Date: Fri, 14 Jan 94 22:28:41 PST
From: Info-Hams Mailing List and Newsgroup <info-hams@ucsd.edu>
Errors-To: Info-Hams-Errors@UCSD.Edu
Reply-To: Info-Hams@UCSD.Edu
Precedence: Bulk
Subject: Info-Hams Digest V94 #38
To: Info-Hams
Info-Hams Digest Fri, 14 Jan 94 Volume 94 : Issue 38
Today's Topics:
DIPOLES FED BY LADDER LINE - Q
Land mobile mailing list?
Multi-User Dungeons on Packet?
Need Source for Gunn Diodes.
Never-ending search for FT-530 mods
ORBS$014.2L.AMSAT
Packet to Internet
Portable 2m Antenna for Mountaineering???
Repeater database?
Repeater Interference
WANTED: Mods for ALL radios
why 29.94 fps?
Send Replies or notes for publication to: <Info-Hams@UCSD.Edu>
Send subscription requests to: <Info-Hams-REQUEST@UCSD.Edu>
Problems you can't solve otherwise to brian@ucsd.edu.
Archives of past issues of the Info-Hams Digest are available
(by FTP only) from UCSD.Edu in directory "mailarchives/info-hams".
We trust that readers are intelligent enough to realize that all text
herein consists of personal comments and does not represent the official
policies or positions of any party. Your mileage may vary. So there.
----------------------------------------------------------------------
Date: Thu, 13 Jan 1994 08:42:58 -0500
From: foxhound.dsto.gov.au!fang.dsto.gov.au!yoyo.aarnet.edu.au!news.adelaide.edu.au!basser.cs.su.oz.au!harbinger.cc.monash.edu.au!yeshua.marcam.com!news.kei.com!sol.ctr.@@munnari.oz.au
Subject: DIPOLES FED BY LADDER LINE - Q
To: info-hams@ucsd.edu
In article <CJJAEK.G1J@srgenprp.sr.hp.com>, alanb@sr.hp.com (Alan Bloom)
wrote, in part:
>
> On the higher bands, the main difference with the 260-foot antenna would be
> the radiation pattern. On 80 meters, the pattern would be a cloverleaf
> (maximums at approx. 45-degree angle from the wire) instead of bi-directional
> perpendicular to the wire. On 40-10 meters, the antenna would tend to be
> more directional off the ends of the wire than with the 135-foot antenna.
>
Don't forget that, to see the bidirectional pattern of a half-wave antenna,
or the cloverleaf pattern of a pair of half-wave antennas fed at the
center, you've got to be a _significant_ fraction of a wavelength above the
ground. We're talking close to a half wavelength here, and that's about
125 feet on 80 meters, and about 250 feet on 160 meters. When I model
antennas at realistic heights above real ground on AO-5 (less than a
quarter wavelength on 80 and 160 meters), the radiation pattern looks like
an _egg_ sitting on its broader end, with the narrower end pointing
straight up. In the horizontal plane it's _circular_, not directional at
all. (The classic cloud-burner.)
The real world doesn't look like all those pretty pictures in the
textbooks.
--
73 de John Taylor W3ZID
rohvm1.mah48d@rohmhaas.com
------------------------------
Date: 13 Jan 1994 18:44:48 GMT
From: usc!sol.ctr.columbia.edu!news.kei.com!ub!dsinc!netnews.upenn.edu!eniac.seas.upenn.edu!depolo@network.ucsd.edu
Subject: Land mobile mailing list?
To: info-hams@ucsd.edu
Does anyone have the subscription address for the land mobile mailing list?
--- Jeff
--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Jeff DePolo WN3A Twisted Pair: (215) 337-7383H 387-3059W
depolo@eniac.seas.upenn.edu RF: 443.800+ MHz 442.700+ MHz 24.150 GHz
University of Pennsylvania
------------------------------
Date: 13 Jan 1994 15:32:21 GMT
From: concert!inxs.concert.net!clapton.concert.net!dcc@decwrl.dec.com
Subject: Multi-User Dungeons on Packet?
