Getting Started — Your Calculator
The TI-84 Evo is the newest TI-84 graphing calculator. It works like the familiar TI-84 but adds an icon-based home screen, a redesigned keypad, and USB-C charging. This guide covers exactly what you need for Ham Space Camp, plus some extras worth exploring.
Home screen: the Evo opens to an icon home screen. Press the Home key (the house icon) any time to return to it. To do calculations, highlight the Calculator app and press [ENTER].
[2nd] (blue key): accesses the second function printed above each key. Press it once, then the key — don’t hold them down together.
[ALPHA] (green key): accesses the letters printed above the keys, used for stored variables (Skill 6). Press once, then the key.
[ENTER]: runs a calculation — the same idea as = on a basic calculator.
[CLEAR]: clears the current line without erasing your stored variables. Safe to press whenever things look wrong.
[<>] (toggle key): new on the Evo — switches an answer between an exact form and a decimal, and shows on-screen syntax help for a command. The TI-84 Plus CE has no equivalent key.
Shortcut menus: the Evo’s f1–f4 keys pop up FRAC (fractions), FUNC (math templates), MATRIX, and VVAR (Y-variables) for quick entry.
Storing and recalling values
The TI-84 has a dedicated [STO▸] key for storing a value, and you recall a value just by typing its letter with [ALPHA]. (There is also a RCL function at [2nd][STO], but you won’t need it.) See Skill 6.
A few keys to confirm on your Evo
The Evo redesigned its keypad, so a few keystrokes below are worth a quick check against the calculator (or its on-screen guide). These are the standard TI-84 keys and almost certainly unchanged, but the merged power key (x^n) is why we flag them:
• Scientific notation (EE): [2nd][,]
• Square root: [2nd][x²]
• Pi (π): the 2nd-function on the [x^n] key
Everything else in this guide is confirmed for the Evo.
New to this calculator? TI’s own Getting Started guide walks through the home screen, keypad, and soft keys, with short videos: open the TI-84 Evo eGuide.
The half-wave dipole formula gives you antenna element length in feet: 468 ÷ f(MHz). For a quarter-wave element: 234 ÷ f(MHz). The calculator handles the division, you handle the frequency.
HOW TO DO IT — KEY SEQUENCE
Basic division:
468 [÷] 146 [ENTER]
Result: 3.205 feet — the length of a half-wave dipole element for 146 MHz.
Convert to inches:
[2nd][(−)] (ANS) [×] 12 [ENTER]
Result: 38.46 inches. ANS automatically uses your last result (see Skill 5).
For whole inches, multiply by 12 and read the whole-number part.
TRY THESE
Calculate the half-wave dipole length for the 2m satellite downlink: 468 ÷ 145 = ?
Calculate for the 70cm satellite uplink: 468 ÷ 435 = ?
Calculate for the 23cm band: 468 ÷ 1296 = ?
Calculate for AM broadcast at 1 MHz: 468 ÷ 1 = ?
Try 468 ÷ 2400 for Wi-Fi. Convert to inches. Compare to the chip antennas in your phone.
CHECK YOUR ANSWER
145 MHz: 3.228 ft = 38.7 inches. 435 MHz: 1.076 ft = 12.9 inches.
1296 MHz: 0.361 ft = 4.33 inches. 1 MHz (AM): 468 ft. 2400 MHz (Wi-Fi): 0.195 ft = 2.34 inches.
HANDY TOOL · Session 1
The Numeric Solver — Working a Formula Backwards
Skill 1 finds length from frequency (468 ÷ f). Sometimes you have the length and want the frequency — or you have a wavelength and want the frequency. Instead of rearranging the formula by hand, let the calculator’s Numeric Solver do it for you. It works on any of our division formulas: 468 ÷ f (antenna length), 234 ÷ f (quarter-wave element), and 300 ÷ f (wavelength in meters).
HOW TO DO IT — STEP BY STEP
Open it: press the Home key, highlight the Numeric Solver app, and press [ENTER].
