KE7GH asks:
>>Not to beat a badly mutilated horse into subatomic particles, but is there
>>the slightest chance this may have happenned on 14.230 once or twice?
in regards to my observations of ignorance of operators in determining
whether a frequency is in use.
Nope.
As a matter of fact, I rarely have the problem on SSB. Obviously more people
understand spoken English than know the code. The events I was referring to
are most memorable in CW contests.
I learned many years ago not to even approch the bedlam between 14225 &
14235. Let the other guys fight those jerks; I'll go where I can make
contacts!!
PS: Send comments to either me OR the reflector, but NOT BOTH. If it goes
to the reflector, I'll see it. No need to wade thru duplicate messages.
73, Gator N5RZ ------------------------;--;<< N5RZ@aol.com
>From ni6t@ix.netcom.com (Garry Shapiro ) Wed Jul 12 22:17:11 1995
From: ni6t@ix.netcom.com (Garry Shapiro ) (Garry Shapiro )
Subject: max length of RS-232 network link?
Message-ID: <199507122117.OAA09321@ix4.ix.netcom.com>
You wrote:
>
>
><del>
>Bob-
>
>The maximum length of the RS-232 runs is not affected by the fact the
>you are using the -LOOP mode of CT. It will solely be determined by
>the robustness of the particular interfaces you are using, and the
>RF integrity of the cables. Check me on this, but I think RS-232
>is spec'ed to a max of 500 feet.
^^^
Is this a recent development? I have not worked professionally with
interfaces for about 5 years, but I recall no such number. In fact, 50
feet seems more like it. Over longer runs, the "robustness of the
particular interfaces" is certainly the key. Received RS-232 levels are
spec-ed to be >3V and <-3V; many/most receivers will work reliably with
signals smaller than that, but it is de facto risky. Many drivers run
from only +/-5V supplies and thus put out something less than +/-5V,
but the early/classic 1488-type drivers ran from +/-12 to 15V supplies
and so put out a much larger voltage swing. Ergo, one has a lot more
headroom and therefore more distance.
>
>Things you can do to help it work:
>
>1. Make all your cables out of coax. RG-58 should work fine.
That's fine for shielding, but it's a helluva lot of capacitance. The
large but finite slew-rate capability of RS232 drivers is spec-ed for a
modest amount of capacitive load--but I do not recall the number. 500
ft of RG58U is roughly 15,000 pF, and the resultant degradation in slew
rate could make your following solution #3--lower data rate--a
necessity.
>2. Bring ferrite beads, just in case.
Always a good idea!
>3. If you have trouble, try running the network at a lower baud rate.
See above.
>4. Ultimately, you could go with optical fiber on the RS-232 links.
> It's expensive, but it works. Talk to Rich, K5NA, who has done it.
With respect to WB4IUX's comments on dissimilar voltage levels at
either end of the interface, this is a well-known and serious problem,
even within the same building or room, when serviced by more than one
power circuit. In a perfect world, ground is ground everywhere, but in
reality, grounds differ even in cirucits emanating from the same ground
bus strip in an panel entry cabinet. In industrial situations, where
the panels may be hundreds of feet from the outlets, large
differentials may be encountered. I personally have seen 60 to 80V
differentials! These pose a real shock danger as well as a peril to
your interfaces. Bottom line: unless all the interconnected equipment
is running from the SAME power circuit or one can GUARANTEE common
hardwired grounding of all equipment in the station(s), one should
consider isolated interfaces. One cannot so guarantee in the 500-foot
apart contest situation proposed by the source messagee.
Much has been published on optoisolated interfaces and some commercial
add-on boxes for radios have such circuitry. There are even IC's
available (hybrids, really) with the optoisolators already combined
with the RS232 transceivers, with UL ratings to boot. These are not
cheap, but neither is 500 ft of RG58 (times at least two) or a blown
interface. Maxim Integrated Circuits, Sunnyvale, CA makes these devices
in conventional wide-DIPs.
You might also consider a balanced interface, like RS485, which I
believe is used, among other places, in SCSI and LocalTalk
applications. RS485 is a logic-level interface and does not deal with
the voltage isolation problem, but the balanced lines, used with
twisted pairs, give good noise immunity.
