[Elecraft] 8R - 8T lines
I'm trying to understand exactly (well, more or less) what the 8R/8T settings do. In the primary menu, under T-R, you set it as either '8r hold' or '8r nor'. The manual says to user the 'hold' option for all modes of operation. It also says that it ...holds the 8R line low during the user programmed QSK delay. Does this imply that if I choose the 'nor' option, and have the T-R delay time set to a longer period (say, 1 second), that the 8R line will not be held low during the entire 1 second delay? And if not, what is the result? Can anyone help me understand this? Thanks, Mike, NJ2OM ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] 8R - 8T lines
[EMAIL PROTECTED] wrote: Does this imply that if I choose the 'nor' option, and have the T-R delay time set to a longer period (say, 1 second), that the 8R line will not be held low during the entire 1 second delay? And if not, what is the result? I think that if you are talking about a K2 by itself, the result will be absolutely nothing. The receiver will be muted for the period of the t-r delay regardless of the setting. However, the amplifier keying output of the K2/100 and (I think) the transceiver t-r switching is based on the 8r line. So if, for example, you are using the K2 with an external amplifier or transverter that has slowish mechanical relays for t-r switching, you should use the 8r hold option so that you can control the hold time of the external relay with the t-r parameter. 8r normally goes low about 15ms (someone will correct me if this is inaccurate) before the K2 begins to make RF, and goes high again some time after output stops. It can be used to key an external amplifier that has vacuum relays or pin diode switching directly without hot switching. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Which Audio Filter Kit?
On Wed, 09 Feb 2005 00:36:49 -0500, Dale Boresz wrote: So, in my opinion, the KDSP2 offers far more performance and versatility, and is worth the extra money. I have the same experience as Dale, and the same rigs. My 746 (not a pro) is loaded with Inrad filters for CW and SSB. My K2/100 has the DSP module, and although I'm primarily a CW op, I used it on SSB in a couple of contests to see what it would do. My 746 is used almost exclusively on 6 and 2 meters (with outboard preamps), both CW and SSB. I LOVE the DSP in both radios. I use it both in narrowband audio filter mode and as noise reduction, and I am very happy with both. I have not used a K2 with a KAF2. Jim Brown K9YC ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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] Bencher/Elecraft Hex Paddle Dust Cover
Hi Gang, I am SOOO pleased with my Bencher/Elecraft Hex paddle that I want to make sure it stays clean and pretty until I become a SK. Does anyone know of a source for a Paddle Dust Cover (plexiglass) for this jewel? I have been given a couple of references (one WB3EVL and a WP4). One source says EVL is no longer in business (an email has been sent to him) and the WP4 doesn't appear to be a satisfactory option per reviews of his work and reliability. Appreciate any tips. If you are in the market for a great paddle, check this one out. 72 Tony, W4FOA Chickamauga, GA K2 #2213 (Usual disclaimers apply) ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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] Re: Bencher/Elecraft Hex Paddle Dust Cover
On Feb 9, 2005, at 8:29 AM, Tony Martin W4FOA wrote: Hi Gang, I am SOOO pleased with my Bencher/Elecraft Hex paddle that I want to make sure it stays clean and pretty until I become a SK. Does anyone know of a source for a Paddle Dust Cover (plexiglass) for this jewel? I have been given a couple of references (one WB3EVL and a WP4). One source says EVL is no longer in business (an email has been sent to him) and the WP4 doesn't appear to be a satisfactory option per reviews of his work and reliability. Thanks for your comments, Tony. To the list: If anyone would like to go into business making dust covers for this paddle, please let us know! We would definitely stock them. 73, Wayne N6KR --- http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Re: Bencher/Elecraft Hex Paddle Dust Cover
wayne burdick wrote: Hi Gang, I am SOOO pleased with my Bencher/Elecraft Hex paddle that I want to make sure it stays clean and pretty until I become a SK. Does anyone know of a source for a Paddle Dust Cover (plexiglass) for this jewel? I have been given a couple of references (one WB3EVL and a WP4). One source says EVL is no longer in business (an email has been sent to him) and the WP4 doesn't appear to be a satisfactory option per reviews of his work and reliability. Thanks for your comments, Tony. To the list: If anyone would like to go into business making dust covers for this paddle, please let us know! We would definitely stock them. And I would definitely buy one of them! Joe, W2RBA KX1 #0020 K1 # 1005 K2 # 1299 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] on the topic of autotuners
