortland KA5S -----Original Message----- >Date: Fri, 21 Mar 2008 15:43:28 +0100 >From: "Simon Brown (HB9DRV)" <[hidden email]> > >Hi, > >This applies to phase shift keying modes. RTTY seems to be OK with some >ALC - remember it's the peak power that matters, not the average. > >Simon Brown, HB9DRV _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
I think you are correct if one is running FSK but most
people, at least a lot of people these days are running AFSK, so need linear amps. One would just about have to build a Class C amp these days anyway. I don't know of any on the market. Cookie, K5EWJ --- Cortland Richmond <[hidden email]> wrote: > RTTY works even with Class C finals! > > > Cortland > KA5S > > -----Original Message----- > >Date: Fri, 21 Mar 2008 15:43:28 +0100 > >From: "Simon Brown (HB9DRV)" <[hidden email]> > > > >Hi, > > > >This applies to phase shift keying modes. RTTY > seems to be OK with some > >ALC - remember it's the peak power that matters, > not the average. > > > >Simon Brown, HB9DRV > > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
WILLIS COOKE wrote:
> I think you are correct if one is running FSK but most > people, at least a lot of people these days are > running AFSK, so need linear amps. One would just > about have to build a Class C amp these days anyway. > I don't know of any on the market. Whether a RTTY signal is generated by actually shifting the frequency of an oscillator or by driving an SSB transmitter with a single tone that changes frequency, the result is the same: a continuous signal whose frequency shifts between two values. In other words there's no difference between FSK and what people call AFSK except the means used to generate it; and it can be amplified with a class-C amplifier if you wish! -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
Exactly correct
Jim K4JAF ----- Original Message ----- From: "Vic K2VCO" <[hidden email]> To: "WILLIS COOKE" <[hidden email]> Cc: <[hidden email]> Sent: Friday, March 21, 2008 4:05 PM Subject: Re: [Elecraft] Re: K2 and digital modes > WILLIS COOKE wrote: >> I think you are correct if one is running FSK but most >> people, at least a lot of people these days are >> running AFSK, so need linear amps. One would just >> about have to build a Class C amp these days anyway. >> I don't know of any on the market. > > Whether a RTTY signal is generated by actually shifting the frequency of > an oscillator or by driving an SSB transmitter with a single tone that > changes frequency, the result is the same: a continuous signal whose > frequency shifts between two values. > > In other words there's no difference between FSK and what people call > AFSK except the means used to generate it; and it can be amplified with > a class-C amplifier if you wish! > -- > 73, > Vic, K2VCO > Fresno CA > http://www.qsl.net/k2vco > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by n6wg
Bob speaks the truth here. The K6XX fast relay circuit
is the answer. The problem with Elecraft rigs switching Ameritron amps has existed with the K2/100 and, so it appears, now with the K3/100. I have had the K6XX fast relay circuit in my AL-1200 working with the K2/100's. No KPA-100 shutdowns since I put it in a couple of years ago. And there has been no problem with the K3/100. It is a simple fix to allow the K2/100 & K3/100 to work with the slower 12VDC Ameritron amp relays ..... if you need it. 73 Hank K8DD <quote author="Robert Tellefsen"> Roger Go to this site http://www.k6xx.com/radio/fastrely.pdf K6XX has a need relay speed-up circuit that might be applicable to the relay in your amp. I suppose that it requires the relay to be a 12v relay, though. Don't know what you actually have. Good luck and 73 Bob N6WG |
|
|
On Fri, 2008-03-21 at 18:33 -0700, hank k8dd wrote: > The problem with Elecraft rigs switching Ameritron amps > has existed with the K2/100 and, so it appears, now with > the K3/100. I think the problem is not elecraft rigs but amplifiers that have unreasonably slow switching times. 10msec or longer is unreasonably slow and I think it's 'unreasonable' to blame the manufacturer of the radio because the amp manufacturer saved a few bucks and used a cheap, slow relay instead of a proper RF relay. None of my Icoms give me the ability to alter the key delay for slow amplifiers either. The correct approach is to mod the amp to improve matters. the other option is to use the PTT input with a footswitch to take care of RX/TX changeover 73 Brendan EI6IZ -- Don‘t complain. Nobody will understand. Or care. And certainly don‘t try to fix the situation yourself. It‘s dangerous. Leave it to a highly untrained, unqualified, expendable professional. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by alsopb
I agree an inhibit pin is a very good idea. One must always remember to connect it of course. The system needs to fail safe. QSK is not used above HF as much and a radio that automatically allows a delay is far safer than one that produces power immediately unless an inhibit line is used. If that inhibit line was an enable line, I think it would be far safer still.
