Index to sheets contained in RF1.XLSM
2. WAVE PORTION
Use for instant calculation of commonly used wave portions in air and cable.
Uses include calculation of stacking distances, calculation of quarter wave stubs, and whip
3. ERP/EIRP and CABLE LOSS
This sheet lets you see actual cable loss, and its effect on ERP for a range of
standard cable types, at your selected frequency and desired cable length.
You can also enter cable specs for cables that are not listed, and obtain the same
information. For this you only need to enter manufacturer's data of cable loss at any two
frequencies. No twelve digit ‘factors’ are required!
4. ERP/EIRP and SYSTEM ANALYSIS
Calculator allows entry of essential system parameters, and gives indication of signal
available at receiver. Takes into account Tx power, Tx cable losses, Tx antenna gain, Balun
and Filter losses, and Connector losses. Free space losses are calculated, and Rx antenna,
feed cable and other losses are considered to finally give estimated 'uV on 50 Ohm receiver
load'. Fading margin can be taken into consideration if desired.
Cable losses for Rx and Tx feeds are pre-entered for RG213, but details for any cable
can be entered as long as losses at any two frequencies are known. These are generally
available from manufacturers spec. sheets.
5. TWO WAY SYSTEM PERFORMANCE
A similar calculation to the above, but set out differently.
After entering all the factors normally taken into consideration for analysing your two-way
system performance, expected signal strengths received both at base and mobile are given. The
effect of any change to any system parameter can be instantly evaluated. Additionally, line
of sight is calculated taking into account earth's curvature and antenna relative heights.
This sheet also separately calculates received signal strength where antennas are not
optimally aligned, as at 3dB fringes (or other chosen reference).
YOUR TWO WAY SYSTEM MUST BE PLANNED WITH THE SERVICES OF A COMMUNICATION ENGINEER, AND GOOD
PRACTICE WILL USUALLY CONFIRM THE DESIGN WITH FIELD TRIAL.
6. MICROWAVE SYSTEM ANALYSIS
Using standard equations for obtaining received signal strength in a Microwave system.
Results from several accepted methods are presented.
For those who use a GPS for quick determination of location, Great Circle distance, and
Azimuth calculations have been added to the lower portion of this sheet.
ALL ASPECTS OF YOUR MICROWAVE SYSTEM MUST BE PLANNED WITH THE SERVICES OF A COMMUNICATION
7. SWR HINTS for WHIP INSTALLERSQuick assistance for determining whether whips are long or
short. Includes a ratio calculator to estimate amount to trim (or add!) to a whip to bring it
8. COAXIAL CABLE INTERFERENCE TRAPS
Often a simple stub trap on a feedline can deal with interference. This sheet makes the
options clear. Often there are choices other than a simple quarterwave trap.
Enter two frequencies, and instantly see all intermod. products to fifth order. Very
handy for checking potential problems in advance of installing. Some useful products
resulting from combinations of three frequencies are given.
10. SWR CORRECTION for LINE ATTENUATION
Long, lossy cables mask a high VSWR at load. This calculator gives true VSWR at load,
for a range of cable types when VSWR has been measured at transmitter end.
12 INSTALLATION ADVICE
Head off intermods and call-backs with good installation practice. A simple list of
things to attend, to ensure a good installation.
13 KNIFE EDGE
Often diffraction over an obstacle is needed. The losses are high, and some basic
criteria need be satisfied.
Edge to be greater than 100 wavelengths long, a minimum of 100 wavelengths high, and the
closest station to be distant from the edge a minimum of ten times the edge height.
Caution:- Very few natural obstacles form an ideal diffracting edge, and you would not plan a
system on the figures calculated without an actual field assessment.