Type the equation as two sides (E1 = E2):
E1 = [ALPHA] L (the green L above the ) key)
E2 = 468 [÷] [ALPHA] F (the green F above the COS key)
(Older software shows 0 = … instead — enter 0 = L − 468/F. The = sign is already on screen either way, so you don’t need to find one.)
Press the down arrow (or [GRAPH]) to reach the solve screen:
L = ____ F = ____ bound = {−1E99, 1E99}
Type in the value you know — say a measured element L = 3.205 ft. Give F any rough guess, like 100.
Put the cursor on the unknown (F) and press [ALPHA][ENTER] — the green SOLVE above [ENTER] (or press [GRAPH]).
F ≈ 146 → 146 MHz (the ▪ marker and ‘left−rt = 0’ confirm it found a real answer)
To go the other way (known F, find L): type F, put the cursor on L, and SOLVE.
Good to know
The Solver is numeric — it finds the answer nearest your guess (fine here, there’s only one positive answer). ‘bound’ is just the search window; leave the default. For wavelength in meters, use E2 = 300 ÷ F instead of 468 ÷ F.
TRY THESE
Known element length L = 3.228 ft. Solve 468 ÷ F = L for F → about 145 MHz (the 2 m band).
Wavelength backwards: solve 300 ÷ F = 0.69 for F → about 435 MHz (the 70 cm band).
Frequencies in radio span an enormous range: from 1 Hz to 300 GHz. The EE key lets you enter these without typing a long string of zeros.
HOW TO DO IT — KEY SEQUENCE
The EE key is entered with [2nd][,] (the comma key). The display shows a small E. Examples:
1.45 [2nd][,] 8 [ENTER] → 145,000,000 Hz = 145 MHz (shows 1.45E8)
4.35 [2nd][,] 8 [ENTER] → 435,000,000 Hz = 435 MHz
2.4 [2nd][,] 9 [ENTER] → 2,400,000,000 Hz = 2.4 GHz
Unit prefixes: k = ×10³ M = ×10⁶ G = ×10⁹
146 kHz = 1.46E5 Hz. 146 MHz = 1.46E8 Hz. 1.296 GHz = 1.296E9 Hz.
TRY THESE
Enter 145 MHz using the EE key. Confirm the display shows 1.45E8 or 145,000,000.
Calculate wavelength in meters: speed of light ÷ frequency. c = 3×10⁸ m/s.
λ = 3E8 ÷ 1.45E8 = ? meters (your 2m wavelength — should be close to 2.07 m)
Try the same for 435 MHz. Should get about 0.69 meters (69 cm — the ‘70cm band’).
Try GPS at 1.575E9 Hz. Should get about 0.190 meters (19 cm).
CHECK YOUR ANSWER
2m (145 MHz): λ = 3×10⁸ ÷ 1.45×10⁸ = 2.069 m. 70cm (435 MHz): λ = 0.690 m.
GPS (1.575 GHz): λ = 0.190 m = 19 cm. This is why GPS antennas are small.
Decibels (dB) are a logarithmic scale. The key insight: adding dB values is the same as multiplying power ratios. A link budget is just a running total of dB additions and subtractions.
HOW TO DO IT — KEY SEQUENCE
The dB rules — memorize these:
+3 dB = ×2 power −3 dB = ÷2 power
+10 dB = ×10 power −10 dB = ÷10 power
+20 dB = ×100 power −20 dB = ÷100 power
Chaining example — link budget running total. Start: +44 dBm (transmit power)
44 [−] 3 [ENTER] → 41 dBm (feedline lost 3 dB = half the power)
[2nd][(−)] (ANS) [+] 7 [ENTER] → 48 dBm (antenna added 7 dB gain)
[2nd][(−)] (ANS) [−] 143 [ENTER] → −95 dBm (free-space path loss)
TRY THESE
A 100W transmitter feeds an antenna with 7 dBd gain through a cable with 3 dB of loss. What is the effective radiated power in watts? (Hint: 100W = 20 dBW. Apply gains and losses, then convert back.)
A signal arrives at −90 dBm. The receiver needs −117 dBm minimum. What is the link margin?
If you double the transmit power (add 3 dB), how much does the link margin improve?
