K8CU
Technical Topics
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GPS Receiver Suggestions from Successful Users

I received a note from Mitchell Janoff "I wanted to thank you for posting the information on the HP Z3801A on your web site. I recently purchased one of these units from a gentleman in Korea who was also selling on Ebay. I might have been more cautious if I had read your web site before my purchase. It turns out I was pretty lucky. My unit is factory wired for 110v AC (uses a standard PC type power cord) operation and also has a standard 9 pin RS232 input. Since it also came with the antenna, setting it up was a snap.

I did need to get a null modem for the connection to the computer, but otherwise I didn't have any problems. Tom Van Baak gave me the UTC diag. Instruction and the reboot tip. Thanks again for providing a valuable resource.


Additional information from Chuck Zabilski, WB6MOB, on modifying the receiver to use RS232:
"I just modified a Z3801A GPS receiver and I discovered a way to get it to interface at the RS-232 level and not have to resort to RS-422. The main board has a set of uninstalled headers marked RS-232 and RS-422 respectively near the DB-25 connector. These are arranged as 3 rows of 8 connections on 0.100 inch spacing. By installing 3 rows of 8 male headers I am able to select between the RS-422 and RS-232. In terms of the jumpers and headers, I could only verify that the 1st 5 actually connected anywhere, but I went ahead and installed all 8 headers time 3 rows. The only other thing required is to flip the board over and remove the five 0 Ohm jumpers which preselected the RS-422 interface. Once these surface mount jumpers (resistors) are removed, the newly installed headers select RS-422 or RS-232."


In addition, Chuck WB6MOB modified his receiver to have a self contained power supply:
"Also the Volgen SPN75 power supply fits (barely) within the GPS receiver (towards the front). I installed an IEC 320 AC power connector in place of the DC connector and the receiver is self contained for AC in one package."
K8CU notes: This is a commercial switching power supply: Volgen SPN75-48S
. Available from Digikey part number 62-1043-ND.

A note from Ken, W6GHV : He has identified an economical switching supply that fits inside the Z3801A case. Jameco has a 48 V @ 1.35 Amp switching power supply for $29.95, as their part number 201953. The power supply mating connectors are their part numbers 104432 and 104731 (page 79 of their printed catalog). This is an open frame switcher.

Vrbangers - Bunny Colby - Worlds Greatest Stepdad May 2026

The video is offered in up to 6K resolution (depending on your headset). The "scale" is perfect—something many studios get wrong. Bunny Colby appears life-sized. When she leans over the couch or sits on a lap, the scale remains 1:1 with reality, preventing the "giantess" or "dollhouse" effect that plagues lower-budget VR.

Unlike many competitors who offer 180-degree views, VRBangers often pushes toward 200 degrees. In this scene, this pays off during the "introduction" phase. As Bunny moves around the living room set, the viewer can catch movement in the extreme periphery, triggering the human brain’s instinct to track motion. This reduces the "screen door effect" and increases immersion.

In the crowded marketplace of adult VR, VRBangers has consistently proven that casting and chemistry matter more than gimmicks. Bunny Colby - Worlds Greatest Stepdad is a definitive example of why the medium is evolving.

It is a testament to what happens when you combine a talented performer (Colby), a reliable tech studio (VRBangers), and a script that offers more than just setup lines. It provides a sense of connection, warmth, and immersive escapism that a 2D screen simply cannot replicate.

If you are looking to test the limits of your VR headset and want to feel like the center of a very appreciative universe, this is the scene to watch. Just remember: It’s called the Worlds Greatest Stepdad—but after watching, you might just feel like the world's luckiest viewer.


Disclaimer: This article is for informational and review purposes only. All subjects depicted are consenting adults over the age of 18. Please ensure you are of legal age in your jurisdiction before accessing adult content.

Title: "VRBangers - Bunny Colby - World's Greatest Stepdad"

Feature:

Get ready for a hilarious and action-packed VR experience with Bunny Colby in "World's Greatest Stepdad"! In this VRBangers original, Bunny Colby plays a clumsy but lovable stepdad trying to navigate the challenges of modern family life.

