QRZ! Ham Radio 4/QRZ Ham Radio Callsign Database - Volume 4.iso/digests/homebrew/940119.txt

Internet Message Format | 1994-11-13 | 14KB

Date: Thu,  5 May 94 04:30:22 PDT
From: Ham-Homebrew Mailing List and Newsgroup <[e-mail]>
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Reply-To: [e-mail]
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Subject: Ham-Homebrew Digest V94 #119
To: Ham-Homebrew


Ham-Homebrew Digest         Thu,  5 May 94       Volume 94 : Issue  119

Today's Topics:
                     *<NE 5534 PINOUT DIAGRAMS>*
       Anyone interested in talking about frequency standards?
               FTP site with 16,000 CIRCUIT references
                    Help with Homemade Capacitors
                      Please report from DAYTON
                      Screen Supply for 4cx250B
      SEARCHING FOR LOW POWER FM TRANSMITTER for BROADCAST BAND
                   Vertical yagi mounting (2 msgs)
                      Yagi detuning due to mast

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Problems you can't solve otherwise to [e-mail].

Archives of past issues of the Ham-Homebrew Digest are available
(by FTP only) from UCSD.Edu in directory "mailarchives/ham-homebrew".

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: 3 May 1994 21:09:06 -0400
From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!howland.reston.ans.net!europa.eng.gtefsd.com!news.ans.net!hp81.prod.aol.net!search01.news.aol.com![e-mail]
Subject: *<NE 5534 PINOUT DIAGRAMS>*
To: [e-mail]

Does anyone have the pinout diagram for the NE 5534 op amp??  Operating voltage
and other specs would be nice, but I really need the pin diagram.

Thank you!


73 de JimN0OCT

ENTROPY AINT WHAT IT USED TO BE!

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Date: Tue, 3 May 1994 14:08:37 GMT
From: ncrgw2.ncr.com!ncrhub2!ranger!cn292.DaytonOH.NCR.COM![e-mail]
Subject: Anyone interested in talking about frequency standards?
To: [e-mail]

Howdy --

I've been interested for a while in time and frequency measurement, and have
been collecting bits and pieces of equipment.

At the Hamvention last weekend, I finally found my dream:  a rubidium
standard.  It's a little Efraton thing (part number 100323-101 for what that's
worth) and it seems to work.

But one problem is that it only has a single 10MHz output, and my other
equipment all wants either 1MHz or 100kHz inputs.  So, I need to design some
divider and distribution stuff -- and I'm clueless about how to minimize phase
shift and jitter, and how pure a sinewave output I need to shoot for (or will
my other equipment be happy with squarewave input?).

To get to the point, I'd be interested in corresponding with anyone out
there who's knowledgeable about frequency standard/measurement systems, so I
can get this thing lashed up properly.

Thanks...

John Ackermann   AG9V
[e-mail]

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Date: 3 May 1994 16:19:44 GMT
From: ihnp4.ucsd.edu!swrinde!cs.utexas.edu!news.tamu.edu!cs.tamu.edu![e-mail]
Subject: FTP site with 16,000 CIRCUIT references
To: [e-mail]

[Description of very neat archive of circuits deleted]

Man, if you could put in a WWW server, and GIF up the circuits, that would
be a DYNAMITE thaing to have!!!!

73/Kurt
--
Kurt Freiberger, wb5bbw      [e-mail]   409/847-8607  fax:[phone]
Dept. of Computer Science, Texas A&M University      DoD #264: BMW R80/7 pilot
     "Even MY hypocrisy has its limits." - "Doc" Holliday, in Tombstone
          *** Not an official document of Texas A&M University ***

------------------------------

Date: 4 May 94 22:49:04 GMT
From: dog.ee.lbl.gov!ihnp4.ucsd.edu!sdd.hp.com!hp-pcd!hpcvsnz![e-mail]
Subject: Help with Homemade Capacitors
To: [e-mail]

Bart Rowlett ([e-mail]) wrote:

: er = dielectric constant of dielectric relative to free space.
:      Somewhere around 2.0 for glass as I recall.

Fused quartz is 3.78; I believe any glass will be higher than
that.  Most I've seen has been in the 4.5 to 8 range, and
different types of glass really do have rather different er's.
Also, not all glass is low loss...

------------------------------

Date: Tue, 3 May 1994 14:27:49 GMT
From: ihnp4.ucsd.edu!usc!elroy.jpl.nasa.gov!ncar!uchinews!kimbark![e-mail]
Subject: Please report from DAYTON
To: [e-mail]

Anyone attending DAYTON Hamvention care to SUMMARIZE
QRP developments for the homebrew group ?

