Thursday, January 30, 2014

The QRP Diaries #4 - AGC for the X1M

Anyone thinking of purchasing an X1M QRP radio needs to join the YahooGroup. This is by far the most active YahooGroup / email reflector that I've ever been a member of.

The group started in March of 2013, and less than 1 year later there are 750 members, and 500-700 messages per month of activity.

AGC for the X1M

Dale Parfitt , W4OP was an early adopter of the X1M radio and took it upon himself to remedy the radios lack of automatic gain control.  For the newbies, that is the radio feature that tries to balance the volume levels of different signals. In Amateur radio imagine two guys talking on the same frequency. One is operating at 100 watts and the other at 1000 watts. Your roughly in the middle and listening to both. This experience is like standing between two people talking to each other, one is whispering, and the other is yelling.

From Wikipedia...Automatic gain control (AGC) is a technique found in many electronic devices. The average or peak output signal level is used to adjust the gain to a suitable level, enabling the circuit to work satisfactorily with a greater range of input signal levels. For example, without AGC the sound emitted from an AM radio receiver would vary to an extreme extent from a weak to a strong signal; the AGC effectively reduces the volume if the signal is strong and raises it when it is weaker.

The AGC SMD kit for the X1M was originally created by Dale and was designed to be extremely small and fit inside of the X1M , Dale designed and sold the kit in it's first iteration, and then moved onto working on a crystal CW filter KIT, also intended to be an internal board upgrade for the X1M.

Charlie , W5COV then picked up the reigns of the AGC kit and starting in Dec of 2013 was taking orders for it online. For this $12 little kit he used the same boards and parts as what Dale included in his kit. You can check it out in the Photos and Files section of the YahooGroup for more information.

I personally ordered the AGC kit before my X1M had even landed on my door step. Conversations on the YahooGroup gave me enough of a warning that is was a 'must have' mod if you could do it.

Earlier this week a tiny little package arrived in the mail, at first I wasn't sure what it was. When I opened it up, I was a little surprised at the size. A tiny circuit board the size of a nickel, and some small components. At closer inspection most of these parts were the size of a sesame seed, they had some plastic packaging around them since they were cut right off a reel of SMD parts.

I work for an electronics manufacturer, we have our own SMT line so I'm familiar with the tiny parts that the pick and place robots pull off the reels and place on the boards. In our line we move the circuit boards through in this order.

  1. A screen printer puts the solder paste on the pads throughout the circuit board. All the tiny pads get solder, the rest of the board is left clean. When completed a conveyor moves the board to the next machine.
  2. The next SMT machine places all the small SMD parts on the pads. This machine has lots of reels of parts. The multiple hands, and fingers in the machine (those are my terms, not official SMT speak) can place about 100,000 parts per hour. When completed a conveyor moves the board to the next machine.
  3. The next pick and place machine has less reels, but specializes in larger parts. The type of products we build require some larger components, it's not all tiny SMD sized parts. When completed a conveyor moves the board to the next machine.
  4. The final machine is an oven. In our case it's a 4 zone convection oven. A 'recipe' is made for each type of product to bring it up to temperature, just enough to properly melt the solder paste and fix the SMD parts to the circuit board. But not too much to damage the parts large or small. When completed a conveyor moves the board to a quality control station.
  5. Our SMT staff check the board, inspect the parts, and in some cases use a special cutter to split larger circuit boards into the small ones we would fit into our products. It's more efficient to make larger boards that consist of many smaller ones, that way more product moves through the line with less adjustments to the equipment.

So why all that level of detail?

  1. I think it's pretty cool and not everybody get's to see how stuff is made.
  2. To put into perspective the size of the parts that came in this kit.

SMD sized Capacitor - The actual part is smaller than a grain of rice, more like the size of a sesame seed.

So when I opened the kit and saw the parts I must admit I panicked a little. I built my first thru hole electronics kit only one month ago and I thought that was a size of part at the edge of my eyesight and dexterity.

So for this kit I cheated.  I know my soldering skills are C+ or B at their best. But when you work for an electronics manufacturer and your best friend works on the hardware side of R&D, you can cheat and take it to Dave.

So after hours I gave it to Dave and in less than 15 minutes he scanned the diagram, put it under his microscope and soldered it all together, I was reading the instructions and skipping ahead just to keep up with him.

His comment when it was all done "I wish we still used these sized parts in our SMT line, they're so big and easy to work on".

Dave's Work - Nice job Dave!
So knowing that the rights tools make a big deal I brought the X1M into work and over the lunch hour snuck into the lab and installed it. I was feeling a bit guilty for using Dave and I figured with the right tools I should be able to complete the job myself. Four precise solders later I was done.

AGC Kit wired into the radio and tested. Fixed into place with double sided tape
Now I sitting back at home in the shack, tuning around on 80m and WOW what a difference, all the audio so far has been very balanced, a very nice improvement!

Thanks to Dale W4OP for the great design, 
and Charlie W5COV for keeping the kit alive.

Friday, January 17, 2014

RTL-SDR Adapters and Pigtail Cables

MCX to BNC pigtail cable (bottom) - BNC to UHF adapter (top)
Thanks to Ron VA7VW for providing this information for me and the other NORAC club members as we prepare our bulk order of some RTL-SDR's.

Ron is a 'VHF and Up' enthusiast so his expertise is appreciated. 

