QRM
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R
ART
Bulletin issued by the Northern P.O. Box 1010
Branches of the Wireless Institute Launceston
of Australia, Tasmanian Division. Tas. 7250
February 1978
Vol.7 No.9
Registered for posting
as a Publication Price 40¢
Category B.
MEETINGS
Feb. 10 Northern Branch, clubrooms 34 Burke St. 8 p.m.
Feb. 14 North West Branch, Lakins Hall, Ulverstone 8 p.m.
CONTESTS
; Feb. 4 - 12 ARRL Novice Contest
Feb. 11 - 12 John Moyle Memorial National Field Day
Feb. 11 - 12 Ten-Ten QSO Party
Feb. 11 - 12 OCWA QSO Party
Feb. 18 -~ 19 ARRL DX CW Contest
Feb. 18 - 19 YL _ OM Phone Contest
Feb. 25 - 26 French Phone Contest »
Feb. 25 - 26 THE ATHOL JOHNSON MEMORIAL CONTEST
Feb. 18 Deadline for the March issue of QORM
Page 2 QRM February 1978
Northern Branch Notes by Mac VK7CCC.
Greetings- So much has happened since the last
notes appeared that it is difficult to remember all thats
happened- However here goes.
At the November meeting members were advised that
of the club funds $1500 had been placed in an investment
account and the balance in a chequeing account. Some of this
money w: 11 be used to purchase items for the club rooms.
To date we have aquired 30 new chairs, wood for shelving
and we «re about to acquire an electric urn.
Donations are flowing into the club in the form of
books, :tems for the eventual museum and latest, a 6 metre
rig donated by VK7ED., Thanks Ed . At the present time the
radio journals are being catalogued, if you have occasion
to use :hem please put them back in order.
Due to pressure of work Peter VK7PD has had to
stand down as treasurer, his place has been taken by Tony
VK7TP, . dont know where you get all the time and effort
Tony .
The Northern members for the Amateur Advisory
Committee are VK7JV and VK7BC both John and Frank therefore
will also be the official observers for this area.
The pig roast in December went well, as did a
few of -‘he members. I'm sure Brian Eyre would fall down
if he d..dn't have his glass to support him ! Everyone
enjoyed it, some even stayed the night. David Chadderton
has som: slides available if anyone requires prints of the
days ef:iort. A good few items were left over from the
auction. these items will be available shortly at one of
the mee:ings.
REMEMBER that very shortly a new committee will
be required. It requires new faces for new ideas, without
an active committee a club can become dormant. Think about
it, if you can improve on the last lot, the club needs you.
For those of you who are not sure what to do, but would
like a job the present member will draw up a"duty statement"
listing duties, contacts etc.. Put forward names if there
is someone you think can do the job.
"Mini-Hamfest", The North West group are again
challenqging for the trophy and the tentative date is
March 1l.'th, place to be decided, keep your eye on this spot.
Thats all for now
73 Mac VK7CCC
FOR_SALE
Europa B transverter, mint condition, all modes.
Plugs in to Yaesu series, 28MHz I.F., 2 metres out $180
FM transceiver Trio 7200G, R1l, 2, ch40, 50 and other
dozen assorted plus 50 Watt amplifier $170
Contact Mac VK7CCC
February 1978 QR M Page 3
DX notes by Col VKTLZ.
Once again its back to work, although the last
notes ware written in November to write about DX during the
preceeding two months would be less than useless and as we
connot predict the future we'll just have to concentrate on
the present.
Listening on the bands over the last couple of
weeks gives the impression that 28MHz is now a band to watch
very closely, signals can be heard almost every day and
althougnh its mostly only JA's or W's 28MHz has always been
a band to produce the unexpected so its well worth checking.
On 21MHz the same pattern exists although the
range cf stations is somewhat wider with the odd station
from Africa and Europe being logged.
For those looking for new countries 14MHz is
still tne band warranting the most attention and VK7's
AE, BC and HL have been constantly adding to their DXCC
tally o1 this band. Over the last few days of limited
listeniag during our evenings 40 countries have been logged
and all seven continents. VK7BC recently copied ZS7SD,
H5FXT aad an S8 on 14MHz SSB at 2100Z however the W's were
too strong and no QSO's resulted. 9N33 was another unusual
call sign, this station was celebrating the 33rd birthday
of the King. Conditions to Central America are at present
quite good during our evenings and several of the rarer
Caribbean area stations are constantly appearing on 14MHz
SSB, from around 1100Z stations from AP, VU, EP, 9K, 45,
VS6 and USSR countries can be heard and QSO'ed with
European stations also showing up but with rather less
signal strength.
