Wednesday, December 7, 2016

A Small Experimental Receiver Circuit

I have finally found some time to "melt some solder" at my new location and new eShop bench. The bench is not finished yet, but I needed a Solder FIX.

This, like all of my project, is an attempt to make projects as small as my abilities allow.

New eShop Bench
The project that I am working on is some boards I just received back from OSH Park. The boards are a small and part of an experimental HF Receiver. The boards edge connectors are "Castellated" to allow them to be used within a larger PCB circuit, and with attached Headers, they can be used with/on a Solderless Proto Board.

The size of these boards are:
Left: 0.8x1.0 inch,
Right: 0.5x1.0 inch

This is my experimental design, it is a circuit that contain the:  HF VFO Mixer, Band Pass Filter (BPF, 40MHz), and BFO Mixer.

The bigger boards on the left are similar to those on the right, except they also contains the Oscillators for both the VFO and the BFO, along with the voltage regulator for the oscillator chip.

The components on the lower half are installed
Ready for some testing
Unpopulated is the VFO/BFO and Voltage Regulator
LTSpice suggests this circuit will work, but assessing the actual performance is the real reason for building this experimental circuit.

Additional circuits will be needed, to make this a real receiver, like: Band Select Filters, Automatic Gain Control, Audio Circuit, a Microcontroller, and Display. Likewise, I will make each as small as I can.

Testing will start when I have some (more) time.

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Sunday, November 20, 2016

My new eShop

UPDATED: 11/21/2016

I have NOT posted anything for several (6) months, my life has been in somewhat of turmoil (maybe, I am getting too old for this), but now, maybe things are starting to get back to normal.

Regardless, I have been thinking of many HomeBrew projects that I want to build and blog. But first I have to set up my eShop in this new (and better) location.

This is the beginnings of my new eShop setup:

My new eShop Bench
I just finished building the wooden shelves. My previous eShop shelves were about the same but fixed, these shelves are movable, and therefore this setup should be more effective for varying sized electronic equipment.

Adjacent to that,  is my current MS 10 WorkStation, Raspberry Pi, and Orange Pi set ups:

Computer Workstation
The three bottom screens are connected to the MS WorkStation, and the three uppers are for the PI's.

Note: and the refrigerator is only about 15 feet away, hihi.

Unfortunately, I have not started my Ham Station and Antenna System yet.

I have some small Ham Radio related PC boards out for manufacturing at OSH Park, if they works as expected, I may be blogging about those, soon.


The day after installing my shelves and turning on the Oscope for the first time in a long while, the (calibration) trace is going bonkers, with a short bright spot at the beginning of the trace. Trace INTEN has little control.  DANG, now something else to repair.

Tuesday, May 3, 2016

FORD Rant - Oil Cooler Bypass Valve - is a non replaceable part.

UPDATED: Tue May 17 11:19:46 PDT 2016

This is post not about Electronics, it is a RANT about FORD.

For the last few weeks, my Son and I have been working on his F350 6.0L Diesel Engine, to replace; the Exhaust Gas Recirculation (EGR) Heat Exchanger, and the Oil Cooler. This work is a pain because most of the top of the engine, including the Turbo Charger has to be removed to get to the parts being replaced. There are several good Youtube video showing the details.

We ordered parts and gaskets bases on information available. This repair is somewhat of a difficult task due to engine compartment large size and the long reaches necessary to access everything.  There is one very dirty mess when the Oil Cooler cover is removed, where about a quart of oil spills over the engine valley, but that cleanup marked the beginning of the actual part replacement and rebuild.

Most of the previously dis-assembled parts where replaced in the order they were removed without difficulty.

But Then

FORD Failed
Oil Drain Back and Oil Cooler Bypass Valve Assemble
On top of the Oil Cooler Cover there is a small assemble which is held in place with two screws within the Oil Filter Case (Can). This small assemble is about 3 inches wide.