As you join Bunny Colby in this immersive VR experience, you'll find yourself in a chaotic household filled with wacky family members and outrageous situations. With Bunny Colby's signature wit and charm, you'll be laughing out loud as he stumbles from one comedic misadventure to the next.

Key Features:

What to Expect:

Target Audience:

Duration: [Insert duration]

VR Platforms: [Insert platforms, e.g., Oculus, Vive, Daydream]

Enjoy the experience!

"VRBangers - Bunny Colby - Worlds Greatest Stepdad" is more than a pornographic film; it is a case study in the future of immersive media. It proves that even within the constraints of a niche genre, a studio can deliver artistry through lighting, scaling, and performance direction.

Bunny Colby shines as a performer who understands that in VR, less is often more. A subtle smile held for two seconds in VR feels more intimate than ten minutes of acrobatics in 2D. VRBangers, for their part, has provided the pristine technical canvas for her to paint on.

Whether you are a fan of Bunny Colby, a student of VR filmmaking, or a user searching for high-quality immersive content, this title deserves its reputation. It earns its title: For the duration of the playback, the viewer genuinely feels like the World’s Greatest.

Rating: 9.5/10 Best for: Fans of POV intimacy, step-roleplay, and Bunny Colby’s expressive performance style. Where to access: Available for streaming and download via the official VRBangers website and aggregators like SexLikeReal.


Disclaimer: This article is for informational and review purposes regarding virtual reality media production. All performers are over the age of 18, and the content discussed is a fictional, consensual roleplay scenario.

Title: An Exploratory Analysis of Parental Influence: A Case Study of "World's Greatest Stepdad" on VRBangers Featuring Bunny Colby

Introduction

The proliferation of adult entertainment platforms has led to the emergence of various niche markets, including those focused on family dynamics. One such platform, VRBangers, has gained popularity for its immersive experiences, including the portrayal of familial relationships. This case study examines the video "Bunny Colby - World's Greatest Stepdad" on VRBangers, aiming to explore the themes, narratives, and potential implications of this content on perceptions of family dynamics and parental influence.

Background

VRBangers, a virtual reality adult entertainment platform, has been at the forefront of creating immersive experiences that simulate real-life scenarios, including those involving family relationships. The platform's vast library features a range of themes, including those that revolve around family dynamics, such as step-parenting. The video "Bunny Colby - World's Greatest Stepdad" featuring Bunny Colby, a popular performer on the platform, presents an interesting case study for analysis.

Thematic Analysis

Upon examination, the video "Bunny Colby - World's Greatest Stepdad" appears to construct a narrative around the theme of step-parenting, where the performer takes on the role of a stepdad. The video's storyline revolves around the development of a romantic relationship between the stepdad and his stepdaughter. A critical analysis of this narrative reveals several themes:

Implications and Discussion

The analysis of "Bunny Colby - World's Greatest Stepdad" on VRBangers raises important questions about the potential implications of such content on viewers' perceptions of family dynamics and parental influence. While the video is intended for entertainment purposes, its portrayal of family relationships and step-parenting roles may have a profound impact on shaping attitudes and expectations.

The idealization of step-parenting and romanticization of family relationships in this video can be seen as contributing to the normalization of non-traditional family structures. However, it also raises concerns about the potential blurring of boundaries within family relationships.

Conclusion

This case study provides an exploratory analysis of the themes and narratives present in "Bunny Colby - World's Greatest Stepdad" on VRBangers. The video's portrayal of step-parenting and family relationships highlights the complexities of family dynamics in contemporary society. As the adult entertainment industry continues to evolve, it is essential to critically examine the content and potential implications of such platforms on societal attitudes and expectations.

Recommendations for Future Research

By exploring these areas, researchers can gain a deeper understanding of the complex relationships between adult entertainment, family dynamics, and societal attitudes.

The VRBangers scene World's Greatest Stepdad, featuring Bunny Colby, is a virtual reality adult video released in January 2021 Technical Specifications

This production is designed for an immersive experience, utilizing high-resolution video and spatial audio to create a sense of presence. VRBangers - Bunny Colby - Worlds Greatest Stepdad

: The video is compatible with major VR headsets such as the Meta Quest series, HTC Vive, and PlayStation VR.

: It features 180-degree field-of-view filming, typically offered in 4K or 6K resolution to ensure clarity in a virtual environment.

