AM broadcast band filter

For the W5TSU.net:8030 receiver I build a broadcast band filter. This should front end overload and intermod created by these stations and allow for better Ham band receiption. I also wanted to learn how to build my own coils.

I found a design at the vk3il blog. This filter was modeled with the ELSIE (free version). It is a 7-pole Chebychev filter with cutoff frequencies of 1.7MHz.

Scmatic

I started by winding some coils from 22, 26 and 30 awg magnet wire. I use a MingHe model LC100-A meter to masure these coils. I found holding the coils with my fingers didn’t make a sizeable different in the coil. What did make a difference was how tight the coile was wound and the lingth of the wire used. The size of the winding did make some difference but not as much as the amount of wire and how stable the winds where.

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APRS Transmitter

I’m working on the design of a APRS Tracker transmitter. The dream is a self contained radio transmitter, modem, and controler with a bluetool connection to a tablet running Xastir.

There are lots of designs and APRS Trackers. Some are almost what I’m looking for. Many are out of date or the designer is dormant. The bigest example is MicroModem. Wounderful design from 2014 but the deveoper is… In his how words… “Long Time, No See”.

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W5TSU started in 1951

This is my grandfather’s ham license from 1952.

Image of W5TSU License 1952

My mother told me stories of her and her father lessioning to the radio. Him teaching her morse code. I picture in my mind, mon sitting on her fathers lap and her talking to some ham on AM.

My mother tough me my name in code when I was five. – .- .-. -.-

W5TSU

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New WSPR station

I’m fascinated by the WSPR (http://wsprnet.org) network and found out you can build a transmitter station with an Raspberry Pi.

So, because I have a few Raspbery Pi comptuers setting about doing nothing, it’s time to put one to work. The code for this is at (https://github.com/JamesP6000/WsprryPi). WSPR net has some documentation on it (http://wsprnet.org/drupal/node/5353). The output from the RaspPi is a square wave so lots of filter is needed. (http://www.gqrp.com/harmonic_filters.pdf). A kit is avaible at (http://www.kitsandparts.com/univbpfilter.php).

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KiwiSDR (UPDATED)

Start here:

I have a new radio. I picked up a KiwiSDR (http://kiwisdr.com/) receiver from Seeed. (https://www.seeedstudio.com/KiwiSDR-Kit-p-2725.html).

The KiwiSDR was developed by the Funkamateur John Seamons ZL / KF6VO, is a branch of the OpenWebSDR project and realy started life as a kickstarter project.

This is the best HF (10kz-30mz) receiver I own. With the propagation so bad (its 2017) hams are using web based SDR receivers to make contacts. I share my SDR because I use other’s SDRs. Check out the list at (http://sdr.hu).

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