CHECK YOUR ANSWER
100W + 7 dBd − 3 dB = +4 dB net = 100W × 2.5 = 250W equivalent ERP.
Link margin: −90 − (−117) = 27 dB. Doubling power: margin improves by exactly 3 dB to 30 dB.
The TI-84 has two keys that look like a minus sign: the subtraction key (−) for subtracting, and the negation key [(−)] for entering a negative number. Using the wrong one causes an error.
HOW TO DO IT — KEY SEQUENCE
The subtraction key: the [−] key on the right side, in the operator column. Use it between two numbers: 10 − 3.
The negative key: the [(−)] key on the bottom row, just to the left of [ENTER]. Use it to enter a negative number: [(−)] 90 enters −90.
Entering a negative number:
[(−)] 90 [ENTER] → −90
Running total with negative dBm values:
44 [−] 3 [+] 7 [−] 143 [ENTER] → −95
Check if the link closes: −95 − (−117) = +22 dB margin
[2nd][(−)] (ANS) [−] [(−)] 117 [ENTER] → 22
TRY THESE
Calculate: (−45) + 10 − 3 − 10 = ? (answer: −48)
What is −90 dBm − (−117 dBm)? That’s your link margin. (answer: 27 dB)
Type the full link budget in one line: 44 − 3 + 7 − 143 − (−117) = ? (should give 22 dB margin)
ANS automatically recalls the result of your last calculation. This lets you chain steps without retyping intermediate results, and without storing values in variables.
HOW TO DO IT — KEY SEQUENCE
ANS holds your last result. Start a new line with an operator and it is used automatically, or insert it with [2nd][(−)].
468 [÷] 145 [ENTER] → 3.228 ft
[×] 12 [ENTER] → 38.74 inches (line begun with × auto-uses ANS)
[÷] 2 [ENTER] → 19.37 inches (one element of a dipole)
Warning: ANS changes every time you press [ENTER]. If you calculate something else in between, ANS loses your value. When you need the same value several times, use Skill 6 (STO▸) instead.
TRY THESE
Calculate the speed of light in miles per second: 299,792,458 ÷ 1609.344 = ? Then ÷ 1,000,000 for millions of miles per second.
How far does Voyager 1’s signal travel in one hour at light speed: (c in miles/s) × 3600 = ?
Chain: 468 ÷ 435 × 12 → should give 12.9 inches (70cm half-wave element in inches).
CHECK YOUR ANSWER
c in miles/s: 186,282 miles/sec. Per hour: 186,282 × 3600 = 670,616,629 miles/hour.
70cm element: 468 ÷ 435 = 1.0759 ft × 12 = 12.91 inches.
When you need to store several intermediate results and reuse them in different calculations, ANS isn’t enough. The TI-84 stores values in named variables A–Z (and θ) using the [STO▸] key. Store a value, then recall it by typing its letter with [ALPHA].
Good to know
A RCL function also exists at [2nd][STO], but you won’t need it — [ALPHA] + letter is simpler.
HOW TO DO IT — KEY SEQUENCE
Store a value:
value [STO▸] [ALPHA][letter] [ENTER]
The [STO▸] key is on the far left, just above [ON].
Recall a value:
[ALPHA][letter] (inserts the stored value into your calculation)
Example — Doppler shift at two frequencies:
7000 [STO▸] [ALPHA] V [ENTER] (orbital velocity, m/s → V)
3 [2nd][,] 8 [STO▸] [ALPHA] C [ENTER] (speed of light, 3E8 → C)
1.45 [2nd][,] 8 [STO▸] [ALPHA] F [ENTER] (145 MHz → F)
[ALPHA] F [×] [ALPHA] V [÷] [ALPHA] C [ENTER] → 3,383 Hz
Now change F for 70cm:
4.35 [2nd][,] 8 [STO▸] [ALPHA] F [ENTER]
[ALPHA] F [×] [ALPHA] V [÷] [ALPHA] C [ENTER] → 10,150 Hz
TRY THESE
Store a for the ISS: a = 6779 (altitude + Earth radius).