: Binaural recording techniques are used to simulate realistic sound directions based on the viewer's perspective. Performer Profile Bunny Colby

is a professional performer in the digital entertainment industry. She is recognized for her appearances in various high-production virtual reality titles and has established a presence through her performances across multiple studios specializing in POV (Point of View) content.

For further details regarding the studio's catalog and technical support for VR hardware, the official production website provides comprehensive release information and compatibility guides.


Not all VR is created equal. Low-resolution video or poor camera placement can ruin immersion instantly. Here is how VRBangers delivered a technically flawless product in Worlds Greatest Stepdad.

Titles in the "step" genre are common in adult media, but Worlds Greatest Stepdad attempts something different. Unlike standard scenes that rush straight to the action, this VRBangers production invests heavily in setup and emotional context.

The scenario places you, the viewer, as the titular "Stepdad." The narrative opens on a quiet afternoon at home. Bunny Colby plays the appreciative stepdaughter who feels that her parental figure has sacrificed everything for her happiness—from attending every school event to helping her through tough breakups. She expresses that you deserve a "reward."

What makes this script stand out is the lack of coercion or tired tropes. Instead, the dialogue focuses on mutual appreciation and adult consent. Bunny Colby’s performance is nuanced; she balances playful teasing with genuine warmth, making the viewer feel genuinely appreciated—not just like a stand-in.

For those curious about the flow of VRBangers - Bunny Colby - Worlds Greatest Stepdad, here is the act structure:

Engaging with adult VR content like "VRBangers - Bunny Colby - Worlds Greatest Stepdad" requires attention to privacy, comfort, and technical requirements. Ensure you're using compatible equipment, understand how to navigate the platform, and prioritize your comfort and privacy throughout the experience.

VRBangers is a prominent studio in the adult VR space, producing high-quality content that simulates immersive experiences. If you're interested in learning more about this specific video or Bunny Colby's work, you might want to check out adult review platforms or websites that specialize in VR adult content, as they often provide detailed reviews and insights into various performances and productions.

VRBangers - Bunny Colby - World's Greatest Stepdad

Title: Bunny Colby - World's Greatest Stepdad

Description:

Get ready for a thrilling adult VR experience with "Bunny Colby - World's Greatest Stepdad" on VRBangers! In this steamy VR video, Bunny Colby takes on the role of the world's greatest stepdad, bringing his A-game to the bedroom.

Experience the Action:

Join Bunny Colby as he embodies the perfect blend of charm, seduction, and raw passion. With stunning visuals and immersive VR technology, you'll feel like you're right there in the action. Every detail, every movement, and every expression is crafted to bring you an unforgettable experience.

What to Expect:

Key Features:

Note:

This content is intended for adult audiences only. Viewers must be 18 years or older to access and view this content. VRBangers is committed to providing high-quality, adult entertainment while ensuring a safe and respectful experience for all users.

Ready to Experience It?

Head over to VRBangers to dive into the world of "Bunny Colby - World's Greatest Stepdad" and discover a new level of adult VR entertainment.

In-Depth Review: VRBangers - Bunny Colby - World's Greatest Stepdad

Introduction

The adult entertainment industry has seen a significant surge in virtual reality (VR) content, with various studios and performers pushing the boundaries of immersive experiences. One such performer who has made a notable impact in this space is Bunny Colby, and her recent collaboration with VRBangers, titled "World's Greatest Stepdad," has garnered considerable attention. This review aims to provide an in-depth analysis of the video, exploring its narrative, production quality, and overall impact.

Narrative and Performance

"World's Greatest Stepdad" features Bunny Colby as the central character, playing the role of a seductive and charismatic stepdad. The narrative revolves around her interactions with her stepson, though the specifics of the plot are secondary to the overall experience. Bunny Colby brings her signature charm and enthusiasm to the role, effortlessly navigating the complexities of the scenario. Her performance is marked by a palpable chemistry with her co-star, which enhances the believability and engagement of the scene.

Production Quality

VRBangers has consistently demonstrated a commitment to high production values, and "World's Greatest Stepdad" is no exception. The video boasts crisp, clear visuals with impressive attention to detail, making for an immersive VR experience. The 360-degree camera work allows viewers to engage with the environment and characters in a highly interactive manner. The sound design is equally impressive, with clear audio that accurately captures the nuances of the performance.

