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Total 691 documents matching your query.

341. Re: [TowerTalk] Idealized low band system designs (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Thu, 17 Feb 2005 11:20:12 -0800
I think folks like N4HY and SM5BSZ have been working on the rudiminents of what you describe, Jim. I recall N4HY describing a DSP noise blanker whereby you would look at the time samples and then ess
/archives//html/Towertalk/2005-02/msg00433.html (13,757 bytes)

342. Re: [TowerTalk] RF Inquiry HI-Q Filter CF5KV? (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sun, 20 Feb 2005 10:49:27 -0800
realist, This is where the ARRL could help. The have a very nice lab that all past and present members have helped to pay for. They could easily test stuff like this a publish the data in short produ
/archives//html/Towertalk/2005-02/msg00464.html (9,166 bytes)

343. Re: [TowerTalk] RF Inquiry HI-Q Filter CF5KV? (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sun, 20 Feb 2005 16:54:56 -0800
time I be 100-200 Yes, that is where forum's like this can come in. Why pay an engineer or test lab to do destructive testing when your customers will pay you full price for the priviledge of doing i
/archives//html/Towertalk/2005-02/msg00467.html (10,264 bytes)

344. Re: [TowerTalk] RF Inquiry HI-Q Filter CF5KV (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Mon, 21 Feb 2005 09:50:02 -0800
Cable Xperts advertises that they will build custom coax jumpers to order. It wouldn't surprise me if you could arrange to send them the beads and let them do the assembly. Might be a good thing for
/archives//html/Towertalk/2005-02/msg00481.html (8,839 bytes)

345. Re: [TowerTalk] LMR-240 Ultraflex/Heat (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Mon, 21 Feb 2005 16:22:28 -0800
RG8X jumpers will run noticeably warm at 1.5KW key down at 30 MHz. Power loss is still pretty negligible, however, for short runs (.11dB for a 6' jumper at 28.5 MHz -> 38 watts distributed across 6 f
/archives//html/Towertalk/2005-02/msg00497.html (9,620 bytes)

346. Re: [TowerTalk] ground and conductivity (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Mon, 28 Feb 2005 13:34:17 -0800
I was under the impression that soil conductivity mattered a great deal when using vertical polarization. With respect to horizontal polarization, however, I would agree that it doesn't matter all th
/archives//html/Towertalk/2005-02/msg00646.html (9,023 bytes)

347. Re: [TowerTalk] substandard aluminum? (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Tue, 1 Mar 2005 10:04:31 -0800
Dave, Junk antennas are not a recent invention. Telrex made some pretty shaky antennas too. Back in the 80's KS8S had two of their 3 element 40 meter yagis stacked on a 180' tower. The stainless stee
/archives//html/Towertalk/2005-03/msg00024.html (8,238 bytes)

348. Re: [TowerTalk] substandard aluminum? (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Tue, 1 Mar 2005 19:14:10 -0800
Dean had a pair of the 29 foot boom model - one at 90', and the other at 180'. When I went up there, my expectation was that I would be the loudest guy on the band (there weren't many 40 meter stacks
/archives//html/Towertalk/2005-03/msg00038.html (10,059 bytes)

349. Re: [TowerTalk] amplifiers for phased arrays (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Fri, 4 Mar 2005 22:57:55 -0800
This is a pretty interesting discussion. I don't quite have my head wrapped around a few of the issues, but I would like to make the following comments: 1). The concept Jim describes is used at highe
/archives//html/Towertalk/2005-03/msg00127.html (12,307 bytes)

350. Re: [TowerTalk] amplifiers for phased arrays (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sun, 6 Mar 2005 04:27:12 -0800
There's have seems Some interesting class E designs have been demonstrated by Dave Rutledge at Caltech using really cheap MOSFETs. These are narrowband, however, and also require somekind of envelope
/archives//html/Towertalk/2005-03/msg00138.html (12,551 bytes)

