HP 11004A Ham Radio Transformer Frequency 5KC-600KC

( Brand: Hp ), ( Manufacturer Part Number: 11004A ), ( Compatiblebrand: Universal ), ( Type: Other )

Review HP Ham Radio Matching Transformer Frequency Good Condition

The **HP 11004A** is a high-performance, precision-engineered **broadband intermediate-frequency (IF) transformer** designed for demanding applications in amateur radio, communications systems, and RF test equipment. Built to exacting specifications by Hewlett-Packard (now part of Keysight Technologies), this transformer excels in the **5 kHz to 600 kHz frequency range**, making it an indispensable component for intermediate-frequency stages in superheterodyne receivers, signal generators, and modulation circuits. Its robust construction ensures minimal insertion loss and superior impedance matching, delivering consistent performance across its entire operating bandwidth while maintaining exceptional linearity and low distortion. The transformer features a **high-quality ferrite core** optimized for low magnetic hysteresis and reduced core losses, ensuring efficient energy transfer with minimal heat generation even under prolonged use. With a **1:1 impedance ratio** (typically 50 ohms or 600 ohms, depending on configuration), the HP 11004A provides seamless integration into circuits requiring precise signal coupling, whether in crystal-controlled oscillators, IF amplifiers, or balanced mixer stages. Its compact yet durable design, combined with reliable solder lug terminals, facilitates easy installation in both breadboard prototypes and permanent circuit assemblies. Whether used in vintage radio restoration projects, modern QRP (low-power) transceiver builds, or professional-grade test equipment, this transformer embodies the engineering excellence expected from Hewlett-Packard s legacy components, offering unmatched reliability and performance for decades of service.

### Pros and Cons of buying a HP 11004A Ham Radio Transformer (5 kHz 600 kHz)

1. **High-Quality Construction** The HP 11004A is a well-engineered transformer designed for professional radio applications, built to last with durable materials and precise winding techniques.

2. **Wide Frequency Range** Covers 5 kHz to 600 kHz, making it suitable for shortwave, amateur radio (HF bands), and some medium-wave applications.

3. **Low Distortion and High Efficiency** Designed for minimal signal degradation, ensuring clean audio transmission and reception in radio systems.

4. **Compatibility with HP Equipment** Originally manufactured for Hewlett-Packard (now Agilent/Keysight) radio gear, meaning it integrates seamlessly with vintage or modern HP-based systems.

5. **Reliability in Critical Applications** Used in broadcast, military, and amateur radio setups, indicating robustness in demanding environments.

6. **Replacement Part Availability** As a legacy component, it may still be sourced from surplus markets, eBay, or specialized electronics dealers.

7. **Precision Winding** Likely features tight tolerances for consistent performance across its frequency range.

1. **Age and Obsolescence** Being a decades-old component, finding replacement parts or technical support may be difficult.

2. **Limited Modern Compatibility** May not fit directly into newer radio designs without modifications or adapters.

3. **Potential for Wear** If sourced from a used or refurbished market, it may have degraded insulation or winding integrity over time.

4. **Cost** New units are rare; used ones may be expensive due to scarcity, especially if in good condition.

5. **No Warranty or Support** Unlike modern commercial components, there s no manufacturer warranty or technical assistance.

6. **Specialized Knowledge Required** Installing or repairing it may require expertise in RF engineering or vintage electronics.

7. **Alternative Solutions Exist** Modern RF transformers or custom-wound coils may offer better performance or flexibility at a lower cost.

---

### **Conclusion**

The HP 11004A is a high-quality, specialized transformer ideal for enthusiasts working with vintage or HP-compatible radio equipment. Its wide frequency range and reliability make it valuable for shortwave and amateur radio applications, but its age and limited availability pose challenges. If you need a drop-in replacement for an existing HP system or are restoring classic gear, it may be worth the investment despite its drawbacks. However, for modern builds or general-purpose use, newer or custom transformers could be more practical and cost-effective.

---

### **Recommendation**

- **Buy if:** You have a specific need for an HP-compatible transformer in a vintage or restored radio system, and you re willing to invest in a high-quality, long-lasting component despite its limitations.

- **Avoid if:** You re building a new radio setup, need broader frequency coverage, or prefer modern, supported parts with easier availability.

- **Alternatives:** Consider modern RF transformers (e.g., from Mini-Circuits or custom-wound coils) or check surplus markets for similar but newer models (e.g., from Amidon or Wima). If restoring an HP radio, verify the exact model requirements before purchasing to ensure compatibility.