14 FRESNEL ZONE
This worksheet allows the calculation of clearances necessary along a radio path to
avoid the losses. As obstructions within the first 0.6 Fresnel zone cause the greatest
losses, and this is calculated for you for line of sight paths. You require to enter the
distance of a chosen point from each end of path. the program calculates the clearance each
side of path center needed at that point. You may also calculate other Fresnel zones using
15 POWER DENSITY
Information re. calculation of Power Density in the Far Field. Preliminary calculations
are possible on this sheet, but compliance with a standard is a job for a certifying
Index to Disk 2 (RF2.XLS)
1. RET. LOSS MEASUREMENT UNCERTAINTY
This is not the type of calculation most of us need on a daily basis, but the sheet is
really an easy way to EDUCATE that return loss (and hence VSWR) is a measurement that has
potential for high uncertainty. By simply entering figures from your equipment manufacturer,
and exploring some values of VSWR for your Test Port Adaptor, it will become very clear that
IMMENSE uncertainty can arise from using cheap adaptors, or worn adaptors between test port
On occasions clients have said, "Our SWR measurements are not the same as yours". A
knowledge of the uncertainties involved will soon help you understand the fragility of VSWR
readings when not made under laboratory conditions. And even then!
2. VELOCITY FACTOR
A halfwave length of coaxial cable when shorted will show a voltage null at the
feedpoint. The exact frequency of this null, in conjunction with measured line length is used
to calculate the velocity factor of the cable. Experience has shown that antennas designed
using cable sections can give problems if using a substitute cable, and simply assuming the
VF is as expected. Some may prefer the errors to be treated per RSS .
3 STUB ANALYSER
Gives results equivalent to the proprietary "Smith Chart". Match Load to line with this
interactive tool, using one or two stubs. Naturally, load must be known.
4 STUB ANALYSER 2
Once R and jX of load are known, this enables exploration of size and placement
solutions for single and dual stubs.
5. STUB PLACEMENT from R and jX
Any time R and jX of load are known, stubs can be calculated and placed mathematically.
6. STUB PLACEMENT from R and jX (2)
As above, but different types of stubs are explored.
7. SLOTTED LINE (Uncorrected)
Using figures for your load obtained from a slotted line measurement, automatically gives
stub placement and dimension.
For ‘homebrew’ slotted lines, calculation of VF is possible from line measurements, and a
portion of this worksheet does this for you.
8. SLOTTED LINE, w/DIODE CORRECTION
Slotted lines can be purchased as ‘lab’ items, or constructed by slotting a 9.5mm od.
Tube, and filling it with a RG213 core. A simple saddle with a voltage probe can be made up.
If a current probe is used, remember that a current minimum represents the voltage maximum
needed. This technique is accurate enough for stub calculations, as some field adjustment is
always needed and should be allowed for in stub selection.
This sheet allows the calculations to be automated. If used with a HP805 line, a diode
corection curve is applied, to greatly reduce ‘square law’ errors.
The program calculates a correct stub solution for your match.
9. SLOTTED LINE, using ATTENUATOR
A slightly different technique, using an attenuator, allows any detector to be used on
a slotted line, and detector errors are avoided.
10. SERIES SECTION TRANSFORMER
Calculations for those who wish to use series-section line transformers for matching.
11. SLUG TRANSFORMER CALCULATOR
Slugs of varying ‘e’ inserted as sliding elements in a section of constructed
transmission line give matching opportunities. This sheet allows interactive exploration of
SLUG TRANSFORMER DESIGN NOTES ‘README’
Design notes for practical implementation of the slug match to a feed tube to a
12 POWER DIVIDER DESIGNER
Further design material for power dividers.
13 IMPEDANCE CHART
A simple chart in the traditional format, allows plotting of three measured impedances.
This sheet is included basically to allow perusal of the VBA code by those interested in
seeing how the chart works.
Broadband matching is always tricky. Improvement at one end of the band invariably
results in problems elsewhere. This sheet allows selection of elements to be assessed
visually, and values to be stepped. Used similarly to the ARRL program ‘Microsmith’, Load is
at left hand end.
‘Lumped 1’ is lumped element at load. Directly underneath is where you declare type and value
of the element you are adding, if any
‘Line 1’ is a line section. It may be of any declared impedance and length.
