The personal website of Scott W Harden
July 20th, 2019

QRSS Stitch and Stack

If the transmitter frequency is stable, transmissions start every 10 minutes, and grabbers are time-aligned to be every 10 minutes, multiple grabs can be averaged together to enhance signal-to-noise ratio. This is called QRSS Image Stacking. To simplify the process of making these images I created a new tool for the job: QRSS Stitch and Stack.

Markdown source code last modified on January 18th, 2021
---
title: QRSS Stitch and Stack
date: 2019-07-20 21:00:00
tags: qrss
---

# QRSS Stitch and Stack

If the transmitter frequency is stable, transmissions start every 10 minutes, and grabbers are time-aligned to be every 10 minutes, multiple grabs can be averaged together to enhance signal-to-noise ratio. This is called QRSS Image Stacking. To simplify the process of making these images I created a new tool for the job: [QRSS Stitch and Stack](https://github.com/swharden/QRSS-Stich-and-Stack).

<div class="text-center">

[![](qrss-stitch-and-stack-screenshot_thumb.jpg)](qrss-stitch-and-stack-screenshot.jpg)

</div>
July 20th, 2019

Started Transmitting Letters

I finished writing the microcontroller code to read the GPS time and only start transmissions when the minutes value ends with a zero. The signal now stacks nicely in 10-minute grabs. Now that GPS and the oven is working well I've started sending my call sign (AJ4VD).

AJ4VD spotted in Pensacola, FL (W4HBK)

First spot occurred while I was actively adjusting the transmission length

AJ4VD spotted in Greensboro, NC (WD4ELG)

5x frame stack (mean frame) from the WD4ELG grabber reveals the AJ4VD signal much better, and confirms the GPS timer is working well.

Markdown source code last modified on January 18th, 2021
---
title: Started Transmitting Letters
date: 2019-07-20 21:00:00
tags: qrss
---

# Started Transmitting Letters

I finished writing the [microcontroller code to read the GPS time](https://github.com/swharden/QRSS-hardware/tree/master/builds/keyer) and only start transmissions when the minutes value ends with a zero. The signal now stacks nicely in 10-minute grabs. Now that GPS and the oven is working well I've started sending my call sign (AJ4VD).

### AJ4VD spotted in Pensacola, FL (W4HBK) 

First spot occurred while I was actively adjusting the transmission length

<div class="text-center img-border">

[![](W4HBK-first-callsign_thumb.jpg)](W4HBK-first-callsign.jpg)

</div>

### AJ4VD spotted in Greensboro, NC (WD4ELG)

<div class="text-center img-border">

[![](WD4ELG-first-callsign_thumb.jpg)](WD4ELG-first-callsign.jpg)

</div>

5x frame stack (mean frame) from the WD4ELG grabber reveals the AJ4VD signal much better, and confirms the GPS timer is working well.


<div class="text-center img-border">

[![](WD4ELG-5x-stack_thumb.jpg)](WD4ELG-5x-stack.jpg)

</div>
July 18th, 2019

OSK and FSK

I got OOK and FSK working together (the S shape in the middle). I'm also now using a crude oven, but am not sure yet how stable frequency is over long time spans.

AJ4VD spotted in Pensacola, FL (W4HBK)

AJ4VD spotted in Greensboro, NC (WD4ELG)

I kept thinking my oscillator was drifting frequency because the line wasn't straight. Turns out it was my curved monitors!

Markdown source code last modified on January 18th, 2021
---
title: OOK and FSK
date: 2019-07-18 21:00:00
tags: qrss
---

# OSK and FSK

I got OOK and FSK working together (the S shape in the middle). I'm also now using a crude oven, but am not sure yet how stable frequency is over long time spans.

### AJ4VD spotted in Pensacola, FL (W4HBK)

<div class="text-center img-border">

[![](W4HBK-OOK_thumb.jpg)](W4HBK-OOK.jpg)

</div>

### AJ4VD spotted in Greensboro, NC (WD4ELG)

<div class="text-center img-border">

[![](WD4ELG-Greensboro-NC-OOK_thumb.jpg)](WD4ELG-Greensboro-NC-OOK.jpg)

</div>

I kept thinking my oscillator was drifting frequency because the line wasn't straight. Turns out it was my curved monitors!

