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HF Radio Systems and Circuits (Electromagnetic Waves)

by William E. Sabin

Rated3.2(5 ratings)Only 2 left

Good price

$94.14 is 10% below the $105.59 it normally sells for, and the lowest we've seen in 143 days.

Now
$94.14
Normally
$105.59
Lowest in 143 days
$94.14(Nov 12)
Highest
$109.99
Evidence: Strong143 days tracked10 price changes

Where today's price sits

View on amazon.com (opens in a new tab)

Prices change. Confirm the price on Amazon before you buy. TrackPin may earn a commission if you buy, at no cost to you; it never changes a verdict.

Get an email when the price drops

Good: 5%+ below normal. Great: 20%+ below. One email when it happens, at a price below today's $94.14. No account, no newsletter.

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The listing's crossed-out price

Smaller than shown

The listing shows

crossed out: List $145.00 −35%

Against its normal price

−10% vs $105.59

The listing shows −35%. Against its normal price it's −10%.

The crossed-out price is the reference shown on the listing. We don't know how it was set; we only compare it with prices we've observed. How we check →

Price history

Tracked since Jun 22 · 143 days · 10 price changes

Ahead of Black Friday 2026 (Nov 27), it is already 10% below its normal price of $105.59. HF Radio Systems and Circuits (Electromagnetic Waves) price history, checked Nov 12, 2026: current price $94.14, normal (typical) price $105.59, average $106.17 over 143 days, lowest $94.14 (Nov 12, 2026), highest $109.99 (Sep 19, 2026).

Loading the price chart.

  • Price
  • Not checked for 3+ days
  • Normal $105.59
  • 5% or more below normal

How often does it drop below normal?

In the 143 days we've tracked it, it stayed 5% or more below today's normal price for an hour or more twice, typically lasting about 3 days. It's below normal right now.

A count of what happened, not a prediction.

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Get this as JSONThe same verdict and prices, from the TrackPin API.
GET/api/v1/product/1884932045
Request
curl https://trackpin.co/api/v1/product/1884932045 \
  -H "x-api-key: $TRACKPIN_API_KEY"

This is exactly what the API returns for this product. Free keys include 100 requests a day.

Request a key
Live response, As of 23:51 UTC
{
  "asin": "1884932045",
  "title": "HF Radio Systems and Circuits (Electromagnetic Waves)",
  "image": "https://m.media-amazon.com/images/I/51Vf1KLwN8L._AC_SL500_.jpg",
  "currency": "USD",
  "category": "Book",
  "category_label": "Books",
  "in_stock": true,
  "price": {
    "current_cents": 9414,
    "reference_cents": 10559,
    "discount_pct": 10.84,
    "is_deal": true,
    "observed_at": 1794525415964,
    "changed_at": 1794495176542,
    "checked_at": 1794525415964,
    "source": "stored"
  },
  "verdict": {
    "label": "good",
    "text": "Good price",
    "pct_vs_normal": 10.84,
    "evidence": "strong",
    "stale": false,
    "suspect": false,
    "steady_since": null,
    "sentence": "Good price. $94.14 is 10% below the $105.59 it normally sells for, and the lowest we've seen in 143 days."
  },
  "listing_claim": {
    "label": "List:",
    "listing_reference_cents": 14500,
    "claimed_pct": 35,
    "real_pct": 10.84,
    "class": "smaller",
    "observed_at": 1794508714328
  },
  "stats": {
    "min_cents": 9414,
    "max_cents": 10999,
    "avg_cents": 10617,
    "history_days": 143,
    "price_levels": 45,
    "price_changes": 10,
    "distinct_prices": 5,
    "lowest_at": 1794495176542
  },
  "history": [
    {
      "price_cents": 10559,
      "from": 1792306974301,
      "to": 1793133795208
    },
    {
      "price_cents": 10314,
      "from": 1793151179364,
      "to": 1793308167085
    },
    {
      "price_cents": 10559,
      "from": 1793319401844,
      "to": 1794305835743
    },
    {
      "price_cents": 10298,
      "from": 1794321842868,
      "to": 1794488079303
    },
    {
      "price_cents": 9414,
      "from": 1794495176542,
      "to": 1794525415964
    }
  ],
  "last_seen": 1794525415964
}
// … 40 more steps in the full response

Normal price: the lowest price level the product held for at least 15% of the last 45 days (about a week). Prices within 3% of each other count as one level, and we use the lowest price in that level. How we calculate it → Prices are observations of amazon.com and may be incomplete or delayed. TrackPin is not affiliated with Amazon.