‘Stub 1’ is either a series or parallel stub.(or no stub at all)
‘Lumped 2’ gives opportunity to add a lumped element at this point instead of a stub.
This pattern can be continued, and the final impedance at end of feed line appears at the end
of line three.
Basically, this combination of possible setups will offer the possibility of achieving any
possible broadband match.
In the words of one of Australias foremost RF engineers, ‘There are infinite match
possibilities, but only one is optimal’ .. I leave it to the reader to ensure that the
selected match is stable enough to be practical.
My advice is that when using the step feature on this sheet, and your marker goes
through the chart center like a comet when you click the mouse to increment a value, then
it’s time to start again!
I urge users to read ARRL publications, especially information on ‘Outer Boundary’
Users of this page will find a useful chart for forming various impedance line sections
from brass stock commonly available. These line sections are very commonly used in industry,
and deserve serious consideration in seeking matching solutions.
The sheet is designed for broadband matching, so entries should be made at mid
band, and at band ends. If a single entry only is used, use the topmost entry row. Some
garbage will appear in odd boxes. If you check the code, Excel has been told not to display
in this case, but does it anyway!
15. HP803 BRIDGE
Still a few of these bridges about, and this page Illustrates how the tedious
calculations associated with their use can be reduced to a simple spreadsheet exercise.
16 STAGGER MATCH
A simple adaptation of work by Henry Drillich in his paper to the Australian Electrical
Engineering Congress, Nov 1984, entitled 'A New Approach to Modelling Complex Impedances'
.. Here we use two consecutive sections that match the load at offset frequencies to
efectively broadband our match.(Rather like we used to step-tune IF transformers to get the
IF passband characteristic we needed) Because this page is specifically designed to provide
matching solutions that will suit the feed tube of coaxial gain antennas that are fed from
the bottom via a metal 50 ohm coaxial section, both the matching sections consist of a line
section followed by a closed stub.
When we make measurements along the coax from the load, we need to apply transmission
line equations to ascertain load values. This sheet will allow you to look up-line to the
18 SITEMASTER' STUB MATCH
Working the above concept, from values ascertained by the ‘sitemaster’, we look up-line
to the load feed point, and calculate appropriate stubs and their placements.
19 IMPEDANCE MATCH for INSTRUMENTS
Resitive matches for instrumentation purposes
20 DIRECTIONAL COUPLER
This simply constructed directional coupler is amazing. The core element costs but a
few dollars, and comes from high quality TV splitter. The results obtained equalled in every
way a commercial $A3000 unit to 500 MHz. Care in construction is essential, and in use, a 6
or 12 dB attenuator must be used at Source input and Detector output, and a precision 50 ohm
termination is needed for the Reference. With a little more thought to construction, I expect
this design is useful to 1 gHz.
21 TWELFTH-WAVE TRANSFORMER
Interesting comments, and a calculator for those interested in exploring the twelfth
22 TRANSMISSION LINE
A few handy calcs for making / analysing transmission lines.
23 QUARTER WAVE TRANSFORMER
Calcs for making and using quarter-wave transformers.
24 TRANSFORMER and STUB
calcs for designing broadband matches with quarterwave transformer series and shunt
25 MATCH BOX 1
26 MATCH BOX 2
27 MATCH BOX 3
These automate calcs for the matching sections in the ‘Motorola’ Handbook
28 QUARTER-WAVE BINOMIAL TRANSFORMER
Balanis, "ANTENNA THEORY", 2nd Ed Sect. 9.8.2, sets out matching ideas for quarterwave binomial transformers. A
note in this page of calculations contains a caveat
Index to Disk 3 (RF3.XLS)
1 COAXIAL GAIN ANTENNA
Crossed cable sections provide the basis of an antenna that has been around for a long
time. Easy to build, and gives good, tight gain patterns.