6779 [STO▸] [ALPHA] A [ENTER]
Cube it:
[ALPHA] A [x^n] 3 [STO▸] [ALPHA] B [ENTER]
Divide by μ (398,600):
[ALPHA] B [÷] 398600 [STO▸] [ALPHA] C [ENTER]
Square root:
[2nd][x²] ( [ALPHA] C ) [STO▸] [ALPHA] D [ENTER]
Multiply by 2π:
2 [×] [2nd][x^n] (π) [×] [ALPHA] D [ENTER]
Answer should be about 5,553 seconds = 92.5 minutes. That’s one ISS orbit.
CHECK YOUR ANSWER
ISS orbital period: T = 2π√(6779³ ÷ 398600) ≈ 5,553 seconds ÷ 60 = 92.5 minutes per orbit.
Doppler at 145 MHz (7 km/s): Δf = 1.45×10⁸ × 7000 ÷ 3×10⁸ = 3,383 Hz.
Doppler at 435 MHz: Δf = 4.35×10⁸ × 7000 ÷ 3×10⁸ = 10,150 Hz. (3× higher freq = 3× more shift)
In Session 1 you watched a sine wave appear on the oscilloscope. Your calculator draws the very same wave — the shape of every AC signal and every radio wave. It is also your first real graph, the gateway to the high-school graphing skills at the end of this guide.
HOW TO DO IT — KEY SEQUENCE
Set the angle mode: press [MODE] and choose RADIAN (the standard for graphs).
Enter the wave in the Y= editor:
[Y=] Y1 = [SIN] [X,T,θ,n] )
Get a clean window automatically: press [ZOOM] and choose ZTrig — it frames a few full waves for you.
Press [GRAPH] to draw it, then [TRACE] and arrow along the curve — the Y value is the height of the wave at each point.
TRY THESE
Higher frequency: add Y2 = sin(2X) and graph both. The wave squeezes together — more cycles in the same space, exactly like turning the signal-generator frequency knob up.
Bigger amplitude: graph Y3 = 2 sin(X). The wave gets taller — a stronger signal at the same frequency.
Add a DC offset: graph Y = sin(X) + 2. The whole wave lifts up — an AC signal riding on a DC level.
CHECK YOUR ANSWER
A sine wave has two key traits: amplitude (its height) and frequency (how tightly the cycles pack). Those are the same two things you measured on the scope — how strong, and how fast.
Calculator Functions Not Useful for This Program
The TI-84 Evo is a powerful calculator with many menus and functions. Some are not useful here — and some look relevant but aren’t. This section saves you the trouble of figuring out what to skip.
| Function / Menu | Why Not Useful for This Program |
| STAT menu ([STAT]) | Lists, regression, and statistics. Not related to radio, RF, or satellite work. |
| Finance (Finance app on the Home screen) | Time-value of money — loan payments, interest, present value. Not used in this program. |
| Matrix (f3 MATRIX shortcut, or the Matrix menu) | Matrix math for linear algebra. Not needed for any calculation here. |
| Probability distributions ([2nd][VARS] = DISTR) | Normal, t, and chi-squared distributions — college statistics. Beyond this program. |
| CATALOG ([2nd][0]) | An alphabetical list of every command. Useful later, but overwhelming now — come back once you know what you’re looking for. |
IMPORTANT NOTE
This isn’t a criticism of these functions — statistics, matrix math, and probability are genuinely important in other fields. They’re just not part of what we do in radio and satellite work.
If you take physics, engineering, or statistics in high school or college, you’ll find many of these menus very useful there.
Explore on Your Own
The six curriculum skills cover exactly what you need for Ham Space Camp. The explorations below go further — things you can try at home with your calculator after camp, not things we’ll cover in sessions. They connect to what you’ve learned but go deeper.
EXPLORE ON YOUR OWN · Not in the curriculum
Exploration 1: Graphing — Visualizing Formulas
The TI-84 can graph any equation. This is powerful for visualizing how two quantities relate — for example, how antenna length changes with frequency.
Press [Y=] and enter:
Y1 = 468 [÷] [X,T,θ,n] (the [X,T,θ,n] key types X)
Set the window: press [WINDOW]. Set Xmin=50, Xmax=500, Ymin=0, Ymax=5.
