Re: [Elecraft] K2 #5549 some questions/remarks
In a message dated 25/12/06 10:53:49 GMT Standard Time, [EMAIL PROTECTED] writes: 1. when looking at the transmitted signal using a spectrum analyser, the signal didn't seem as clean as we liked it. We didn't have time (it was the day before X-mas!) to really start counting the dB's, but on 30, 12 and 10 m we saw some signals around the main signal. Is there any chance we can get these bands 'cleaner' by further tweaking the filters? - Hi Jurgen, Are you 100% sure that the spurii you are seeing are just not due to you overloading the input of the spectrum analyser? This is a common cause of apparent excessive spurii! Merry Christmas to all, 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] K1 -- VW Solar Panel -- Controller Help
In a message dated 06/11/06 09:06:10 GMT Standard Time, [EMAIL PROTECTED] writes: The VW panel reads about 20V in full sun. When connected to Don Brown's low power controller, it drops to 12.75V (full sun). I have a few panels and tried them allsame results. Even paralleled two. :- --- Hi Ken, I would think the VW panels are too puny to provide sufficeint power to fully charge a battery as they were designed only to trickle charge an auto battery in transit. The 20V you describe out of the solar panel is the open circuit voltage. Most 12V solar panels depending on type will give 17V to 21V under these circumstances. However, when you connect it to a battery, the voltage will fall to the charge voltage of the battery depending on it's current state of charge. Disconnect the controller and connect the panel direct to the battery if you want to check for sure. With most types of controllers the effect will be the same in that the readings will be identical less the current needed to run the controller. Unless you get hold of some solar panels with the necessary capacity the result is going to be the same in that you can only trickle charge the batteries. Apart from long term float charging where the controllers would only come into use after a long period of charge. For most cases with low power solar panels a controller is not needed unless the panel does not have a series diode fitted. Many more of the VW solar panels in parallel or a larger solar panel(s) to increase the power is the only answer if you need to use this facility in real terms. The VW solar panels will most probably have series isolation diodes fitted to prevent discharge of the auto battery back through the solar panel at night or when not insolated sufficiently As a quick test to see what your panel is capable of, remove the solar panel from circuit and place a current meter directly across the solar panel terminals. The current reading will be limited to the available capacity of the panel. This is how we checked the 15kW solar arrays at the workplace when they were originally commissioned. These were built up from about 200 of the 75W solar panels arranged in series/banks to provide the necessary voltage/current capacity and each individual one had to be tested to ensured that it met specification. Was not unusual to see 120A going into the 7500Ah 48V battery plant in the morning sun. For that we really did require multiple solar controllers of sturdy proportions! Regards, Bob, G3VVT (ex civilian desert rat) ___ 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] k2, freq readout calibration
In a message dated 14/10/06 09:01:37 GMT Daylight Time, pc5m, Carel [EMAIL PROTECTED] writes: Verified setting of C22 with both methods (parallel freq counter on TP1 and measuring the offset of TP1 and TP2 with a 10MHz signal). --- Hi Carel, Have a care connecting an extra frequency counter in parallel with the K2 counter as the loading capacitance of some counters may pull the readings off what they really are. The K2 frequency counter via the supplied probe gives relatively light loading on the circuits you are measuring. The extra frequency counter may not cause a problem in the case of TP1, but better to play safe and isolate the parallel frequency counter with a high impedance probe. I fell into this trap when setting my K2 4MHz control board clock oscillator with a Racal Dane counter. This has a ovened xtal clock, hence retains a fair degree of accuracy from calibration. However the extra load capacitance of the frequency counter input undid all that and gave an erroneous reading. A high impedance scope probe gave enough level to operate the frequency counter, yet still provided sufficient isolation not to affect the K2. May not be causing problems in your case, but something to be aware of. Regards, 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
[Elecraft] Re: Solar Panels (Douglas Todd
From: charles allison [EMAIL PROTECTED] who wrote: These are needed because the open circuit voltage could be 20 VDC for a 12.6 volt panel without the regulator. -- - This is not really correct as this open circuit voltage will fall to the normal charging voltage for the battery(s) depending on their charge state as soon as these are connected, with or without a charge regulator. Otherwise the reply to the original question is excellent. Charge regulators are definitely needed when the capacity of the solar panel(s) exceed the current drain of the equipment connected and the battery charging current requirement. The result of failing to have charge regulation under these circumstances is that permanent damage to the battery(s) can occur and also possible damage to the equipment connected due to excess voltage. Using 5 to 15W solar panels the average amateur would probably never need a charge regulator as the panel could struggle to provide anything more than replenish the power used in running the equipment. However, the charge regulator could be looked on as an insurance policy to protect the batteries and the connected equipment, so if affordable will not be lost. With solar charge regulators what is needed is a type that will automatically restore charging when the battery voltage starts to fall sufficiently, though with some hysterisis to prevent the charge regulator going into oscillation. I worked on solar powered communication equipment in the Middle East from 1981 for over 20 years and a problem was that some types of solar charge regulator after disconnecting the solar charge would not come back on charge again until the next day after a night time reset. Not a desirable situation for a 24/7 system. There was certainly some junk marketed commercially in the early days! A lot of our early systems had the compact (3ft x 1ft) USA made Arco 55W 12V panels (Exxon) which I rated very highly for dependability. The only things that seemed to slow them down were bullets or rocks directed at them, though even then they often carried out working to a degree. These are now marketed by the Siemens after Exxon apparently pulled out of the business. Sadly a lot of these early systems were let down by shortcomings of the solar charge regulators apart from the simple shunt regulator type which bypassed excess charge voltage as heat. These however could contribute to problems in site cooling. The latter systems worked on before retirement were 15kW 200 panel solar arrays to run microwave sites. These used the larger 75W 12V BP solar panels which also seem to work well. They were configured into 12 banks of 48V by paralleling them in series banks of 4 to provide the nominal comms -48V supply. Everything was on a much larger scale in these systems as with a 7500Ah battery plant it need to be. The regulation was done by switching banks of panels with large switching contactors to regulate the charge voltage when the float charge period was reached. It was not uncommon to see up to 140A at 54V or higher during the early morning boost charge phase when all 12 banks of the 200 solar panels were on line. A point to note with solar panels is that most seem to be rated at 25C temperature. The available current falls with increased panel temperature above this, as will be seen in the hotter desert regions of the USA. Conversely in winter time on cool clear days the available current can rise substantially from the nominal rating. This means that solar power can be a reality in more temperate regions due to lower solar panel surface temperatures. All a thing of the past after returning to the UK in 2002 on mandatory retirement at 60. No work in UK comms for wrinklies, so a change of direction to working at the local Walmart store checkout area. At least it provides food for the kitchen table and funds for new radio equipment. Regards, 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] Variable Inductors Stuck
Hi Gary, A tip passed on to me when I was having the same problems with some very small inductor cores in a commercial 2 way was to place a small amount of petroleum jelly on the thread topside of the core and carefully warm it with a heat gun or hair dryer before attempting to shift it. It is very important to use the correct trimmer tool for moving inductor cores as some of the ferrite types are very brittle and unforgiving. Quite a lot of the small inductor cores also have a trimmer slot both sides which means the core can be reversed if one side gets broken or can be sometimes be accessed from the opposite side, though you cannot usually make much headway if the core splits. At this point the easiest option is to order a new variable inductor. The worst situation is if the inductor core jams solid and no spares are available. One way out at this point is to add another ferrite/iron dust core if the inductance is too low or a brass core if too high. Not a problem with Elecraft products, but what can be a solution with obsolete equipment when in that situation. 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] Re: Elecraft Digest, Vol 20, Issue 22 Headphone for hard of h...
In a message dated 22/12/05 11:42:04 GMT Standard Time, [EMAIL PROTECTED] writes: I partially understand how a speaker works and in order to decrease its audio output I will have to remove or partially remove the paper which joins the core to the outer body - but will it still vibrate ?. Any suggestions would be most welcome. Hi John, The most probable answer is no as the paper cone centralises the voice coil within the gap between the magnet poles. Without this centring effect the voice coil would just jam against the magnet poles and the output would be extremely low. This effect is noticeable when the voice coil is placed off centre by the paper cone. A low and distorted output is all that occurs as has been noted on some K2 with damaged speakers. Another solution may be to use one of the old type headphones with a metal diaphragm under the screw on earpiece. Another way would be to convert the morse signal to some visual form such as for displaying on an oscilloscope or use a morse reader. Compared to the human brain however, all the morse readers I have tried come off very much second best. 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] Power Supply Question
Hi all, A diode was my first try, but there are several problems with that approach. The first being the additional volt drop can make battery charging more of a problem with a fixed supply, though a schottky diode would help to some degree on that score. The biggest problem was the generation of heat was greater than would have comfortable with and there was not enough room within the PSU case to add the additional heat sinking required for the diode. However, the DC current requirements were rather higher for the repeater application than would be required to drive a basic K2. Yes, a diode could certainly be used with care. 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] Power Supply Question
Hi Fred, Your PSU has probably suffered the same fate as our local 70cm repeater PSU did when we floated a battery across the output for emergencies. When the PSU was switched off it blew the DC fuse on the output of the PSU. The reason is the battery is capable of feeding enough power back into the PSU to exceed the current rating and rupture the output fuse which normally protects the PSU. The solution in our case was to fit a relay on the PSU DC output with it's coil powered from the AC supply. When the AC supply fails, the DC output link is cut off from the PSU. Not all PSU suffer this problem as we never had a problem with the 2m repeater with floating a large gel cell across that, but yours apparently did! Regards, 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] PSK Microphone input
In a message dated 28/10/05 12:35:50 GMT Daylight Time, [EMAIL PROTECTED] writes: The K2 is capable of quite high quality transmit audio, but it isn't as apparent with the electret microphones. Icom et al have made the break with electrets starting with their Pro II and later rigs. The selection of a microphone type may take a little more care as it depends a lot on the tonal range of your voice to which type is suitable and more particularly so in the case of SSB. One type may be OK for one person yet may be useless for another. I struggled for many years to find a suitable microphone for SSB where there was no problem with 2m FM. Ended up with a varied selection of dynamic microphones from Shure, Kenwood, Yaesu and many other manufacturers. The type that finally worked was the old Adonis AM-303G electret microphone. However, when I tried to use the same type of electret microphone on 2m FM was firmly told what to do with it. Have yet to try the Heil dynamic microphones to see what the effect is with them. Have an old Heil desk microphone (HM-5?) which came from an S/K sale that had been modified to high impedance use. Will change it back to original configuration and see how that works out. The insert in this is the HC-3 which have been unable to find any info about. Did approach Bob Heil for details about the microphone and though he gave favourable comments for the microphone itself, was not forthcoming with any information or data about the HC-3 insert. Does anybody have any information about this Heil HC-3 insert? 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] OT Handheld Antenna connector
In a message dated 25/10/05 14:38:28 GMT Daylight Time, [EMAIL PROTECTED] writes: Can someone tell me the name of the antenna connector on the newer VHF/UHF handhelds? Hi Chas, It is called an SMA. There are adaptors widely available that have the necessary SMA male plug fitted, the most common having a BNC female socket on the other end. Regards, 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] DMM for XG2 testing
In a message dated 23/10/05 15:32:01 GMT Daylight Time, [EMAIL PROTECTED] writes: Most multimeters, when used for AC measurements, do in fact read RMS values. Specialized meters do exist which will read peak (or average, or whatever), but the common meters do read RMS only. If you measure your household AC voltage (in the US) with your meter, and you find a reading somewhere about 115 or 120 volts, you can be assured that the meter is displaying RMS values. - The only thing to be careful with some DMM are that whilst they will measure RMS voltage at AC power frequencies, will be inaccurate at frequencies in the kHz range. A early Tandy (Radio Shack) DMM I purchased was wildly inaccurate when trying to measure audio frequencies whilst checking large audio PA systems, where the 8000 series Fluke was perfectly OK in measuring audio up to at least up to 5kHz. Regards, 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] Mic plug
In a message dated 15/10/05 09:44:48 GMT Daylight Time, [EMAIL PROTECTED] writes: We did have in the form of Tandy, but they are long gone. We do, however, still have Mc Donalds Hi All, The local Mc Donald seem to be out of stock on 8 pin mic plugs, though did offer a Big Mac as an alternate. The differences between what is available in various countries can be a problem. One gets comfortable with what is available in your own country in terms of products and vendors when such things may just not exist in other countries. One of the minor problems here in the UK in respect to working on USA sourced radios and test equipment is a lack of small bolts and nuts to USA thread standards. Europe and the Far East seem to be standardised on metric for the equipment produced there, which makes life a whole lot easier. Regards, 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] Mic plug
In a message dated 14/10/05 23:24:44 GMT Daylight Time, [EMAIL PROTECTED] writes: The type is 8 pin Foster connector. I don't know if the UK has a different name for it. Hi Lee, Known as a locking line socket 8-way in one of the main component supplier's catalogue in the UK. Not heard the term Foster used in the UK though presume that may be the Japanese microphone manufacturer who may have been the originator. They are a socket rather than a plug as that plug part is mounted on the K2 or whatever transceiver uses this type of connector. Despite this are commonly referred to as an 8 way mic plug. Still prefer them by a long way to the RJ45 connector that has just about become standard for anything used mobile. Regards, 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] Samlex SEC 1223
In a message dated 12/10/05 16:25:36 GMT Daylight Time, [EMAIL PROTECTED] writes: Quite a few of you are using the Samlex SEC 1223. I have a European version with 240v input. There is supposed to be a pair of jumper points inside which allows you to switch to 120v input. I can't find my handbook . Can anyone confirm the two jumper point refernces and also where are they located on the board? Reply --- Hi Vic, I had the same problem when taking a European version to Saudi Arabia and ended up contacting a technician in Samelex America for the info. To quote their reply: The European model is permanently set for 230V 60Hz input (the manual you have is for the American version) Conversion to 110V can be done by a technician. It will be at your own risk and will void the warranty. For conversion to 115V, the terminals C and E on the circuit board are required to be connected together (shorted). The brown wire connection from one side of the interference suppression choke to the male terminal post at point C should not be disconnected. You may connect another piece of wire between points C and E (aim is to short points C and E). You will have to solder these connections using 18 AWG wire as we do not have a special jumper for the European model. Also you should increase the fuse capacity to 6.3A in order to draw the full 23A at 110V input. 4A fuse is used when powering from 230V. !!Remember to undo this modification if you are going to convert it back to 220V operation otherwise you will blow the unit !! So Vic there you have it as described by Samelex in 2001 when I was in the same position. Regards, 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] Phillips Screws
Will reply to the topic of corrosion with chassis screws on this thread. The reply from John, G4BOU on the subject of lubricating chassis screws to help prevent corrosion was: 'petroleum jelly' despite being a very good insulator has a lubrication factor of 1 and any pressure (via the screw threads) will break through the skin and make good contact. It will of course also cover the joint and limit corrosion. It sticks in my mind there was some controversy with the use of petroleum jelly for use in preventing corrosion on lead acid battery terminals as it was reputed to be hygroscopic, i.e. attracts water. This may not be a good property for preventing corrosion on screw threads as it may even make the effect worse. Perhaps somebody on the list who is more expert on the chemistry could comment. Must admit however to filling the high gain UHF 8 stack antenna connection boxes on a Cable TV head end to the brim with the same petroleum jelly to prevent moisture entry in 1971 and that never ever suffered over many years in what is reputed to be the wettest area in England. (the true rainfall figure may have been inflated by small boys assisting in the collection data by adding a certain yellow colored liquid) Really all of this is academic as the biggest cause of non conductivity with the chassis screws must be the coating on the outside of the case panels. This must be quite a good insulator and no way would I for one want to try removing it to ensure a good metallic contact. The inside of the case is a different matter and consequently with case bonding the connectivity must rely on pressure between the inner of the case and the chassis 2D fastener, not the screw thread directly. The problems that come up with trashing the Phillips screw head is usually made worse by using the wrong type of Phillips driver. There must be a wide variety of types internationally to compound the issue. In the UK we seem to have two types. The earlier Phillips British type which still appears in instrument screws and has a quite sharp pointed shallow angle tip. The current usage is with what is referred to as the Posidriv type which has an almost square end with a slight dome on the tip and has a much wider angle on the tip blades. Equivalent screws to this are used commonly on Japanese equipment and are marked with a single dot on the screw head. Using one of the earlier Phillips drivers on these screws is a recipe for disaster. With the Stanley drivers we buy here, the Phillips has a red plastic handle and the Posidriv has a blue one to easily identify the type. The K2 case screws seem to fit my Phillips British type driver better and even using a small Posidriv driver with a no.1 point would soon trash the heads due to the poor fit. May be different with Phillips drivers available in other countries. 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] 5119 is alive!