No listening and few reports have been received
about conditions on 7 or 14MHz however VK7AE has been
working W's on 3.5MHz SSB and QSO'ed a YB@ at 1400%.
Now to what we may be able to QSO in the next
few weeks; HF@POL is expected to commence operating from
King George Island any time now (if he hasn't already
done so) this counts as the South Shetland Islands for DXCC
the operator will be SP2BHZ, QSL to SP2BEBD.
VU4RES Laccadive Islands should be a good one
for many, the team will be headed by VU2TN and operation
is due to commence in the latter half of February.
A35TV is a new licensed operator in Tonga and is
restricted to 3.5MHz, guess this will be a CW only job.
OSL INFO
CN8CX - via - WB@PMSZ KM6FC/KH6 - via - W5RU
FKBCR 2.0. Box 544 Noumea, New Caledonia
J3AG Box 27 St.George, Grenada B.W.I.
KC6DA 30x 358 Ponape, East Caroline Islands
KZ5UH 3ox 44 Fort Davis, Canal Zone
VP2LDJ Box 335 St.Lucia, B.W.I.
WABOHZ/7Q9 - wvia -~ K5HWO
ZD7PV 30ox 8 St.Helena Island via Cape Town
9J2JN ?2.0. Box 222 Lusaka, Zambia
Page 4 QRM February 1978
VHF notes by Joe VK7JG.
Quite a lot has happened since writing the VHF
notes for the December QRM. Openings have been to numerous
to mention although activity was not as high as last year.
On 6 metres a lot of new call signs were worked
and a large number of IC502's, 3 Watt SSB units were being
used. VKINI was active but not worked from VK7.
On December 3rd there was a very good opening
to JA lasting about 3 hours, I came home late and worked
9 statiois in an hour.
All Australian States have been worked although
most opeiings were to VK2, 4 and 5.
Two metres has been good with many openings to
VK3 and 5. On most contacts with VK32QV, Mike who is as
strong as a local, 432MHz contacts were also made.
On January 2nd when 6 metres was wide open to
VK2, Ker-y VK2BXT was worked on 2 metres by myself running
10 Watts, Daniel VK7DA and Kevin VK7ZAH. The opening lasted
10 minut=2s and at times signals were up to strength 7.
At about the same time John VK4ZWB in Dalby was hearing
weak SSB signals on 144.1MHz but was unable to identify
them.
Dont forget the Athol Johnson contest to be
held in february, also the John Moyle National Field Day,
both shoild provide plenty of VHF activity.
73 Joe VK7JG
When Col Perger VK@JV/VK7KW, the Million Dollar Man and
reluctart hero of the four Nation emergency hook-up, was
in the Frincess Margaret Hospital in Christchurchunndergoing
surgery, his wife Doreen was informed of the fact by Amateur
Radio scme time before being officially notified by the
Australian authorities, in fact Doreen knew of it whilst
the emergency operation was still in progress, she was
again brought up to date on his condition when the operation
was comgleted. Guess we must be catching up on the C.B.
boys for efficiency.
FOR SALE
Yaesu F1220, 2 metre multi mode 20 Watt transceiver
with repeater xtals fitted. $350
SE501, 27MHz 23 channel transceiver modified for use as
a driver for a 2 metre transverter, matching xtals to
cover 144.000 to 144.250MHz and 145.9 to 146MHz for
Oscar use. $120
contact Joe VK7JG, phone 443882 or P.O. Box 1311 L.ton
February ..978 QR M Page 5
THE ATHCL JOHNSON MEMORIAL CONTEST
Following the poor support we received when holding the
Athol Johnson Memorial contest in cor junction with the R.D.
contest, it has been decided to hold the contest early in
the year.
The contest will be held from 1800 local time 25th February
to 1800 26th February.
Object, To promote VHF activity in VK7
Rules;
1) Ther is only one section, transmitting open.
2) All r odes may be used, cross mode contacts are allowed
but 1 ot cross band. except for satellite contacts.
3) Repe:ters may be used, but score 1 point per contact.
4) A sccring contact may be made every 2 frours.
5) Entrants must operate within the terms of their license.