To: info-hams@ucsd.edu
In article <swood.758436360@vela.acs.oakland.edu>,
Scott Wood <swood@vela.acs.oakland.edu> wrote:
>Would it be possible or plausible to run Multi-User Dungeon (MUD)
>on packet radio? Would anyone like to help me hack code to play with
>this concept?
Don't need to hack, it already exists. Just find some DX Packet-Cluster
software.
73 de KC4WEJ,
Derrick
--
| / _____/ | / _____/ Derrick Cole, KC4WEJ
/ __/ / / / | / / MCNC Information Technologies, RTP
/ / / / | / / cole@concert.net
__/ __/ _______/ __/ __/ _______/ "Janet!Dr.Scott!Janet!Brad!Rocky!"
------------------------------
Date: 13 Jan 1994 13:11 CST
From: usc!cs.utexas.edu!news.tamu.edu!summa.tamu.edu!pjc3151@network.ucsd.edu
Subject: Need Source for Gunn Diodes.
To: info-hams@ucsd.edu
Hello all,
I am looking for a source for Gunn oscillators for X-Band applications
specifically in the MA/COM case style 30. I am interested in very low
volume purchases and have tried dealing with MA/COM, Alpha industries, and
Richardson electronics to no avail.
To be even more specific, 10 mW would be an adequate power.
If you can be of any assistance in helping me locate a source, please e-mail
directly to me.
73 & tnx,
Pierre Catala - WA1UAT/5
Dept. of Engr. Technology
Texas A&M University
catala@entc.tamu.edu
------------------------------
Date: Thu, 13 Jan 1994 14:12:42 GMT
From: netcomsv!netcom.com!wy1z@decwrl.dec.com
Subject: Never-ending search for FT-530 mods
To: info-hams@ucsd.edu
I'm on the neverending search for any mods for the Yaesu FT-530 HT.
I have the internal mod for expanded tx and rx, but is it all possible to
do anything from the keypad?
Also, what else is there?
What is Yaesu hiding from us?
Thanks much.
Scott
--
===============================================================================
| Scott Ehrlich Internet: wy1z@neu.edu BITNET: wy1z@NUHUB |
| Amateur Radio: wy1z AX.25: wy1z@k1ugm.ma.usa.na |
|-----------------------------------------------------------------------------|
| Maintainer of the Boston Amateur Radio Club hamradio FTP area on |
| the World - world.std.com pub/hamradio |
===============================================================================
------------------------------
Date: 14 Jan 94 13:46:00 GMT
From: news-mail-gateway@ucsd.edu
Subject: ORBS$014.2L.AMSAT
To: info-hams@ucsd.edu
SB KEPS @ AMSAT $ORBS-014.N
2Line Orbital Elements 014.AMSAT
HR AMSAT ORBITAL ELEMENTS FOR AMATEUR SATELLITES IN NASA FORMAT
FROM WA5QGD FORT WORTH,TX January 14, 1994
BID: $ORBS-014.N
DECODE 2-LINE ELSETS WITH THE FOLLOWING KEY:
1 AAAAAU 00 0 0 BBBBB.BBBBBBBB .CCCCCCCC 00000-0 00000-0 0 DDDZ
2 AAAAA EEE.EEEE FFF.FFFF GGGGGGG HHH.HHHH III.IIII JJ.JJJJJJJJKKKKKZ
KEY: A-CATALOGNUM B-EPOCHTIME C-DECAY D-ELSETNUM E-INCLINATION F-RAAN
G-ECCENTRICITY H-ARGPERIGEE I-MNANOM J-MNMOTION K-ORBITNUM Z-CHECKSUM
TO ALL RADIO AMATEURS BT
AO-10
1 14129U 83058B 94012.88782746 -.00000337 00000-0 10000-3 0 2527
2 14129 27.1999 346.8463 6020165 145.8302 274.3239 2.05879874 79582
UO-11
1 14781U 84021B 94010.08597013 .00000380 00000-0 72457-4 0 6563
2 14781 97.7948 32.1580 0013012 56.2907 303.9538 14.69119704527098
RS-10/11