<div class="text-center img-border">

[![](2019-07-19-curved-monitors_thumb.jpg)](2019-07-19-curved-monitors.jpg)

</div>
July 14th, 2019

Amplifier Improvements

I improved my amplifier (now output 500mW) and am impressed how well my attic dipole is doing! It runs east/west so it radiates north/south. I saw my signal on a few more grabbers.

AJ4VD spotted in Northwood, OH (N8NJ)

AJ4VD spotted in Las Cruces, NM (WA5DJJ)

AJ4VD spotted in Florida (WD4AH)

This grab shows a nice airplane reflection in the middle

AJ4VD spotted in Ontario, Canada (VA3ROM)

AJ4VD spotted in Pensacola, FL (W4HBK)

This 8-hour grab reveals when my AC kicks on and off and demonstrates the necessity of ovenizing my setup. It's the signal around 10,139,980 Hz.

Markdown source code last modified on January 18th, 2021
---
title: Amplifier Improvements
date: 2019-07-14 21:00:00
tags: qrss
---

# Amplifier Improvements

I improved my amplifier (now output 500mW) and am impressed how well my attic dipole is doing! It runs east/west so it radiates north/south. I saw my signal on a few more grabbers.

### AJ4VD spotted in Northwood, OH (N8NJ)

<div class="text-center img-border">

[![](N8NJ-Northwood-OH-USA_thumb.jpg)](N8NJ-Northwood-OH-USA.jpg)

</div>

### AJ4VD spotted in Las Cruces, NM (WA5DJJ)

<div class="text-center img-border">

[![](WA5DJJ-LasCruces-NM-USA_thumb.jpg)](WA5DJJ-LasCruces-NM-USA.jpg)

</div>

### AJ4VD spotted in Florida (WD4AH) 

This grab shows a nice airplane reflection in the middle

<div class="text-center img-border">

[![](WD4AH-FL-USA_thumb.jpg)](WD4AH-FL-USA.jpg)

</div>

### AJ4VD spotted in Ontario, Canada (VA3ROM)

<div class="text-center img-border">

[![](VA3ROM-Ontario-Canada_thumb.jpg)](VA3ROM-Ontario-Canada.jpg)

</div>

### AJ4VD spotted in Pensacola, FL (W4HBK)

This 8-hour grab reveals when my AC kicks on and off and demonstrates the necessity of ovenizing my setup. It's the signal around 10,139,980 Hz.

<div class="text-center img-border">

[![](W4HBK-Pensacola-FL-USA-unstable_thumb.jpg)](W4HBK-Pensacola-FL-USA-unstable.jpg)

</div>
July 13th, 2019

QRSS Spots

This week I strung-up a 30m dipole in the attic and built an oscillator, keyer, and amplifier (all as separate modules). I finished the amplifier this morning and spotted the signal (the rectangular squiggle) on two grabbers. I was running 3 PPV into 50 Ohm so I think that's about 22 mW.

AJ4VD spotted in Pensacola, FL (W4HBK)

AJ4VD spotted in Greensboro, NC (WD4ELG)

Markdown source code last modified on January 18th, 2021
---
title: QRSS Spots
date: 2019-07-13 21:00:00
tags: qrss
---

# QRSS Spots

This week I strung-up a 30m dipole in the attic and built an oscillator, keyer, and amplifier (all as separate modules). I finished the amplifier this morning and spotted the signal (the rectangular squiggle) on two grabbers. I was running 3 PPV into 50 Ohm so I think that's about 22 mW.

### AJ4VD spotted in Pensacola, FL (W4HBK)

<div class="text-center img-border">

[![](W4HBK-Pensacola-FL-USA_thumb.jpg)](W4HBK-Pensacola-FL-USA.jpg)

</div>

### AJ4VD spotted in Greensboro, NC (WD4ELG)

<div class="text-center img-border">

[![](WD4ELG-Greensboro-NC-USA_thumb.jpg)](WD4ELG-Greensboro-NC-USA.jpg)

</div>
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