This small assemble holds two valves; one to Drain Back oil from the Oil Filter Case (helpful during oil and filter changes), and the other is the Oil Cooler Bypass Value (OCBV) which opens in case the Oil Cooler get clogged up. These two valves are very simple; the first is held shut by gravity and can pressure; the other is a spring loaded Brass Plunger with a small flat plastic/rubber (of some sort) washer (flapper) that opens at 25lbs of Oil Cooler pressure.

Spring Loaded Oil Cooler Bypass Value
The Brass Plunger shows scoring
The Wood Chip holds open the washer at the failure.

The Problem

According to FORD, these two small values are NOT replaceable parts !!

And therefore, normal Auto Parts stores do not have the parts, nor does FORD.

Our OCBV plastic/rubber seal is damaged, and the Brass Plunger is scored showing that it had failed long ago.

The values can only be replaced with a NEW Oil Cooler Cover, which is about $180.00, the plastic/rubber part, if available, should only cost about $2.00, even though it is about $0.10 worth of plastic/rubber.

My Conjecture

I suspect that the OCBV failure contributed to the EGR Cooler failure and therefore the need to repair this engine - it is a $0.10 part ?

Our Planned Fix

Google searches provided very little help or suggestions of a solution.

Our current plan is to create a new Teflon washer (value flapper). A Teflon rod is now on order. Experiments with different on-hand materials failed to hold up in a gas/oil environment.  Teflon appears to have the right properties; inert and high temperature resistant.

Thanks FORD, my Son's truck has be on blocks for about three weeks now, while finding a workable solution.

End Rant

If this works as planned, I will be selling Teflon washer, and or Teflon Plunger with integrated Teflon Value seat, . . . soon :-).

Teflon Washer
The engine has now been running with the new Teflon Value Seat for several weeks, when the oil is changed it will be removed and inspected for ware.

Here is a photo of the Bypass Valve Assembly reinstalled ( I had forgotten I took this photo). The Oil Filter Tower and Canister have not been reinstall yet, as can be seen, two screws hold the assembly in place. Inspection for ware at the next oil change, will be easy.


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Monday, February 1, 2016

ASCII Strings within the Largest Known Prime Number

Someone on the Youtube Numberphile Channel was wondering if after converting the Largest Prime Number  to base 26 (see previous post) would there be any interesting ASCII strings within the Number.

I think I have created a Unix Function that will do the conversion.

( echo "obase=16;"; echo "obase=26; 2^74207281-1" | bc | tr -d '\n\\' | sed 's/ /;65+/g' ) | bc | xxd -r -p

This will take a while (maybe several hours, or days), but if I find something interesting, I will report the results.

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Friday, January 22, 2016

The New Largest Prime Number Found

Added Details and Links

Recently (Jan 7. 2016) the next and Largest Prime Number has be found (so far), it has about 22 Million Digits long, See, YouTube at:

The number can be expressed as a small-simple math function, that is: "2^74207281-1"

The previous Large Prime Number (17 Million Digits) was found about 3 years ago on Jan 25, 2013, see:

Hopefully, and if history hold true, we will see the next Largest Prime sometime within the next 3 to 5 years.

Just for fun, I decided to see how long it would take my 3.4GHz Workstation to perform the calculation and print the full 22 Million Digits to the screen - it took about 154 minutes - it was like watching paint dry.  :-)

Note: To verify that it "is actually prime" would probably take several months (or more actually several years) on my computer.

Here is the linux command that I used to print this New Prime, and a few of the Beginning and Ending Digits of the results:

$ time echo "2^74207281-1" | bc

 .  ( 22 Million More Digits )


real 153m50.931s
user 92m34.588s
sys 0m13.496s

Note: To capture the number on the screen, a large display buffer of more than 22 Meg Bytes (of RAM) was necessary.

I need to check with YouTube and/or Numberphile to see if my calculated number is correct  :-)

My computer is current checking four large numbers to see if they are Prime, this consumes about 100% of the Quad Core CPU, but it runs at a very low priority so it does not effect my use of the computer. Each is expected to finish at different times, Below shows the number being tested, and number of days until I should have the results:
As you may have expected, . . . I am a fan of Very Large Numbers !