In a message dated 28/09/05 16:43:04 GMT Daylight Time, [EMAIL PROTECTED] writes: After 6 months, I'm finding the chassis screws are getting stuck in the 2-D mounts from corrosion or galling between the aluminum mounts and the steel (I guess) screws. :--- Hi Bob, As I understand it in certain climates there is a problem with electrolytic corrosion between disimilar metals, with some combinations worse than others. For use in my motorcycles the use of Copperslip or some similar anti-seize compound is essential for this purpose. Also use this for stainless to stainless steel bolts/nuts to prevent what you termed as galling. Had a near disaster with this very subject about five years back where our work airstrip Southern Avionics non directional beacon antenna was damaged in a violent sandstorm. The technicians decided to impress me by getting the new antenna assembled before I arrived on site. Alas they had assembled the upper loading coil part of it upside down and try as we might the bolts on stainless steel straps retaining the loading coils would not come apart. Eventually after some hours work managed to loosen the straps enough to get it assembled correctly. This was a warning to me at least of the problems that can arise with stainless steel bolts. All it needs is a little oil, grease or preferably anti-seize compound on assembly to prevent the problem. 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] WA3WSJ.com Summit Award!
Hi Ed, Have a look at the Summits on the Air (Sota) web site in the UK who have had a summits activation scheme in operation for a number of years which is now starting to be taken up internationally: http://stockportradiosociety.co.uk/sotaweb/ Regards, 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] Re: Ordering form PA (AND UK!)
In a message dated 04/09/05 17:27:02 GMT Daylight Time, [EMAIL PROTECTED] writes: Import duty rules are the same for all of Europe and I would expect that Elecraft already know the correct codes and descriptions to use. Reply:-- Yes, Elecraft appear to be well aware of the correct commodity codes that should be included with the shipping documents and mark everything accordingly. In the case of equipment of this type there is a concession in place at present for this to be imported free of import duty, at least in the UK. The VAT applicable still has to be paid on the price of the equipment and any shipping costs plus the customs handling charge of the shipping route used. It would be great if all this worked, but am sad to say you are still at the mercy of the official at the point of import who may not understand or want to understand the rules and can place import duty on the package. This ramps up considerably the price you have to pay before the package will be released. The easist route at this point appears to be to pay this cost and go though the saga of reclaiming the amount from Customs, which took about 3 months in my case. The UK Customs involved were unreachable by telephone, did not answer e-mail and the only route appears to be snail mail. Getting agitated does you no good, only tends to raise your blood pressure. Others have got their consignment without any hindrance of this type. Just the luck of the draw on the day or which way your personal Customs official gets out of bed in the morning. Bob, G3VVT K2 #4168 ___ 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] K2 speaker
In a message dated 24/07/05 23:06:17 GMT Daylight Time, [EMAIL PROTECTED] writes: Sometimes the speaker frame gets warped after shipping or some other mechanical shock. The speaker magnet is very heavy, which helps contribute to the efficiency of the speaker. If it is warped, you can straighten it by hand. Reply:-- Used to be a common problem in mainly tube type TV receivers in the past due to heat build up in the cabinet. As Lyle mentions it can be corrected in modern speakers by adjusting the speaker frame to stop the effect, though a better solution can sometimes be to change the speaker. The effect is caused by the speaker voice coil being out of alignment and rubbing on the speaker magnet pole pieces. This causes distortion particularly on lower audio frequencies. Earlier broadcast radio speakers had an adjustable voice coil on the speaker cone that was adjusted with non magnetic feeler gauges (latterly plastic) to center the voice coil in the speaker magnet pole pieces. With all of these different types a test of the speaker cone with the finger tips, carefully moving the cone through it's range soon detects any misalignment. 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] What battery to use?
In a message dated 15/07/05 15:37:09 GMT Daylight Time, [EMAIL PROTECTED] writes: I had one rig that wouldn't function much below about 11.0 volts due to that effect. Under transmit loads on the battery and with the voltage drop in the power cables, 11 vdc at the rig happens a lot sooner than you'd think for a QRO rig. Reply: The basic K2 at least seems a lot more tolerant than most radios with an operating voltage range quoted in the specifications from 9 to 15VDC. An Icom IC-706 mkII I have will not work below 11.75VDC as the PLL section voltage regulator goes out of regulation below this point causing severe FM on the TX signal. With a 12V lead acid type battery it is unwise to expect too much life left available when the voltage measured directly at the battery is approaching 11V as the droop in voltage starts to accelerate at that point. Most comm systems that I worked on with lead acid battery plant are usually set to disconnect the batteries at 1.75V per cell or 10.75V with a 12V system to prevent permanent damage to the batteries. Even if they did not take this action the available battery charge would not last too long in any case. 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] knob
In a message dated 12/07/05 00:56:02 GMT Daylight Time, [EMAIL PROTECTED] writes: I must be missing something. Whats wrong with the knob that comes on the K2? Why change it? Guess I just don't get it. Jerry - NR5A - South Dakota Reply: --- For limited casual use not a thing as the knob is well balanced as regards weight/size and fits the available front panel space perfectly, however if you have to move frequency a lot searching for stations the hard edges of the knob become a somewhat wearing to the fingers. Had exactly the same problem with an earlier JRC JST-135 HF transceiver and that was solved by installing a knob from the later JRC NRD-535 RX. The only difference between the two was the NRD-535 had a rubber ring (tire) on the outer edge. What a difference this makes when searching for stations! With this in mind it would perhaps be a good idea for Elecraft to consider the provision of a suitable rubber ring to fit externally on the circumference of their stock VFO knob as outside the USA not all users will have the access to the reported solutions to the problem. My attempts to find a suitable rubber band of the type reported to come with asparagus supplied in the USA (asparagus tips?) have got nowhere. Have got a crony of mine visiting the USA at present switched on to finding sources. Of the two Yaesu solutions with the FT100D and the FT900 rubber tires which is the best? The prices quoted for supplies of these in the USA will have absolutely no bearing on the final UK cost. 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] NiMH Battery Question
In a message dated 04/07/05 19:56:32 GMT Daylight Time, [EMAIL PROTECTED] writes: There are some small charge controllers out there, but a relay configured to open when the battery reaches full charge is the simplest. Reply:-- The problem with using a relay for solar charge control is the current needed to activate the coil of the relay. This could be as high as 100mA and with a charge budget available of only 250mA you would have to select the relay used with care. If a solar charge controller was seen to be necessary I would have thought a solid state version similar to the type Don Brown is making the kit for would have been a safer bet for minimising power losses in the control mechanism (pity these are only available in the USA as I could have used one). The usable solar power available for solar panels is usually calculated at 8hrs per day, though does depend on the seasons further away from the equator. With 8hrs @ 250mA that would equate to 2000mA per day which is the total rating of the NiMH cells being used. The charge needed would depend on the initial state of the batteries and what the consumption of the radio was to offset the available charge. Some device to monitor the battery voltage and an on/off switch would also work as a charge controller in this case at probably even less cost. With regard to the point when full charge is reached with NiMH cells, I was checking out a motorcycle racing ignition pack last week and using a commercial charger built for the purpose, the end voltage for a 6 NiMH pack was 8.40V, which equates to 1.40V per cell. These guys can get exceedingly upset if they are leading a race and the batteries die, so had to ensure that all was OK. The point with this type of cell and many others including gel cells is that the initial voltage at the end of charge is higher than the nominal voltage of individual cells, though the voltage soon droops with use to the nominal voltage of approx 1.20 to 1.25V per cell. This carries on pretty well constant until the battery is almost empty then there is a rapid fall as the battery dies. Under these circumstances using NiMH cells it would be better to maintain the charge to prevent the voltage falling as was recommended. Understand with the earlier NiCADS it was better to take them as far as possible before recharging otherwise cell capacity could reduce. 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] Ser 4993 - First Problem
In a message dated 30/06/05 03:24:07 GMT Daylight Time, [EMAIL PROTECTED] writes: Applied power for the first time: heard the relays engage backlight came on Display is blank, nothing whatsoever in the display turned rig off and back on, no relays this time, but still nothing in the display Reply:-- Tim, The item you should check is that you have soldered pin 1 on the K2 Front Panel LCD driver U1. I did miss this when I built my K2 as did a number of others. Not sure why this happens. Pin 1 of all IC on the PCBs are different being a circular copper track, though that is no answer why it is missed in the soldering. The pin 1 on front panel U1 can be inspected with the board removed. However due to the front panel switches and the LCD display positioned above it is rather difficult to get a soldering iron in to solder the pad. Some builders have removed the LCD to access the pad. As I had concerns in damaging the LCD in the removal, ended up cutting a tiny V out of the plastic corner on the lower edge of the IC socket, just enough to get a very small soldering iron bit to the pad there and solder the pin. The IC socket plastic removal is not seen as it is hidden when assembled. Bob, G3VVT K2 #4168 ___ 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] KNB@ non-operation
In a message dated 30/06/05 13:35:58 GMT Daylight Time, [EMAIL PROTECTED] writes: I also see that Q5, the transistor that shorts out the output filter tank, has no bias at all. There is no DC return for the base to ground. Is this correct? Maybe the base should not be floated? Maybe Q5 is open? Reply:--- Rich, Q5 on the KNB2 is either on or off, there is no in-between state so no bias is applied to the transistor apart from when it is switched on by the one shot Q3/4. Possibly looking at the base and collector of Q5 with a scope would help to see the spikes of enabling voltage and suppression of the segment of signal during a short duration noise burst. The circuit details with the schematic on the last page of the KNB2 manual should give an insight into the method of operation. The problem with checking most noise blanker is generating the necessary test conditions to see if the operation is correct. Most radio equipment manufacturers are rather vague in this respect and I have yet to find a piece of test equipment that will provide interference pulses on demand. Possibly an automobile spark plug driven by an ignition coil and contact breaker pulse source may be the answer. Have tried using electric drills and other brush motors for generating noise pulses with only limited success. Otherwise it is sometimes a case of awaiting a RF noisy auto to go past as the KNB2 only functions on short duration spikes of noise. Regards, Bob, G3VVT K2 #4168 with KNB2 ___ 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] whips
In a message dated 29/06/05 23:50:28 GMT Daylight Time, [EMAIL PROTECTED] writes: Check the base impedance at hf. Some antennas have a vhf matching circuit in the base that will look like nearly a short at hf. If it doesn't show an open circuit at hf, Reply:- What Bob, N6WG mentions are the VHF antennas that are 1/2 wavelength or multiples of this and where the antenna feed end is at a high impedance. To match this a coil is inserted into the antenna base with the incoming 50 ohm feeder tapped in at an early point on the coil. Normally this type can be located even with a sealed marine type antenna by checking the resistance across the unplugged antenna lead should read S/C looking towards the antenna. This type of VHF antenna should not be capable if working on HF. However if there is no measurable S/C there is a good chance the antenna is one that is a multiple of a 1/4 wavelength and as such could be used as a short whip antenna for HF, though with rather limited efficiency. 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] O.T. Datong FL3.