1 18129U 87054A 94012.18938195 .00000043 00000-0 30277-4 0 8534
2 18129 82.9265 84.1595 0012815 92.4751 267.7871 13.72329421328513
AO-13
1 19216U 88051B 94012.80728378 -.00000496 00000-0 10000-4 0 8646
2 19216 57.8771 273.8452 7205596 332.6950 3.3813 2.09726405 42750
FO-20
1 20480U 90013C 94010.95413140 -.00000034 00000-0 50320-7 0 6518
2 20480 99.0159 192.6118 0541004 335.8403 21.8259 12.83223133183969
AO-21
1 21087U 91006A 94012.62069919 .00000094 00000-0 82657-4 0 4150
2 21087 82.9431 257.8282 0035513 155.4415 204.8441 13.74531504148215
RS-12/13
1 21089U 91007A 94003.81201797 .00000013 00000-0 -16601-5 0 6449
2 21089 82.9224 133.3515 0028470 204.2513 155.7306 13.74032105146079
UO-14
1 20437U 90005B 94010.77417742 .00000091 00000-0 52567-4 0 9554
2 20437 98.6020 97.6365 0010436 297.1869 62.8248 14.29816216207093
AO-16
1 20439U 90005D 94010.27599894 .00000090 00000-0 52081-4 0 7569
2 20439 98.6100 98.2182 0010807 299.7021 60.3085 14.29872172207037
DO-17
1 20440U 90005E 94010.24566329 .00000085 00000-0 49855-4 0 7553
2 20440 98.6104 98.4590 0010937 298.8420 61.1664 14.30010001207045
WO-18
1 20441U 90005F 94010.77802339 .00000076 00000-0 46420-4 0 7562
2 20441 98.6102 98.9976 0011564 297.9734 62.0277 14.29986901207120
LO-19
1 20442U 90005G 94010.27687465 .00000090 00000-0 52015-4 0 7551
2 20442 98.6110 98.7224 0011738 298.7184 61.2818 14.30080180207066
UO-22
1 21575U 91050B 94010.20521252 .00000086 00000-0 43783-4 0 4569
2 21575 98.4527 87.7827 0008506 45.5057 314.6824 14.36880739130394
KO-23
1 22077U 92052B 94010.71614680 -.00000037 00000-0 10000-3 0 3510
2 22077 66.0891 249.6865 0008292 327.4530 32.5976 12.86283043 66534
IO-26
1 22826U 93061D 94010.74365142 .00000064 00000-0 44049-4 0 2544
2 22826 98.6708 88.0424 0008909 315.3567 44.6895 14.27703185 15226
AO-27
1 22825U 93061C 94010.75128956 .00000091 00000-0 54921-4 0 2533
2 22825 98.6699 88.0360 0008369 315.3218 44.7287 14.27601262 15225
KO-25
1 22830U 93061H 94010.22919834 .00000033 00000-0 30715-4 0 2557
2 22830 98.5723 86.4575 0010974 282.5588 77.4365 14.28026996 15156
NOAA-9
1 15427U 84123A 94012.02966378 .00000111 00000-0 83070-4 0 6750
2 15427 99.0745 60.5237 0014518 302.8342 57.1432 14.13578753468283
NOAA-10
1 16969U 86073A 94012.05489049 .00000088 00000-0 55662-4 0 5743
2 16969 98.5117 25.8091 0014292 65.7755 294.4914 14.24856833380370
MET-2/17
1 18820U 88005A 94010.49966547 .00000056 00000-0 36696-4 0 2532
2 18820 82.5404 34.0252 0015326 265.7718 94.1693 13.84704489300534
MET-3/2
1 19336U 88064A 94010.21677031 .00000051 00000-0 10000-3 0 2554
2 19336 82.5411 75.4737 0015967 300.1181 59.8358 13.16963401262462
NOAA-11
1 19531U 88089A 94011.93062008 .00000138 00000-0 99115-4 0 4766
2 19531 99.1569 357.1352 0011172 210.6074 149.4447 14.12949121273153
MET-2/18
1 19851U 89018A 94010.22638494 .00000114 00000-0 88700-4 0 2549
2 19851 82.5234 269.8530 0013932 316.1413 43.8640 13.84355084245838
MET-3/3
1 20305U 89086A 94012.21817743 .00000044 00000-0 10000-3 0 9699
2 20305 82.5469 17.8121 0006413 326.0438 34.0268 13.04399384202568
MET-2/19
1 20670U 90057A 94010.36092796 .00000024 00000-0 79036-5 0 7558
2 20670 82.5461 333.8268 0014612 227.3560 132.6370 13.84186139178782