Hi Geoff, I'd add one more option/possibility: one suitable for remote (at the antenna) mounting. Keep the kit form option. It's a very easy build. cheers, Julius n2wn --- Geoffrey Mackenzie-Kennedy [EMAIL PROTECTED] wrote: Hi Julius, Thanks for the fill in. I still have not received the early postings h. Strange, I just sent Eric and Wayne a wish for the KAT100 and that is for a Silent antenna coupler that does not require watts to be radiated during tune, but only a few milliwatts. It would provide for free a dummy load, not only for testing but also a default load for the TX when the antenna falls down. Like you I would much prefer a meter, I do not like the LEDs at all as a VSWR indicator to be honest. Fine for status indicators.Ability to bypass coupler, Yes. CU off list re antennas. 73, Geoff. GM4ESD 'ello Geoff, We're discussing the wish list for an updated KAT100, or modifying the current version. I show my advanced decrepitude by waxing philosophically about adding a power out/SWR METER. LEDs are fine, but I just prefer a meter! ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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] Keying Waveform Measurement
I was wondering if anyone on the reflector has tried to observe a transmitted keying waveform using the technique described on page 25.50 of the 2005 ARRL Handbook, and depicted in Figures 25.86 and 25.87. The Handbook makes no mention of what the Keying Test Generator is or how to correctly set it up. I'd be most grateful if someone could explain what a Keying Test Generator really is. 73, Steve Kercel AA4AK ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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] RF probe
Hi Guys, Just ran into a problem with the K-1 vfo checkout. Not getting signal from the vfo so I need a schematic for an RF probe. I tried to take a look at one on the Elecraft site, but all I got was a blank page. Double checked every component for correct value and all solder connections look good. Could be q1 on the FP board. Thanks Don K8EAA sn 1979 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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] K1 Polyfuse
Noticed that Eric just made a reference to adding a polyfuse to a KX1. I added one to K1 # 1423. Details at: http://tyrrell.us/amateur/k1modpolyfuse.html. Comments please. 73, Ty __ Do you Yahoo!? Yahoo! Mail - now with 250MB free storage. Learn more. http://info.mail.yahoo.com/mail_250 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] RF probe
Don, All it takes is a 0.01uf capacitor, a 1N34 diode, and a 4.7 megohm resistor plus some wire and plugs to fit your DMM. There is a circuit diagram in the troubleshooting section of the K2 manual, just download the manual from the Elecraft site and search for 'RF Probe Assembly'. If you want to see a neat implementation of an RF Probe, take a look at N5ESE's Ballpoint RF Probe http://www.io.com/~n5fc/rfprobe2.htm - it is a tight fit, but I have built a couple of these from time to time. 73, Don W3FPR -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Don Scippa Sent: Wednesday, February 09, 2005 1:03 PM To: elecraft@mailman.qth.net Subject: [Elecraft] RF probe Hi Guys, Just ran into a problem with the K-1 vfo checkout. Not getting signal from the vfo so I need a schematic for an RF probe. I tried to take a look at one on the Elecraft site, but all I got was a blank page. Double checked every component for correct value and all solder connections look good. Could be q1 on the FP board. Thanks Don K8EAA sn 1979 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: Elecraft@mailman.qth.net 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] Rf probe
Thanks for pointing me in the right direction! Nice photo on the pen probe. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Keying Waveform Measurement
Steve, The setup pictured is IMHO overkill, but it covers all bases for any kind of transmitter. No doubt the ARRL Lab has a semi-permanent setup for this test, but all that equipment may not be required depending on what you wish to conclude from your test The Keying Test Generator is nothing more than a keyer - but that one has a special output for triggering the 'scope. In most cases, the 'scope can be triggered on the channel that the keyer output is connected to. The setup shown requires a 'scope with a 50 ohm input to properly load the attenuator. Commonly available 'scopes have a high impedance input rather than a 50 ohm input. If the 'scope and probe input will accept the voltage level presented by the transmitted