For those who naively carp one should simply speed up ones amplifier - be aware that there are several things that must happen in the correct sequence. The RF relays must switch and settle, then the PA bias must switch, e.g. 350V to the screens for a tetrode. All this before the RF arrives. At HF this is easy, just use a pin diode or a vacuum relay for RF and a triode. At VHF is is much harder. PIN diodes are too detrimental to the noise figure for RF and the 350V screen supply tends to need a relay because of the shunt regulation. Good chunky high power coaxial RF relays available for sensible prices tend to be slow, even with a speed up circuit. They may switch in a few mS but the contacts may bounce for considerably longer. The TX might not mind but the isolation will be poor and the pre-amplifier will suffer. When you are switching a kW VHF amplifier all this really matters and asking for it to be done in less than 10mS is a challenge. Most of it is the RF relays and although small SMA relays do switch RF very quickly, they are only good for a few 100W. There are many K3 features that are totally useless for me. I don't suggest removing top band or AM to save money because I don't need it, so please don't suggest useful firmware features are unnecessary just because you don't need them. |
|
|
In reply to this post by Brendan Minish
If Elecraft could add a menu item that allows the user to select from a list
of delay times, including the current value set as a default, then everyone would be happy and not have to make hardware changes to their amps and those with faster amps won't have to do a thing. I for one am not blaming Elecraft for the deficiencies of my amp, but am just asking if they could modify the firmware in the K3 to allow me and others to select from various delay times. So far there's been no response from Elecraft concerning this subject after a few days of discussion on this list. We don't even know if they could easily make the modification in the firmware. If they decide to respond to this issue and say they won't or can't do it then I'll be glad to look for a hardware modification to my amp. 73, Roger W1EM -----Original Message----- From: Brendan Minish Subject: Re: [Elecraft] K3 and linear amp On Fri, 2008-03-21 at 18:33 -0700, hank k8dd wrote: > The problem with Elecraft rigs switching Ameritron amps has existed > with the K2/100 and, so it appears, now with the K3/100. I think the problem is not elecraft rigs but amplifiers that have unreasonably slow switching times. 10msec or longer is unreasonably slow and I think it's 'unreasonable' to blame the manufacturer of the radio because the amp manufacturer saved a few bucks and used a cheap, slow relay instead of a proper RF relay. None of my Icoms give me the ability to alter the key delay for slow amplifiers either. The correct approach is to mod the amp to improve matters. the other option is to use the PTT input with a footswitch to take care of RX/TX changeover 73 Brendan EI6IZ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by AD6XY
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1 IMHO it all depends on how much development time and valuable flash memory these "enhancements" take. The K3 is marketed as an HF rig. I'd be willing to bet the vast majority of those in service are used as HF rigs and NOT as a VHF/UHF IF. The MFJ/Ameritron amps have been notorious for slow switching times. Of course they also make money selling the QSK-5 to speed them up. I have been reading this reflector for some time and depth and breadth of suggested firmware "tweaks" is staggering. Most of which come from people who haven't the slightest clue what they are asking for from a programming perspective. The most ridiculous one I've seen so far is the auto volume compensation after engagement of the noise reduction. How lazy is that? TURN THE DAMN KNOB! How about if we get Wayne to program the K3 to stand on one leg, cook breakfast, and sing the national anthem while were at it? Off my soapbox. AD6XY - Mike wrote: | I agree an inhibit pin is a very good idea. One must always remember to | connect it of course. The system needs to fail safe. QSK is not used above | HF as much and a radio that automatically allows a delay is far safer than | one that produces power immediately unless an inhibit line is used. If that | inhibit line was an enable line, I think it would be far safer still. | | For those who naively carp one should simply speed up ones amplifier - be | aware that there are several things that must happen in the correct | sequence. The RF relays must switch and settle, then the PA bias must | switch, e.g. 350V to the screens for a tetrode. All this before the RF | arrives. At HF this is easy, just use a pin diode or a vacuum relay for RF | and a triode. At VHF is is much harder. PIN diodes are too detrimental to | the noise figure for RF and the 350V screen supply tends to need a relay | because of the shunt regulation. Good chunky high power coaxial RF relays | available for sensible prices tend to be slow, even with a speed up circuit. | They may switch in a few mS but the contacts may bounce for considerably | longer. The TX might not mind but the isolation will be poor and the | pre-amplifier will suffer. | | When you are switching a kW VHF amplifier all this really matters and asking | for it to be done in less than 10mS is a challenge. Most of it is the RF | relays and although small SMA relays do switch RF very quickly, they are | only good for a few 100W. | | There are many K3 features that are totally useless for me. I don't suggest | removing top band or AM to save money because I don't need it, so please | don't suggest useful firmware features are unnecessary just because you | don't need them. - -- R. Kevin Stover, ACØH -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFH5P/S11jxjloa2wsRArotAJ97lboupzCTGWJPoeZ/F371bv8nowCbByon BAPBqxVM/pHlIeBsftAsy9M= =5cm8 -----END PGP SIGNATURE----- _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by Roger Marrotte-2