TNX,
Ken N9VV

------------------------------

Date: 4 May 94 13:43:15 GMT
From: [e-mail]
Subject: Screen Supply for 4cx250B
To: [e-mail]

It is important to get the screen supply right. It needs to be between 250
and 350V depending on class of operation, 330V is good for SSB. Grid needs
to be -100 or more for cut off and about -50 during operation. Standing
current in linear mode is 100mA. I know that is 200W dissipation at 2Kv on
the anode but those are the specifications for a clean signal. The screen
supply must be very stable and capable of sourcing or sinking 30mA. When I
say stable I mean to a few 10s of mV with speech, not long term drift. It
needs to be an active shunt regulator, definately not a string of zener
diodes! There are some good designs in the VHF/UHF DX Book. If you are not
interested in a clean signal and only want to run in calss C, set the
screen at 250V with zeners, bias current to a few mA with the grid at -60V
or so and you will get 400W from a single valve. It won't be linear but it
wouldn't be in class C would it?


Mike

------------------------------

Date: 4 May 94 15:38:50 GMT
From: dog.ee.lbl.gov!agate!howland.reston.ans.net!wupost!crcnis1.unl.edu![e-mail]
Subject: SEARCHING FOR LOW POWER FM TRANSMITTER for BROADCAST BAND
To: [e-mail]

----------------------------------------------------------------------
This is the circuit for a simple FM wireless microphone, published in
the 1990 Radio Electronics "Electronics Experimenters Handbook", pp.
155-157.  It's simple and handy to have - pretty much the same as the
"Mr. Microphone" they sell (or used to) at Radio Shack.  Range of maybe
100 feet, on standard broadcast FM receivers.

___    ______________________________________________________________
\|/   ___     )       |       |      |           |        |         |
 |    ---     )       R      ___     R           R        |       -----
 |_||__| C10  ) L1    4      --- C3  5           7        |        ---
   ||  |      )       |       |      |           |       ___ C6  ----- B1
   C1  -------          |       |      |           |       ---        ---  9VDC
       |_____          |       |  C9  __R6__       ----     |         |
       |     \    Q1    |       |      |       |       |   |    |         |
       |      \|______|_______|__|(__| Q2  |       R   |    |         |
      ___     /|      |       |  |(  \       |  C5   8   |    |         |
C2    ---    / BF199  |       |       \|___|__|(___|  _+_   |         |
       |____V          R       |       /|      |(   |  ---   |         o
       |          2      ___     / BC183C       |   | C7 |      \
       |          |  C4  ---    V           |   |    |       \  S1
       R          |       |     |_______  MIC / \  |    |        \
       1          |       |     |       |      \_/  |    |         O
       |          |       |     R      _+_       |   |    |         |
       |          |       |     3      ---  C8  |   |    |         |
       |          |       |     |       |       |   |    |         |
       ---------------------------------------------------------------

R1 = 100 ohms        C1 = 1.5 pf cer. disc        Q1 = BF199, NTE 229,
R2, R4 = 10K ohms    C2 = 100 pF, NPO             ECG 229 or eq.
R3 = 1K ohms        C3, C4 = 330 pF NPO        Q2 = BC183C, NTE199
R5, R7 = 47K ohms    C5, C9 = .1 uF NPO             ECG 123AP or eq.
R8 = 4.7K ohms        C6 = .001 uF NPO        L1 = approx. 1 uH
M1 = electret mike    C7 = 22 uF electrolytic     S1 = SPST switch
B1 = 9V battery     C8 = 6.8 uF electrolytic
C10 = 10 - 40 pF trimmer capacitor.

The coil L1 is so small that in the PC board version of this, it's just a coil
etched on the board with traces.  I think I breadboarded it with about four or
five turns of bell wire around a pencil and that made about the right value.
You tune the sucker with the adjustable cap C10.  If I remember, the
transistors are garden variety ones, though I think Q1 was reasonably high
frequency.  I was feeding in a signal other than an electret microphone.
This is neat to use with a cheapo FM walkman-type radio for cheap telemetry.
(We were actually going to build a device to transmit strain gauge signals
from someone's teeth over a whole day's time, and it was to be small enough
to be relatively unnoticed INSIDE THEIR MOUTH the whole time.  Never did
get the O.K. to proceed with that one.    Working for university research
gets pretty strange sometimes.)