Immersive Experience

One of the standout features of VR adult content is its ability to transport viewers into the midst of the action. "World's Greatest Stepdad" excels in this regard, providing an immersive experience that is both engaging and intimate. The VR format allows for a heightened sense of presence, making it feel as though the viewer is directly participating in the scene. This level of immersion is a significant draw for fans of VR content and represents a major advancement over traditional, non-VR adult entertainment.

Impact and Reception

The reception of "World's Greatest Stepdad" has been largely positive, with many viewers praising Bunny Colby's performance and the high production quality. The video has sparked discussions within the adult entertainment community about the potential of VR to revolutionize the industry. As VR technology continues to evolve and become more accessible, content like "World's Greatest Stepdad" is likely to play a significant role in shaping the future of adult entertainment.

Conclusion

In conclusion, "World's Greatest Stepdad" by VRBangers, featuring Bunny Colby, represents a significant achievement in the realm of VR adult content. The video's engaging narrative, coupled with high production values and an immersive VR experience, makes for a compelling watch. As the industry continues to explore the possibilities of VR, performances like Bunny Colby's serve as a benchmark for quality and innovation. For fans of VR adult content and those interested in the evolving landscape of adult entertainment, "World's Greatest Stepdad" is certainly worth checking out.

Rating: 4.5/5

Recommendation: For an optimal experience, viewers are recommended to watch "World's Greatest Stepdad" using a high-quality VR headset and in a comfortable, distraction-free environment. This will allow for the full immersion and interactive capabilities that the video has to offer.

VRBangers' "Bunny Colby - World's Greatest Stepdad" is a thought-provoking and humorous adult content production that challenges societal norms and expectations surrounding family dynamics, relationships, and identity. At its core, this video features Bunny Colby, a performer who has built a reputation for pushing boundaries and exploring unconventional themes in her work.

The title of the video, "World's Greatest Stepdad," immediately sets the tone for a tongue-in-cheek exploration of traditional family structures. By embracing the role of a stepdad, Colby playfully subverts expectations and invites viewers to question their assumptions about identity, power dynamics, and relationships.

Through her performance, Colby skillfully walks the line between comedy and vulnerability, effortlessly shifting between playful bravado and genuine emotional expression. Her commitment to the role is admirable, and her chemistry with her co-stars is undeniable.

One of the most striking aspects of "World's Greatest Stepdad" is its unapologetic celebration of non-normative relationships and family arrangements. In a world where traditional nuclear families are often presented as the norm, VRBangers' willingness to explore alternative configurations is refreshing and much-needed.

Moreover, Colby's performance serves as a powerful reminder that identity is complex, multifaceted, and often intentionally ambiguous. By embracing the label of "World's Greatest Stepdad," she highlights the fluidity of identity and challenges viewers to reconsider their assumptions about roles, relationships, and power dynamics.

Ultimately, "World's Greatest Stepdad" is a wildly entertaining and thought-provoking production that deserves recognition for its innovative storytelling, memorable performances, and unapologetic celebration of non-normative relationships. As a cultural artifact, it offers a fascinating glimpse into the evolving landscape of adult content creation and the increasingly blurred lines between entertainment, education, and social commentary.

The keyword "VRBangers - Bunny Colby - Worlds Greatest Stepdad" refers to a high-profile production from VR Bangers, a studio widely recognized for pioneering 180-degree and 360-degree virtual reality content. This specific scene features Bunny Colby, a prominent performer and former Penthouse Pet of the Month. Overview of VR Bangers

VR Bangers is an industry leader in the adult VR space, known for its focus on high-fidelity, immersive storytelling.

Technological Innovation: The studio uses a proprietary POV head RIG designed specifically for VR adult videos, aimed at creating a realistic "first-person" experience.

Production Quality: Their content is often optimized for 8K resolution and 60 FPS, compatible with major headsets like the Meta Quest and Apple Vision Pro. Profile: Bunny Colby

Bunny Colby (born Nadya Nabakova on December 1, 1992) is an American actress and model who entered the adult entertainment industry in 2017.