signal, the attenuator may be replaced with a dummy load (keeping the power output under the speced limit for the 'scope). In fact if all you want to look at is the shape of the output waveform, you only need one channel connected directly to the RF output (and a dummy load)- just trigger on the input and display 2 or 3 dot times. If you need to measure the relative timing of the RF envelope with respect to the keying, a dual trace 'scope is needed. Trigger the 'scope on the channel connected to the keyer output (trigger on the negative going slope) and you can read the delay from the onset of keying to the beginning of the RF wavefront. That is about all I can tell you other than those test setups shown will work and can tell you all you need to know about the keying characteristics of any transmitter. 73, Don W3FPR -Original Message- I was wondering if anyone on the reflector has tried to observe a transmitted keying waveform using the technique described on page 25.50 of the 2005 ARRL Handbook, and depicted in Figures 25.86 and 25.87. The Handbook makes no mention of what the Keying Test Generator is or how to correctly set it up. I'd be most grateful if someone could explain what a Keying Test Generator really is. 73, Steve Kercel AA4AK ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] on the topic of autotuners
One of the issues in the operation of an auto tuner, is that it has to transmit enough power to be rectified by silicon diodes detecting and operating in a linear manner. Also, you have to transmit enough power to break down the oxides on connectors, RF switches, antenna connections and anything else in the Antenna circuit before you get enough conduction to look like the higher transmitter power action on the Antenna circuit. Thus, there is a lower limit on the detection and effectiveness of the RF source used to tune the antenna tuner while making the changes in tuner adjustment easily detected and not too touchy. The ideal is to have enough power used that you have a nice peak to the detected signal, and a smooth slope up and down around it for the peak detection to work well. -Stuart K5KVH ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Keying Waveform Measurement
Don: Thanks very much. Yes, the ARRL setup is serious overkill. However, I have a Tek 465, and I thought it would be kind of nifty to try to set it up to look at my keyed waveform. As for the matter of running a 50 Ohm source into a high Z scope input, Tek has a slick solution. They use these 50-Ohm 2-Watt terminators that you apply right at the BNC connector at the scope input. Essentially, the source, the 50-Ohm load and the high-Z scope impedance are tied in parallel. Of course the gotcha is that you have to use some fairly expensive high-power attenuators to bring the transmitter output down to 2 Watts into the terminator. (The reason for running high power through attenuators instead of simply cranking down the rig power is that the test is intended to observe the keying waveform at full power.) It had occurred to me that a cheaper strategy would be to run the rig into my Heath Cantenna (remember those?) and connect a regular high-Z compensated scope probe (the probe is good up to 100 MHz) across the dummy load resistance. Is there some gotcha to doing that? Maybe that is not such a good solution; 100 watts RF into a 50 Ohm load will have a voltage of something like 200 Volts peak to peak, and I expect that that is way more than the scope could handle. I also expect that to observe full power, you'd need to construct a high-Z voltage divider to tie across the dummy load, being very careful to keep its reactance low. I also dimly recall that there was a piece in QST a few months (years?) back describing a little sampling device (something like a directional coupler) that you could insert in the coax line. The device was supposed to have trivially small insertion loss, but let you look at your on-air output on the scope direct and in real time. Any chance you remember when that came out? The reason the ARRL test is so fancy is that it is intended to measure timing, the time delay between key down and the beginning of occurrence of RF output, and the shortening of the first dot in semi-QSK schemes. Thanks for your help with this. 73, Steve AA4AK At 02:24 PM 2/9/2005 -0500, you wrote: Steve, The setup pictured is IMHO overkill, but it covers all bases for any kind of transmitter. No doubt the ARRL Lab has a semi-permanent setup for this test, but all that equipment may not be required depending on what you wish to conclude from your test The Keying Test Generator is nothing more than a keyer - but that one has a special output for triggering the 'scope. In most cases, the 'scope can be triggered on the channel that the keyer output is connected to. The setup