351. Re: [TowerTalk] Computer control antenna switch (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Wed, 9 Mar 2005 21:37:56 -0800
Wayne, This guy had a display at the DX Convention in Visalia, Ca last year: http://www.hamation.com/ Looks like a nice concept for remote control of antenna switches and the like, but I am not aware
/archives//html/Towertalk/2005-03/msg00198.html (9,938 bytes)

352. Re: [TowerTalk] Help in planning a new QTH (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Wed, 16 Mar 2005 08:34:27 -0800
Steve, For the "optimized" yagi's in the ARRL antenna book what were the optimization criteria? There is a tradespace between forward gain, pattern and VSWR bandwidth, and F/B. With a SteppIR you mig
/archives//html/Towertalk/2005-03/msg00393.html (12,050 bytes)

353. Re: [TowerTalk] SteppIR gain (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Wed, 16 Mar 2005 11:31:01 -0800
I have been thinking the same thing, Kelly. I think a 3 element SteppIR with 13.9 MHz parastitic elements and a the 6.9 MHz MonsterIR driven element would be a big hit. Rotary dipole performance on 4
/archives//html/Towertalk/2005-03/msg00413.html (8,691 bytes)

354. Re: [TowerTalk] Ground planewire. Insulated or uninsulated? (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sun, 20 Mar 2005 07:57:39 -0800
In terms of RF performance, I don't think you would notice the difference between insulated and un-insulated wire. If the wire is going to be on the surface of the ground or buried just below it (you
/archives//html/Towertalk/2005-03/msg00671.html (8,911 bytes)

355. Re: [TowerTalk] Toroid Core Material Selection (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Mon, 21 Mar 2005 19:24:03 -0800
Yes, good suggestion, Raj. I just made some measurements on a 2.4 inch O.D. type 31 Fair-Rite Products core that K9YC sent me. 7 turns on this core will give you >1000 ohms choking impedance from 1.8
/archives//html/Towertalk/2005-03/msg00724.html (8,887 bytes)

356. Re: [TowerTalk] Toroid Core Material Selection (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Tue, 22 Mar 2005 21:27:06 -0800
TV, or a phone in your house or in your a neighbors? What bands where you TX'ing on and how much power. Dave, I am not sure who you addressed this question to, but here are some examples of what I us
/archives//html/Towertalk/2005-03/msg00759.html (9,474 bytes)

357. Re: [TowerTalk] Model done for 4SQ supported by center tower (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Wed, 23 Mar 2005 23:53:16 -0800
You could also put a shunt arm (20 to 30 ft long) near the base of the 175' tower and then adjust it for parallel resonance at the operating frequency of the 4 square using a variable capacitor in se
/archives//html/Towertalk/2005-03/msg00787.html (9,116 bytes)

358. [TowerTalk] Remote Antenna Sites and Security (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Tue, 29 Mar 2005 17:58:48 -0800
I was talking to a friend of mine recently about the frustrations of low-band DXing from a small city lot and the possibility of purchasing some land in the boonies for purposes of building up a remo
/archives//html/Towertalk/2005-03/msg00908.html (7,952 bytes)

359. Re: [TowerTalk] Guying a self-supporting tower - Yes (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Sun, 10 Apr 2005 13:22:15 -0700
One element of this debate is whether or not you can generally say that for any free standing tower structure there exists a specific guy wire configuration that will result in an increase in the ove
/archives//html/Towertalk/2005-04/msg00330.html (12,500 bytes)

360. Re: [TowerTalk] Real numbers for Rohn BX-64 Re: guying (score: 1)
Author: "Michael Tope" <W4EF@dellroy.com>
Date: Tue, 12 Apr 2005 22:21:22 -0700
It occurred to me that my 45' tall tilt-up vertical made from 2" O.D. thin wall tubing may be germane to this discussion: http://www.dellroy.com/W4EF's-Ham-Radio-Page/Stew-Perry_El-Mirage/El-Mirage.h
/archives//html/Towertalk/2005-04/msg00421.html (13,915 bytes)


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