2 HELICAL ANTENNA
A complete calculator for helical antennas. Allows design offset to allow for pull down
effect where the coil is wound on PVC tube with wire or copper tape. From experience, a 2400
helical wound on 38mm PVC using ¼” leadlight foil, needs to be designed for a 20% higher
frequency. For winds with 1mm wire you would do your first trial design at 10% higher. The
most interesting result of my work in this field, is to show that the use of reduced ground
planes can result in very effective point to point link antennas, at 2.4 gHz, that can be
totally enclosed in a 50mm PVC tube.
Matching of these foil wound antennas is a lot easier than current articles suggest. Simple
tabs up from the groundplane, placed by trial and error (in conjunction with the scalar
analyzer) work fine.
3 STANDARD GAIN ANTENNA
Calculator for building the Standard Gain Antenna, and a few comments re the design!
Some calculations for DDDR antennas, loop ring elements
and calculations for constructing the anti-phased helical.
Whilst the anti-phased helical antenna is most often used in broadcasting, the design
could have use where a high gain antenna is needed for broadband use, as in SCADA
systems where TX/RX splits may be 75 MHz. Whilst I have not fully trialled this design,
a 6 dBd prototype for 900 MHz was built prior to my retirement. Later it was spun on
the range, and reports were that the pattern was ‘tight’. The intention was to try and
produce a design that would service the 853 - 927 MHz split of a local SCADA
allocation. Getting an effective broadband match with this split, on a colinear 6 dB
gain antenna had proved daunting, as had keeping a reasonable gain (pattern) at band
Analysis of the Biconical is well covered in Jasik, ‘Antenna Engineering Handbook’, so
by calculating his ‘Ka’ factor, proposed broadband designs can be assessed from his published
6 MICROPATCH ANTENNA
Calculator for a simple 6 dB patch antenna.
Calculator for designing beamtilt into a phased array. Includes commnt on beamtilt in
vertical colinear antennas.
8 POWER DIVIDER
An aid to designing traditional power dividers using metal tubing.
9 POWER DIVIDER DESIGNER
Some notes on an experimental power divider
10 ANTENNA SCALING
Re-scaling an antenna to a new frequency requires attention to scaling every dimension,
and this sheet is to assist.
Calculate ‘K’ factor for shortening ‘thick’ antenna elements per formula.saves
interpolating the ARRL chart!
12 SLUG COMPENSATION:- CUT OFF CHOKE and CABLE SECTION 1/2 WAVE RADIATORS
Vertical skirted colinear designs can fail because of a lack of understanding that ‘K’
factor reduced resonating elements do not naturaly form quarterwave cut-off chokes. A
compensating slug is needed, and can be calculated.
13 ANTENNA GAIN (Method 1) Calculating antenna gain using several different methods.
14 ANTENNA GAIN (Method 2)
15 ANTENNA GAIN (Method 3)
16 SWR via ATTENUATOR
An old method of calculating VSWR using a delay line and attenuator avoids ‘square law’
17 THIRD HARMONIC
calculator for an old method of supressing third harmonic.
18 YAGI MAKER
Automate the calculations for yagi elements.
19 DIPOLE BANDWIDTH
Calculateds an estimate for dipole bandwidth. Borrowed, with acknowledgement.
20 WHIP ANT CALCS
calculate loading inductances as loading coil is moved up the whip.
21. NIST DIPOLE
calcs for the NIST reference dipole.
22. ANTENNA EFFICIENCY
Explaining energy capture at HF and UHF
Index to Disk 4 (RF4.XLS)
1 PASSIVE FILTERS
Calcs for simple L / C filters
2 HANDY CALCULATIONS for the WORKSHOP
A page containing many small calculators needed occasionally in the workshop.