Press [GRAPH] to draw the curve — antenna length vs. frequency.
Press [TRACE] to move along the curve. At any X (frequency), the Y value is the element length in feet.
Notice: the relationship is a hyperbola (1/x curve). As frequency doubles, length halves.
Try Y1 = 300 ÷ X (wavelength in meters vs. frequency in MHz). Set Xmin=100, Xmax=3000, Ymin=0, Ymax=3. At X=145, what is Y? At X=435?
Try two functions at once: Y1 = 468/X and Y2 = 234/X. What does Y2 represent? (Quarter-wave.)
EXPLORE ON YOUR OWN · Not in the curriculum
Exploration 2: More Solver Practice — Finding Frequency from a Measured Antenna
You met the Numeric Solver right after Skill 1 (open the Numeric Solver app from the home screen, enter E1 = L and E2 = 468 ÷ F, fill in what you know, put the cursor on the unknown, and press SOLVE = [ALPHA][ENTER]). Here are more real cases to practice solving a formula backwards.
You measure a rabbit-ear element at 31.5 inches = 2.625 feet. Solve 468 ÷ F = 2.625 for F → 178.3 MHz. That lands near the FM broadcast band, so it’s a hint to double-check your measurement.
A wire cut to 14 inches per side is 28 inches = 2.333 feet total. Solve 468 ÷ F = 2.333 for F → about 200.6 MHz, roughly the 1.5 m band.
Wavelength version: solve 300 ÷ F = 2.07 for F → about 145 MHz (the 2 m band).
Sanity check by hand: since length = 468 ÷ f, the frequency is just f = 468 ÷ length — the Solver should agree with that division every time.
EXPLORE ON YOUR OWN · Not in the curriculum
Exploration 3: Free-Space Path Loss Calculator
The single biggest term in any satellite link budget is free-space path loss — the signal spreading out across distance. You can calculate this exactly.
FSPL formula: FSPL (dB) = 32.4 + 20×log(f_MHz) + 20×log(d_km)
On the TI-84, log is the [LOG] key. 20 × LOG(145) = 20 × 2.161 = 43.22
Store f = 145 in F and d = 800 (AO-91 altitude, km) in D:
1.45 [2nd][,] 2 [STO▸] [ALPHA] F [ENTER] (= 145)
800 [STO▸] [ALPHA] D [ENTER]
32.4 [+] 20 [×] [LOG] ([ALPHA] F) [+] 20 [×] [LOG] ([ALPHA] D) [ENTER]
Result: about 32.4 + 43.2 + 58.1 = 133.7 dB
Now try 435 MHz (same distance): change F to 4.35 [2nd][,] 2. Result ≈ 141 dB — the value used in the Session 2 link budget.
Try the Moon: d = 384,400 km, f = 1296 MHz (our EME frequency). FSPL ≈ 32.4 + 62.2 + 111.7 = 252.3 dB — the value from Session 6.
EXPLORE ON YOUR OWN · Not in the curriculum
Exploration 4: Orbital Period from Altitude
Given a satellite’s altitude, you can calculate its orbital period exactly using Kepler’s third law. This is the same calculation Gpredict uses internally.
Formula: T = 2π × √(a³ ÷ μ), where a = altitude + 6,371 km, μ = 398,600 km³/s², and T is in seconds.
Store constants:
6371 [STO▸] [ALPHA] R [ENTER] 398600 [STO▸] [ALPHA] M [ENTER]
For the ISS (altitude ≈ 408 km):
408 [+] [ALPHA] R [STO▸] [ALPHA] A [ENTER] (a = 6779)
[ALPHA] A [x^n] 3 [STO▸] [ALPHA] B [ENTER] (a³)
[ALPHA] B [÷] [ALPHA] M [STO▸] [ALPHA] C [ENTER]
2 [×] [2nd][x^n] (π) [×] [2nd][x²] ([ALPHA] C) [ENTER] (= T in seconds)
[÷] 60 [ENTER] → about 92.5 minutes per orbit
Try GreenCube (altitude 6,000 km): a = 12,371 km → about 215 minutes = 3.6 hours.