shown requires a 'scope with a 50 ohm input to properly load the attenuator. Commonly available 'scopes have a high impedance input rather than a 50 ohm input. If the 'scope and probe input will accept the voltage level presented by the transmitted signal, the attenuator may be replaced with a dummy load (keeping the power output under the speced limit for the 'scope). In fact if all you want to look at is the shape of the output waveform, you only need one channel connected directly to the RF output (and a dummy load)- just trigger on the input and display 2 or 3 dot times. If you need to measure the relative timing of the RF envelope with respect to the keying, a dual trace 'scope is needed. Trigger the 'scope on the channel connected to the keyer output (trigger on the negative going slope) and you can read the delay from the onset of keying to the beginning of the RF wavefront. That is about all I can tell you other than those test setups shown will work and can tell you all you need to know about the keying characteristics of any transmitter. 73, Don W3FPR -Original Message- I was wondering if anyone on the reflector has tried to observe a transmitted keying waveform using the technique described on page 25.50 of the 2005 ARRL Handbook, and depicted in Figures 25.86 and 25.87. The Handbook makes no mention of what the Keying Test Generator is or how to correctly set it up. I'd be most grateful if someone could explain what a Keying Test Generator really is. 73, Steve Kercel AA4AK ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Keying Waveform Measurement
Steve, Regarding the Heath CantennaI have been scratching around with power out readings recently and after a search of the archives for the word cantenna yeilded some intersting results. What I thought over all these years (since 1964) a 50 ohm load was actually a 68 ohm load after many years in oil and many heating cycles. Thought that topic would be timely again here on the reflector. Roger WA7BOC K2#755 Don: Thanks very much. Yes, the ARRL setup is serious overkill. However, I have a Tek 465, and I thought it would be kind of nifty to try to set it up to look at my keyed waveform. As for the matter of running a 50 Ohm source into a high Z scope input, Tek has a slick solution... It had occurred to me that a cheaper strategy would be to run the rig into my Heath Cantenna (remember those?) ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Keying Waveform Measurement
Thanks to several commentors. Looks like I need to check the resistance of my 30-year-old cantenna. 73, Steve AA4AK At 04:11 PM 2/9/2005 -0500, you wrote: Steve, I have no problem with my 10x probes at 100 watts and a 50 ohm load. I use a Tek 465 here too. But watch that Cantenna - check its actual resistance, they tend to climb in resistance as they age - just helped a guy out whose Cantenna was now a good 68 ohm dummy load. Yes, I know about those 50 ohm terminators - but as you know, they are power limited, and not commonly available except from Tektronics. The UHF 'scopes (or rather vertical plug-ins) that I have encountered have only 50 ohm inputs, and not many hams have those available. I didn't really say so in my post to the reflector, but if you are going to catch the first pulse, you will need a storage 'scope of some variety. Which reminds me - if you are looking at the time delay between keying and RF, put your 'scopes' vertical amplifiers on chop rather than alternate - that will assure you the keying input you are looking at does indeed produce the RF that is shown on the other channel. If the timing of each pulse is exactly the same it won't make a difference, but it is good to double check anyway. 73, Don W3FPR -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Stephen W. Kercel Sent: Wednesday, February 09, 2005 3:31 PM To: elecraft@mailman.qth.net Subject: RE: [Elecraft] Keying Waveform Measurement Don: Thanks very much. Yes, the ARRL setup is serious overkill. However, I have a Tek 465, and I thought it would be kind of nifty to try to set it up to look at my keyed waveform. As for the matter of running a 50 Ohm source into a high Z scope input, Tek has a slick solution. They use these 50-Ohm 2-Watt terminators that you apply right at the BNC connector at the scope input. Essentially, the source, the 50-Ohm load and the high-Z scope impedance are tied in parallel. Of course the gotcha is that you have to use some fairly expensive high-power attenuators to bring the transmitter output down to 2 Watts into the terminator. (The reason for running high power through attenuators instead of simply cranking down the rig power is that the test is intended to observe the keying waveform at full power.) It had occurred to me that a cheaper strategy would be to run the rig into my Heath Cantenna (remember