1. dBm to mW
2. Ret Loss from SWR
3. SWR from Ret Loss
4. Attenuation from SWR
5. Attenuation from Ret Loss
6. dBm to V rms, 50 ohm system
uV to dBm, 50 Ohm system
8. R/C Time Constant
9. Output and range from a Voltage Divider
10 DC Clamp voltage for Surge Supressor
11 Convert Signal to Noise plus Noise ratio, to S/N Ratio
12 Power After Attenuation or Gain Stage
13 Power in 50 Ohm system with Mismatch Power Head
14 Attenuator Needed to Improve Source Match of Generator
15 Improved Source Match of Generator
16 Coaxial Line Impedance, normal Concentric Line
17 Coaxial Line Dimension, Impedance and Inner Known
18 Coaxial Line Dimension, Impedance and Outer Know.
20 Lathing. Stock removal calcs.
21 Delay Line length
22 Convert Grains to Grams
3 MEMORY JOGGERS
Resistor color codes, and capacitor values
4 RESISTOR COMBINATIONS
An automated calculator for determining parallel combinations of resistors to obtain a
desired value. E12 and E24 series
5 INDUCTOR CALCS
calculator for solonoids, cavity, and transmission line elements.
6 STRIP INDUCTOR
When building amplifiers 1700 and 2400 MHz, strip resonators were very easy to build
once the basic design had been tracked. These graphs should assist those working at these
7 WINDLOAD, YAGI
8 WINDLOAD, VERTICAL ANTENNA
Basic assistance in calculating windload
9 DELAY LINE
calculate line lengths for desired delay.
10 POWER METER
On occasions a calibrated signal gen. can be used to calibrate old diode detectors to
enable their use to make (low)power measurements. Useful, in conjunction with reference
loads, for verifying that power dividers are actually dividing evenly.
One thing to check with these old detectors, is that they are still 50 ohms!. If
‘burnt’, they may be way off. My advice, after being ‘burned’ myself, is to give these a
simple ohm-meter test before forking out any money!
11 NICAD PACK CAPACITY CORRECTION
Manufacturers specify capacity at a specific discharge rate, and temperature. We often
test at different rates and temperatures. This sheet is an attempt to correct our
measurements for rate and capacity, and was used as the basis of a simple nicad tester for a
government service who had set a ‘throwaway’ baseline at 80% rated capacity.
12 NOISE GENERATOR
A simple white noise source. Because your source should be 50 ohm, the output should be
used with a 12 - 20 dB attenuator. The noise from the transistor equals that from the special
noise diodes that I have. I decided to build a high power unit with a string of MMIC’s, to
use with a bridge. After a week, I decided it was best to buy a commercial unit!
13 IN-LINE AMPLIFIER
Design idea for a coaxial amplifier
14 OP AMP
Calculator for op-amp elements.
Reflected signals contain important info that can give important circuit info. This
field is made understandable in the reference material contained within the old HP ‘1S1’ and
‘1S2’ TDR ‘scope plug-in manuals, and well worth chasing up.
The helical antenna described earlier, wound on PVC tube was examined with the TDR
capability of the 1S2, and verified the even transition of impedances from 50 to 120 ohm at
about four inches up the spiral.
16. RSSI CALIBRATIONS
By stepping a calibrated signal generator feeding into a receiver with RSSI, a
calibration curve can be derived. (Give due care to impedance matching!)
Several programs, such as ‘KyPlot’ and ‘DPlot95’,will convert this data to give an
equation for the curve.
Using this curve, and again paying attention to matching, your receiver can be used for close
to lab quality measurements. The only thing to watch is that your measurement range does not
straddle an internal electronic band change.
A typical curve for an ICOM R7000, and WINRADIO card is given. Note the WINRADIO data
is returned as raw 8-bit data, and is of not much real use. Adequate settling time is needed
on both these receivers, and after a set of experiments with a high speed aquisition card
(LABCARD PCL-818), I suggest 80 msec is needed for both cards.
17 VSWR REFERENCES
Handy ‘general purpose’ VSWR references can be made from attenuators and loads found in
18 ICOM C STUFF
Routines in Microsoft C to enable setting of frequency and mode in an ICOM R7000, via a
‘C1-V’ interface. I use this to step the ICOM at the same time as the R&S ‘SMS’ sig gen. The
RSSI resulting is read on a PCL-818 Labcard, enabling me to plot VSWR’s via a bridge.