In a message dated 29/06/05 21:50:12 GMT Daylight Time, [EMAIL PROTECTED] writes: Actually, Mike, I think I've seen mention of Datong in recent years. Not totally dead yet. Dr. D. A. Tong was a very clever designer, but he kept his designs very close to his chest. To the best of my knowledge, the schematics for the FL3 or others were never published. I too have an FL3 and would like to see the schematic, but no joy so far. 73, Bob N6WG Reply:--- As Nigel mentions in an earlier posting, Datong Ltd are still very much in business in more upmarket RF tracking equipment sold to government agencies. I did contact the company recently trying to obtain a schematic for their earlier Datong DF1 FM direction finding unit that was marketed in the mid 1980's. I have obtained one of these items to help in the tracking an interfering signal (moron) on the input to our local 2m repeater. Unfortunately the antenna combiner part of the DF1 had got lost over the years, so the only option was to build another to get the DF1 working. Contacted Datong via their website listed address and though they were initially willing to help, became unable to do so when a schematic was requested. Only suggestion they made was to post a request for help in Radcom or similar. Never have seen any of their schematics available so possibly none were ever given out. I traced out a schematic for their AD170/AD270 active RX antenna from the PCB as a necessity to repair the unit after it got zapped by static electric during my years in the Middle East. Other than having a go yourself to trace out the schematic from the FL3 PCB, it may be worth contacting Datong via their website address to see if they will help with the FL3 schematic. As a footnote did finally find a project unit that was very similar and compatible to the Datong DF1 that had the schematics available plus the necessary blank PCBs. In process of constructing this unit at present. 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] K2 1E field day
In a message dated 27/06/05 16:37:10 GMT Daylight Time, [EMAIL PROTECTED] writes: The only glitch I'm having right now is that I'm getting reports of FM/Chirp, and I can hear this when I transmit into a dummy load, listening on a TS-940. I thought it might be voltage drop under load, but reducing power doesn't change it. I haven't gone through the TX alignment so maybe this is an alignment thing(?). Reply:- Hi Paul, Check that RFC15 the 100uH choke that feeds the 5V supply to the PLL chip U4 pin 16 on the RF board is not O/C. Apparently a common cause of this problem as it is very easily damaged during installation. Need to check it with a DVM for a low through resistance as voltage tests can be misleading. Can be temporarily replaced with a wire link until a new choke is obtained if it is faulty. When installing a new choke carefully hold the wires next to the body of the choke with a small pair of needle nose pliers and bend the free end of the wire with your fingers only. This helps to keep mechanical stress off the choke body. 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] K2, Noise Gen and Spectrogram
James, Sometimes in addition to a noise generator and a PC with a soundcard running Spectrogram you may need to add a 600 ohm 1:1 isolation transformer between the LS output of the K2 and the PC sound card input. Perhaps I was unfortunate in that both my PC and a separate laptop had spikes on the display from harmonics of the AC power frequency. In the UK we use 50Hz AC power so that was present as a very large spike followed by 150Hz and every 100Hz after that through the audio spectrum. With your use of 60Hz AC power in the USA would possibly expect that plus multiples through the audio test range if afflicted. The use of an audio isolation transformer killed these spikes stone dead. Don, W3FPR suggested the audio transformers from scrap PC modem cards as a possible source of suitable 600 ohm transformers. The Spectrogram program turned out to have other uses for me beyond checking K2s. Having done a hurried rebuild on a 2m repeater for a semi local repeater group, when installed on site the through audio was poor and sounded muffled. With the aid of a VHF noise generator plus my laptop running Spectrogram was able to follow the audio through from the repeater RX audio output, through the logic and right up to the TX modulator. Apart from the normal RX de-emphasis and the blocking of the audio below 300Hz in the logic to remove the incoming CTCSS, the audio was correct right the way through the system. The problem in the end turned out to be the TX modulation pre-emphasis was not functioning. No doubt there are many other uses for the Spectrogram program, but on this occasion saved me a lot of time in fault finding on the repeater. 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] Using the KX1 on Solar Power
In a message dated 22/06/05 15:26:09 GMT Daylight Time, [EMAIL PROTECTED] writes: You can test the output current by connecting a 10 ohm 5 watt resistor across the panel and measuring the output voltage Reply: . In practice you do not even need to do that. During some commissioning of a large solar powered microwave system I was involved with about 5 years back that used up to 15kW of solar power at each site (200 x 75W 12V solar panels), the contractors who installed the system tested the output by connecting an ammeter effectively directly across the solar panel output terminals. When I raised the question would this not cause damage? They came back quite rightly, no, the current will limit at what the solar panels are capable of providing. In these installations the total array was divided into 12 banks of 48V sections with panels in series and parallel to make up the arrangement. As the current involved was considerable the method involved was to place a heavy gauge piece of wire after the solar panel breaker and when the bank was activated measure the resulting current through the piece of wire with a calibrated AC/DC clamp type current sensor and a DVM. With the type of solar panels normally used by hams, probably a DVM on a suitable current range direct across the solar panel terminals would do the job. You have to take care that the panel being tested is isolated from all other power sources such as batteries, but at the end of the day the panel will not supply any more than what it is rated to give. Don, KD5NDB was very correct on the need for a blocking diode to be inserted in series with each solar panel when multiple panels are in use, otherwise a panel in shade where the other(s) are in illumination, could absorb the power being generated by back feeding into this panel. Larger sized panels normally have the blocking diode included inside the panel assembly or terminal box. In addition they have internally what I believe are called bypass diodes to prevent the panel limiting the voltage within itself when part of the panel is in shade where the rest is illuminated. 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] Dummy Loads and SWR
I mistakenly gave the wrong christian name for G5RV in reply. Was pointed out correctly by Peter, G3PDL that it was Louis Varney. Reg Varney was a more infamous UK TV personality of the past. Senility creeps up on you and you don't know it is happening until too late! 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] K2/100 Power Requirements
In a message dated 03/06/05 04:10:11 GMT Daylight Time, [EMAIL PROTECTED] writes: Given the size and weight of batteries, I had hoped to use a 36 Ah battery, and then recharge it with solar power. But it seems that these batteries charge rather slowly, and that might not be possible. For example, I think it is powerportstore.com that has a 1.2 amp flexible solar panel recharger that puts out approximately 5.6 - 7 Ah per day. The solar panel is about $ 500.00.The general size/weight and price is ok, but it doesn't appear that such output would be sufficient to fully recharge a big battery. Reply: -- The problem of recharging the battery from the 1.2A solar panel (about 16 -18W capacity) is related to the solar panel being rather lacking in capacity and would not do much more than delay the battery being run down considering the drain of a K2/100 on TX. It all depends on the TX to RX ratio used with the K2/100 and the mode of usage to how long the battery will last. RX is no problem with the K2 as that is in the 0.25A range, but the 100W on TX can draw something in the region of 20A at full output. However a 1.2A solar panel would be very usable with a basic K2 which has much lower TX current requirements of usually 2.0 to 2.5A at 13.8V. Even with this a charging controller would probably not be needed as the battery would provide much of the needed voltage regulation. A diode would be needed in series with the solar panel to prevent the battery discharging back into the panel when the solar insolation is insufficient to provide any charge. This diode is provided internally with most of the larger solar panels. For use with a K2/100 a much larger solar charging capacity would be better, probably in the 55W range (4A at 13.8V) or higher together with a suitable charge controller to prevent any possible over charging of the battery and consequent over voltage being applied to the K2/100. With the solar powered communications systems I was involved with from 1981 to 2002, these initially used multiple 55W panels (approx 3ft x 1ft) with individual controllers on each to provide the charging for the battery plant. Later 15kW systems used 200 x 75w panels (approx 4ft x 1.5ft each panel) and switched the solar panels in banks controlled by an intelligent charger system. A matter of balancing the required charging voltage with the amount of panels on line. This was needed to provide for the current drain of the comms systems and allow for days when the sun did not appear, where the available charging current would be insufficient to balance the 24 hr drain. With the latter systems running a microwave site it was normal to see 120A or greater charge current at 54 to 58V when the battery plant was in the morning full charge cycle. 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] (no subject)
In a message dated 31/05/05 08:37:43 GMT Daylight Time, [EMAIL PROTECTED] writes: To all. I ordered 8 rechargable batteries from ZBattery at a good price. I have stayed away from rechargable batteries because of the 1.2 volts per AA battery. However these are the high capacity batteries 2450 amp hr. What do you think for my K1? At 9.6 volts I am not sure what power output I will have... If it doesn't work out for the K1 I can always use them in my dig. camera! Hi Paul, Presume you meant 2450mAhr AA size. 2450Ahr is something quite huge that unless the very latest high capacity (and expensive) block NiMh cells are used, would entail you using a trailer to haul them about. We had 3750Ahr 2V lead acid batteries cells in the workplace com site's solar powered battery plant and they were big! The 2450mAhr AA version is as you say very usable in digital cameras, but you do need to keep them charged up as they seem to gradually go flat if left in the camera for a long period of time. Another downside is the increase in capacity had brought on a very definitely noticeable rise in weight. 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] Antenna problem / phenomenon
The answer to the problem is an old one in that it is difficult to get an HF antenna to work with a mag mount due to the low capacitance between the magnetic base and the vehicle body. VHF/UHF antenna mounted on a mag mount is OK as the effective low capacitance does not present a problem. I even tried a 3 magnet type of mount on HF with the same dismal results. Am told that if you can install a very short wide grounding strap from the mag mount to the vehicle body this can be the answer to the problem, but admit that I was never entirely successful with this either. There seems nothing better than getting a good metallic contact with the vehicle body to get an HF mobile whip to tune and correctly which is what I had to do in the end with a bolted on mount. 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] Power Supply Ferrite Beads.
In a message dated 16/05/05 23:08:10 GMT Daylight Time, [EMAIL PROTECTED] writes: First, for the ac cord, use a large enough toroid so that you can get a number of turns through it. Try to get them to lay smoothly next to each other, rather than bunching and crossing over each other. You can remove the ac plug for the winding, then install a new one when the windings are done. Reply: --- Like Bob, N6WG I used a large ferrite ring that was sold at a hamfest for use to construct a filter for hi-fi interference and TVI suppression at HF at about US$1.00 each. Through this wound as many turns of 3 conductor AC power cord that would fit laid flat with it's outer sheath removed. Ended up with about 12 turns secured with plastic cable ties. In my case was using this to suppress a noisy PC switched mode supply at HF so added an IEC free socket on the end of the short cable tail. The incoming power was taken through one of the shielded IEC chassis mounting filter with male connector that are available in the market. Mounted the whole lot in a plastic box with an added MOV suppresser to remove spikes mounted at the terminals of the IEC filter. This is only added for the benefit of the PC to prevent spikes causing system crashes. Mounted the box next to the power socket on the PC switch mode PSU to keep any leads short. Works well allowing me to have the PC running at the same time as working HF which was just about impossible before. Purposely suppressed all three conductors including ground which decoupled the PSU case and by default the PC to contain the interference sources. Noted that a commercial power filter for telephone switch use was found to be similar, with all three conductors including the ground lead decoupled with an inductors. 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] Noise blanker [was: K2 battleplan?]
In a message dated 30/04/05 16:12:07 GMT Daylight Time, [EMAIL PROTECTED] writes: I've noticed the majority of K2s seem to be built with the NB. I don't have it, and since I don't seem to be having any man-made noise problems I've been wondering when where the NB is useful. Is it mainly for presumably noisier urban and suburban areas? Without it would something like Spectrogram show continual spikes at certain frequencies? And finally, would the DSP board have any substantial effect on the sort of man-made noise the NB addresses? Reply: -- At first I thought the KNB2 noise blanker in my K2 was not working as it had no effect on the normal type of noise received at my QTH. Then after quite a few months found that the NB did indeed work and very well, but only on impulsive noise with sharp rise times like automobile ignition interference. Seems that the KNB2 is a lot more selective in what it will suppress. My old faithful Yaesu FT-480R 2m multimode on the other hand is not as choosy and will work over a wider range of noise types. The FT-480R if anything is rather simpler in the NB circuit design than the KNB2. The FT-480R picks up the RX wide band input half way through the two roofing filters that provide initial bandwidth control after the first mixer. It uses a relatively high gain IF section controlled with AGC to feed a detector circuit that gates G2 in the 2nd mixer MOSFET. It does work exceptionally well though, removing a variety of noise types. If the KNB2 worked to the same degree I would be very happy. The incidence of the type of interference that the KNB2 will gate out is seldom experienced at my QTH, so it gets very little use. In retrospect could have saved a some money by leaving the KNB2 out in my K2, though as has been pointed out in other postings there are some QTH where this noise blanker is really useful. Only hope that eventually some future mod or redesign of this module may be of benefit with the type of noise I suffer from. As regards use of the DSP2, I do not have one in my K2, but do have an external Timewave DSP-9+ available. The DSP-9 works I would guess in a similar way to the DSP2 in that it is in the audio chain. Impulsive noise is not removed by this device in noise reduction mode (NRr), though longer term noise that the normal noise blanker will not touch is suppressed in amplitude during it's duration. I would guess the audible effect is in a way similar to what used to happen with ANL circuits in the AM days. The DSP-9 and would presume other audio DSP devices have a longer delay in response time and so prevent any chance of removing sharp rise time noise. Though it may be looked on as heresy by the K2 CW fraternity, in the Timewave DSP-9+ SSB mode, morse can be almost completely eradicated by the action of noise reduction on tone (NRt). When going over to CW with an external DSP device, the user has to be careful that this NRt facility is switched off, otherwise little morse is heard. Bob, G3VVT K2 #4168 ___ 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: KPA100 question
In a message dated 23/04/05 11:55:05 GMT Daylight Time, [EMAIL PROTECTED] writes: It's always a good idea to leave a LITTLE air under power resistors, to help them dissipate some heat. Mine stood off the board about 1/8 Reply: --- Can concur with that idea. When I worked in TV repairs in the 1960s and PCBs first came into use, we used to slip a small ceramic bead over the lead to give a small stand off to prevent charring of the early laminated paper PCBs. Failing this a small full loop in the lead was made around a jewellers screwdriver to raise the heat generating component above the PCB, and also provide mechanical support to the soldered joint. Anybody who worked on these early PCB will be well aware of the effects that could occur. The other problem apart from charring being when carbonised tracking between the layers caused an internal break down between adjacent component leads due to the higher tube voltages employed. Latterly the method seems to be to joggle (kink) the component lead to provide a mechanical stop against the PCB and assist in component cooling where needed. The use of fiber glass PCB made the effect of heat generation in the PCB less of a problem, though should still be avoided. 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] KX1 battery
In a message dated 22/04/05 19:50:27 GMT Daylight Time, [EMAIL PROTECTED] writes: I had a 33 Ohm resistor of 5W in stock which was only 0,3 inch, so it fits very nicely. I have mounted it on the component side of the pcb, otherwise it gets in the way of the battery! The result is very positive, it charges nicely. I have mounted a timer in line with the charging supply, an old Nokia 12V GSM supply, to avoid overcharging as I read that NiMh cells dont like that. Reply: --- Hi Dick, Yes, that method will work and is used in most simple hand held radio battery chargers to limit the charge current. However to get the best life out of NiCad and NiMh cells/batteries I have always understood that they should be charged under constant current conditions at the recommended rate given with the cells or battery. The series resistor method does limit the maximum current though may partially fall down on not providing a constant current. There are several methods of providing a constant current, the most common being to use a voltage regulator with a series resistor providing feedback. I use an earlier method with two transistors and two resistors that is easily adapted to any required constant current and will cope with a wide range of input voltages. Not sure how the charging of the KX1 is configured so your options may be limited. Contact me off the list if you need the two transistor schematic. Gross Overcharging of *any* rechargeable cell/battery is always a problem resulting in heat generation and eventual destruction of the cells unless this is limited to a charge rate of 2.5% or less of battery capacity. I had something like 400 UHF HH to maintain at an oil terminal/gas plant and apart from the operators using the radios instead of a hammer, the main problem was gross overcharging which could lead to failure of the battery in as little time as a year. Some automatic chargers received more recently were the answer to this problem, though these are even today far from being widely available. Time limiting the charge will work as long as the battery is fully discharged to start with. A partly discharged battery subjected to a full charge cycle will only dissipate the resultant continuation of charge after full charge is reached as heat. Note that all modern cellular mobile telephones are fitted with an automatic charger to get maximum recharging life from the battery. 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] Re: SMD-based kits and retirement [not!]