Cyphers: Before points may be claimec for a contact, a 5 or
6 figure number must be exclanged, this will
consist of a R.S.(T). report plus three figures
to commence with 001 and to increase by one for
each succesive contact.
Scoring; 2 points for each QSO on each of the VHF bands
52 , 144, 432, 1296 and above.
Repeater contacts 1 point .
Cover sheet to show, call sign, name and address, details
of equipment, points claimed and a signed declaration that
all rules and regulations have been cbserved.
All logs to be sent to,
The VHF Officer
P.O. Box 1311
Launceston 7250
THE A.G.4. DINNER is to be held at tl= Kings Meadows Hotel
on Satur iay 18th March starting 8 p.n.
Cost of 1linner is $8.50 per head. Accomodation is available
at $17.C) double
No of pe-sons attending....ceeeeee. Call sign cieecaceanes
Accomodz zion required yes/no details ....... ceeeeeceenas
Please r 2turn the above to J Gelston, P.0O. Box 1311 Launceston
as soon is possible.
Page 6 QRM February 1978
MUTING FOR PORTABLE FM RECEIVERS by Wally VK7ZWX
There are quite a few transistor receivers
available which have FM bands covering for example,
76 - 90MHz, 88 - 108MHz, 108 - 136MHz, 108 - 174MHz etc.
Having obtained one of these receivers, I thought
it would make a useful monitor for 2-way services, amateur
or otherwise.
The following circuit will mute the audio output
of this type of receiver during no signal conditions, with
a minimum of parts (see fig. 3).
The first thing to do is to identify the FM
detector in the receiver and with a sensitive voltmeter
find the diode in the circuit which will provide a signal
sensitive voltage. Most receivers have a ratio detector
so a voltage which goes positive or negative with received
signal is readily available.
A typical detector circuit is shown in Fig.1l
and I used the negative voltage obtained at point A to
control the muting circuit, Fig. 3.
IN‘) [C)
AuDro
oUTPUT Tys Lass FM IFT
ffliuni /
Next, identify the emitter of the driver stage transistor
in the audio amplifier section of the receiver, point B in
Fig.2 below.’
The muting circuit, Fig.3, can then be connected
between these two points. Any audio NPN transistor will
work in the circuit.
The operation is simple. Under no signal condition
the 100K pot is adjusted to cut Q2 off. This occurs when
the voltage at point B exceeds - 0.5 Volt. As soon as a
signal is received, Point A goes negative which cuts Q1
off and the bias voltage at point B returns to normal,
restoring normal operation of the audio driver transistor
Q2. '
NOTE: Typical component values are shown in figures 1 and 2.
February 13878 QR M Page 7
- b Volr
e—
¢ e
Bc1o8
loe
i Qo
FOR SALE
DAIWA C166, HF antenna coupler, 500 Watts $90
18AVT, 5 band trap vertical antenna $85
Daniel Apted, 31 Vale St. phone 446886
EICO three band (80, 40, 20) transceiver, modified as per A.R.
in very good condition and going order, 5 new spare
valves included, ideal for transverter. $135
Tony Polowy, 42a Quarantine Rd.
pPage 8 ORM February 1978
Reprinted by kind permission from AMIDON ASSOCIATES TECHNICAL DATA.
IRON-POWDER and FERRITE TOROIDAL CORES
Materials
When selecti1ig a powdered core for a specific purpose it may be helpful to understand the basic differences
between the Iron Powder and the Ferrite materials. Although there are several classifications of powdered cores,
this paper shall t 2 concerned only with the Ferrite and Iron-Powder groups. Each group offers a number of
various sizes in different mixes and each mix will have slightly different characteristics in regard to permeability,
frequency range, saturation-flux-density, temperature co-efficient, etc., giving the design engineer a wide choice
in his selection of cores.
Iron-Power cores belong to the low permeability class ranging from a mu of 90 down to a mu of 3 or less,
making them an leal choice for high and very high frequency work. They will yield inductors with an excellent
‘Q’ factor and ex remely good stability over a wide range of temperatures, DC drives and flux levels. Iron-Powder
cores are not easily saturated and therefore are especially useful in RF tuned circuits, [.F. circuits and frequency
determining circuits where good stability is essential. They are also used in filter and noise circuits, Pi and ‘T’
networks, impedance matching transformers, tank circuits, wide band baluns, and etc. Cores of the No. 41 ma-
terial are low ‘Q’ (levices which are most commonly used for filter and noise circuits where high ‘Q’ is not required.