19 NICAD DISCHARGER in C
The TL549 a/d converter chip is ideal for applications where eight bit accuracy is ok.
Here is a simple circuit where a Nicad pack is discharged via a load (R1), and the pack
voltage is read via LPT1
20 GRAPHS in C
My routines for Microsoft ‘C’ to place a graticuled display on your PC, and plot data.
21 PORT READS in C
Some routines for port reads in ‘C’.
22 HANDY C
Just some routines to do odd jobs,in ‘C’.
23 PORT I_O
Port reads are available in Win95/98. This page, and the associated code module shows
how to do it, via a publically available DLL. Required is Win95io.dll, which is included in
24 OPTO and SMS CONTROL
An encouragement to use older equipment, with a bit of modern technology to assist. The
advantage of writing your own code is that displays/reports can be exactly what you want.
25 COST SHARE
Only included to show that simple, neighbourly problems, are occasionally well
solved with the power of Excel.
26 CYLINDER HEAD FLOW BENCH
Excel provided a low cost way of analyzing results from a cylinder head flow bench.
Build details are alluded to, and the clever person should find sufficient detail to
replicate the project. The major difficulty will be finding a GM-671 blower, driving it with
a single phase motor, and finding neighbours that will tolerate the noise!
27 FOUR RUN BALANCING
Graphical and mathematical solution to dynamic balancing of a turbocharger rotor. Client had
built a wonderful balancing machine that was the equal of any commercial machine on offer,
looked to me to provide the electronics, and assistance! Whilst I knocked up this sheet for
the client, have not yet had reports, as the ‘two run method’ was working well.
28 STEPPER MOTOR
Some calcs arising from the need to assess the size of stepper motor needed to drive
the table of an X-Y-Z table we have put together for PCB milling.
29 RC FILTERS
Calculates elements for a notch filter from ‘National’ handbook
30 NF105 SIG STRENTH
Automates field strength calcs for the old Singer NF105
31 TX HARMONICS
Often a ‘spot’ source can be obtained from a harmonic of an existing oscillator, or
32 555 CALCS
A couple of ‘555’ relates calculations
Using these old counters required a little calculation ability. Worth keeping if you
had the Type M with its high stability option.
34 WINRADIO RSSI SETTLING
This sheet came together as I attempted to use the RSSI as part of an instrumentation
project. Eight bit resoloution, and a 75 millisecond settling time killed it.
35 CAPACITOR CALCS
Capacitance calculator. Handy for the Tesla fans.
37 ANTENNA FACTOR
calculator for Antenna factor
38 TUBE TRANSMISSION LINES
Some calculations for calculating impedance of odd line sections. Basically, this was
used to help evaluate the useability of drums of ‘imported’ RG213 that had a central core
with very offset conductor.
39 ELEMENT COMPENSATION
When yagi elements go through a boom, a length correcytion is needed. This is borrowed,
40 CAPACITIVE DISCONTINUITY
Adding series section transforming pieces in a line introduces step discontinuities.
Effectively adding a capacitance. This is a calculator for the capacitance value.
41 EQUIANGULAR SPIRAL
Co-ordinate generator for these spirals.
Calculator for PI attenuators.
Calculate wire size for wanted fuse.
44 COIL DESIGNER
Design air spaced coil, to 60 MHz, or analyse an existing coil.
45 DATA SLICER
To analyse data coming back from a 27 MHz control link, we had to translate the data
stream from the ICOM R7000 into a readable stream. This slicer worked perfectly.
46 NOISE FIGURE
Noise measurement calcs for an AILTECH receiver.
47 FOLDED DIPOLE
Several calculators for feed point impedance of folded dipole.
48 INSTALLATION WOES
Just a story of trouble, where the job seemed so basic!
Sheets included in these books should assist in making those basic calculations that
are needed regularly by those working in the RF field. We stress that these calculations are
for generalised guidance only, and commercial systems should be planned in conjunction with a