In a message dated 20/04/05 06:06:43 GMT Daylight Time, [EMAIL PROTECTED] writes: Don't worry -- leaded parts aren't going away anytime soon. We still have access to every part we designed into the K2 over five years ago. Reply: - Leaded parts may not go away, but may be increasingly difficult to obtain. Some types of IC are a case in point where the DIL type are getting very difficult to source and new types of devices are only available as SMD. There is a way around this in adapting a similar SMD IC with a DIL header adaptor, but this would become impractical if the number involved get too great. All volume manufacturers of equipment seem to be changed over to using SMD which can only hasten the decline. Have been involved recently with sourcing some CTCSS decoders for home constructed repeater logic systems. Very little is now available in DIL format as the radio manufacturers have only only used SMD for quite a long period. What is little still available in DIL commands quite a hefty price premium compared to the SMD type. More worrying if the information turns out to be correct is that Toko are reported in the UK PW radio magazine for May 2005 to be ceasing manufacture of through hole PCB type transformers and concentrating on surface mounted types. Unless another source is found of these components, this could make home construction though not impossible, a great deal more difficult. 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] KSB2 firmware
In a message dated 17/04/05 16:25:51 GMT Daylight Time, [EMAIL PROTECTED] writes: Well, I had never read this procedure before, so I gave it a try. SSBA entry to BAL, then held VOX and got . . . nothing. Reply: -- Try activating BAL mode, go back to frequency display and then press VOX. Mine gives a display of 1.08 for a second or so then before reverting to frequency. 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] To drill or not to drill, that is the question
In a message dated 16/04/05 11:11:43 GMT Daylight Time, [EMAIL PROTECTED] writes: What I use is a wooden cocktail stick ( bought in lots of 1000 for a quid from your local Pound Shop ) or a wooden toothpick that I have previously preformed by gently pushing it through an empty THP hole of the correct size. I then heat the hole to be cleared until the solder melts and then push the stick through the molten solder. Its easy, non destructive and very quick to do. I also use this wooden tool to prevent ingress of solder to ajacent holes when soldering a component located close to other THP holes. Reply What a good idea Mike. I had the misfortune to solder joints that should have been done later particularly on the K2 RF board. This idea would have saved me the grief of removing the solder in a THP hole that was required later without affecting other joints in the area. The builder who ended up having to buy a new board about a year back after clearing the THP holes with a Dremmel tool is a good testimony for not using a drill bit to clear solder. 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] Antenna Analyzers
I had the analog MFJ-209 for a number of years without any problems and bought the later MFJ-259B with digital readout two years back. Also have the AEA SWR-121VU for VHF/UHF antenna tests. No complaints with any of these analyzers as they have worked faultlessly since purchase. The surplus MFJ-209 was sold the same evening it was advertised at the local radio club. A point to remember with antenna analyzers built for the ham market, is mostly that they will not work in areas of high RF field strength such as at communications sites. Have to resort to the old faithful Bird Thruline or other professional test equipment to get anywhere in these cases. Can also occur at contest sites where multiple stations are in use. Like a lot of ham gear these antenna analyzers are built to a price otherwise they would not sell. I doubt very much if more than a few affluent hams would be willing to pay the price demanded for new professional test equipment. Prices in the USA for ready built ham gear are low in any case compared what we have to pay in the UK. The Robber Barrons here have an exclusive grip on our market which appears to be in some cases supported by the manufacturers. The normal ploy seems to be to rub out the $ sign and replace it with the £ sign, a 155% mark up at present exchange rates when local taxes are removed. Have even seen some cheaper items of MFJ that cost more numerically in £ than in US$ on the market here. Importing the items from the USA seems to be hindered by inflated shipping charges. Thankfully, Elecraft at least leave it open to the buyer which shipping method is used, so allowing costs to be minimised. 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] Calibration Interval
In a message dated 14/04/05 05:36:04 GMT Daylight Time, [EMAIL PROTECTED] writes: Jonesy,K9NX wrote: My K2 #4198 is running just fine and I am wondering how often to check the Calibration of my K2 to help make sure it is running at peak performance Say every 6 months or yearly? --- Just a guess, but I'd say you can ignore it for a couple of years at least. Even then, 'recalibration' will catch any tuned circuits drifting, but isn't really a test to see if there's performance degradation from other reasons. I have a habit of recalibrating or doing other repairs only when I see something wrong. I see something wrong when some critical values change. I log the key data about a new rig so I can look back from time to time if I'm suspicious that something's amiss or if I'm simply bored and want to tinker -- What Ron says sums up the situation very well, why would you want to recalibrate the radio unless the performance is falling off. To quote the often used phrase if it ain't broke, don't fix it. Not many hams would do this to the latest Japanese/USA black box, so why do this to a K2? The radio is tested to a degree every time it is switched on and used on the bands. A fall off in TX power output or RX sensitivity soon becomes apparent. Is important however, to record *all* the tests you make on original commissioning, calibration and after any mods that may be done for future troubleshooting if required. By and large unlike earlier tube equipment, solid state equipment performance does not change all that much unless a fault develops and one is usually made aware of this pretty quickly by other hams if not apparent to yourself. Apart from odd quirks that can occur with some radios, I would be rather more worried if the performance does drift as that would not say much about the quality of the original design or the components used. With commercial communication systems these are tested with specific routine maintenance programs on a regular basis to ensure that any defect is picked up before it becomes a problem. The reasoning behind this is to prevent unforeseen outages as these can mean lost revenue for the company or a possible threat to safety. Ham radio does not normally fall into this category, so unless tinkering with the K2 calibration really turns you on, it is far better to use the radio for the purpose it was designed for in the first place, communicating with other hams. Bob, G3VVT (retired comms maint tech) ___ 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] Quoted text
In a message dated 14/04/05 13:26:26 GMT Daylight Time, [EMAIL PROTECTED] writes: Is there a specific reason why some of you folks don't have your email software adding the quote characters to the quoted material from the messages to which you are replying, or is it just an accident? It makes it very hard to see what the reply is and who has replied (see below for an example). I've never seen this behavior before I joined this mailing list. Thanks, Paul -- -- Paul, My particular e-mail software just does not appear to do what you ask, only quotes any parts I happen to highlight on the original document. This shown at least to me as indented text as is your original message quoted at the head of this reply, but which unfortunately gets lost through the system. Also, which I think is even more important, try to keep the parts of the original included brief, only use the parts that have relevance to my reply. One day may find the method of doing what you ask to include the characters and let you go away rejoicing. Conversely I find the use of continual characters cloud the whole message with semi useless information that is even more frustrating when posters persist in adding the whole message when it is not really needed, plus *all* of any previous multiple replies with double and triple characters. Must really use up Eric's storage space for the Reflector. It sometimes gets bewildering to search though such messages to find what the poster's reply actually is! 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] Potential Elecraft Kit
In a message dated 13/04/05 01:44:15 GMT Daylight Time, [EMAIL PROTECTED] writes: One of the insturments I always wanted for home use was a spectrum analyzer. Nice to have sound card analyzers with software and all, but a real rf analyzer in a small, functional package would be so great. With some careful trade off decisions it might even be affordable! The display is a big headache if you don't have a good Oscope handy but a creative designer [or two] might be able to do the job. I suppose it would not have the broad appeal of a K1, 2 or even a very compact antenna tuner, but it might appeal to a few hundred hams and others who do bench work. Wayne K9NE Yes, I know about the projects already on the web, but how many of you have actually rounded up all the stuff to build that one? -- Al Helfrick, K2BLA did a series of articles in the 1980's on just such an idea. The one published in RF Design, January 1988 had a 3 chip design for use with a cheap general purpose oscilloscope and was based on the MC3356 chip as the heart of the project. In November 1989, Radcom published an article by Roger, G4PMK that expanded on Al's ideas with a practical version that would cover 1 - 90MHz with a logarithmic display, 50dB dynamic range and a built in marker generator. The MC3356 converts the incoming 1 - 90MHz up to 145Mz where a Toko helical filter provides some selectivity. Is then down converted to 10.7 IF with an NE602, at which point the main selectivity is achieved with filters. The clever bit after this is the use of the second section of the MC3356 chip to provide a logarithmic IF and detector. A kits of parts and a PCBs were offered at the time so one was built. My basic analyser covers up to 97 MHz and have extended the range with external converters up to the 70cm UHF band. Believe the MC3356 chip is now obsolete so could be difficult to replicate. A handy tool for tracking down RF spurii and interference problems within it's capability. Commercial small spectrum analysers tend still to command a premium price on the surplus market and the main that are available tend to be large and heavy. I have such a one, the HP 141T/8554B combination. Can make your eyes bulge carrying the instrument, but still has a good performance considering it's age. This was our instrument of choice up to recent years with the HP 8555A plug in for maintaining analog microwave systems. For my own personal use at home tend to use the homebuilt device first and only pull out the HP 141T when circumstances force me to. Noticed a more recent design offered at a hamfest last year that covered up to 500MHz or more with what appeared to be a cable TV tuner at the front end. There are probably other built and kit versions of these spectrum analyser adapters available in the market. 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] Spam bounce?
In a message dated 09/04/05 09:10:45 GMT Daylight Time, [EMAIL PROTECTED] writes: But this morning turning it on, I just got a vigorous howl ( very low freq nois !). I turn it off, and on after a few second. The Rx start normaly and the noise start again after a few second. Re-turn off and tunr on and no howl and Rx is working correctly! - With the RX problem a good point to start with would be to check the PSU as the symptoms can sometimes be caused by a very low supply voltage. A common problem with battery powered equipment is to have LF instability when the batteries were dying. The same can apply with a defective PSU. To Martin, OK1RR, I can assure you that AOL are not a freemail provider, far from it as they charge more than many others for the service. 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] RF Noise canceller ?