Try GPS (altitude 20,200 km): about 718 minutes ≈ 12 hours.
Try GEO (altitude 35,786 km): 1,436 minutes ≈ 24 hours — the point of geostationary orbit.
Extra Skills for High School — If There’s Time
These are not part of the camp, but they are the calculator skills you will lean on in high-school math and science — especially on the PSAT/SAT and ACT. Each one says what it does, gives a quick example, and links to TI’s official walkthrough (most include a video). Try any that catch your eye when there is time at the end of a session.
1. Fractions & the fraction↔︎decimal toggle
Enter fractions with the FRAC template, and flip an answer between an exact fraction and a decimal with the [<>] key. Example: 3/8 + 5/12; then turn 0.4 into 2/5.
Tested: SAT/ACT · Algebra 1 ▶ TI eGuide
2. Smart parentheses & order of operations
The calculator follows order of operations exactly — so −3² is −9 but (−3)² is 9. Wrap the whole top or bottom of a fraction in parentheses. Example: (4+6)/(2×5), and compare −3² with (−3)².
Tested: #1 calculator mistake · SAT/ACT ▶ TI eGuide
3. Roots & radicals
Square root, cube root, and any nth root live in the MATH menu. Example: ∛64 = 4, the 5th root of 32 = 2, and √50 ≈ 7.07.
Tested: Geometry · Algebra ▶ TI eGuide
4. Graphing a function & picking a good window
Type a function in Y=, then use ZOOM and WINDOW to frame it and TRACE to walk along it. Example: graph y = x² − 4x + 1.
Tested: SAT/ACT gateway skill ▶ TI eGuide
5. Zeros, maximum & minimum from a graph
The CALC menu finds where a graph crosses zero and its highest or lowest point. Example: for y = x² − 4x + 1, find the two roots and the vertex.
Tested: SAT vertex & root problems ▶ TI eGuide
6. Solving equations by intersection
Graph the left side as Y1 and the right side as Y2, then find where they cross — that x is the solution, no algebra needed. Example: solve 2x + 1 = −x² + 5.
Tested: SAT calculator-section staple ▶ TI eGuide
7. Tables of values
TABLE and TBLSET print a function’s values so you can spot patterns and sign changes fast. Example: a table of y = 2ˣ to watch it double.
Tested: Algebra ▶ TI eGuide
8. Systems of equations
The Simultaneous Equation Solver app solves two (or more) equations at once. Example: solve y = 2x − 1 and y = −x + 5 together.
Tested: Algebra 1/2 · SAT ▶ TI eGuide
9. Quadratics & polynomial roots
The Polynomial Root Finder app gives every root of a quadratic or cubic — including complex ones. Example: roots of x² − x − 6 (3 and −2) and of x² + 4 (±2i).
Tested: Algebra 2 ▶ TI eGuide
10. One-variable statistics
1-Var Stats reports mean, median, standard deviation, and quartiles for a list of numbers. Example: enter a set of test scores and read the mean and standard deviation.
Tested: SAT data · AP Stats · science labs ▶ TI eGuide
11. Scatter plots & line of best fit
Enter paired data, plot it, and fit a line (linear regression) with a correlation r. Example: signal strength vs. distance — fit a line and predict the strength farther out.
Tested: SAT/ACT line of best fit · AP Stats ▶ TI eGuide
12. Right-triangle trig & degree/radian mode
sin, cos, and tan — plus the MODE setting that decides whether angles are degrees or radians (a classic mistake). Example: find the missing side and angle of a right triangle.
Tested: Geometry/Trig · ACT · physics ▶ TI eGuide
13. Logarithms & exponentials
log and ln let you solve exponential equations and handle growth and decay. Example: solve 2ˣ = 50, and compute pH = −log[H⁺] in chemistry.
Tested: Algebra 2/Precalc · chemistry ▶ TI eGuide
14. The normal distribution (bell curve)
normalcdf and invNorm work with the bell curve and the 68–95–99.7 rule. Example: the probability a value falls below z = 1.5.
Tested: AP Stats · SAT data/probability ▶ TI eGuide
© Jonathan W. Pearce 2026 · W2MMD Ham Space Camp
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