Re: [Elecraft] Elecraft AT1 Attenuator
Thanks to John, Joe and Mike for the feedback. Mike hit it on the head when he mentioned the slide switches. It was oxidisation and some vigorous switch gymnastics cured it. I now have readings that complement John's matrix. I know right well I should have guessed this, but I knee-jerked as usual. Cheers to all, Steve, G4VRR. e ... __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] AT1 Attenuator
I have purchased a second user AT1 recently, largely due to the ruinous TransAtlantic logistics costs, but also the ongoing absence of any support here in The UK. Although purely from observation of the circuit topology it seems reasonable to assume that it is not a constant impedance array of resistors, I was quite surprised to see the high SWR readings recorded after connecting a good dummy load and an antenna analyser- encroaching as it does well into double figure readings. My received wisdom being that these devices need to look into a 50 Ohms load to preserve accuracy. I have checked all the resistors and they are extraordinarily accurate leading me to believe that it has not been cooked by the/a previous owner, and confirming the quality of Elecraft dedigns. I also noted that the greater the level of attenuation, the lower the SWR is with the lowest attenuation displaying the worst result, and the highest displaying a near perfect match, but I guess that is not surprising because it is attenuating the reflected RF too. What I would like is some reassurance that such elevated SWR readings are to be expected for a nominally 50 Ohms stepped attenuator of this nature set to the lower levels of attenuation. Steve, G4VRR. e ... __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 microphone nut size
This is supposed to be addressed to the group, not Rich specifically, but on this so-called "smart" 'phone, I cannot see how to do that, nor how to strip out the miles (kilometres!) of duplicated commentary. Mea culpa my friends. One day! While I was still working, I used to build aircraft interior equipment, specifically galleys and associated structures, and everything was in imperial (actually decimal inches.) We used UNF and UNC attachment fasteners. Even Airbus tolerated our decimal inch drawings and Boeing was a given. I became completely conversant with imperial- both fractional and decimal, but also metric. I routinely read fractional tape measures as a decimal inch converted mentally on the fly. What I'm saying is it's only a cocktail of laziness, stubborness and * to plough ahead with one system completely in denial of another potentially better one. In my closing years I did Q.A. and First Article Inspection. I wouldn't have survived with Boeing or Airbus if I'd refused to be conversant in all systems. While at college (I did Environmental Engineering) we were taught dimensional analysis of equations. Everything is reduced to Length, Mass and Time (ignoring wild cards like viscosity). When you see an equation substantiated in this way, a light goes on in your head and the benefits of the S.I. System are obvious. Until that is inculcated into your skull, you take equations as something that is commited to memory but maybe never stopping to consider why or who the heck figured that out? Sure you can arrive at the same results using imperial units, but only if you remember (without fail) to deploy empirical fudge factors so inches can be used alongside ounces and so on. That said, the S.I. unit is the metre. The recognised sub unit is the millimetre. (not the centimetre). Suppose you want to cut something six feet long (1,829 millimetres)? You pull out the tape measure and it happens to be upside down. Enough times for it to be a lurking threat you measure (eg) 1,819 instead of 1.829 by mistake. It's your own fault, but for humans interacting with the world I submit that feet and inches are a better way, but for engineers (or anyone that likes to think of themselves as such.) The S.I. System is a far better way to do things. I also think that the evolved usage of centimetres is a tacit admission that inches were better than millimetres. $0.02 of course. Steve, G4VRR. -- Sent from: http://elecraft.365791.n2.nabble.com/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Waterproof SO-239 covers
I use "Plasticene" (maybe known as modelling clay?) In my experience it never hardens, it is waterproof and easy to remove. I used to use the orange tapered vinyl boots that were used on mineral insulated "Pyro" cable over the top since they are a great seal over PL259s but I have used up my stock. I make sure that the cable is not free to flap around and "Plasticene" does the job. If there's only two "teeth" on the PL259 connector then I frequently file them off and ignore the slight plating loss. I cover the threads with a mixture of zinc and Vaseline anyway. This is a concoction that we used to use at work (in a loosely aerospace related company) to facilitate riveted ground points on galley structures prior to Meggar tests, but that process fell into disuse. It came about because the guys were using heatsink compound until I arrived and pointed out their error! I still use the zinc and Vaseline on threads though because it lubricates and the zinc helps conductivity a little, but my stock has all but gone. Steve, G4VRR. -- Sent from: http://elecraft.365791.n2.nabble.com/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