In a message dated 03/04/05 12:11:33 GMT Daylight Time, [EMAIL PROTECTED] writes: There have been several schematics using such technics over the last 20 years. Most of them use a seperate short antenna, feeding the signal pase shifted into a combiner which combines the main Antenna Signal with the phases shifted extra antenna signal. This construction can reduce a lot of man made noise. I remember there was a commercial available stand alone unit sold by a small english company. --- The Antenna interference cancelling unit in the UK was from SEM a company in the Isle of Man (GD). No longer seem to be in business. There is one from MFJ still on the market and believe a model may have come from a company called NIR (now part of Timewave? cannot find any info on the Timewave web site) though could be wrong on this latter unit. I built my own from a design from G4WMX for a Null Steerer that was circulating in the UK in 1989. I can remember my late father in law Ted, G3UUA building one at the time and was impressed with how well it worked, taking his S9 level of interference out totally. About two years back when suffering from local electrical interference I had a go at building the same unit. There is a PCB produced by Geoff Steedman, M0BGS available now as well as a kit of parts to populate the bare PCB. For the kit of parts with PCB, I paid £25 (US$47 approx). Built it up into a diecast box and have it permanently in the RX antenna feed. Easy for me as I have a separate TX/RX on the QRO rig. Alternately has PTT switch feed to enable it to be used in the antenna feed of a 100W HF transceiver. With a suitable auxiliary antenna it can null out quite high levels of local interference, the limiting factor being the amount of wanted signal also picked up by the auxiliary antenna. With the power off the unit is totally bypassed. The downside with mine is that with the unit active, the wanted signal is attenuated somewhat and even more when nulling out interference. The upside is that it can still make a vital difference in hearing signals buried under local interference. I believe Geoff, M0BGS has modified more recent PCB to add an emitter follower to the outgoing main antenna feed to offset through losses. Will have to try to modify my PCB to add this. I have the scanned circuit and notes somewhere in my PC for the original unit before the emitter follower was added. If anybody wants to have a go at constructing this device and needs the info, contact me direct. 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] XV-50 LNA problems
In a message dated 31/03/05 19:42:07 GMT Daylight Time, [EMAIL PROTECTED] writes: Not inexpensive, but works well: http://www.dci.ca/ Specifically: http://www.dci.ca/?Section=Amateur We installed one of the 2M units on our repeater to eliminate bandpass and to give a DC ground to our preamp on our repeater system. It was intolerant of the energy from Lightning. One of these solved all our problems. Looks like the specs say -72dBm @ 135Mhz on the 2Mhz wide unit. The 4Mhz wide unit is better documented, and shows -89dBm @ 126 Mhz. That should knock down any nastys that will get your 6m XV-50. Have been using the DCI-145-2H, 4 section helical filter since 1999 on the local 2m repeater GB3LD which I hold the license. Without this we would be swamped by pagers in particular located on ours and adjacent masts. The normal bandpass and notches found in the repeater duplexer whilst they are efficient in preventing energy from it's own TX entering the RX, work relatively poorly in keeping out energy from external sources. Notch filters are only really successful when a single fixed frequency is involved. The bandpass filter on the repeater worked so well that I ended up buying one for my shack when 153 MHz pagers were installed close to the home location. For these devices to work you need to have a bandpass filter of this type on the receiver that is being affected and not the TX that is causing the interference, unless the TX output purity is sufficiently poor to warrant this. In other words if the 6m receiver is being affected, a 6m bandpass filter is needed and not really much use in installing one on the 2m TX. Bandpass filters incur a penalty in that they are lossy and usually mean a loss of about 1dB in the case of the 2m unit and greater at UHF. If it is installed in the common antenna feed of the TX/RX mean the same loss on TX power. All too often the designers of normal every day amateur receivers for VHF/UHF skimp on the selectivity of the front end to achieve a better sensitivity and the price is blocking or even damage if the local field strengths from other sources are too high. By comparison commercial 2 way radios by virtue of performance regulations are far superior in the selectivity stakes, quite often using miniature helical filters at the front end to achieve the performance. Good bandpass filters are expensive, but if transmitters on other frequencies are causing a problems, are a necessary evil. Bob G3VVT Keeper GB3LD/GB3LF ___ 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] XV-50 LNA problems
In a message dated 31/03/05 23:06:29 GMT Daylight Time, [EMAIL PROTECTED] writes: I'm thinking external T/R relay is the smart move. If the relay is rigged to rest in the transmit position, when the transverter is powered off, the out of band signal will land in the PA output, I suspect the output of the PA module is a big strong MOSFET or bipolar, that can take a few volts on it's drain (or collector) when it's biased off. When I add a real amp, the plate of an 8877 can take big voltage ;-) -- External T/R relays to isolate the unused antenna feed and dump any unwanted energy into a dummy load with some form of interlock to prevent transmission until the feed is enabled would be the cheapest option by far to resolve the problems with damage to the XV-50 RX front end. The commercial systems I worked on had ferrite isolators in the TX antenna feed to stop exactly what you talked about, i.e. TX power from another TX coming back down the feeder into the PA as this could generate unwanted RF products at the PA. The ferrite isolator works as a directional coupler, allowing TX power towards the antenna, but any energy coming back from the antenna towards the PA from another source is dumped into a dummy load. Not normally needed for ham equipment working in simplex, though essential with systems on busy sites working in duplex such as repeaters. Used universally with transmitter combiners into a single antenna. 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] Looking for 40m RF amp design for my K2
In a message dated 30/03/05 17:03:47 GMT Daylight Time, [EMAIL PROTECTED] writes: I was wondering of anyone has built the amp shown at the link below. It had my interest for a while until it's power requirements were pointed out to me as being a drawback, price-wise. --- Check Motorola designs AN762 and EB63 on the given website. Both of these are designed to run from 12 to 14V DC at maybe something like 22A, so cannot understand the power supply problem. There are suitable power supplies available relatively cheaply for this in abundance. Believe the classic design AN762 which is the basis of the linear amplifier in most HF 100W transmitters is featured in ARRL publications and is described in detail in the RSGB Radio Communications handbook. 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] z5 resonator leads
In a message dated 30/03/05 17:45:28 GMT Daylight Time, [EMAIL PROTECTED] writes: What do I do with the leads of Z5? Do I clip them, or leave them alone? - The usual rule is if the component wire ends stick out chop 'em off. It can pay dividend in avoiding shorts sometimes and with Z5 there is nothing that would be adversely affected by doing this. 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] z5 resonator leads
After you have you have soldered Z5 into the correct place on the PCB trim the free wire ends as normal as with most other components. Just to avoid any confusion! 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] KX-1 switches - anyone else having problems?
In a message dated 30/03/05 00:09:46 GMT Daylight Time, [EMAIL PROTECTED] writes: One thing I have noticed on the KX1 is that the shaft encoder is a tad flaky ... sometimes I'll be tuning downward and the freq goes up one or two numbers in the least significant position. It sort of depends on how you hold the knob. A little pressure toward the top will increase the flakiness, toward the bottom will cure it. - I had an Alinco DX70 for repair recently where the sub dial gave a very similar result. On this the parts of the shaft encoder are held together with two split tabs. Over time these had slackened off slightly and allowed the encoder to flex slightly. Was able to reduce the effect by mechanical tightning of these tabs, but the only full cure was to replace the encoder with a new one. Possibly the KX1 has similar problems. 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] K2 RF board - components on bottom?
In a message dated 26/03/05 15:27:54 GMT Standard Time, [EMAIL PROTECTED] writes: After several failures, and much thought and preparation with pre-bending and tinning of leads, I was finally able to get C91, C88, RFC15 soldered to the correct points on the bottom of the board - with no shorts. However, I now have no continuity through RFC 15. I assume that means I destroyed the choke during the mounting process, so I'm ordering a replacement and will try again next week. --- I found the easiest way to mount these was to get the component in approximately the correct position holding it with the end of a finger (asbestos tipped from many years of pulling hot tubes) and then quickly tack one end with solder to hold it. Then the component can be positioned correctly. First the opposite end is soldered and finally the end that was tacked soldered. RFC15 has to be handled with great care. I would recommend holding the RFC15 leads next to it's body with fine needle nosed pliers and then bending the free end of the lead to the required shape. That way strain is kept off the component. Some disagree with this method, but it does work successfully for me at least. There are other components in the K2 that benefit from such gentle treatment. 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] K2 mic hole plug specs?
In a message dated 23/03/05 19:53:12 GMT Standard Time, [EMAIL PROTECTED] writes: I seek a plug for the hole, not for the jack...my intention is not to install the jack in the first place. Try an auto accessory shop for blanking plugs/caps. They come in small packs in the UK with assorted sizes, so probably just as readily available in the USA. Come in handy for various construction projects. 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] Phase noise suggestions
In a message dated 22/03/05 07:38:18 GMT Standard Time, [EMAIL PROTECTED] writes: Any modulation of the K2 PLL will now appear as sidebands to the main signal. They will be spaced at either 50Hz (Europe) or 60Hz. If the problem is intense there may be harmonics. - Take care with this test as the PC itself also can produce these effect I presume due to the PC PSU. I ended up having to put in a 600 ohm 1:1 transformer to remove the effect here with harmonics going well up towards the top end of SSB bandwidth at 100Hz intervals from 150Hz after the initial 50Hz spike. Thought it was the inclusion of an LF/RF filter system in the 230AC power input to the PC, but find I get exactly the same effect with a recently acquired laptop on it's own 230VAC SM PSU. The bottom line is before condemning the K2 check that the effect does not occur on other radios first! 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] K2 SSB BOARD MODS
In a message dated 22/03/05 03:04:24 GMT Standard Time, [EMAIL PROTECTED] writes: There was also a circuit in one of the worst radio's I have ever owned. The yeasu Ft707 used dual 8 pole filters in the 2nd IF. In between the 2 filters was a VCO. This gave an excellent IF width control. far superior to simple IF shift. I had the Yaesu FT707 for a number of years and regretted parting with it for the later Yaesu FT757 (mkI). For SSB I found the FT707 RX very good and coped well with the hostile RF environment of 40m in Europe. In receiver terms that band here sorts out the men from the boys in signal handling. The FT707 coped well with this, far better than any radio I had previously owned. There were warts with the radio in that the VFO initially drifted with temperature and had a pretty basic transmitter with limited power output on the higher bands, but that continuously variable bandwidth system really worked well. The variable bandwidth function on the FT757 was just a shadow of the one on the FT707. Far from being the worst radio I have owned. Another point and I am not sure if others have experienced or agree with this, is that the FT757, TS440 and some other radios I have owned are fatiguing to listen to for long periods. Not sure what causes this effect, but some radios are like this. The FT707 was good in being easy to listen to for extended periods as is the K2 and I find the various older JRC radios I have are also superb. 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] Problem with routers and K2?
It may also be a good idea to try the K2 on a dummy load to see if there is any effect then. The entry point of the interference needs to be tracked down somehow to enable a cure to be made. Another problem that must be getting closer with ever wider bandwidths being employed on broadband, we are getting closer to the point where normal broadband from the telcos is using part of the lower HF bands. I would guess when that happens there really will be trouble. I did have a chart that laid out the frequency span of data systems that is somewhere in my effects I shipped back to the UK. From memory 2Mb when used for low definition digital video (VHS video compatible) occupies the frequencies up to about 1.1MHz and the 34Mb needed for a compressed full definition video system goes up to about 12MHz. See there are 8Mb broadband systems on the loose now. I wonder what frequency span they need? Perhaps a list member with more knowledge on the subject could comment. 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] K2 phase noise
In a message dated 18/03/05 01:27:47 GMT Standard Time, [EMAIL PROTECTED] writes: I don't expect the K2 to have lab grade performance, nor to outperform high price rigs. My sole reason for looking into this (believe me I've got better things to do) is due to complaints about my signal on air. These have been from respected and technically competent amateurs. -- From a later posting by S55M-Adi it may appear there is some distortion reported from the K2's KSB2, SSB adapter under certain circumstances. Rather than resorting to shotgun troubleshooting a rather more thorough examination of the problem seems necessary. Firstly the basic QRP CW K2 TX is reported to be clean. Is it? Check that it is by removing all the additional boards from the K2, install the necessary straps/capacitors to return it to basic and test with a known good spectrum analyser that has the resolution capability or other test equipment as deemed appropriate. The spectrum analyser *must* be connected via suitable external attenuators to protect it's input and prevent the generation of non existent spurii within the instrument due to overload. Many an unwitting technician has been led astray with this point and can also result in the spectrum analyser having to be returned for repair to a burnt out front end and recalibration. An expensive process. If the K2 passes this test, install the KSB2 and start again with the testing. Follow this through board by board until the culprit for the perceived TX distortion is found. This would then be a good time to contact Elecraft Support or post on the Elecraft reflector for assistance with known specifics. Blanket criticism of the K2 is unlikely to succeed, only generating hostility from the satisfied users. It may be something as simple in some cases as wrong bias levels on the K2 PA transistors when that stage is used as part of the system. The K2 will still work on CW with no bias at all, but does sound extremely poor on SSB. This should show up in the testing and simple DVM tests will pin down the cause if this is so. Any non linearity in the TX signal path will degrade SSB where it has little if any effect on CW. Sensible testing with the knowledge of how to correctly use the test equipment should localise the problem. However having the best test equipment that money can buy still is no good if the person that is operating it does not know how to use it! In my latter years at work was involved in commissioning/acceptance testing of new communication sites that contained SDH digital microwave, SDH fiber optics plus all the various power systems and other support needed to run these systems. Due to the complex nature of the testing, the design engineers had thoughtfully documented precisely what test equipment should be used and all the settings for the various tests. Without this the job could have been rather chaotic with the engineers and technicians from many nations involved in the testing process. In my original posting I used the term slagging. Fred, K6DGW pointed out to me quite rightly that the non UK members of the list may not understand this UK slang term. The nearest translation for this would be castigate. Will follow the outcome of the reported problem with interest. Bob, G3VVT K2 #4168 ___ 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] Still blank display
In a message dated 18/03/05 19:27:35 GMT Standard Time, [EMAIL PROTECTED] writes: I should have added if it wasn't clear that you need to remove U1 before trying the heated socket procedure. --- Think I must have removed the chip before soldering the joint, but cannot be sure a year later. Being on the bottom side of the board it is accessible in any case, though could be difficult to refit as the LCD display prevents you supporting the board at the opposite side to apply pressure. As you cannot get at U1 pin 1 on the top side of the board due to the LCD display, without removing this the method is to shave a V off the edge of the plastic corner of the socket at pin1 with an Exacto knife or similar to expose a small area of the tinned print of the through hole in the PCB. Take off enough to insert a very small pointed soldering iron on the socket side of the front panel board and solder it quickly. Speed is the secret and small diameter solder/soldering iron bit. I have both so no problem doing the work. 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] K2 S/N 4787 First QSO
In a message dated 16/03/05 22:48:02 GMT Standard Time, [EMAIL PROTECTED] writes: The K2's I've tested fall down on LO phase noise performance. Also note that the K2 measurements on the Sherwood web site state that the receiver performance is limited by phase noise. I agree the RX works very well, but I've attracted comments on the air (when running QRO) re transmitted phase noise. I wonder if there is an obsession with numbers. To place the matter in perspective, the Sherwood Engineering web site does list the K2 which is serial #3170 or about 2 years old? as being the 7th from the top of all the ham radio receivers tested. The aspect of the effects of phase noise being only one of many parameters that determine the final result. I would presume that to measure phase noise needs the resources of a well equipped professional lab. Whilst personally I am well equipped to carry out servicing of radios from HF through to UHF, cannot even really scratch the surface in terms of measuring phase noise. The professional communications systems servicing organisation I worked for despite being well equipped for testing from HF though to microwave in the field had little that could be used seriously for testing phase noise except for probably some rather expensive HP spectrum analysers that were issued only recently to maintain a new 8GHz digital microwave system. Before slagging the K2 one should take more seriously what it represents in terms of outlay, costing only a fraction of cheapest HF transceivers available on the market. Admittedly you have to build it yourself, but still the performance of the K2 as what it was primarily designed for, a QRP CW transceiver takes a heck of a lot of beating. There are shortcoming that occur with the additional added components, though even these have been mitigated by later modifications. Do the persons reporting phase noise on K2 TX really know what they are talking about or just pushing out some mumbo jumbo that just happens to be the popular quotation of the day? To be frank most hams including myself would probably not be be aware what phase noise is even if it jumped out and bit them. Bob, G3VVT K2 #4168 ___ 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] K2 #4661 Takes It's First Breath!