those?) and connect a regular high-Z compensated scope probe (the probe is good up to 100 MHz) across the dummy load resistance. Is there some gotcha to doing that? Maybe that is not such a good solution; 100 watts RF into a 50 Ohm load will have a voltage of something like 200 Volts peak to peak, and I expect that that is way more than the scope could handle. I also expect that to observe full power, you'd need to construct a high-Z voltage divider to tie across the dummy load, being very careful to keep its reactance low. I also dimly recall that there was a piece in QST a few months (years?) back describing a little sampling device (something like a directional coupler) that you could insert in the coax line. The device was supposed to have trivially small insertion loss, but let you look at your on-air output on the scope direct and in real time. Any chance you remember when that came out? The reason the ARRL test is so fancy is that it is intended to measure timing, the time delay between key down and the beginning of occurrence of RF output, and the shortening of the first dot in semi-QSK schemes. Thanks for your help with this. 73, Steve AA4AK At 02:24 PM 2/9/2005 -0500, you wrote: Steve, The setup pictured is IMHO overkill, but it covers all bases for any kind of transmitter. No doubt the ARRL Lab has a semi-permanent setup for this test, but all that equipment may not be required depending on what you wish to conclude from your test The Keying Test Generator is nothing more than a keyer - but that one has a special output for triggering the 'scope. In most cases, the 'scope can be triggered on the channel that the keyer output is connected to. The setup shown requires a 'scope with a 50 ohm input to properly load the attenuator. Commonly available 'scopes have a high impedance input rather than a 50 ohm input. If the 'scope and probe input will accept the voltage level presented by the transmitted signal, the attenuator may be replaced with a dummy load (keeping the power output under the speced limit for the 'scope). In fact if all you want to look at is the shape of the output waveform, you only need one channel connected directly to the RF output (and a dummy load)- just trigger on the input and display 2 or 3 dot times. If you need to measure the relative timing of the RF envelope with respect to the keying, a dual trace 'scope is needed. Trigger the 'scope on the channel connected to the keyer output (trigger on the negative
[Elecraft] Still some trouble
Hi all. Still having some toruble getting my KPA100 aligned properly. After finding and fixing the T4 SNAFU I successfully complete the SWR Bridge Null Adjustment. Looking good with C1 having a 1.0-1 range of about 10 degrees. Hit the middle and double checked the voltage on U5 pin 1. Moved on to Power Calibration and got all the way down to checking the SWR on all bands. everything normal moving up in frequency till I hit 30m. Power drops to 0.1W and SWR of 1.0-1. Check the rest of the bands and they are now the same low power out. What do you think is going on? Thanks. -- R. Kevin Stover ACØH Reclaim Your Inbox! http://www.mozilla.org/products/thunderbird ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Keying Waveform Measurement
In a message dated 09/02/05 20:33:27 GMT Standard Time, [EMAIL PROTECTED] writes: As for the matter of running a 50 Ohm source into a high Z scope input, Tek has a slick solution. They use these 50-Ohm 2-Watt terminators that you apply right at the BNC connector at the scope input I picked up some of those with an ex military scope probe kit. Previously used a BNC T adapter with a 75 ohm termination on the spare port for CATV testing with a scope where a terminated line was required. A 50 ohm termination could be used in the same way if only one has the facility to dissipate the 10 or 100W as needed. What I did for this purpose for 2 way VHF radio testing in earlier times was to borrow an idea from the CATV industry where close into the line amplifier, the tap off unit from the coax feeder line (T unit) is constructed from a resistive divider to provide the necessary attenuation. These can contain as little as a single resistor or can be of the terminated type. For my purpose an attenuator was made up in a small in line filter box with a straight through connection which goes from the TX to the dummy load. Off this a resistor or a string of resistors is arranged from the center conductor to a socket for feeding into the test equipment. The test equipment socket was also terminated to achieve optimum attenuation. Once the voltage level has been reduced to reasonable levels cheaper low power coaxial attenuators can be used if needed. The resistors have to be carbon or other non inductive types and the divide ratio/resistor wattage can easily be work out by math. Made this up many years ago and still have the unit today. It is amazing what one can do with bits of junk when you have hardly two cents to rub together! The old UK made, KW Electronics PEP meter which can measure up to 300W worked in a similar fashion I found years later was using a resistive divider to bring down the voltage levels from the through RF to a level that can be used by the metering circuit. Bob, G3VVT ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Keying Waveform Measurement