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Thursday, January 21, 2016

Simple Complexity - By Proxy

Added Details and Links

For sometime I have struggled with how to allow public access to my home web servers and Esp8266 modules without opening up my network to abuse. In the past I have managed public access via my Router, by changing its configuration of Port Forwarding and NAT.  This works, but it is a pain to manage and generally requiring a re-boot of the network for each change.

Recently, I have discovered (actually re-discovered) that an Apache2 Web Proxy Server is much easier to manage, but it has a bit of a steep learning curve, with a lot of manual pages to read. One key concept is that Apache2 ReWriteRules are a super-set of the functionality of ProxyPass, each have their own documentation web pages.

After building the Required Config files

Now, on my Router I allow only Ports: http 80, 8040, 8160, and a private ssh port for access from the Internet. Ports 8040, and 8160 are still open for historical reasons, that is, they are used for my published Web Pages at:, and my Esp8266 Server Farm devices.

The Apache2 Web Server supports: Virtual Host Names with Proxy Redirects, ReWriteRules, and ProxPass. By setting up "*" as a CNAME (an aliases) to "" at my DNS Provider, I can use any "device name" I would like in the config files to initiate a proxy process. For example: I can now use and publish "" for one of my Esp8266 Web Server modules. The actual connection details and security are all hidden behind the proxy curtains.

The normal web page port 80 is setup with a default virtual host page of; "Error 404", only configured virtual hosts and named devices are let through the proxy.

Note: The service and/or host that is selected is a combination of both Port Number and Host Name (or alias). For an incoming connection, the file is scanned from top to bottom, only the first match is used to select the service.

The following are excerpts from my Apache2 Default Virtual Host configuration file.

LogLevel alert rewrite:trace1

<VirtualHost *:80>

    ServerAdmin webmaster@localhost
    DocumentRoot /var/www/DEFAULT/Public

    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined


# End

The following are excerpts from my Apache2 Named Virtual Host configuration file.

## Main Web Pages

## Loft Raspberry PI
<VirtualHost *:8040 *:80 >

        RewriteEngine on
        ServerSignature Off
        RewriteRule /(.*)$      http://192.168.___.___/$1 [P,L]


## Loft Raspberry PI
<VirtualHost *:8040 *:80 >

        RewriteEngine on
        ServerSignature Off
        RewriteRule /(.*)$      http://192.168.___.___/$1 [P,L]


# Esp8266 Node on Published Port 8160
<VirtualHost *:8160 >

    ServerAlias node*.wa0uwh.*
    ServerAlias localhost
        RewriteEngine on
        RewriteRule /(.*)$    http://192.168.___.___/$1 [P,L]


## Loft Esp8266 Nodes
<VirtualHost *:8040 *:80 >

    ServerAlias node*
        RewriteEngine on
        ServerSignature Off
        RewriteCond %{HTTP_HOST} ^node(129|162|164|168|169|170|172)\.wa0uwh\.com [NC]
        RewriteRule /(.*)$      http://192.168.___.%1/$1 [P,L]
        RewriteRule /(.*)$ -  [R=404,L]


## Loft WA0UWH Web Server
<VirtualHost *:8040 *:80>

    ServerAlias *
    ServerAlias localhost 192.168.__.__ 
        DocumentRoot    /var/www/WA0UWH/Public
        Alias /gallery  /var/www/WA0UWH/Public/Gallery


# End

Note, the above is just an excerpt from my Apache2 Virtual Host config file. For security reasons, the details; actual IPA's (___), BlackListing, Hacker Traps, Web Abuse Traps, and HoneyPots, are NOT included . Google is your friend for suggested configurations.

Now, with simple edits of the Apache2 Virtual Host config file, I can turn ON or OFF, devices and/or services as desired, while leaving only the http and ssh ports open for public access at the router.

Also note: each of my Raspberry PI Web Servers also have similar Apache2 Virtual Host config files, that is: Proxies are serving Proxies, and most often the actual destination is at different physical locations, and on different Networks! All unseen for my Internet users.

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