Ferrite mate ials are a combination of manganese, magnesium, coblat, nickel, iron and zinc oxides, and can
offer permeabilit: factors from below 100 mu to more than 10,000 mu. The higher permeability provides the ad-
vantage of achiev ng a relatively large inductance value with a minimum componet size. Also, they will have a
somewhat lower ¢ ituration point which can be used to advantage in applications requiring core saturation, such as
switching circuits counting circuits, memory circuits, inverters, converters, etc. Ferrites are also very useful for
shielding beads an | numerous mid and low frequency, non-saturable applications having low flux density.
All toroidal nductors are highly self-shielding since most of the flux lines are contained totally within the
toroidal form, thereby keeping the flux lines essentially uniform over the entire magnetic path. Stray magnetic
fields will have ve 'y little, if any, effect on a toroidal inductor. It is seldom necessary to enclose each RF circuit
in a little metal enclosure of its own to prevent feedback and cross-talk. Toroids simply do not talk to each other.
'‘Q-Factor
When designing for the best figure of merit (‘Q’), the fol- Typical curves resulting from various windings onthesamecore.
lowing suggestions a)ply: Use the entire periphery of the core
for winding and us¢ the largest wire size that is practicable,
space the turns if necessary. ‘Q’ is the inductive reactance
divided by the coppear resistance, so the wire or wires offering
the least resistance will yield the highest ‘Q’. It is sometimes
advantageous to use smaller wire sizes in a bifilar or trifilar
“ribbon”’ to create u low resistance-high ‘Q’ inductor. The ‘Q’
can be measured on 1 Boonton or Heathkit ‘Q” Meter. Relative
‘Q’ can be observed by noting the depth of the dip on a GDO
or Tunnel Dipper. Such readings are difficult on the smaller
toroids and the use of a simple temporary link between the
toroid and the GDO is suggested.
The ‘Q’ of a tunzd circuit is sometimes purposely reduced by bridging the circuit with a “‘swamping” resistor.
Inadvertant ‘Q’ reduction can result from swamping the toroid by incorporating it inte a low impedance circuit.
Use links, taps or secondaries to match impedance and thus protect the toroid ‘Q’. The toroid lends itself to
broadband RF transiormers that offer wide spectral excursion and good efficiency. These are made by winding
the primary and the secondary(s) bifilar or trifilar. This method is particularly effective in interstage work where
extra tuning controls are not wanted. The high ‘Q’ of the toroid and the convenience of the “slug tuned” coil
can be combined by connecting the two in series in a tuned circuit.
IRON-POWDER and FERRITE TOROIDAL CORES
POWER CAPABILITIES and SATURATION
There are several factors to be considered when calculating the power capabilities of a given size powdered toroidal core. Formulas
and charts for this calculation are shown below. Core dimensions and material specifications will be found on other pages of this flyer.
Chart ‘A’ will show maximum flux density limits for safe operating level of each material when used in a non-saturable application.
When a Ferrite core is being considered for an application requiring saturation of the core, the flux density should be sufficient to
drive the core well beyond the limits shown in the chart, see Hysteresis Loops for Ferrites elsewhere in flyer. Chart ‘B’ will show how
the permeability of various materials will increase as the flux density increases. If the flux density should increase beyond a certaimr
point, the permeability will start to decrease. This is also the point at which the core will begin to saturate. Chart ‘C’ will show how
the permeability of various materials will decrease as the applied magneto-motive force ( mmf) is increased.
AC Application: When AC is applied across a coil, use Faraday's Law to find the maximum AC flux dens ty (‘B’-Kilogauss). This
figure should not exceed the limit shown in chart ‘A’ for the material being used. If exceeded, the core being considered is to small
for use in a non-saturable application.
DC Applications: When DC is applied across a coil, use Ampere’s Law to find the DC magneto-motive force (mmf) (‘H’-Oersteds).
With the aid of chart ‘C’. determine the percent permeabilitv decrease for the material being used. If the initial permeability falls
below 80% of its original value, the core must be larger if being considered for a non-saturable application.
Both AC and DC: If a substantial amount of both AC and DC are being applied across a coil, Faraday’s Law and Ampere’s Law may
be re-arranged as shown below. Solve for maximum (total) flux density (‘B’-kilogauss). If this figure exceeds ‘he limit shown in chart
‘A’ for the material being used, a larger core should be considered if it is for a non-saturable application.