Roger: The topic is extremely timely. I expect there are a lot of Cantennas still floating around out in Hamdom. One is tempted to naively treat it like a precision 50 Ohm RF load. I measured the DC resistance of mine with a DMM and the reading was 46.1 Ohm. I dimly recall doing some noise bridge readings at various HF ham frequencies a few months back, and it seemed to me that the readings all came out reasonably close to 50 Ohms. When things quiet down, I suppose I should revisit the readings with a bit more of a critical eye. I do not dispute than many Cantennas eventually evolve into a 68 Ohm load. I built mine in 1977 (it is only 28 years old and not 30 as I said earlier). I was inactive from 1983 through 2004. When I have been active it has been mostly QRP and never above 100 W. Thus, I never really got the puppy hot, and that may explain why the resistance is still close to 50 Ohms. For what its worth, the resistor has been continuously immersed in oil, and I have never changed the oil since I built the device. BTW. Does anybody know if the reactance also tends to creep with age/use? I cannot think of a good reason why it should, but RF properties are strange. 73, Steve AA4AK At 01:10 PM 2/9/2005 -0800, you wrote: Steve, Regarding the Heath CantennaI have been scratching around with power out readings recently and after a search of the archives for the word cantenna yeilded some intersting results. What I thought over all these years (since 1964) a 50 ohm load was actually a 68 ohm load after many years in oil and many heating cycles. Thought that topic would be timely again here on the reflector. Roger WA7BOC K2#755 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Keying Waveform Measurement
Hi Steve, Check the spec on your scope probe. (try Google). If it can handle the voltage at high frequencies, that is the easiest way to go. 100 watts into 50 ohms has a peak 100 volts (the peak-to-peak is 200V but the probe only sees +/-100 volts max). If you need to make an attenuator, it doesn't have to be compensated if you are only interested in the shape of the waveform and not it's exact amplitude. As long as you use linear components (no toriods), the shape of the leading and trailing edges will be proportional to the actual waveform and the frequency spectrum is the same. Even 50K or 100K film resistors would work, with something around 1K to ground. As an alternative, it doesn't take much capacitive coupling to get a usable signal. A piece of wire near the dummy load might pick up enough signal when your running 100 watts. In this case, a small resistor to ground can used to control the amplitude of the signal. 73/ Bob - W5BIG It had occurred to me that a cheaper strategy would be to run the rig into my Heath Cantenna (remember those?) and connect a regular high-Z compensated scope probe (the probe is good up to 100 MHz) across the dummy load resistance. Is there some gotcha to doing that? Maybe that is not such a good solution; 100 watts RF into a 50 Ohm load will have a voltage of something like 200 Volts peak to peak, and I expect that that is way more than the scope could handle. I also expect that to observe full power, you'd need to construct a high-Z voltage divider to tie across the dummy load, being very careful to keep its reactance low. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Keying Waveform Measurement
Mark: Yes, you're right; the 465 does have a 20 V/div max using 10:1 probes. The lesson from you is essentially that when all else fails, read the instructions. According to my probe manual, the probes are actually good to 500 V up to 10 MHz, then they derate to about 175 V at 30 MHz. They are much more than adequate for observing the output of a full-featured K2. Yes, I remember hot carrier FETs and the lethally high voltages required to operate them. 73, Steve AA4AK Sheesh...these young uns! 200V P-P should be no problem for a 'scope. (If you look carefully, the probe is probably a 10:1 voltage divider.) To show 200V p-p as a full scale deflection (assuming 10 divisions vertically on the screen) would require 20v p-p per division. Just set the vertical scaling at 20v p-p/div. If you're using official Tek probes, you can ignore the 10:1 built into the probe because the scope will compensate for it automatically. If the thing doesn't have scalings up to 20v p-p you would need the high voltage probe set, but I don't remember using them for normal (non broadcast) transmitter service. Shouldn't be a problem -- after there are those of us who used this scope, (and its predecessors) to trouble shoot vacuum tube equipment. (Remember vacuum tubes? sometimes known as 'thermionic FETs'? They take high voltages!) ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Keying Waveform Measurement