Hallo Roger,
> delay times. So far there's been no response from Elecraft concerning this > subject after a few days of discussion on this list. We don't even know if > they could easily make the modification in the firmware. Elecraft has said in the past, several times, that they will be adding this to the menus sometime in the future. Also The FAQ on the Elecraft web site has the following information (for at least 6 or 7 Months now): ======================================================================= Is there a relay output from the K3 to switch on an external amplifier? If so, is it done via the accessory connector on the rear panel? Yes; it has its own connector (KEY OUT) on the rear panel. The KEY OUT line is a MOSFET, open-drain (equivalent to open collector in a BJT device). It can handle a lot of current AND a lot of voltage. Exact specs TBD. Does the K3 have a variable delay (0-50ms) to control older amp TX relays (i.e., SB-220, L4B, etc.)? Yes. It also has a separate PTT input jack, so you can pre-switch the amp using a footswitch, etc. This delay is provided to prevent hot-switching of amplifiers and the adjustment range will cover any likely need. The variable delay is a feature that will be available after initial shipment. What is the voltage and current limit to control TX amp relays? The keying device is rated at 200 volts, 6 amps. ======================================================================= <http://www.elecraft.com/K3/K3FAQ.htm> vy 73 de toby _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by Brendan Minish
>>>>>>>>>>>>>> I think the problem is not elecraft rigs but amplifiers that have unreasonably slow switching times. 10msec or longer is unreasonably slow and I think it's 'unreasonable' to blame the manufacturer of the radio because the amp manufacturer saved a few bucks and used a cheap, slow relay instead of a proper RF relay. >>>>>>>>>>>>>>>>>> You can't blame home-brewers of amplifiers who has to search for reasonable priced HIGH power relays. That's a group of people who were respected by Elecraft builders, isn't it? 73's, Evert PA2KW -- Don't complain. Nobody will understand. Or care. And certainly don't try to fix the situation yourself. It's dangerous. Leave it to a highly untrained, unqualified, expendable professional. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: Fix the old amplifier......leave the K3 alone!
|
|
In reply to this post by AD6XY
>>>>>>>>>>>>>>>>>>>
I agree an inhibit pin is a very good idea. >>>>>>>>>>>>>>>>>>> Thanks a million for the developers for giving this inhibit possibility. This makes serious VHF high power applications possible. Don't remove this option please!! THANKS (waiting for my K3 as the IF stage for my VHF station) 73's, Evert PA2KW _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by Brendan Minish
On Sat, Mar 22, 2008 at 6:10 AM, Brendan Minish <[hidden email]> wrote:
> > On Fri, 2008-03-21 at 18:33 -0700, hank k8dd wrote: > > > The problem with Elecraft rigs switching Ameritron amps > > has existed with the K2/100 and, so it appears, now with > > the K3/100. > > I think the problem is not elecraft rigs but amplifiers that have > unreasonably slow switching times. > 10msec or longer is unreasonably slow and I think it's 'unreasonable' to > blame the manufacturer of the radio because the amp manufacturer saved a > few bucks and used a cheap, slow relay instead of a proper RF relay. > > None of my Icoms give me the ability to alter the key delay for slow > amplifiers either. > > The correct approach is to mod the amp to improve matters. the other > option is to use the PTT input with a footswitch to take care of RX/TX > changeover > > > 73 > Brendan EI6IZ Well, that's a tough call to say it's not a problem with the Elecraft rigs. I took a fair amount of flak from the "true believers" because a long time ago I said the Elecraft shut down and other radios did not shut down, so it must not be a problem with the Ameritron amps. Before I put the Relay Accelerator on my AL-1200 the KPA-100 on the K2 would shut down. The relay would still key, but no output. No other indication that there was no output until I glanced at the wattmeter. Great way to lose a run frequency!! None of my Icom radios exhibited this problem - They may chop off a tad of the first element, but this has never caused a problem without the relay accelerator. And I'm not about to take it out to see what happens with the K3/100. Maybe the K2's RF comes up to quick compared to the other radios. Maybe the K2 shuts down too quick with that short time that it takes the relay to pick. I don't know ..... and at this point - I don't care - I've worked around the problem ..... whether it's an Elecraft problem or not! 73 Hank K8DD -- 'Never argue with an idiot. They drag you down to their level then beat you with experience.' -anon - _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
«
Return to Elecraft
|
1 view|%1 views
| Free forum by Nabble | Edit this page |