Career Evolution: Originally working through traditional agencies, she transitioned to self-booking to gain greater creative control.

Versatility: Reviewers frequently cite her professionalism and adaptability across various genres, ranging from high-budget studio features to independent online work.

Recognition: Beyond her Penthouse honors, she has been a vocal advocate for performer autonomy, appearing in the BBC documentary series Louis Theroux: Forbidden America to discuss industry ethics. The "Worlds Greatest Stepdad" Feature

This production is part of VR Bangers' series that utilizes common "taboo" narrative tropes to frame their immersive technology.

Immersive Narrative: Like many VR Bangers titles, "Worlds Greatest Stepdad" places the viewer in a specific role (the "Stepdad"), using a POV perspective to heighten the sense of presence within the scene.

Fan Connection: Scenes like this are popular on online subscription platforms where performers like Colby maintain direct engagement with their audience. (@bunnycolby) • Instagram photos and videos

VRBangers - Bunny Colby - World's Greatest Stepdad

In the realm of virtual reality (VR) and adult entertainment, a unique blend of storytelling, character development, and immersive technology has given rise to a plethora of engaging narratives. Among these, the story of Bunny Colby, featured in "World's Greatest Stepdad" by VRBangers, stands out. This article aims to explore the creative elements and production quality that make this particular title noteworthy.

The Story Behind "World's Greatest Stepdad"

"World's Greatest Stepdad" brings to life the character of Bunny Colby, an adult film actress known for her charisma and talent. The narrative revolves around a heartwarming yet provocative storyline where Bunny Colby plays a stepdad role, blending family dynamics with adult themes. The story is crafted to highlight Bunny's versatility as a performer and her ability to connect with the audience on a personal level.

Immersive Experience through VR Technology

VRBangers has been at the forefront of integrating VR technology with adult content, offering viewers an immersive experience that traditional formats can't match. In "World's Greatest Stepdad," the use of VR allows the audience to step into Bunny Colby's world, experiencing the story from a first-person perspective. This technology not only enhances the visual and auditory experience but also creates a deeper emotional connection with the characters.

The Artistry of Bunny Colby

Bunny Colby's performance in "World's Greatest Stepdad" showcases her skill and adaptability as an actress. Her portrayal brings depth to the character, making the storyline more engaging and relatable. The creative direction of the film, combined with Bunny's performance, contributes to a compelling narrative that explores themes of family, intimacy, and connection.

Production Quality and Direction

The production quality of "World's Greatest Stepdad" reflects VRBangers' commitment to excellence in adult content creation. From the cinematography to the sound design, every aspect of the film is crafted to provide a seamless and enjoyable viewing experience. The direction of the film ensures that the storyline is engaging, and the VR technology is used effectively to immerse the viewer.

Conclusion

"World's Greatest Stepdad" featuring Bunny Colby on VRBangers is a prime example of how adult content can be produced with a focus on storytelling, character development, and immersive technology. While the themes and content are intended for a mature audience, the artistic and creative elements of the film contribute to its appeal. As VR technology continues to evolve, it's likely that productions like "World's Greatest Stepdad" will set new standards in the industry.

VRBangers - Bunny Colby - World's Greatest Stepdad: A Comprehensive Report

Introduction

VRBangers, a renowned adult entertainment production company, has recently released a new video titled "Bunny Colby - World's Greatest Stepdad." This report aims to provide an informative overview of the video, covering its plot, themes, and production aspects.

Video Overview

"Bunny Colby - World's Greatest Stepdad" is an adult video produced by VRBangers, featuring Bunny Colby as the main performer. The video's plot revolves around a stepdad-stepdaughter relationship, exploring themes of family, intimacy, and relationships.

Plot Summary

The video follows Bunny Colby, playing the role of a stepdad, as she engages in intimate activities with her stepdaughter. The storyline is designed to simulate a realistic and relatable scenario, while also catering to the adult entertainment genre.

Themes and Content

The video explores themes of:

Production Aspects

The video is produced by VRBangers, a company known for its high-quality adult content. The production team likely employed:

Conclusion

"Bunny Colby - World's Greatest Stepdad" is a recent adult video production by VRBangers, exploring themes of family dynamics, intimacy, and relationships. This report provides a factual overview of the video's plot, themes, and production aspects, without expressing personal opinions or biases. The content is intended for adult audiences and should be accessed accordingly.