FY-1/2
1 20788U 90081A 94003.03844225 -.00000027 00000-0 10000-4 0 8621
2 20788 98.8453 28.3934 0015034 108.6050 249.2585 14.01339724170575
MET-2/20
1 20826U 90086A 94010.22431973 .00000087 00000-0 65344-4 0 7546
2 20826 82.5269 271.6566 0013720 125.9243 234.3192 13.83570021165910
MET-3/4
1 21232U 91030A 94010.23936452 .00000050 00000-0 10000-3 0 6627
2 21232 82.5496 281.2627 0011829 219.1707 140.8560 13.16459166130574
NOAA-12
1 21263U 91 32 A 94010.55261609 .00000178 00000-0 88514-4 0 8341
2 21263 98.6367 41.6836 0012890 338.0944 21.9680 14.22355318138129
MET-3/5
1 21655U 91056A 94010.09455474 .00000051 00000-0 10000-3 0 6584
2 21655 82.5580 228.3870 0012144 230.2532 129.7521 13.16826852115655
MET-2/21
1 22782U 93055A 94010.28911561 .00000060 00000-0 41889-4 0 2544
2 22782 82.5489 331.5590 0021925 312.2133 47.7166 13.82996559 18264
MIR
1 16609U 86017A 94013.23246154 .00007501 00000-0 98220-4 0 931
2 16609 51.6178 244.1498 0005389 191.8997 168.1855 15.59710416451871
HUBBLE
1 20580U 90037B 94012.60564155 .00000841 00000-0 69070-4 0 4277
2 20580 28.4679 155.2431 0006043 261.7035 98.2865 14.90421224 6150
GRO
1 21225U 91027B 94011.88639997 .00004606 00000-0 10634-3 0 540
2 21225 28.4618 236.3958 0003410 244.2475 115.7767 15.39803980 32819
UARS
1 21701U 91063B 94011.32398713 -.00003119 00000-0 -25223-3 0 4629
2 21701 56.9840 67.6091 0005313 102.6819 257.3568 14.96361954127456
POSAT
1 22829U 93061G 94010.23145061 .00000090 00000-0 54208-4 0 2465
2 22829 98.6671 87.5394 0009751 303.3262 56.6985 14.27996332 15156
/EX
------------------------------
Date: 14 Jan 94 18:47:24 GMT
From: ogicse!henson!henson.cc.wwu.edu!n8117105@network.ucsd.edu
Subject: Packet to Internet
To: info-hams@ucsd.edu
My dad would like to be able to packet to Internet but has no access in any
way at all as yet. Would some sympathetic Ham out there packet to him with
infor about packeting? I am very new to this and am trying to search out
help for him....hope this is okay to do it here. His call is
KN6WB and his name is Frank Phillips, Redding, CA
phone: (916)241-4403.
He is very eager to do this and would really appreciate a call.
Thanks, Judy
------------------------------
Date: Thu, 13 Jan 94 17:35:49 GMT
From: tijc02!eri316@uunet.uu.net
Subject: Portable 2m Antenna for Mountaineering???
To: info-hams@ucsd.edu
> I am an avid climber/backpacker etc and want to be able to use my HT in
> the backcountry. I require a design for an antenna (with better gain
> than my rubber duck) that is light, easily packable, and not too bulky,
> which will allow me to work repeaters in the 2m band. In case it
> matters, most (but not all) of the use will be from mountain tops.
>
Well I'm not so avid, but I'd like to be. Make the roll-up J-pole.
Around here, the mountain tops are where the repeaters ARE, so I
look for a better signal from the bottom of the Gorge.
Hey maybe you could load up a variety of wired nuts and see if any
might present a match???
--Ed
------------------------------
Date: Sat, 15 Jan 1994 04:30:38 GMT
From: dog.ee.lbl.gov!agate!iat.holonet.net!bwilkins@network.ucsd.edu
Subject: Repeater database?