FARADAY'S LAW AMPERE'S LAW RE-ARRANGEMENT (both laws
)
Egpg 10 0.4 T N | Ems 10° lgc AL N
Byax = —————— H= @ —_— Brax (total) = St
_ 444 A, N f |e 444 A N T Ae 105
Where: B = flux density (kilogauss), H = magnetizing force (oersteds), AL = Mfr’s inductance index (uh/100 turns) E = volts (rms)
f = frequency (hertz), 1= current (amps), Ae = eff. cross-sectional area (cm)2, Il = eff. magnetic path leagth (cm), N = tums.
IMPORTANT: The A -value in the above formula is in uh/100 turns. This is standard for Iron-Power materials, however the A -value
for Ferrite materials is usually given in mh/1000 turns. Therefore, when working with Ferrite materials and the above formula a
conversion must be made. To convert mh/1000 turns to uh/100 turns, multiply by a factor of 10. For instznce, 50 mh/1000 turns
is the same as 500 uh/100 turns.
Chart 'A' Flux densi Chart 'C' Permeability vs, DC Etias
>
=
F
©
@
£=
D
Q
-
c
@
o
g
DC mmf. Oersteds
10 20 40 60 100
percent permeability
1
10 20
AC Flux Density —Kilogauss DC mmf. Qersteds
Rule-of-Thumb Estimate: For those who would like to make a quick estimate, and are willing to settle for an ‘in-the-ballpark’
figure, we offer the following suggestion: An Iron-Powder T-200-2 toroidal core will handle 1000 watts w' en used as an Antenna
Balun, or 100 watts when used in a properly tuned LC tank circuit. A core one half the size will handle on 7 about one quarter the
amount of power when used in similar circuits. Using this as a guide, power capabilities of other smaller Irc 1-Powder toroidal cores
can be estimated when used in like applications. This method of calculation should be used ONLY for Iron-Po 'der cores, not Ferrites.
Reminder 1: The power capability of a powdered toroidal core is related to the ability of that core to ¢ ssipate heat, therefore,
attention should be given to ventilation as well as core size and core area.
Reminder 2: To minimize the possibility of saturation on power peaks, we advise the use of the largest practical size core that
space and cost will permit.
Page 10 ORM February 1978
IRON POWDER TOROIDAL CORES
Physical dimensions
Quter inner Height Mean Outer inner Height Cross Mean
Diam. Diam. Length Diam. Biam, Sect Length
Core Area
(in.) (in.) (in.) cm Size (in.) (in.) (in.) cm? cm
2.000 1.250 550 1.330 1297 500 .303 .190 121 3.20
1.840 .950 710 2.040 11.12 T- 44 440 229 .159 .107 2.67
1.570 950 570 1.140 10.05 .375 .205 128 070 2.32
T-130 1.300 .780 437 930 8.29 .307 151 128 065 183
1.060 560 437 .706 647 255 120 096 042 1.50
942 560 312 .385 6.00 .200 .088 067 034 1.15
.795 495 .250 242 5.15 .160 078 060 016 0.75
690 .370 190 196 424 125 062 050 010 0.74
IRON POWDER TOROIDAL CORES Ay, VALUES (uh/100 turns) ALL STOCK ITEMS
3-Mix 12-Mix = 0-Mix
Grey Gn & Wh | Tan
CORE u=35 u=3 1 u=1
SIZE + |.05-.5MHz |.I- 10- 90 MHz |60- 150 MHz {100- 200 MHz 150 - 300 MHz
'r184 -| 1640 |
970
&40 120 M
NA
NA
— NA
T-157 -
NA 15,0 |
NA 19,2 |
T- 94 -- 32 10,6