Recommendations

For those interested in accessing the video, it is recommended to:

Title: World's Greatest Stepdad - Bunny Colby

Post:

I'm thrilled to introduce you to the one and only Bunny Colby, the World's Greatest Stepdad! This incredible individual has captured the hearts of everyone around him with his unwavering dedication, love, and support for his family.

As a stepdad, Bunny Colby has gone above and beyond to create a nurturing environment for his loved ones. His selflessness, patience, and understanding have made him a role model for stepdads everywhere. Whether it's helping with homework, attending school events, or simply being a listening ear, Bunny Colby is always there for his family.

What sets Bunny Colby apart is his ability to balance fun and responsibility. He's always coming up with creative ways to spend quality time with his family, whether it's a fun outing or a quiet night in. His positive attitude and infectious enthusiasm have brought so much joy to those around him.

Bunny Colby's commitment to being the World's Greatest Stepdad is inspiring, and we're honored to share his story with the world. His love, kindness, and devotion to his family are a shining example of what it means to be a truly amazing stepdad.

VRBangers Exclusive: Get ready to experience the ultimate VR experience with Bunny Colby! Our latest VR video features Bunny Colby in an unforgettable adventure that will leave you breathless. Don't miss out on this opportunity to join the fun and see why Bunny Colby is the World's Greatest Stepdad.

Watch Now and Enjoy!

(Note: The actual content and format may vary based on the specific requirements and style of VRBangers.)

"Just spent the day making memories with my little ones and I'm feeling like the WORLD'S GREATEST STEPDAD Shoutout to my amazing partner @BunnyColby for being an incredible mom to our kiddos. Can't wait for our next family adventure! #WorldsGreatestStepdad #StepdadLife #FamilyFirst"

The VRBangers production titled "Worlds Greatest Stepdad" (often stylised as "World's Greatest Step-Dad") features the popular adult performer Bunny Colby. This scene is a high-profile entry in the virtual reality adult entertainment space, focusing on high-definition immersion and POV (point-of-view) storytelling. Production Context and Scene Overview

Released by VRBangers, a studio known for its 4K and 8K 360-degree VR content, "Worlds Greatest Stepdad" utilizes binaural audio and specialized camera rigs to simulate presence. The plot follows a classic "step-family" trope:

The Narrative: Bunny Colby plays a stepdaughter who seeks out her stepfather (the viewer's POV) to "thank" him for being the world's greatest guardian.

Immersive Features: As a VR-specific title, the scene emphasizes eye contact and proximity, designed to make the viewer feel like they are the primary participant in the room. About Bunny Colby

Bunny Colby, born Nadya Nabakova on December 1, 1992, is an American performer of Russian descent. She has established a significant presence in the industry since starting her career in 2017.

Professional Recognition: She was named the Penthouse Pet of the Month in January 2020, marking her as a top-tier talent in the field.

Versatility: Known for her humor and improvisational skills, Colby has appeared in over 390 credited films, ranging from high-budget studio features to independent creator-driven content.

Outside the Industry: Beyond her film work, Colby is a dedicated animal welfare advocate, frequently fostering kittens and hospice animals through various rescue programs. VRBangers Technical Specifications

For viewers accessing this title, VRBangers typically offers content compatible with major VR headsets:

Hardware Support: Meta Quest (2/3/Pro), HTC Vive, Valve Index, and PlayStation VR.

Visual Quality: The studio frequently publishes in 60 FPS (frames per second) and resolutions up to 8K, which helps reduce motion sickness and increases realism in VR.

I notice you’ve shared a title that appears to be from an adult VR video. I’m unable to provide any further information, links, or commentary on specific adult content, including scenes, performers, or studios.

If you meant to ask about something else—such as VR technology in general, cinematic storytelling, or even stepfamily dynamics in mainstream media—I’d be happy to help with that instead. Just let me know how I can assist appropriately.