To: info-hams@ucsd.edu
jmaynard@nyx10.cs.du.edu (Jay Maynard) writes after my editing:
: In article <2h6lmf$qk4@inxs.concert.net>,
: W. M Wood -- The Signal Group <mikewood@rock.concert.net> wrote after my
editing:
:
: The simplest way to stay out of trouble is to follow the rules. Period. No
: politics, no favoritism, no under-the-table deals. The last thing I want is
: trouble, so I do all of those.
:
: >I do contour studies professionally as a communications system engineer..so
: >yes I DO KNOW what is involved in doing a proper study. I also
: >know that a decent one can be done in an hour or so with out
: >a computer..just radial lines in a topo map. If you are just
: >drawing 85 mile radius circles on a map you aren't really
: >coordinating ...you are just OFFICIATING. If a job is worth
: >doing it should be done right.
OK lets bring this out in the open. Where are you going to draw the line?
Is your contour 39 db 45 db or 115 db as most amateurs would like to see.
Does this line measure the transmitter or the receiver? Does your
propagation model take into consideration diffraction and normal ducting
conditions?
In California the applicant for coordination conducts the engineering
studies or field trials on the air. The applicant must satisfy the
coordinated stations. The coordinators monitor the test phase often making
technical recommendations. There are test pairs or shared non protected
channels to conduct these tests to minimise interference to the
coordinated group working with them. Coordination is based on repeater
receiver coverage area in northern california. Many times the coordinated
trustee and the applicant agree that certain overlap ares can be shared.
Would you be willing to a close share with a paper engineered repeater on
your local repeater?
: Why not volunteer to do it, then? Or is it simply easier to bitch?
:
: >YOU are already the volunteer. Why aren't you doing ANY kind of study?
:
: The 85-mile rule was found to fit the conditions of Texas very well. There
: would not be any significant changes if we were to study repeaters
: individually, but a massive proliferation of work.
Remember the rest of the world is not flat :)
: >Now to the meat of the matter ....the INFORMATION I am referring
: >to is LAT/LON/HAAT/ERP for all the commercial stations mentioned.
: >This thread is about WHY LAT/LON/HAAT/ERP info is being
: >witheld by people/groups like you and yours. I am not asking
: >or suggesting that engineering studies be released. JUST
: >LAT/LON/HAAT/ERP.
This is not enough information to conduct a proper coverage contour for
any transmitter. Consider the 100 watt station operating into a
quarter-wave monopole with 100w erp will have a different coverage contour
than a 10 watt station operating into a 10 db collinear antenna. Both have
the same ERP. Each station will have different coverage models due to the
patterns of the antenna. This is most noticible in rolling or mountainous
terrain. Sorry ... we are in the real world out here not a laboratory.
: As I've said: we got the information in confidence. The trustees would simply
: not give it to us if we were to pass it out to every Tom, Dick, and Harry who
: asked. We would be violating our confidence to release it. Do you break
: promises and expect to have folks trust you again? This is exactly the issue
: here.
Remember we are dealing with amateur radio service repeaters not common
carriers that have different reporting requirements.
: Besides, you WERE demanding the engineering studies:
:
: >>>I dare ANY so called coordinating group to prove me wrong by PUBLISHING
: >>>there engineering studies for all their "coordinated" repeaters.
:
: >If you are just drawing 85 mi. radius circles THEY DON'T EXIST TO
: >ANY DEGREE.....
:
: By your standards, maybe not. The process happens to work, though, even
: without your mountain of paperwork.
:
: >Well the hard cold reality is coordinating groups do not want
: >to publish this information because they cannot justify the
: >ARBITRARY AND POLITICAL manner in which they pass out frequencies
: >if the FACTS are publicly available.
The facts are available to any amateur with a mobile transiever. Do your
study and field check your model using a simplex frequency or a test or
snp pair. One should easily find the edge of any coordinated repeater as it
relates to your proposal. Read your coordinating councils policy and
procedures for coordination. Talk to other trustees. There are vary few
secrets as radio waves seem to be consistant.
: >A final note : Until the FCC requires CTCSS (or similar) instead
: >of carrier squelch on Amateur repeaters, this debate will
: >continue forever. Carrier squelch repeaters are archaic and
: >the root cause of many repeater interference problems.