Details:

This transformer is in good cosmetic condition. If you do not see it in the photos, is likely included sale. That includes manuals, packaging, power cords, etc. The bottom line is this.

part #: 11004a prices

• $25.00-$144.39

specifications hamamateuradio:

• brand: Hp
• mpn: 11004a
• compatiblebrand: Universal
• type: Other

shipping hamamateuradio:

• transit: 3-8 Days
• class: Standard
• cost: $10.00
• service: Standard
• type: Fixed

offer hamamateuradio:

• quantity: 2
• started: February 25, 2026
• availability: In Stock
• options: Ship-to-home
• sold: 0

returns hamamateuradio:

• method: Money back
• time: 30 Days
• paid by: Seller
• policy: Returns Accepted

general hamamateuradio:

• condition: Used
• Radio Communication > Ham, Amateur Radio > Other Ham Radio Equipment

payments hamamateuradio:

• credit card: Diners-club
• other
• wallet: Paypal

seller hamamateuradio:

• rating: 100.0%
• city: Sparks, Nevada
• # reviews: 28365

Hp 11004A Is Similar To:

• 11005 Hp Transformer Excellent Bridging Condition (54.8% similar) ...(February 25th, 2015)
• 200cd Hp Model Wide Range Oscillator Tube Ham Radio Project (29.9% similar) This offer is for the one Hewlett-Packard 200CD wide range oscillator in pictures. He collected ham radio equipment. This unit powers on, but no further testing has been done. Cosmetically, the unit has scratches and wear see pictures. This offer is for one used vintage Hewlett-Packard Hp model ...(May 2nd, 2018)
• 5381a Frequency 80 Mhz Hp Counter (36.7% similar) I have an identical one listed in test equipment as well. Not seen in the photo are a couple of DE lamination scratches that are real common on these old but very fine pieces of test equipment. 1SEC, 1HZ in 1 sec, and. It is designed to deliver reliable, high quality operation in such diverse areas ...(March 4th, 2015)
• 58503b Symmetricom Hp Agilent Gps Time And Frequency Reference Receiver (28.8% similar) When locked to the GPS signal, 58503B provides a 10 MHz signal with an accuracy of better than 1X10 12 using 1 day average. The Hp agent symmetric om 58503B GPS time frequency reference receiver is a high quality source of precision time, interval, and in lightweight compact package. The high-...(November 19th, 2018)
• 5kc-600kc Excellent Condition Hp Ac60a (35.4% similar) Hp AC60A 5KC 600KC excellent condition it comes with a 14 day guarantee...(February 25th, 2015)
• 8559a Hp Spectrum Analyzer Frequency Range To (36.7% similar) 01 to 18 GHz maximum cumulative error v for 8 division deflection on CRT blanking, aux BBC output provides pen down unblinking signal at low impedance 15 pen lift blanking 10 k IMPEDANCE21 all frequency bands calibrated display RANGELOG70 db with scale 1 SCALELINEAR8 divisions linear Lin amplitude ...(November 9th, 2018)
• Cx-3300 Connex Hp Nice Adjustable Echo Board Talkback Cb Radio L993 (16.9% similar) Create listings that get noticed. Nice convex CZ 3300 Hp adjustable echo board, talk back CB radio...(July 14th, 2016)
• Cx-4600 Fm Turbo Transeiver Meter Radio 150w Connex 10 Mobile Hp Ham Amateur (23.8% similar) The convex CZ 4600 turbo has been a popular radio from convex for a few years now due to it's high output power equal to or exceeding over 100 watts pep. Designed with simple, easy to use controls and trucker specific features, this is a radio that will offer massive performance but won't require ...(October 1st, 2015)
• Hdp-21a Hw-101 Heathkit Hw 101 Radio Transceiver Hp-23 Power Supply (36.6% similar) Its a fun old radio to use, but I hate the stopping to tune the output stage, and also miss the digital display of newer radio's so after much thought it's going on to the next ham. This system is no barn find or spent years setting in a basement somewhere. This offer includes the Haw 101, Hp 23 ...(July 10th, 2016)
• Hp-23c Heathkit Model Vintage Ac Power Supply For Ham Radio Operations (29% similar) Tested on my HW-101 and works good. Heath kit model HP-23C vintage ac power supply for ham radio operations...(June 4th, 2018)
• Hp 5328a Hewett Packard Frequency (33.3% similar) Hp 5328A frequency counter with Dem option and calibrated on rubidium std. Missing blank plate on front panel but does not affect the operation. Good to over 100 MHz as well offering put functions. Ships FedEx ground. Unit has a few scratches on the case, front panel is clean...(November 14th, 2017)