Bob and Bob: Thanks to both. The advice is very useful. 73, Steve AA4AK ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] 2 k2
On Jan 31, 2005, at 3:23 PM, David wrote: okay I am a bit naive here but why would anyone need two k2s? 1) If you are into contesting, you'd need a second K2 to run SO2R (Single Operator 2 Radios) 2) You need one for the shack, and one for the moble / RV / summer home 3) You need a spare K2 so you can still operate radio while you are putting the latest mods into your other K2. 4) You never USE the K2, you just build them Bill Coleman, AA4LR, PP-ASELMail: [EMAIL PROTECTED] Quote: Not within a thousand years will man ever fly! -- Wilbur Wright, 1901 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] Keying Waveform Measurement
Hi Roger: Actually, I'm quite happy with my 46.1 Ohm reading. After 28 years of mysterious chemical reactions, my Cantenna impedance is still well within 10% of its nominal value. I wonder if a brand new MFJ dry dummy load would be that close. My Cantenna also contains the Heath-recommended transformer oil. It is (was back then anyway) readily available from commercial electrical suppliers. (BTW, I hope yours is not using askarel; it contains PCBs. Although it was illegal to use askarel in 1978, Heath still published performance figures for Cantennas filled with askarel.) Although I see no present need to overhaul my Cantenna, I'd definitely be interested in seeing your pictures. If there is a way to post them to the reflector, I expect that other participants would like to see them as well. You do raise a valuable caution. Cantenna impedance values apparently range fairly widely over the map. If people are trying to measure the power out of a K2 (or whatever rig) by using a voltage measurement and assuming a 50+J0 load impedance, they should only do so if the measurements of the impedance of their specific Cantenna are close to that value. 73, Steve Way Down East and bracing for the Nor'easter of '05 AA4AK At 07:48 PM 2/9/2005 -0800, you wrote: Hi Steve, I have never changed the oil either, mine is actual transformer oil as my father worked for the local utility company as the time. I was having KPA100 difficulties and decided to attach the MFJ analyzer to the cantenna just to check it out...imagine my surprise when it read 68 ohms. I then put the leads from my Fluke dvm on it and it read the same. So what I thought was 50 watts was really 36using P = V^2/50 and in this case 50 was really 68. I have the unit apart, there is a deposit of some kind on the body of the resistor. One has to reverse assemble the resitor holder from the lid in order to get it all apart. I am going to take photos of the unit if you are interested in seeing what I have. I since borrowed a Bird dummy load, 51.2 ohms and a Bird wattmeter and now have the KPA100 KAT100 all recalibrated as well as found one end of C5C not soldered!! Smooth sailing now!! 73, Roger WA7BOC, way out here in Montesano, WA. and on the home e-mail address! -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Stephen W. Kercel Sent: Wednesday, February 09, 2005 2:05 PM To: elecraft@mailman.qth.net Subject: RE: [Elecraft] Keying Waveform Measurement ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: [Elecraft] 2 k2
2 K2s come in handy as bookends for all of your amateur radio literature! It just does not look right to hold your books up with one if them and a KX1 is just not heavy enough to do the job. The 100 watt amps give the rigs enough heft to handle a goodly number of tomes. 73, Kevin. KD5ONS On Wed, 9 Feb 2005 22:36:42 -0500, Bill Coleman [EMAIL PROTECTED] wrote: On Jan 31, 2005, at 3:23 PM, David wrote: okay I am a bit naive here but why would anyone need two k2s? 1) If you are into contesting, you'd need a second K2 to run SO2R (Single Operator 2 Radios) 2) You need one for the shack, and one for the moble / RV / summer home 3) You need a spare K2 so you can still operate radio while you are putting the latest mods into your other K2. 4) You never USE the K2, you just build them Bill Coleman, AA4LR, PP-ASELMail: [EMAIL PROTECTED] Quote: Not within a thousand years will man ever fly! -- Wilbur Wright, 1901 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 265.8.6 - Release Date: 2/7/2005 ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