Garry, NI6T
>From BILL FISHER" <BFISHER@concen.com Wed Jul 12 18:02:56 1995
From: BILL FISHER" <BFISHER@concen.com (BILL FISHER)
Subject: DSP Choices
Message-ID: <9506128055.AA805593776@concen.concen.com>
My recommendation is save your money for something usefull. That is if you are
planning to use it for contesting. If you are just wanting it for day to day
operating buy it.
73
Bill, KM9P
______________________________ Reply Separator _________________________________
Subject: DSP Choices
Author: Joe Pfeuffer <JP@otc.mhs.compuserve.com>
To:
<cq-contest@tgv.com>
Subject: DSP Choices at INTERNET
Hi:
I am going to invest some hard earned cash for a DSP and am confused as to
the claims, performance, etc.
I would appreciate your reccomendation and/or opinion of the various models.
Thanks
Joe - KW1K
Spoakne, WA
>From Floydjr <floydjr@nando.net> Wed Jul 12 23:10:14 1995
From: Floydjr <floydjr@nando.net> (Floydjr)
Subject: Field Day Scores
Message-ID: <Pine.SUN.3.90.950712180915.20072A-100000@merlin.nando.net>
On Wed, 12 Jul 1995, Mitch wrote:
> Message-Id: 4525_ka2tcq
> From: wb2jsj@ka2tcq (Mitch)
> To: cq-contest@tgv.com
>
> Has anyone compiled ARRL Field Day Scores?
> If so, I'd like to see how everyone did.
> Please send directly to: wb2jsj@amgate.net.plattsburgh.edu
> Thanks & 73,
> Mitch WB2JSJ/WB1GQR
>
>
>
I would also like to see that list. Do not have access to WWW.
73's Jim // WA4ZXA
>From Brian Short <ke7gh@PrimeNet.Com> Wed Jul 12 23:29:02 1995
From: Brian Short <ke7gh@PrimeNet.Com> (Brian Short)
Subject: DSP Choices
Message-ID: <199507122229.PAA13914@usr1.primenet.com>
> I am going to invest some hard earned cash for a DSP and am confused as to
> the claims, performance, etc.
>
> I would appreciate your reccomendation and/or opinion of the various models.
>
> Thanks
>
> Joe - KW1K
> Spoakne, WA
>
A DSP what? I have a DSP multi-mode data controller, a DSP audio filter,
etc. I'll assume an audio filter and recommend what I use, the Timewave
DSP-9+. I also built the kit from the article in QST several years ago,
but this has been polished in the commercial units, in my opinion.
73 de Brian
>From kn5hose@acca.nmsu.edu (kn5hose) Wed Jul 12 23:31:06 1995
From: kn5hose@acca.nmsu.edu (kn5hose) (kn5hose)
Subject: Move wpx cw
Message-ID: <199507122231.QAA25696@acca.nmsu.edu>
The question is: Are you in favor of moving the WPX CW Contest away from
Memorial Day?
Answer: To whoever is counting votes, count mine as YES, move it.
73 de Hose KN5H
>From Brian Short <ke7gh@PrimeNet.Com> Wed Jul 12 23:23:10 1995
From: Brian Short <ke7gh@PrimeNet.Com> (Brian Short)
Subject: Just a Question.
Message-ID: <199507122223.PAA13388@usr1.primenet.com>
I learned many years ago not to even approch the bedlam between 14225 &
14235. Let the other guys fight those jerks; I'll go where I can make
contacts!!
73, Gator N5RZ ------------------------;--;<< N5RZ@aol.com
I agree. Just a question. Have a nice day. :)
>From XTFF35A@prodigy.com (MR CHARLES A CULLIAN) Wed Jul 12 23:37:37 1995
From: XTFF35A@prodigy.com (MR CHARLES A CULLIAN) (MR CHARLES A CULLIAN)
Subject: SQuint
Message-ID: <013.08585221.XTFF35A@prodigy.com>
I saw several items on the Squint but alas, I decided without
opening them that they would be of no interest to me. The I saw the
NCJ article and talked with my daughter and she is interested, so. . .
Can anyone fill me in on the rules and the date and time?
I think it is this coming Sunday??
73,
Chuck (K0RF)
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