: >CTCSS is cheaper than DTMF to install/build in radios.
: >Alternatively the ARRL and coordinators should make this
: >part of the coordination scheme. Since there are no technical
: >regulations regarding coordination it could be done.
: >Again the problem is POLITICAL . EXISTING coordinated
: >repeater owners and users don't want to be burdened
: >by CTCSS on their repeaters and mobiles.....unless
: >it's to keep out "strangers".
:
: PL is something that the majority of hams could use today; nearly every radio
: built in the last 10 years has a PL encoder built in. You're right in that
: it's a political problem, but I don't see the problem you think it's a panacea
: for. In particular, PL will not allow stacking repeaters closer together; that
: would cause interference that most users, never mind trustees, would find
: unacceptable.
:
: It has been suggested that PL be a mandatory part of the coordination process
: in Texas. The proposal was soundly defeated by the Society's membership. We
: can't impose that requirement unilaterally, much as we can't impose other
: things unilaterally. It's called "being responsive to the membership". Just in
: case you've missed my mentioning it in other messages, membership is open to
: any licensed amateur radio operator.
: --
: Jay Maynard, EMT-P, K5ZC, PP-ASEL | Never ascribe to malice that which can
: jmaynard@oac.hsc.uth.tmc.edu | adequately be explained by stupidity.
: "A good flame is fuel to warm the soul." -- Karl Denninger
In northern california the coordinators requested all new repeaters use
ctcss as a way of mitigating interference. This was almost universally
done on 440. The 2meter coordinator finally brought the issue to the
membership where a majority of voters made it a standard. Once users found
out that ctcss was acceptable they demanded the repeater trustees install
it in the repeater. No one wants to monitor a carrier squelch repeater
thrashing all evening. The days of a high mountain carrier access repeater
are over. Many 2meter repeaters have taken on new life...they are a
pleasure to monitor as you only hear the intended transmissions not some
flying pager or distant amateur on an other repeater. Ctcss has enhanced
the repeater and brought it back to life not closing or making it private.
Bob
--
Bob Wilkins n6fri voice 440.250+ 100pl san francisco bay area
bwilkins@cave.org packet n6fri @ n6eeg.#nocal.ca.usa.na
------------------------------
Date: Thu, 13 Jan 94 18:00:54 GMT
From: tijc02!eri316@uunet.uu.net
Subject: Repeater Interference
To: info-hams@ucsd.edu
Recently ran across a instance which I'll share:
We've been suffering local repeater interference on a number of machines
with inputs from 146.10 thru 146.4. I hooked up my trusty Poor Man's
Spectrum Analyzer to my beam and found that sometimes when one of our
local machines UNkeyed, up would pop a blip on that frequency which then
drifted down the band. Sometimes a leisurely drift, sometimes an eye-popping
zip.
Ideas? Repeaters, cavities, circulators, 500W pagers next door?
--Ed
------------------------------
Date: Fri, 14 Jan 1994 23:52:07 GMT
From: netcomsv!netcom.com!wy1z@decwrl.dec.com
Subject: WANTED: Mods for ALL radios
To: info-hams@ucsd.edu
I want to compile as complete a library of mods for every shortwave radio,
ham radio, and scanner.
Once collected, they will each be placed into their respective locations
according to manufacturer in the ham radio FTP area on world.std.com.
Any pointers to FTP, FSP, mailserver, World Wide Web, and Gopher
sites, as well as whatever else you can offer would be greatly
appreciated!
Thanks much!
Scott
--
===============================================================================
| Scott Ehrlich Internet: wy1z@neu.edu BITNET: wy1z@NUHUB |
| Amateur Radio: wy1z AX.25: wy1z@k1ugm.ma.usa.na |
|-----------------------------------------------------------------------------|
| Maintainer of the Boston Amateur Radio Club hamradio FTP area on |
| the World - world.std.com pub/hamradio |
===============================================================================
------------------------------
Date: Thu, 13 Jan 1994 16:22:17 GMT
From: netcomsv!netcom.com!btoback@decwrl.dec.com
Subject: why 29.94 fps?
