Search String: Display: Description: Sort:

Results:

References: [ +from:w8ji@w8ji.com: 971 ]

Total 971 documents matching your query.

241. Re: Topband: [Topband] Antenna analysers in close proximity to BCstation (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sun, 4 Nov 2012 19:42:52 -0500
The proper way to test the MFJ analyzer for RFI is to place the analyzer in frequency counter mode and look at the SWR meter needle. If the **SWR meter** is deflecting off zero when in frequency coun
/archives//html/Topband/2012-11/msg00055.html (9,122 bytes)

242. Re: Topband: Antenna analysers in close proximity to BC station (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Mon, 5 Nov 2012 07:59:23 -0500
Thinking again about this, we have missed out a stage. After measuring the tuner output impedance, we need to make a temporary L network which, when terminated with 50 ohms, looks like the antenna. N
/archives//html/Topband/2012-11/msg00060.html (9,334 bytes)

243. Re: Topband: Antenna analysers in close proximity to BC station (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Mon, 5 Nov 2012 08:19:12 -0500
So, I'm looking at setting a EWE antenna up - what happens if I simply make it a full loop? In other words, instead of driving 4' ground rods in at both ends I run a wire between the bottom of the te
/archives//html/Topband/2012-11/msg00064.html (10,104 bytes)

244. Re: Topband: Further discussions on EWEs (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Mon, 5 Nov 2012 12:37:34 -0500
Tom, et al: is there data that nail down the horizontal wire to vertical wire ratio? I see in that write up by wa1on mention of 2.25:1 h to v but...is that some rule that can't be violated or.../ For
/archives//html/Topband/2012-11/msg00069.html (11,569 bytes)

245. Re: Topband: Feedline; to ground, or not to ground? (score: 1)
Author: "Tom" <w8ji@w8ji.com>
Date: Sun, 11 Nov 2012 00:08:20 -0500
I can't imagine why someone running 400 feet of Heliax, and especially with a tall tower, would not ground feedlines to a radial system at the tower. Lightning concerns alone dictate proper groundin
/archives//html/Topband/2012-11/msg00117.html (8,105 bytes)

246. Re: Topband: Teflon Sleeving vs Heatshrink for the Homemade FCP (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sun, 11 Nov 2012 07:50:09 -0500
The stranded center conductor and dielectric from solid dielectric RG58 coax has a breakdown voltage of over 5000 volts, if you need HV wire. Teflon EE insulation wire is about the same. Teflon is s
/archives//html/Topband/2012-11/msg00121.html (8,164 bytes)

247. Re: Topband: TX/ RX Antenna Switching (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 14 Nov 2012 07:43:43 -0500
Forgot the link to Array Solutions RF Limiter / Front Load Protector (Helps to know what they call these items so you can search for them :-) i.e.. "Front End Protector". http://arraysolutions.com/Pr
/archives//html/Topband/2012-11/msg00198.html (9,886 bytes)

248. Re: Topband: TX/ RX Antenna Switching (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 14 Nov 2012 07:51:07 -0500
It sounds like the DX and MFJ are out because of Watt limitations (200W?). You are misinterpreting the ratings. The ratings are for power from the transceiver sent out THROUGH the device, not transmi
/archives//html/Topband/2012-11/msg00199.html (9,264 bytes)

249. Re: Topband: TX/ RX Antenna Switching (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 14 Nov 2012 08:07:28 -0500
By the way Buck, there is more to this than some people will tell you. The DXE switch uses a unique RF limiter that kicks in hard at about 23 dBm. Below that level there is no intermod at all!! It wi
/archives//html/Topband/2012-11/msg00200.html (8,655 bytes)

250. Re: Topband: TX/ RX Antenna Switching (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 14 Nov 2012 16:25:05 -0500
How do we know what it has with no schematic available? It could be $1-2 worth of parts. I recommend that nobody buy anything from DXE that does not support an at home repair. I certainly agree every
/archives//html/Topband/2012-11/msg00204.html (9,672 bytes)

251. Re: Topband: TX/ RX Antenna Switching (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 14 Nov 2012 20:01:27 -0500
Getting away from what we are discussing now (limiters) and back to the original question... it really is just a few bucks for a relay for a rig (without separate T and R jacks) at the 100W level, to
/archives//html/Topband/2012-11/msg00208.html (12,995 bytes)

252. Re: Topband: 8877 Tube (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 14 Nov 2012 20:15:36 -0500
The Spec Sheet for the 8877 tube lists the "Absolute Maximum Plate Voltage of 4000 Volts" for the tube, and also says in "typical operation" the plate voltage is between 2700 and 3500 volts. In my am
/archives//html/Topband/2012-11/msg00210.html (8,762 bytes)

253. Re: Topband: TX/ RX Antenna Switching (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Thu, 15 Nov 2012 08:24:32 -0500
If something goes wrong in the RX antenna switch, you don't have to worry about the rig transmitting into its own receiver. That can't happen. The only thing that can happen is that you could damage
/archives//html/Topband/2012-11/msg00224.html (11,048 bytes)

254. Re: Topband: Covered /bare antennn wire (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Thu, 15 Nov 2012 14:14:32 -0500
Out of curiosity, has anyone ever really done testing of voltage buildup on a insulated antenna wire, VS a non-insulated wire ? Indoor antennas VS outdoor antennas of equal size? I tested this extens
/archives//html/Topband/2012-11/msg00234.html (9,328 bytes)

255. Re: Topband: Covered /bare antennn wire (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Thu, 15 Nov 2012 15:25:23 -0500
As you have said it is difficult to get a A-B test unless instant switching or direct observation is available. The purpose of my test was to see if p-static was caused by individual charged particle
/archives//html/Topband/2012-11/msg00238.html (12,295 bytes)

256. Re: Topband: Covered /bare antennn wire (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Fri, 16 Nov 2012 11:09:53 -0500
It also doesn't seem to matter if the antennas in the stack have their elements insulated from the boom or bonded to it, the top antenna always has +20 dB or more noise. 73 John N5CQ That agrees with
/archives//html/Topband/2012-11/msg00255.html (11,044 bytes)

257. Re: Topband: Vertical Array Over Uneven Ground (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Fri, 16 Nov 2012 11:21:11 -0500
I suspect most (or at least many) Americans are resistant to change and unwilling to give anything different than what they are used to a fair try before dismissing it. When we were kids, we made fun
/archives//html/Topband/2012-11/msg00256.html (9,417 bytes)

258. Re: Topband: corona noise (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Fri, 16 Nov 2012 18:58:36 -0500
Hi would a static discharge wick mounted on the lightning rod be helpful? They seem to work well for aircraft AM radios. << Anything a lot taller than the antenna being used and close to the antenna
/archives//html/Topband/2012-11/msg00263.html (8,664 bytes)

259. Re: Topband: Covered /bare antennn wire (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Fri, 16 Nov 2012 19:09:15 -0500
From my own exhaustive research and many lab experiments with HV corona discharge, it seems to me that at least some of this could be eliminated by either: 1. Eliminating all the sharp points That's
/archives//html/Topband/2012-11/msg00264.html (11,326 bytes)

260. Re: Topband: corona noise (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sat, 17 Nov 2012 08:32:23 -0500
What is "a lot taller"? I can't answer that question specifically. It varies with e-field conditions and the type of antennas and structures. The corona is a micro power noise generator so it radiate
/archives//html/Topband/2012-11/msg00269.html (10,084 bytes)


This search system is powered by Namazu