In a message dated 12/03/05 17:57:25 GMT Standard Time, [EMAIL PROTECTED] writes: I admit that I was nervous at every test stage, but everything ultimately tested out fine, and so far the rig is working great. It took 2 months, during which I spent a total of 100 hours building (don't laugh; I may not be fast, but at least I'm slow). - No need to worry how long it took to build your K2 Mike, the proof is that the K2 worked correctly at the end of the day. I haven't a clue how long my K2 took to construct about a year or so back, only that it worked correctly at the end and still is. Made a few errors during the building, but these were picked up and subsequently corrected by following the excellent step by step test procedures in the K2 manual. More difficult problems were solved by the assistance of Gary at Elecraft Support or help from the more knowledgeable Elecraft list members. Am not aware or seen any evidence that Elecraft offer any prizes for the fastest builder in any case! Regards, Bob, G3VVT K2 #4168 ___ 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] Speech processing
In a message dated 04/03/05 11:00:07 GMT Standard Time, [EMAIL PROTECTED] writes: I have an old Comdel in-mic-line r-f clipper, which uses fewer than 100 discrete parts on a 4X6in board. --- I have one of the Datong D75 RF speech processors since about 1980 (25 years). The leaflet that came with it shows it as being derived from earlier products, the RFC and the automatic model the ASP, though not sure when these were first on the market. By the time the D75 was introduced the circuitry had been reduced to 7 IC and 2 transistors. Uses the phasing method to generate an SSB signal at 60kHz then clipped before demodulation back to audio. Draws 9mA from a small PP3/6F22 internal 9V battery or can be externally powered from the radio which is what I did with a Yaesu FT707 used at one time. It worked well though the resultant audio quality was not for local usage at higher levels of clipping! What does what inside the box is a mystery as Datong are infamous for not releasing schematics, a policy carried through to this day I found out when trying to obtain circuit information of their DF1 FM RF direction finding system. I have one with a missing head unit and need to get into operation for tracking local morons on the repeaters. A request to Datong who are now in the professional RF surveillance field after pulling out from the amateur market for help and schematic information led to a polite, but firm refusal. The main station HF transmitter in use at this end the JRC NSD-515 (1982 vintage) uses RF clipping in the IF chain with 2 filters cascaded, one either side of the TA7302 clipper IC at 8.7MHz. This works very well with resultant audio quality good enough to leave it in circuit at all times for SSB and just varying the amount of clipping to suit the occasion. A great pity that the K2 does not use something similar with the KSB2, but with available space at a premium, would guess that this would be rather difficult to fit in. 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] Blank display on 1st power up
In a message dated 27/02/05 03:13:02 GMT Standard Time, [EMAIL PROTECTED] writes: I just did the 1st aliment smoke test. Put power to it for the first time. When I turn it on, after a second, something clicks. The display is lit but nothing else. No letters or anything. Now what? I wonder if it's one of those main chips. I got this kit partially assembled in a box. If it is a K2 check that pin1 has been soldered on U1 the LCD driver on the K2 Front Panel board. I and number of other builders missed this for some reason. Difficult to do afterwards as it needs the LCD display removing to really get at it. However it is possible however to bypass this point with care. 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] KSB2 Problem
In a message dated 21/02/05 14:53:44 GMT Standard Time, [EMAIL PROTECTED] writes: I am trying to install the KSBS2 into my K2. Problem symptoms are that I get the Hi Current warning, plus I get no variance on my separate receiver when trying the fine balancing. The rest of the alignment went okay, SSBA on BAL gave me good nulls with tweaking R1 both on USB and LSB (I just cannot hear any null with the receiver. I get a very strong carrier (S9+) on my separate receiver with SSBA at 3. --- It has not come up in any replies to your question, but it looks that you may be getting problems with RF into your microphone socket and the KSB2 audio input. Are the KSB2 tests being carried out into a good 50 ohm dummy load? There have been various methods described on the list for combatting problems of RF getting into the microphone input, the main one being to provide a ground on the microphone socket outer. 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] N fittings
In a message dated 15/02/05 21:20:57 GMT Standard Time, [EMAIL PROTECTED] writes: My understanding of the place to place silicon grease is NOT upon the outside of the connector, but rather in the interface between male and female connectors. The idea is to exclude moisture pooling on the insulator between the center pin and the outer shell conductor. -- Silicon grease would only be placed on the inside of the connector, but enevitably some can be squeezed out, making it's way to the outside and in the process is transferred to your hands. Once that happens there is no way in the world that most tape adhesives or self amalgamating/self vulcanising tape would adhere to the connector or even itself for that matter. It only takes an exceeding small amount and seems impossible to remove by normal cleaning. This would be why Don, W3FPR was wisely advising caution on the amount of silicon grease used. With self amalgamating tape one has to be careful as some types are said to be attacked by UV, though did use one brand of it in waterproofing CATV connectors in the UK for a number of years without any problems. Applied the self amalgamating tape directly over the connector, then applied a layer of heavy duty plastic tape over the top for mechanical strength and protection. What one uses depends where you live and what the exposure to UV levels are. What could apply in latitudes further away from the equator would not be applicable in hotter climates. I lived for many years in the Middle East and most types of self amalgamating tape would probably not be usable there due to extremely high levels of UV. Normal plastic tape had a rather short life and such things one would use normally in cooler climates such as polypropylene rope and plastic cable ties failed very quickly. The rope was turned to dust in the space of little more than a year and plastic cable ties went brittle and snapped. Never managed to source carbon loaded cable ties, though nylon TB Tywraps did last a few more years longer. The only sealant I have seen that seems to stand most situations is the fabric/heavy grease type of tape. This is known commonly as Denso tape in the UK and was pretty well standard on professional telecom installations for external connector sealing. Have seen a similar type used in the Middle East for the same type of installation, so presume it must be resistant to the effects of UV. This tape or a very similar type is also used on small bore natural gas lines for joint sealing and protection, so this could be another source of supply. Rather messy to use, though does give extremely good protection to external connectors over many years. 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] N fittings
In a message dated 14/02/05 19:51:09 GMT Standard Time, [EMAIL PROTECTED] writes: The good quality N connector (the type with ground flange) is much more reliable and mounted with 25Wtts soldering iron in few minutes . If you wish to spend the money, PL259 are available in pressure sleeve type connectors similar to the better class N and BNC types. Used these on our local VHF repeater duplexer which came as original equipment with SO239/PL259. In the right place the SO239/PL259 combination is entirely adequate up to VHF and most VHF 2 way radios seem to come so equipped. All of the GE 2 way VHF radios and repeaters we used at work certainly did. In addition a great deal of the station accessories on the market come already equipped with SO239 sockets. It would be wrong get the idea that just fitting N type connectors will make you bullet proof as there are some extremely poor N and BNC connectors on the market much as there are of the PL259 type. The N type connector has a limited moisture barrier, though if the connector has to be used outside in a damp climate, an external moisture barrier tape over the entire connector assembly would be essential. Even so for any connectors that have to be used outdoors, the N type connector would be desirable. In the end inside the shack for HF and where moisture should not normally be a problem, it is a matter of using whatever connector you a comfortable with and want to adopt as a standard for your station. 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] 40M band pass filter alignment - very little signal getting th...
In a message dated 12/02/05 20:13:17 GMT Standard Time, [EMAIL PROTECTED] writes: All of the checks were in the expected range, except for U6 pin 8, which was 36.8 ohms instead of greater than 100 ohms - Check that RFC14 on Q19 source has been fitted to the correct position. There is an adjacent ground through hole that if used by mistake will reduce the U6 pin 8 (8B rail) reading by 270 ohms as R20 then is effectively shorted out. Otherwise it is a matter of breaking down the direction of the loading of this reading. There are series resistors in some of the paths that can assist to this end. 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
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] KPA100 Middle Side Screw Alteration
In a message dated 06/02/05 23:23:53 GMT Standard Time, [EMAIL PROTECTED] writes: McMaster-Carr http://www.mcmaster.com/ has self locking Threaded Inserts - their PN 90248A016 is 4-40 threaded ID and 6-32 threaded OD - 10 per package. --- Note that you also need a correct sized installation tool to install these inserts. We successfully used larger versions of the threaded inserts to install GE Mastr II radios inside the cab of GMC and similar pickup cabs used in extreme environments. 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] K2 power output
In a message dated 05/02/05 17:50:03 GMT Standard Time, [EMAIL PROTECTED] writes: I have noticed an irregularity on my K2 output. When setting the power level a 2 watts, and then using the ATU I get a reading on my SWR/power meter in the line of 4 watts. Setting power on the K2 to 3 watts, I get 4 watts on the in line meter. I thought the meter might be faulty, so replaced it with another with the same result. And the ATU gives me a reading of, say 1.3:1, whereas the SWR/power unit shows 3:1. - Try replacing the antenna with with a dummy load and see what the result is then. The external SWR meter will be a voltage reading device and you may be at point where the voltage is higher. Changing to a dummy load should give the correct answer. 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] Elecraft: RFI Problems
In a message dated 29/01/05 16:36:57 GMT Standard Time, [EMAIL PROTECTED] writes: If you have a balanced antenna system, or even an unbalanced system with RF properly choked off from the outside of your coax, there will be no RF on the chassis that 'as to go somewhere'. In addition, it is very difficult to provide an RF ground at HF. - With my shack in an upstairs spare bedroom it is difficult to provide an RF ground in any case, the only ground being the power ground. The house is built on rock so I doubt if a ground rod would go in very deep even if I tried. Opted like Vic for a balanced antenna with balanced feeder. Using 100W have not seen any problems unless I try to operate on a band that the antenna is not resonant on. Using 75 ohm balanced twin as the feeder as the use of 300 ohm ribbon or higher would be impractical from my shack. The 75 ohm twin seems quite docile in use and can be installed in close proximity to metallic objects which is not recommended for 300 ohm or higher impedance twin feeder. To date the only interference problem have been with telephones whose drop wires are parallel to my antenna. The phone company fitted RF filters to the affected telephones at the point of entry into the house and one modern telephone had to be suppressed internally. Older telephones seem less affected. A problem that may be coming up is the use of ADSL broadband would probably prevent normal telephone RF suppressers being used at the point of entry to the house as this would also stop ADSL from working. A separate RF filter at each telephone would be the only answer in this case. As a parallel subject there was an interesting article in the February 2005 Radcom, EMC column advocating the use of ADSL telephone filters as being very suitable for use as RF filters on telephones for the lower bands and the performance figures for one type of ADSL filter were quoted. See them available at computer fairs at about £3 each ($5.70 US). 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] Elecraft: RFI Problems
In a message dated 30/01/05 01:32:53 GMT Standard Time, [EMAIL PROTECTED] writes: All of the 75 ohm stuff that I've seen wasn't rated for high voltages anyway, so it's likely to melt at the voltage loop when hit with high power. AT the very least, it'll be rather lossy. --- There is more robust USA sourced 1kW rated 75 ohm twin available in the market though sadly not as easy to obtain now as in the past. Believe red/black power cable makes an effective 75 ohm twin feeder and this is available for quite high currents though not with high voltages. Am using commercial 75 ohm twin feeder cable rated at 300W at present which is very adequate for the 100W maximum I use. In any case we have in the UK a maximum license power of 400W pep which restricts our exposure to high power effects. Guess would be rather different in the USA with your maximum of 2kW pep. QRO can have it's downside! Not sure that the statement that it would be rather lossy is correct as I have been led to believe that twin feeder is less lossy than coax and particularly the 50 ohm version. Even the 75 ohm hard-line coax as used by cable TV companies was always better than the 50 ohm coax in the loss figures for a given diameter cable. I do use a resonant 1/2 wave trap dipole on 40/80m only at present with the feeder cut to the length recommended by the antenna designer of 70 ft (or multiples of this). Working towards adding a two extra pairs of traps for 80/20 to give added bands of 160m and 20m. With always using resonant antennas the problems that could arise on the twin feeder are minimised and hopefully any interference problems as a result. So far telephones seem the only problem area. The wider spaced twin feeder would be impossible in my case as the operating position is on the opposite side of the room from the window and built into a fitted wardrobe. At a previous house the shack was just that, a wood hut under the centre of the dipole and wide spaced twin feeder came direct to a balanced ATU. As always it is a matter of cutting the cloth to suit your circumstances. What will be suitable for one situation may be hostile in another. 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] (no subject)
In a message dated 27/01/05 18:43:15 GMT Standard Time, [EMAIL PROTECTED] writes: The Soloman 4449 is listed as having an isolated tip. Am I correct in thinking that this would not be an ESD safe iron? Believe the isolated tip is done for another reason which was the ability to work on live circuits. Even the venerable Weller TCP soldering iron system had a version that used the 2 wire power supply the PS2D. On this the soldering iron tip was not connected directly to ground, but instead to a a potential balance terminal on the PSU that allowed it to be connected to the workbench static ground for working on static sensitive components or working on live circuits. 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] RFC1 RFC2
In a message dated 24/01/05 16:49:30 GMT Standard Time, [EMAIL PROTECTED] writes: ...I built several early production SSB's in which RFC1 and RFC2 were mounted flat against the bottom of the board, in fact, the silk screening for them still exists there on the bottom of the latest boards...I don't remember reading anything about why they were moved to the top, but there must have been a reason...?... Asked Gary at Elecraft only about a week back the same question and he told me the toroids need to be on the top to prevent interference with the varactors in the CW IF filter, and to prevent additional signal leakage or signal pickup. Have a feeling mine are on the underside as the screen printing shows, so will move them if they are when next inside the K2. Will also compare the Spectrogram responses between the two methods to see if there any difference that can be seen there. Regards, 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] K2 RF board part C72 Identity
In a message dated 23/01/05 12:19:41 GMT Standard Time, [EMAIL PROTECTED] writes: The really confusing aspect of it all is a 270 pfd capacitor should be labelled 271, so you have the case where something marked 270 isn't a 270 pfd capacitor. - The problem with marking small capacitors is providing the value on them so that it is more easily readable. What the manufacturers of the bulk of the capacitors now used by Elecraft is that the last digit of the three provided is the multiplier. This is just the same as with resistor color codes. Following this a capacitor marked 271 is 27 with a multiplier of 10 = 270 pF (27 x 10 = 270). For a 27pF capacitor this would be marked 270 = 27 with a multiplier of 1. (27 x 1 = 27) This can be useful when higher values of capacitor are used. For example 0.1uF = 100nF = 100,000pF and would be marked 104. This is 10 with a multiplier of 10,000 (10 x 1 = 100,000pF). After a while reading the capacitor values becomes automatic just as one learns to read the resistor color code. Not really sure which way I read the values of resistors, but suspect I look at the last digit first to see the multiplier and then the value within that multiplier. Now do the same with the capacitors that Elecraft use. The problem arises with this capacitor marking system with values below 10pF cannot be accommodated and manufacturers either resort to just providing the value direct or adding a *p* where the decimal point should be. Philips use the *p* or the *n* for marking their capacitors. This means a 2.7pF capacitor would be marked 2p7 and a 0.1uF or 100nF capacitor would be marked 100n.To be sure I check all the values of the capacitors in doubt with the capacitance measuring facility in my DVM. A large proportion of the DVM seem to have this facility provided even down to the low cost versions and at least my $50 DVM will measure down to single digit pF values with reasonable accuracy. 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] Low Frequency Modulation of Side Tone.