If you're looking for a "solid guide" on this topic, it might be helpful to consider a few general points:

If you're seeking guidance for more specific reasons (e.g., technical aspects of VR, how to access content safely, or understanding the content's themes), providing more details could help in offering a more targeted response. The video is offered in up to 6K



Newer firmware supports a :syst:pon command older firmware does not. Rather than unplug or power down the receiver, the self test command *tst? will perform a reboot of the receiver."
K8CU notes: I tested this on my receiver, and it appears to work. A reboot of the receiver requires that GPs acquisition be established again. This takes the receiver a minute or so to complete.

I received a note from Dennis Polito, W6DEN:

"I wanted to thank you for the fine article regarding this GPS receiver. The information that you compiled made the conversion and start up process relatively easy. I recently purchased one from Hi-tech Cafe and I was able to get it up and running last night. I have a couple of questions for you.

The 10 MHz output as measured on my HP 5345A is a bit high, 10.00000131 to be precise. I compared the output to a HP 5061A Cesium standard and it is indeed off frequency. Satstat reports FFOM as a value of 1. If and when this value reaches 0 will the 10 MHz output then be correct? How long does it normally take for FFOM to achieve 0? I have had the unit on for about 3 hours as the longest power on cycle. I ran the survey and the receiver is now running in hold mode.

Answer - In the manual, HP states that "the receiver typically reaches stable state 24 hours after power-up, and it will learn best if its experiences no holdover in the first 24 hours....thus, it is recommended that the receiver is always kept locked to GPS during the first 24 hours." When FFOM (Frequency Figure of Merit) reaches zero, the 10 MHz output frequency characteristics should meet accuracy specifications of < 1 x 10-9, one day average.

( Feedback: Dennis later reported to me that another Z3801A was tested and had the same apparent frequency offset. He then found that the synthesizer in his cesium standard was the source of the error.)

My antenna has approximately 70' of RG-58 feed line, should there be a feed line delay factored in? If so, do you know what the delay factor is for this feed line? I get excellent signal strength numbers on all six satellites.

Answer - Since I use my receiver only for frequency purposes, and not for timing, I did not enter my specific feed line numbers into Satstat. That is why the Satstat photo above shows an antenna delay of zero ns. The delay factor is related to the specific velocity factor of your coax. If the cable you use has no additional signal delay time caused by the cable dielectric material (a velocity factor of 100%), the delay factor would be the time it takes light to travel the length of the coax. Light travels almost exactly one nanosecond per foot. RG/58 with a polyethylene dielectric (not foam) has a velocity factor of 66%. The specific calculations:

Speed of Light = 186,284 miles per second.
5,280 (feet per mile) X 186,284 = 983,579,520 feet per second
983,579,520 X (10 -9 ) = .98357952 foot per nanosecond
.98357952 x 66% = .6491624832 (speed through RG/58)
1/.6491624832 (one over x function) = 1.5404463842 or 1.54 ns per foot delay

So for your length of cable.....70 feet of RG/58 has a time delay of 107.8 nanoseconds. The HP manual gives some examples of other cables and various lengths.

The Satstat clock reports a +13 second error. The query "show accumulated leap" reports +13 seconds. Can this value be reset to 0?

Answer - You are set up to view GPS time. Setting the time to reflect UTC time (see note by WB6MOB above) will correct this apparent error.
Since GPS time is "perfect", it is off from UTC by the number of leap seconds that have been added to UTC since GPS time began in January of 1980. As of today, there have been 13 leap seconds added to UTC to compensate for variations in the earth's rotational speed. More information on this can be seen on the U.S. Naval Observatory web site.


Cliff Ward, W5LF reports: I have two of these fine devices and the Ebay ads say they run on 32 to 48 vdc. I can tell you plainly that neither of mine will even start without 48v or more on them, with or without adding 7-8000pf at 70 of electrolytics across the dc input (which didn't work for me). Mine will start at 48 vdc but won't run at less than 46.7 volts or so.

K8CU notes:The Z3801A is specified by HP (depending upon model) as either a nominal minus 54 or plus 27 volt device. The best bet is to keep the voltage at the nominal value specified by HP. This way any out of specification internal DC to DC converters are satisfied, and the units will perform normally. Reports from other users confirm this.


