The resonance method is probably the best, but you have to be a long way from the self resonant frequency of the coil. If you're below about 0.8 of the SRF, the apparent resistance = Ractual/(1-ye2)e
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Tue, 12 Jul 2005 12:28:15 +0200 (CEST)
4558 is a fairly common op amp. 73 Peter G3RZP == Message date : Jul 12 2005, 11:05 AM To : "TowerTalk" Copy to : Subject : [TowerTalk] KENPRO KRC- 400RC controller malfunction Does anybody know an e
itself has become magnetized? Maybe just enough to hold them closed until subjected to a slight vibration? If so, is it possible to degauss the switch?< My experience with reed switches is that stick
application because of the charged coax lines discharging through the reed relay contacts and possibly damaging or welding them together. < Personally, having welded reed relays in the past from capa
be very interested in discovering good information on the cage-vertical.< I shunt my feed my 62 foot tower (top loaded with a 4 ele Steppir now) on 80 and 160 with just such a 'wide conductor'. Three
All cables, beams, rotator, switching relays etc. run down the centre of the far, Firstly, I haven't had chance to get it all finalised yet! What I have done is to bond all the coax outers together a
I use 12 cores ( 2 cables 'liberated' when they re wired LANs at work). This gives 5 data lines, plus return, for selection of up to 32 antennas, a pair of wires for turning on the remote power relay
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Sat, 23 Jul 2005 18:58:03 +0200 (CEST)
Having read Tom's comment about the 2m loop antenna in QST, I went and looked at the article. Back in the 'good ole days' of 2metres, when everything was horizontally polarised AM, and a mobile rig u
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Sat, 23 Jul 2005 19:16:28 +0200 (CEST)
Yes, but both the work Chu and Wheeler have stood the test of time. They say it will have high Q and low radiation resistance. Maybe if we can have room temp superconductors... 73 Peter W7/G3RZP -- W
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Sat, 23 Jul 2005 20:29:15 +0200 (CEST)
I have seen answers to the Extra Class that are just plain wrong. No ifs, ands or buts. That can be the trouble with a multiple choice exam, unless the people setting it really know their stuff......
It's worth talking to Ed Hare at ARRL about this. he does know of ones in the US that are immune. I have the same problem in the UK (except we call them RCD - Residual Current Device) - which was why
I agree with Jim, K9YC. It's impossible to determine the real differences between them. A Cauer Chebycheff can be usefully arranged to have notches at harmonics of the various bands, but it doesn't s
One problem is that filters are generally specified for use in matched systems - a whatever ohms resistive source and a whatever ohms resistive load. Occasionally, you might design filters to go betw
How accurately do you want the 50+j0? For the majority of purposes, anything under about a 1.5:1 SWR is more than adequate: for 30kW autotune HF tx's, we had a limit of a 2:1 SWR. If you really need
FWIW, I have replaced a 5el 20m beam (205BA) on a 34ft boom with a 4 ele Steppir at the same height. It's definitely no worse, and could well be better, so for reasons of weight and windage, I 'd go
If however, it's a disused spur, then it may not even be still connected. A lot depends on what it was - for instance, a small factory siding is unlikely to be track circuited, but a long branch may
Isn't either a lawyer or a politician just as effective as a snake? 73 Peter G3RZP _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wirele
Author: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Date: Mon, 12 Sep 2005 09:12:50 +0200 (CEST)
Earlier this year, I took down a 205BA that had been up for 20 years. OK, I live in a rural area well away from the coast, but it's still OK. The non stainless parts aren't, though. 73 Peter G3RZP (p
QEX paid me somehting like $200 or $300 for about 4 pages. Can't remember exactly, since I hate paying tax, so sent it the League's frequency defense fund. Ian, GM3SEK will tell you that you can't ge
One interesting point is that the definition of radiation resistance has varied between countries and over time. It certainly was just 'the real part of the feed impedance' here about 50 years ago. P