In a message dated 24/01/05 02:07:20 GMT Standard Time, [EMAIL PROTECTED] writes: Problem found. I added a fixed audio out port to the K2. Disconnecting the wire to the sound card stopped the modulation. An audio transformer in line also eliminated the problem. -- A similar solution was of value in clearing up my problems in using Spectrogram. I was getting spikes on the Spectrogram display at 50Hz (our power freq) and every 100Hz from 150Hz upwards. This was believed to be due to my PC having a power line filter installed to clear hash from the PC switch mode PSU and this left the PC case floating above ground at RF. Series capacitors had no effect, where a transformer placed in the audio path completely cured the problem. Used a miniature audio transistor interstage transformer for the purpose with the higher impedance side to the PC sound card. Would guess a transistor output transformer with the usual 1.2K to 4 ohms windings may have been even more suitable, but did not have one in the junk box. The only proviso in going down this path is to use a transformer that has a response well below 300Hz and 50 Hz if possible to ensure correct placement point of the BFO is seen. A totally different problem, though in the end with the same solution. 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] K2 # 4498 - Electrostatic protection
In a message dated 21/01/05 16:18:13 GMT Standard Time, [EMAIL PROTECTED] writes: I'm in a very stormy country (Northern Alps) and we have at least once per month a thunderstorm that already cost me one pair of power Xstors (in my TS-130 - $380!!!) so even with $5 each TO220 part, I did not want to loose them, or at least reduce the chance to loose them. So I instaled on the KAT2 control board an RF Chock (1 mH) and an NE2 neon bulb wired between K18-pin 3/8 and ground just to establish a direct lway to ground for static electricity (via the chock) and in case of a virulent one turn on the NE2 and establish a full short to ground. -- - Hi Robert, It is normal practise to install an RF choke directly across the antenna socket of tube (valve) PA to protect in case of a failure of the coupling capacitors from the tube anode. 2.5kV can be very damaging to your health! Suppose these have ceased to be used since the move to solid state PA's. From memory 2.5mH was the normal value used in the last one I built in the 1960's. The addition of a neon to hold off the path until the neon strikes should not represent any problem though am not entirely sure that it is necessary not knowing the KAT2 circuitry. In professional communication terminal equipment that is connected to external lines the inclusion of gas or carbon arresters is a standard feature at the point where the external line is connected. In addition all of our telecom distibution frames and even the distibution pedestals had arresters built in as standard. The protection operation point was selected to be higher than the normal operating voltages on the line. A QRP K2 is listed as providing 70 to 80V across 50 ohms and the normal striking voltage of a neon is about 110V, so the neon should not strike. There are however some neons on the market that strike at a lower voltage somewhere in the 60V region and to our cost we found these put a S/C across the phone line when ringing voltage and normal telephone battery were present. These would also operate when the K2 was giving normal PA O/P. Probably the choke on it's own would be entirely sufficient to provide the protection needed as long as the component was able to handle the current required. Bob, G3VVT K2 #4168 ___ 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] K2 RF Gain control
Hi Bob, Sounds normal and very much like my K2. The RF gain in the K2 is really an IF gain with the front end RF gain set at a constant level and only affected by switching in the preamp or the attenuator. I have an old JRC receiver where the RF gain works the same as the K2 in that the effect as the RF gain is turned down is the lower level signals fall below the threshold as the S meter rises and are effectively suppressed. This is a useful effect to give arm chair copy of stronger signals and minimises the amount of noise between syllables. 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] Birdie at10m: a choice between a turkey and an ostrich !
In a message dated 15/01/05 23:36:15 GMT Standard Time, [EMAIL PROTECTED] writes: I know there was a recent discussion in the forum about this birdie singing at the low end of the 10m band, but did not recall seeing any definitive way to kill it. In my case, I want to think of the birdie living in my K2/100 as a substantially bigger one, a turkey (with the K2100 enabled -power 11w) at 28.266 (USB), Signal strength S2 with the preamp enabled changes to an Ostrich (think logarithmically) of a solid S5 !!! at 28.264 when disabling the 100W option. -- - As a benchmark with the antenna socket terminated, i.e. no external antenna connected, the only birdie of any real significance with my QRP K2 #4168 is at exactly on 28.000MHz. This is exactly where it should be as the 7th harmonic of a correctly adjusted MCU 4.000MHz clock for U6 on the K2 Control board. There are other birdies between 28.000 to 29.000MHz, but are so feeble that they fall into insignificance and none of them move the S meter at all even with the preamp on. This is with a receiver that gives S9 on 28.200MHz at 50uV PD with the preamp *off* and meets the MDS spec for the K2. I am aware of the birdie at 28.000MHz as that clashes with a band edge beacon I receive via an external VHF transverter. Even with this present it is possible to copy the beacon down to an extremely low level with the K2 preamp on. The reported birdie at 28.276MHz is there, but extremely faint at about 28.275.6MHz on USB and shifts up to about 28.277.7MHz on LSB. I would think it fair to comment that most ham receivers have birdies somewhere if you want to try hard enough finding them. With what I have found on my particular QRP K2 it may be a good idea to remove all the various options added to the offending K2's and go back to basics to see what the effect is then. Once that test is sorted out the gradual addition of the various option boards should find the offending one(s) to enable a solution to be sought. There or no turkeys or ostriches in my K2! Bob, G3VVT K2 #4168 ___ 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] AGC Threshold Adjustment by Changing R1
In the reply to Mike, VK1KCK I said R1 is given as 50K preset. In the world outside the USA this would indeed equate to 47K I found that this is not quite correct as although for carbon presets and controls have changed to the same decade values as fixed resistors in Europe at least, cermet presets which most probably Elecraft will be using for R1, still retain the older values such as in this case 50K for some reason. A visual check on my K2 is that R1 when set for 3.70V at U2B-5, being the optimum AGC threshold setting for my K2, the control is not far from half rotation, i.e. about 25K ohms. Working out the maths for the various resistors in series and parallel, including the RF gain control to form the potential divider from the 8A rail comes out fairly close to this voltage. The preset R1 is as shown in the K2 Control Board schematic, maximum resistance for fully CCW. Bob, G3VVT K2 #4168 ___ 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] Birdy on 28020 with K2?
I monitor 28.020 for long periods with my K2 for a VHF beacon on 70.020 MHz that transverts to that frequency. No detectable birdy in my QRP K2 at all on this frequency. Bob, G3VVT K2 #4168 ___ 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] Birdy on 28020 with K2?
In a message dated 01/01/05 12:11:56 GMT Standard Time, [EMAIL PROTECTED] writes: I found a birdie at 28.000 (QRP K2 #3401), but that's too close to the band edge to worry about. None at 28.020. I'm guessing my birdie is a harmonic of the 4.00 MHz oscillator. -- --- Do confirm this low level birdy on 28.000MHz USB/LSB on my QRP K2. Bob, G3VVT K2 #4168 ___ 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] PLL Reference Oscillator Range Solved
In a message dated 31/12/04 04:52:04 GMT Standard Time, [EMAIL PROTECTED] writes: Now to find out why the BFO range is too low. The BFO high frequency comes in above the expected minimum of =4916.3 at 4918.2 The BFO low frequency comes in above the expected maximum of =4912.7 at 4914.8 with a resulting range of 3.4 compared to the expected minimum range of =3.6. D37 and D38 are of correct values as are X3 and X4 From the schematic the usual suspects would be L33, X3, X4, D37, D38, C173, C174 and posssibly C169 with the gate circuit of Q24. However first a check on the of voltage range on the V BFO rail at U10D-14 on the K2 Control Board may be helpful. According to the K2 manual this should range between 0 to 8V and with varicap diodes the maximum capacity which would determine the lowest frequency of the BFO is with minimum applied voltage. If the voltage does not swing low enough this would inhibit the ability of the BFO to reach it's minimum frequency. The crystals may be a bad batch which may occasionally happen pushing the frequency in this case too high. The varicap diodes D37/38 type 1SV149 can be damaged by excessive heat during installation. When checked on a capacitance meter recently a new diode came out at about 890pF. One that had been fried that I tested was nearer 820pF. Are the capacitors noted the correct values, place correctly and soldered? 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] zulu time
Note in the discussions of using Zulu time that keeping a station log is apparently no longer required in the USA. In the UK a permanent log of station operation is still mandatory, whether it be in a book or by electronic means. Times have to be recorded in UTC (i.e. Zulu/GMT) together with other details such as frequency, class of emission and power used. Presumably this requirement is primarily for tracing sources of interference to other parties. Probably would keep a record even if it was not mandatory as it is invaluable to find out who and when you have contacted in the past. Getting to the point now anyway where I have brain erasure every time it goes dark outside. When this is added to a restricted hearing capability, is a subject to agitate she who must be obeyed in the extreme. 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] K2: AGC versus RF Gain versus AF gain
Micheal, The so called RF gain in the K2 is actually IF gain, which is the same as used in the JRC NRD-515 RX. The difference is the K2 has fixed RF front end gain before the RX mixer with a switchable preamp or attenuator in addition. The NRD-515 has no RF amplifier only a switchable RF attenuator in front of the 1st RX mixer. Not familiar with what the Kenwood RF gain does in the TS-530S or the TS-930S. The K2 has a slightly strange action in that a strong signal goes to a higher S meter reading pretty much as soon as the RF gain is reduced and when the S meter reading goes higher the RX volume does go down as you say. Not a lot but perceptible. It is possible to set the S meter with no signal in to the level required, say S9, though when a station is tuned in that was S9 with full RF gain it now reads higher and the audio volume is less. The JRC NRD-515 volume stays constant until a point is reached that the S meter reading rises with reduced RF gain and becomes greater than the reading for the incoming signal. The RX audio volume then begins to fall beyond that point Looks like a quirk with the K2 AGC action or design. My K2 has had the AGC threshold set to the point where switching the AGC on and off has no effect on the no signal background noise. Came out in my case at 3.70V, though apparently varies slightly from K2 to K2 Bob, G3VVT K2 #4168 ___ 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] OT-well sort of:Short Wave Receivers...Suggestions???
In a message dated 13/12/04 08:29:29 GMT Standard Time, [EMAIL PROTECTED] writes: I'm thinking of buying a short wave receiver like a Grundig or something, and have been looking at them on the web. What I have in mind is a very small, pocket sized rig, 2 AA cells for power... - With could be a problem in how you want to power the radio. Most of the digital radios that will cover the frequencies and have the facilities you require are greedy on battery consumption or at least were up to a few years back. I lived in Saudi Arabia for 20+ years and SW radio for the last 13 years was the prime way of getting news. Lived in an area where the nearest black top road was 100km away and no terrestial television, electric power or telephones outside our camp. We did not get any satellite TV until the mid 1990's, so SW radio was the only way of keeping track of the outside world. I started with a Sony 2001 in 1981 and that was still OK when I retired in 2002. Also had the later 2001D which also has the SSB/CW facilities you need, though again greedy on battery consumption, which meant use on a AC power supply was essential. A popular radio was the Sony 7600D used by many expats at the time which was somewhat better in terms of battery life. Lost track of what is available today, but for SSB/CW use Sony was always at the top of the pile in the past. Maybe the battery consumption problem has been cracked with more recent technology, but the only way at that time was for reasonable battery life was to use an analog radio and most of these did not have the SSB/CW features nor the frequency coverage required. Bob, G3VVT ex desert rodent ___ 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] SLA Battery charge level
In a message dated 12/12/04 00:35:05 GMT Standard Time, [EMAIL PROTECTED] writes: When the battery is exactly at 13.8 volts, there would be no current. In practice found over the many systems worked on professionally this is not entirely correct. After the charging system comes out of the absorptive charge phase where the voltage has been allowed to rise above the normal bulk charge voltage for a limited time and now reverts to the float voltage, the battery indeed does not take any charge. It can even supplement the supply voltage and current for a short while after the main charge cycle. However if one monitors the battery over a longer period after the float charge period has started the battery will start to take a small charge that eventually settles on the 25 to 50 mA region for small SLA's. It all depends on the float voltage and the size of the SLA, but with a float voltage of 13.8V and a 12V SLA does definitely occur. Security and fire alarm technicians when carring out routine maintenance can note the current taken by SLA's in the alarm panels under float conditions as this can give an early indication of the forthcoming failure of the SLA. For critical systems under a maintenance contract they sometimes replace the SLA's at 2 to 3 year intervals to ensure system reliability under all conditions. A good source of SLA's that still have a useful life left in them if you can make contact with one of the technicians and I did! 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] K2 Scratchy received audio
In a message dated 02/12/04 10:30:24 GMT Standard Time, [EMAIL PROTECTED] writes: Symptom:- Received audio sounding scratchy, suspected loudspeaker. Problem:- Bad contact. The plating (Tin ?) had worn through on loudspeaker connector female crimp pins. Had a similar problem with the company's 1979 vintage GE Mastr II truck radios used in an area with no roads. The continuous vibration caused the board connector pins from the front panel to the RF/IF/audio board to go intermittent for exactly the same reason, loss of tin coating on the plugs. The solution apart from replacing the interboard connectors was to apply an extremely thin coating of lubricant to the pins. This seemed to have a lasting effect on the problem. Just a small smear of WD40 worked wonders. The socket must have been acting as an effective abrasive mechanism on the pin. Totally unnecessary if the contact remains undisturbed with normal operating conditions, but essential in our case. Bob, G3VVT ex desert rodent ___ 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] K2 - Strange Problem ?