T so = 22 5
21 7,5
18 4
NA 6.5
15 4,9
T- 30 -- 375 16 6,0
T- 25 -- 225 100 13 4,5
10
[T-16--| 130| 61 | NA | 8
TT-12--] 112| 60 | NA | 7.5
NA - Not available in that size. * See Magnetic Properties Chart, Turns = 100 Ydesired L (uh) =~A |,(a.bove)
Value
Add MIX number to CORE SIZE in space provided (--) for complete part number. All frequency fig ires optimum
NUMBER of TURNE vs. WIRKE SIZE and CORHE SIZHE
Approximate maximum number of turns — single layer wound — enamelled w-n
-“-x- 12 10 4 - ]
B 1-“"'""
— 5]
[ 14 | 54 | 32 [ 21 [ 21[ 18|
7|
13 | 8|
16 | 69 | a1 [ 28 | 28 | 24[ 17 | 13|
1 | —]]
| 18 | 88 | 53 | 37 | 37| 3| 23 [ 18| 10|
20 | 111 | 61 [ 41 | 47| 41| 20 | 23 | 14 | 1
[ 22 | 140 | 86 [ 60 [ 60| 53 [ 38 [ 30 | 19| |2|
[ 24 | 177 [ 109 T 7r [ 77| 61| 49 | 39| 25| 4 |
[ 26 | 223 | 187 [ ov | 97| 8 [ 63 | 50[ 33 |
| 28 | 281 | 173 [ 123 | 123 | 108| 80| 64 | 42 | 9
[ 30 | 355 | 217 | 154 [ 154 | 136| 101| 81 | 54 | 13
[ 32 | 43 | 272 | 194 | 194 -lfit_m
| 34 | 557 | 346 | 247 | 247 | 218 | 162| 132 | 88| 49 |23|
| 36 | 683 | 424 | 304 | 304 | 268 | 199 | 162 | 108 | 2 |30|
-_ln-mmmmm-m- 10 |39|
Actual number of tums may differ slightly according to winding technique, Chart prepared by Michael J. Gor.ion Jr. - WB9HFC
AMIDORN Associates -+ 12033 OTSEGO STREET - NORTH HOLLYWOOD, CALIF. 91607
(FORMERLY AMI-TRON ASSOCIATES)
IRON POWDER TOROIDAL CORES
WINDING DATA
The following data is intended as a guide to help in the selection of suitable toroi lal cores
for your application. Each core/winding combination is shown at near maximum Q.
L/100t Q Test- L/100t Q Test-
+5% Wire Turns L{mh) Freq. (KHz) Q *5% Wire Tums L{ub) Freq. (MHz) Q
70uh #16 25 47 5. 350
#20 20 3 6. 340
#20 35 8.7 3, 339
45uh #20 15 1.1 10. 255
#16 20 1.88 9. 317
#20 28 353 6. 299
47 uh #20 23 212 10. 304
#20 15 118 10. 270
#22 33 51 6. 305
248 uh 40 uh #18 14 36 14, 252
#22 25 2 50 10 260
#26 42 75 6. 244
30uh #20 12 18 18. 181
#22 17 37 14, 194
#26 28 245 10, 195
27 uh #24 10 30 21. 152
#28 20 110 15 164
#36 67 17 6. 138
19 uh #30 1 23 25. 92
#34 18 56 20. 920
#36 25 16 15. 96
34uh #16 10 41 20. 195
#18 15 83 15. 202
#26 30 9 10. 188
32uh #18 10 37 20. 156
#20 15 79 15. 172
#22 30 296 10. 176
31uh #20 10 37 25. 178
#20 15 81 18. 190
L/100t Q Test- #22 20 138 13. 188
+5% Wire Turns L{uh) Freq. (MHz) Q 25 uh #20 8 20 30. 138
: #22 15 61 20. 165
T-130-2 110uh 150/44 #26 25 154 15. 163
220/44 19 uh #22 7 12 45, 136
T-106-2 135uh 15/44 #24 9 18 35. 141
#24 12uh #28 7 06 60. 120
#20 #30 1 16 40. 101
#30 #32 14 26 35. 87
15/44
15/44 15uh #20 4 05 120. 142
#20 #20 6 09 80. 132
#26 13uh #22 6 07 120. 127
#34 #26 10 16 60 130
#20 #26 14 28 45, 130
#28 T-12:12 85uh #28 5 04 160. 113
#34 06 120. 134
#20 11 100. 100
#30 ee
#32
#20
USEFUL INDUCTANCE AND TURNS FORN ULA: L L,
#24
%26 The desired inductance or number of turns, singa —5— %
426 particular core, may be calculated with this f yrmula N1 N2
when the inductance per 100 turns is known.