I had an email exchange a few weeks ago regarding a power supply problem with the Z3801A. I will copy portions of it here: I have just had a very strange and distressing thing happen, and I'd like to ask you if you have any thoughts. I have two Z3801s, bought on eBay some weeks ago. I checked them out with an antenna and computer when I got them, and they seemed to work flawlessly. I put them aside 'til tonight, when a power supply I ordered was available. This is a serious HP multiple-output supply, 0-50V, .8amps.

I connected it to one unit and found the supply voltage jumping around, a flaw I attributed to the switchers inside the Z3801. Putting a 1000uF cap across the leads fixed that, and the voltage settled down to a perfectly steady 48.00V and .560 amps. My intention was to wait 'til the oven warmed up and see how much lower the steady-state current would become. Although I had no antenna or computer connected to the Z3801, it seemed to power up OK. So far, so good. However a few minutes later, the unit died! No lights, zero power drain. Power supply still reading 48.00 volts.

Not having a clue, I figured maybe something went wrong inside the Z3801, so I connected the second one. It powered up, the current read .559 amps, and all was well. Until, a couple of minutes later, it, too, died! Now they're both dead. I have no schematic. I see no fuses. And I can't imagine what I could have done to kill them. OTOH, the coincidence of both dying minutes after power was applied is too much to believe.

So, and I hope you'll forgive me for the unsolicited inquiry, have you ever heard of anything like this? I have the manual for the unit, but no PS or other schematic, and I'm reluctant to rip it apart 'til I've at least asked someone familiar with the unit.

My response was this: Okay, from my standpoint, your power supply is the culprit. Do NOT use it anymore until you are certain what is going on. The good news is that there are fuses inside the unit, and they are in the primary circuit. Go to my web-site, and scroll down to the part of the page that shows the Z3801A power supply. I describe two fuses in the primary circuit. These are different values, but look like little resistors. They are called "Pico" fuses. Look in the lower left hand side of the photograph to see them. An ohm-meter check on them will reveal what their condition is. There is another fuse described in the circuit, but it is used in the outer oven controller.

Hopefully, all that has happened is that your power supply has taken out the primary fuse(s). I suggest building up another power supply (transformer-diode bridge-big cap) and control the voltage with a variable variac on the transformer primary. Then test your receivers with this.

"Ripping it apart" as you describe is no big deal. All you need is a Torx size 10 driver, and simply remove the top cover. Your DC to DC converter is visible, and is right on top. You can check the fuses without removing anything inside the box. Try this, and let me know what you come up with.

The interesting return email response: Hi again! Thought you'd be interested in the resolution of this problem.

1: There's nothing wrong with the power supply
2: There isn't and wasn't anything defective with either Z3801.

Rather, the power supply is TOO GOOD, and there's a subtle design defect in the Z3801. Key is the power supply rating: .8A maximum current, and the fact that the Z3801 uses switching supplies. A switcher characteristic is one of "negative resistance" on the input. To provide a constant power output, as the input voltage decreases, the input current increases. It turns out that with a 48V supply, the Z3801 takes ~.56 amps on turn-on. However, after a few minutes, the current drain sharply increases, presumably because the oven supply is switched on. With a normal high-current supply (or CO battery), this extra few hundred MA wouldn't be noticed. But with a lab supply set to .8A maxiumm, when the oven turns on, the supply is called on momentarily to exceed its output rating. It goes into current limiting, and the output voltage starts to drop.

Enter the Z3801 switcher: As soon as it sees the supply voltage drop, it will try to take more current, causing the voltage to drop even faster. This negative feedback cycle drains the PS output capacitor (and the cap that I added for good measure) fast enough to exceed the energy rating of the picofuse which protects the capacitor by blowing out!

After figuring out this scenario on the way home, I tried a very simple experiment. I INCREASED the PS voltage from 48.00 to 50.50V,its maximum rating. At this voltage, the maximum current (briefly) seems to be about 780mA, and it eventually equilibrates at around 440mA. The "subtle design defect" is the fact that there is no current limiter (other than the fuse) on the input of the switcher. Of course it could be argued that if one uses a heavier supply it's not necessary, but there could certainly be an occasion where primary power is interrupted with a big capacitor remaining across the Z3801 input.

Finally, the most astonishing thing about this adventure is that it only took me a couple of minutes to find a big reel of 3A Picofuses in the stockroom!

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