In a message dated 30/11/04 16:46:51 GMT Standard Time, [EMAIL PROTECTED] writes: That's what I was doing, however, because anything capacitive slows the rise of the 5A rail, and hence the correct MCU initialisation, I was chasing my tail. This is a problem I have come across before about 5 years back where we had a newly developed repeater logic controlled by a PIC chip. I had the prototype running the local 2m repeater and the problem was that there were what appeared to be clock pulses appearing on the through audio of the logic. Attempts to decouple the 5V supply rail were disastrous in that it locked up the PIC chip. Eventually traced to the gremlin of delayed voltage rise on the chip due to charging of the decoupling capacitors. This is poison to the PIC chips as they require apparently a very fast rise time on the supply voltage. In our case the problem was self inflicted and was due to trying to be clever and using two regulators in tandem. Was cured by reverting to only one regulator fed direct from the incoming DC supply and only just enough decoupling to clean up the supply line. There is an additional support you can give the PIC chip in start up I discovered when trying to fault find on a partially defective chip. If instead of connecting the PIC chip MCLR pin direct to 5V (see U6 pin 1, the MCU on the K2 control board), connect it via a 10K ohm resistor and place a 4.7 to 10uF capacitor on the MCLR pin. This resultant delay allows all the voltages to stabilise before the chip is enabled. At least it is my belief of how the modification works. Additionally I added a diode with the anode to the MCLR pin across the 10K resistor to discharge the capacitor quickly in the event of a power interruption or the chip would again lock up. This was a change made to get over a particular problem with a PIC chip, but could be the answer to some odd glitches experienced recently. We now have this incorporated into our repeater logic as a standard. An entirely different usage, though one that could have parallels. Perhaps Eric or Wayne at Elecraft could comment. 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] #4472 transmitter setup problem.
Jerry, Did you use a X10 probe with the scope? The problem could be related to the stub effect at the operating frequency caused by the scope leads and the capacitance the scope input circuit presents to the K2. Particularly with RF a X10 probe or a high impedance detector is just about essential to avoid upsetting the circuit you are monitoring. The same can apply to checks on the 4MHz clock on the K2 control board where the test instrument such as a counter can cause unwanted effects even though it has a high input impedance. 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] SSB low output
Brian, Before you get too disillusioned with the performance of the K2/KSB2 on SSB output with the Heil microphone, what are you using to measure the TX output on SSB? It is essential to use an RF wattmeter that is capable of measuring true PEP, not just one of the joke instruments on the market that add a large capacitor across the meter movement when switched to so called PEP. A normal RF wattmeter will read very low on unprocessed SSB audio. You can go into the K2 menu to maximise the microphone gain and if necessary add a degree of audio compression which may help. Normally for HF SSB I use a PM-2000 peak reading wattmeter to get sensible results. MFJ have a dedicated PEP meter in their arsenal of equipment and it is also possible to adapt a normal wattmeter with an add on circuit to provide PEP measurement with an active peak hold circuit. There was a simple circuit using a single LM358 IC published in the RADCOM magazine in January 1989 that I have used to convert several of my wattmeters. E-mail me if you want to check that circuit out. Bob, G3VVT K2 #4168 ___ 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] How to set up SSB
The option of OP1 or 2.2, etc in the filter selection is for receive only. However you still have to make sure that the BFO is place correct for the TX filter OP1 and the easiest way to do that is to set up with OP1 in FL1 on receive as was finally selected and match the BFO to that with Spectrogram. Otherwise the BFO can end up in totally the wrong place with adverse effects on the SSB TX audio. Unless this is a very recent KSB2, a good improvement to the SSB audio could be made by applying the KI6WX 2,2 or 2.5kHz modification to the KSB2. The BFO again would need resetting to match the new filter parameters. Believe Elecraft have now adopted the KI6WX 2.2kHz mod as standard on present KSB2 kits. An added benefit is that the filter passband ripple appears to be substantially reduced. I did the 2.2kHz mod and find the final result at about 2.3kHz bandwidth with very little passband ripple. All makes for a better sounding K2 on SSB TX. 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] K2 and FM
Why on earth would you want to possibly compromise the excellent performance of the K2 when there are cheap purpose built FM transceivers in abundance on the market and second hand they can be picked up for peanuts? Even without this in mind the immediate problems are: Receiver. Even with using the narrow band FM we have been bullied into adopting in the UK for repeaters, the +/- 2.5kHz deviation will not pass through the 2.0 to 2.5kHz filters found in the K2. The effect is to cut the carrier off on deviation peaks producing what has been nicknamed here the Norman Collier effect by causing the squelch to close at this instant and chopping up the received audio to make it unintelligible. As a repeater license keeper and builder am acutely aware of this effect by mobiles trying to force a +/- 5kHz signal though our now mandatory 7.5kHz (+/-3.75kHz) bandwidth filters. I just does not work! For +/-5kHz deviation an IF filter of 15kHz (+/- 7.5kHz) is the norm. To incorporate this in the K2 would mean extracting the IF signal soon after the 1st mixer Z6 and before the K2 1st IF filters. A totally separate IF, squelch and FM detector strip would be needed with most probably 15kHz filters to cope with older transmitters. Additionally this would really need to be an outboard unit with its own audio amp and speaker. IC's such as the now obsolete? MC3357 would take care of all the IF, squelch and detector functions. Transmitter. FM on transmit could be produced by feeding audio via a suitable coupling capacitor into the K2 VCO control line, though the deviation would probably not be constant on all bands. There is a problem with the TX audio as the peak deviation has to be strictly limited in its amount. Even the use of a compressor just does not give the degree of control needed, so an audio peak limiter stage and subsequent following low pass filter has to be inserted. All in all do you really want to do this when again it could compromise the excellent performance of the K2? Bob, G3VVT Keeper (license holder) GB3LD/GB3LF ___ 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] K2 S meter
Howard, With regard to S meter readings it does appear at least with my K2 #4168 and a later K2 #4324 tested a few weeks back that 80, 40, 30, 20 and 17m bands come out with similar sensitivity in the level required for S9 when switched to the same mode and bandwidth. For 15, 12 and 10m there was a discrepancy with the later serial number being slightly less sensitive. The alignment appeared to be fairly well correct for both K2. With the Elecraft XG1 signal generator the testing for S9 is done at 7040kHz with the higher level output at 50 microvolts PD (50uV PD = approx -73dBm). With the AGC threshold set at 3.80V, 50uV was insufficient to make S9 with both these K2. They both needed about 63uV PD to make S9 with the preamp switched off and were slightly more sensitive when checked with CW at 700Hz bandwidth compared to SSB with the SSB filter in circuit. However during testing it was found that small variations in the AGC threshold voltage had a substantial effect on the level required to make S9. With AGC threshold at 3.80V, as noted 63uV was required for S9. Drop this by 0.1V to 3.70 V, only 40uV was required and again by another 0.1V to 3.60V, only 25uV was now needed for S9. With all of the changes in threshold voltages the CAL S HI and CAL S LO needs to be reset at each step. The effect noted was posted on the Elecraft Reflector though only raised two replies in confirmation. Again has anybody else seen this effect of rising S meter sensitivity when lowering the AGC threshold whilst testing the K2 receiver? The optimum point for the setting of the AGC threshold with my K2 #4168 came out at 3.70V, which meant the S meter sensitivity came out at 40uV PD for S9. This can be fudged to 50uV for S9 by adjusting CAL S HI if desired. Left mine as is for ease of S meter HI/LO setting as per the manual. Assuming the alignment is correct on the K2 reported with low S meter sensitivity, it may be worth checking that AGC threshold has been set to at least the 3.80V initial setting. Well worth checking the K2 Alignment Instructions on Don, W3FPR's web site to ensure that you get everything correct. Bob, G3VVT K2 #4168 ___ 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] Alignment and Test, Part II
Hi Peter, The significant voltage could be the PLL chip PDOUT, U4 pin13. Check for shorts on this pin that would give a zero reading. Not sure if the PLL chip itself would support such a low voltage whilst working normally. Have seen reported of odd effects with RFC15 the DC feed to the PLL chip U4 pin16, so check for actual DC continuity with this component. What you do not appear to state and this is very important, is the VCO oscillating or not?. Checks with the K2 frequency counter at TP1 would at least help as an initial test. The frequency read depends on the band in use and reference to the table at the beginning of Appendix B gives the range of VCO frequencies to be expected. Tests with the RF probe/DMM at TP1 should give a reading between 600mV and 750mV according to the Elecraft trouble shooting guide. 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] OT: Demagnetize Soldering Tip?
Hi Martin, The Weller TCP soldering iron uses a magnetically operated switch in the centre of the soldering iron. The soldering iron tip has a cap on the inner edge of specific magnetic attraction properties that is neutralised by what I believe is called the Curie point effect when this cap reaches a critical temperature. This releases the switch actuator and cutting off the 24V feed to the soldering iron heater. You may have to replace the TCP switch assembly, though it would seem that a permanently magnetised tip may be the cause. Try another soldering iron tip first as the actuator switch assembly is rather more difficult to replace. If the tip is the cause it may be possible to demagnetise it with a TV picture tube degaussing wand. A message to all to keep the TCP iron away from speaker magnets, particularly the Hi-Fi kind. 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] soldering iron story
The Weller TCP soldering iron must be the best thing since sliced bread. Got mine in 1971 or 1972. Has a black hard bakelite cased PU1D 24V PSU with a Bulgin miniature 3 pin power connector on the side for the TCP-1 soldering iron which also uses bakelite for the handle. This version may be UK specific, not sure. Still works fine after all these years, though could do with the 3 core silicon rubber soldering iron cord being replaced. Not seen these listed by UK Weller spares sources of late. Have also inherited a later TCP soldering iron with the thermoplastic cased PS2D PSU from my late father in law, G3UUA. The new thermoplastic though it may look smart does not hold up to abuse like the old hard bakelite did unless dropped. Not sure if the term bakelite is used in the USA, but a similar material was used for panel meters, tube bases and a multitude of other uses throughout the world. Picked up the matching desoldering attachment that replaces the TCP element tube at a junk sale. The rubber bulb has now finally perished with age. Anybody know of a source of replacements for these rubber bulbs? Checks with dealers at later junk sales have drawn a blank apart from thoughts they may have been used by the military in the UK. 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] K2 Noise Blanker Modifications
Hi Sverre, The link to VE3MCF for the mod to increase KNB2 time constant does not seem to work anymore. Any other source of the mod details for suggested values for C11/C12? Regards, 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] Signal Generator
If you are checking the gain of the whole K2 RF and IF strip less the modification of the IF gain by the effects of AGC, yes, it is possible to use a lower output from the signal generator. However if you need to go into troubleshooting in greater depth, the 270mV / 756mV pk-pk found at the 2nd crystal filter output (product detector input) is far from the lowest signal that will need to be measured. The input to the to the RX mixer Z6 with the preamp and attenuator switched off is listed as only 77mV / 215mV pk-pk after the nominal 6dB voltage loss going through the low pass/bandpass filters when 140mV / 392mV pk-pk is inserted at the antenna jack. Whilst this will seem a relatively high level there are several pitfalls to beware of. Firstly, the oscilloscope will probably be using a X10 high impedance probe which would only give 39.2mV pk-pk to the input of the oscilloscope. Secondly, most of the older oscilloscopes had a maximum sensitivity of 10mV pk-pk/cm and with this there could be a further caveat that the bandwidth of the oscilloscope was reduced on the lowest range. The common 5MHz bandwidth TV service oscilloscopes of the past came down to only a bandwidth of only 1MHz or so when on the 10mV range. This is not much use when trying to measure RF levels even on 80m. The high signal generator output level advocated by Elecraft in their K2 troubleshooting info though needed for the use of their supplied RF probe/DVM, may be of significance in doing the same measurement with some earlier oscilloscopes. Modern high bandwidth oscilloscopes with a maximum sensitivity of 1mV pk-pk/cm would fare much better on this score. You need to check out what your particular oscilloscope specifications are and that it can fulfil the task before jumping in with both feet to do the measuring. I approach the troubleshooting of the RX front end and similar measuring tasks by using an RF millivoltmeter with a high impedance probe. Was able to acquire a Racal Dana 9301A some years back and that will go down to 1mV FSD at up to 2GHz. This means that I can use much lower levels of RF injection into the antenna jack to do measuring in the RX RF section. Found it very useful to repair a JRC RX whose front end had been very extensively damaged by a nearby lightning strike. The problem is that modern RF millivoltmeters can be as costly to buy as a good signal generator unless an earlier tube type can be located. There used to be several types available from manufacturers like Heath that would measure RF quite successfully and now are available at very low prices. 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
[Elecraft] Re: [EMAIL PROTECTED]
The recommendation given in the K2 Appendix E, Troubleshooting/signal tracing is to use an input of 140mV to have sufficient level to operate the supplied RF probe/DVM. 140mV PD is approx -4dBm (0dBm/1mW into 50 ohms is accepted as 225mV PD) and the signal generator I have that gives the highest output only reaches 100mV PD or -7dBm. Most of my synthesised generators only go up to approx 70mV or -10dBm maximum or even as low as -20dBm in some cases. It would seem that I cannot make the required output level at all. The only signal generators that reach the level required to do the tests are some of the more specialised signal generators such as some of those in the HP range which border on the realms of a low power transmitter and are far from what the average ham or 2 way radio service shop would have. The only other possibility if a single frequency will suffice would be to build the signal generator given in fig 2 in the K2 signal tracing section and add an external amplifier if needed to make the output level. 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