Paul Marxhausen  University of Nebraska - Lincoln
         Engineering Electronics Shop

------------------------------

Date: Wed, 4 May 1994 04:59:17 GMT
From: ihnp4.ucsd.edu!library.ucla.edu!csulb.edu!csus.edu!netcom.com![e-mail]
Subject: Vertical yagi mounting
To: [e-mail]

In article <[e-mail]> [e-mail] (John Boyer) writes:
>
>So I guess the answer is don't use a metal pole with a vetical yagi.
>
My father used a wooden pole to mount a vertical yagi, but I pointed
out "what about the coax running up the wooden pole to get the radio
connected to the antenna?".  He figured that, yes, it will have some
effect, but the coax being smaller than a metal mast, would not be
as bad.  Don't really know.  Would it help if we used ferrite beads
on the coax spaced something like one every 1/6 th of a wavelength
(or some such smaller than 1/4 wavelength) to be nonresonant?  Idea
is to "break" up the coax into many short pieces to RF on the outside,
so it looks like non-significant short pieces of wire.  ?

------------------------------

Date: Wed, 04 May 94 13:57:37 EDT
From: ihnp4.ucsd.edu!swrinde!cs.utexas.edu!howland.reston.ans.net!usenet.ins.cwru.edu!ns.mcs.kent.edu!kira.cc.uakron.edu!malgudi.oar.net!hypnos!voxbox![e-mail]
Subject: Vertical yagi mounting
To: [e-mail]

[e-mail] (Robert Casey) writes:

> In article <[e-mail]> [e-mail] (John Boyer) writes:
> >
> >So I guess the answer is don't use a metal pole with a vetical yagi.
> >
> My father used a wooden pole to mount a vertical yagi, but I pointed
> out "what about the coax running up the wooden pole to get the radio
> connected to the antenna?".

Why not make the radiator a co-axial sleeve antenna and rotate
directors amd reflectors around it?


/----------------------------------------------------------------------\
| Jim Grubs, W8GRT            Voxbox Enterprises    Tel.: [phone] |
| [e-mail]   6817 Maplewood Ave.                      |
| Fido: 1:234/1.0             Sylvania, Ohio 43560                     |
\-+--------------------------------------------------------------------/

------------------------------

Date: Wed, 4 May 1994 17:58:07 GMT
From: newsgate.melpar.esys.com!melpar![e-mail]
Subject: Yagi detuning due to mast
To: [e-mail]

     This repost replaces "Vertical yagi mounting" and "Adjust-
ing vertical polarization of yagi" posts.

POSTED REPLY:

of RG213). The bottom line is the SWR went way up (over 2:1) within
10 degrees of true vertical, and we settled on about 20 degrees off
vertical (favoring the orientation that improved drainage away from
the balun box) which minimized SWR (not the absolute minimum, but
I accepted a 1.3:1 as OK).

COMMENT:

     Thanks for the info.  BTW, the reduction in gain at 20 degrees
slant relative to vertical is about 0.5 dB; i.e., your yagi has
about a half-dB less gain when you're "looking" at a vertically
polarized signal than it would if it was exactly vertical.  FYI,
45 degree slant linear polarization reduces the gain 3 dB for
either vertically or horizontally-polarized signals.

POSTED REPLY:

I did not measure "directivity" or any other factor in the
straight-vertical orientation, because the higher SWR was disabling
my brick at the bottom of the tower.

COMMENT:

     Well, it looks like no one really has; I feel an experiment
coming on.....

POSTED REPLY:

I've installed a Yagi vertically mounted on a metal mast and I
experienced detuning. I couldn't tell you how the radiation pattern
was affected since at the time I had no way of determining that -
but since I was operating on 2m, I installed a horizontal
counterbalanced boom and remounted the antenna a few feet away from
the mast.  That seemed to help a good deal, although there was
still a little bit of detuning remaining.

COMMENT:

     An interesting variant on overcoming the problem.  In both of
the cases noted, the amateurs involved measured the VSWR and tried
to find a way to reduce it, which is a good approach if pattern
variation is ignored.  I'll wager, however, that there are quite a
few hams using transceivers WITHOUT any automatic VSWR shutdown
who are also using vertical yagis with metal masts and have NO IDEA
that the VSWR is excessive.  Probably won't hurt the rig, but for
any significnt amount of coax they're probably wasting a lot of
power as heat in the feedline.

     I will probably set up an experiment with some locals and try
to map out performance in terms of directive pattern skewing and
VSWR as functions of slant angle.  I'll repost when I have some data
 to report.  Thanks for the replies!

(|_|)  * Paul H. Bock, Jr. K4MSG  * Internet: [e-mail]
 | |)  * Senior Systems Engineer  * Telephone: [phone] x2062

   "You can have my bug when you can pry my cold, dead fingers from
    around it....." - anonymous radiotelegraph operator

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End of Ham-Homebrew Digest V94 #119
******************************