To: info-hams@ucsd.edu
In article <2gs9mk$gd6@aurns1.aur.alcatel.com> powers@aur.alcatel.com writes:
>This requires a good ovenized oscillator(that isn't cheap). Rubidium Oscillators
>go for about $20,000 I think. Cesium Beam clocks are > $200,000.
^^^^^^^ ^^^^^^^^^
>The clocks that NIST uses are the best in the world. They have about 10 of them
>that are all averaged together.
>
>WWV, however loses a lot in its method of transmission and to propagation effects.
>Received accuracy (if you have a stable enough PLL to track it without further
>loss of accuracy) is about 1E-7 (0.1ppm) frequency accuracy and 1ms for timing.
>Even to keep this accuracy would cost you at least $1000. Stratum 3 oscillators used in non-central office telephone equipment are 4.7ppm and cost at least $2000.
The Hewlett-Packard Cesium Beam Standard is US$46,000, plus $5,000 for the
clock display and standby battery (sheesh) and $8,500 for the high-performance
cesium beam tube (improves accuracy from +/- 3E-12 to +/- 2E-12, and
improves short-term stability). I know this because, as a sufferer from
compulsive time fetishism, it's on my shopping list for when I win the
lottery. The 20ms accuracy of my Heathkit clock is OK for now, but I'd
much rather KNOW what time it is than have WWV TELL me what time it is.
Their rubidium standard is US$42,000, plus about $10,000 in accessories that
I couldn't live without. Its short-term stability is about 10 times better
than the cesium beam standard (5e-13 over 100s, as opposed to 5e-12 over 1s).
It's just the thing for netting parties, so maybe this could be a club
purchase.
Just for comparison, they also have a quartz frequency standard for $9,500.
Its short-term stability is about two orders of magnitude worse than that
of the cesium beam standard, but of course its accuracy depends on the
standard with which it's calibrated.
The quartz standard also claims very high spectral purity, saying that
spectra less than 1 Hz wide can be obtained when the 5mHz output of the
standard is multiplied to 10 GHz. Perhaps that poor New York repeater
owner with the 243 MHz spur should consider one of these :-).
-- Bruce Toback
Internet: btoback@netcom.com
Packet: kn6mn@kc7y.az.usa.na
------------------------------
Date: 12 Jan 94 20:22:45 GMT
From: sgigate.sgi.com!sgiblab!uhog.mit.edu!xn.ll.mit.edu!ll.mit.edu!wjc@rutgers.rutgers.edu
To: info-hams@ucsd.edu
References <CJFF8p.56v@spk.hp.com>, <1994Jan11.144946.25480@brtph560.bnr.ca>, <1994Jan11.165851.23593@kodak.rdcs.kodak.com>e.edu
Subject : Re: BRAIN CANCER, LEUKEMIA FROM HAM RADIO
In article <1994Jan11.165851.23593@kodak.rdcs.kodak.com>, ornitz@kodak.rdcs.kodak.com (Barry x24904/ER/167B-TED) writes:
|>
|> ...stuff deleted...
|>
|> This is a common misconception and one that needs to be corrected,
|> especially in regard to a discussion on how radio waves interact with
|> living cells.
|>
|> The lowest resonant absorption frequency for water (rotational
|> spectra) is 22.235 GHz. Home microwave ovens in the United States
|> operate at 2.45 GHz.
|>
|> ...stuff deleted...
|>
I agree with Barry that the common microwave oven frequency of
2.45 GHz does not correspond to a resonance of the water molecule. I
also agree that the lowest resonance for water is around 22 GHz.
However, that resonance is exhibited by _gaseous water_.
So far as I know, neither liquid water nor ice exhibit any RF
rotational resonances, but I'm not certain.
By the way, the dielectric loss factor of pure, liquid water does
show a peak at about 1 GHz at 0 Celsius, moving up to about 10 GHz at
+20 Celsius. Sea water shows a rather constant loss factor over
that frequency range (pretty much the same at 0 and +20 Celsius),
increasing at lower frequencies and falling at higher frequencies.
These are my recollections from data presented in an appendix to
Volume 3 of _Microwave Remote Sensing_ by Ulaby et. al.
73
Bill Chiarchiaro N1CPK
wjc@ll.mit.edu
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End of Info-Hams Digest V94 #38
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