#30
#36
#28 L1 = Known inductance per 100 turns N1 =100 turns
#32
#40 = Inductance (known or unknown N2 = Number of turns
(known or unknown)
"! ARMIDORI Associates - 12033 OTSEGO STREET + NORTH HOLLY\/OOD, CALIF. 91607
Page 12 QR M February'197é
PRICE LIST
IRON-POWDER TOROIDAL CORES SHIELDED COIL FORMS
T=-12- () (specify mix) $ 25 L-43-1
T-16=-( ) (specify mix) L-43-2
T-20- ( ) (specify mix) L-43-3
T-25-( )} (specify mix) L-43-6
T-30-( ) (specify mix) L-43-10
T-37-( ) (specify mix) L-43-12
T-44 - () (specify mix)
T-50- ( ) (specify mix)
T-68 - ( ) {specify mix) - AMI-CAL TRANSFERS (Electronic words) -
" T-80-( ) * (specify mix) “Ami-cal # 1 black - $ 3.50
T-94 - () (specify mix) Ami-cal # 1 . white _3.50
Ami-cal #2 black 3.50
T-106- ( ) (specify mix)
T-130- ( ) (specify mix) Ami-cal #2 white 3.50
T-157-( ) {specify mix)
T-184- ( ) (specify mix) KITS
T-200- ( ) {specify mix) E-Z Etch PC’K:r # 146
E-Z Etch PC Kit # 246
FERRITE TOROIDAL CORES Antenna BalunKit ( 1 Kw.
FT-23- ( ) (specify mix) " RF Toroid Kit
FT-37 - ( ) (specify mix) Filoment Choke Kit ( 10 # np.)
FT-50- ( ) (specify mix)
FT-82 - ( ) (specify mix)
FT-114- () (specify mix) KIT COMPONENTS
Ferrite Rod (4 -inch)
Ferrite Rod ~ (7 1/2 inch )
FERRITE POT CORES (77 mix
) E-Z Etch Circuit board (4 < 6)
PC - 1408 - 77 1.11
E-Z Etch Transfers { sef of 3)
PC - 2213-77 1.62
E-Z Etch Etchant (1/t Ib.)
PC - 2616 - 77 1.83
PC = 3019 - 77 2,34
WIRE: (Heavy ‘ML' msul:fed)
FERRITE SHIELDING BEADS AWG # 14 (per ft. ) $
FB- ( ) -101 (specify mix) $ 2.00/doz AWG # 12 (perft.)
FB- ( ) -801 (specify mix) 3.00/doz AWG * 11 (perft.)
FB- () =901 - (specify mix) 3.50/doz AWG
# 10 ( perft.) .
FB=- (. ) -2401 (specify mix) . 3.50/doz . WIRE:-(Magnet) Sizes 16 f‘tfiU 40
FB- () =5111 (specify mix) 3.25/doz 1/4 1b. Spools
MISCELLANEOQUS
88 mh. Choke $ .75 SPECIAL TOOLS
Glass - Electrical Tape (44' roll) 3,00 Burr Qwik . "
Q - Curve & Data Booklet 2.25 Unibit Drill
ORDER _FORM
Part No Quantity Item and description Price/ea. Total
Total amount for merchandise .........ccceeccecoccns $
Pack and Ship, Foreign - Airmail, (small packet) $ 1.50
Total S
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Iron Powder and Ferrite
TOROIDAL CORES
Wide selection - Large stock
Fast, one-day service
Technical data with each order
Write for free Tech-Data-Flyer
AMIDDON.
AAAD(MI?A
12033 Otsego Street, North Hollywood, Calif. 91607
~Jal. GUNN PTY LTD
50 BRISBANE St. LAUNCESTON
Telephone 319333
DOMESTIC & BUILDERS HARDWARE
MARINE & PLUMBING SUPPLIES
PAINT & TOOLS
SEDDON PRESS
35a GRANVILLE St. LAUNCESTON 7250 R
Telephone 316191
FOR ALL YOUR PRINTING
BUSINESS AND PERSONAL
QSL CARDS
DHz& LS Chillco[& Sons
ALL CLASSES ELECTRICAL INSTALLATIONS AND REPAIRS
INDUSTRIAL AND DOMESTIC MAINTENANCE
SALES AND SERVICE OF ELECTRICAL APPLIANCES
89 OLIVE St., NEWSTEAD, PHONE 311677
AFTER HOURS 444434 or 318659
Athol Lawes Electrics
135 HOBART Rd., KINGS MEADOWS, PHONE 444710
FOR ALL ELECTRICAL APPLIANCES, SPECIALISTS IN,
HI-FI SOUND SYSTEMS
CAR RADIO AND STEREO
SEE US FOR A BETTER DEAL, WE SERVICE ALL WE SELL.