The RTL2382U / R820T USB DVB-T dongle is 24 MHz to 1.850 GHz

So let's look at some common Amateur Radio RF connectors

N type connector
  • 0 - 18 GHz
  • insertion loss is less than .15dB @ 10GHz

BNC type connector
  • 0 – 4 GHz
  • insertion loss is .2dB @ 3 GHz

UHF type connector
  • 0 - 300 MHz
  • insertion loss is 1 dB @ 300MHz
  • As you can see it's good for HF but not really suitable for a very very wide portion of the RTL-SDR’s frequency range 300 MHz - 1.85 GHz)

MCX to SMA is also a very common pigtail/adapter combination on these dongles with very acceptable low loss.

So with lots of cool activities on the full range of the RTL-SDR we need connectors and cables with suitable low loss characteristics.

As Ron says... At VHF and up, every dB counts. 

So with that in mind I suggest that we increase the variety of pigtail cables that we supply to NORAC members with the RTL-SDR.

As mentioned in the original quote we still provide the MCX to BNC pigtail with the BNC to UHF adapter (picture at top of this post).

But we should all ALSO consider some or all of the following.

MCX to N female

MCX to N male

MCX to SMA female

And since a couple of the NORAC members have already expressed interest in an Upconverter, you will absolutely require the pigtail below to connect the RTL-SDR to the NooElec Upconverter board.

MCX to SMA male - This is a required cable for a RTL-SDR to Upconverter connection.

The QRP Diaries #3 - The Unboxing and First Impressions

I love it... ha ha

This is a fun little radio and I can see so many possibilities.

When it first arrived I resisted the temptation to rip open the box and decided to film a quick unboxing. I know when I buy something online these days I appreciate and and all videos that exist about the product. for people like me they are helpful.



Wednesday, January 15, 2014

RTL2832U R820T SDR USB Dongle and SDR# (SDR Sharp) Installation

One of many the RTL2832U/R820T Digital TV USB dongles on the market

Over the last year + certain models of Digital TV (DVB-T) tuners in the form of a USB dongle have been gaining popularity with hobbyists when it was discovered that this tiny USB stick could be used as a Software Defined Radio receiver with a fairly wide range of frequency and use.

The RTL2382U Chip, this is the ADC and USB data pump. It is then mated with different models
of tuner chips.
  • E4000 Tuner - 60MHz to 1700MHz; retired
  • FC0012 Tuner - 50MHz to 1000MHz; retired
  • FC0013 Tuner - 50MHz to 1700MHz; retired
  • R820T Tuner - 24MHz to 1850MHz ; active

The current model is the RTL2832U/R820T, it has just replaced the E4000 which is still available online as well. The RTL2832U/R820T is comparable in performance, wider in receiving range, and less expensive overall.

The frequency range of the RTL2832U/R820T is roughly from 24MHz to 1860MHz.

So this includes 10m, 6m, 2m, 222-band, 440-band, 900-band, 1240-band, and much more. Even lower frequencies (all of ham radio HF) can be received with additional up converter boards available online.

Lots of choices are available.

Most of the USB SDR sticks/dongles include a cheap antenna and use a small MCX antenna jack so adapters are required to connect a better antenna of your choice. With a better external antenna (for example a Discone) the RTL2832U / R820T can be very impressive as a receiver. The basic antenna that it ships with can still be useful for travel or use in cities or areas where signals are already strong.

Once you've ordered and received your RTL2832U/R820T you need to get up and running. I'm going to summarize the steps for a Windows PC or Laptop. Of course there is also software for OSX and Linux, as well as a driver and app for Android.

RTL2832U/R820T Installation for Windows
  1. Visit the SDR# website ( and download the installation Script. Click on Downloads button on the top menu, then scroll down the downloads page and look for the link to the quick installation script to test the latest development version. Download the ZIP file and then unpack it.
  2. Make sure your computer is connected to the Internet and then launch the Install.bat file that was included in the unpacked zip folder. This will execute the command to create a new folder and download everything you need for the latest version of SDR#.
  3. A new folder "sdrsharp" now exists in the location where the Install.bat folder was executed. I personally suggest you move the new sdrsharp folder from this location to a more permanent location on your system. The application is ready to run in this folder so you may not want it on your desktop or in your download folder long term. I moved mine to the root of the C: drive before going on to the next steps.
  4. Insert your RTL-SDR dongle into your USB port on your system. Allow windows to find and install a driver if it can. DO NOT install any of the Digital TV software that may have come with the dongle.
  5. When that's complete open the sdrsharp folder and execute the program zadig.exe. Go to the Options menu and select List All Devices. From the Devices drop down menu select the device named Bulk-In, Interface (Interface 0). Click on the button Install Driver, allow Windows to install an unsigned driver (if prompted). you'll be prompted that the driver install is complete and you can close Zadig.
  6. Browse inside the sdrsharp folder and launch the actual SDR software SDRSharp.exe, you may also want to create a shortcut to this program and place it in your Start menu or on your Desktop for more convenience.
  7. To get started in SDR# you need to complete the following basic setup steps.
  • From the top drop down menu (between the Play and Configure buttons) select the RTL-SDR / USB device.
  • Click on the Configure button  and make sure the Generic RTLxxx OEM is selected. Feel free to leave the sample rate and mode alone for now. Turn on the check box for RTL AGC and drag the slider to the middle. Then turn on the Tuner AGC and click the Close button.
  • Go the top left and click on the Play button and your receiving!


There is a great YouTube video from Clayton Smith (VE3IRR). His video he picks up where my directions end. He walks you thru a lot of the settings in SDR# showing you how they work and also showing example frequencies all over the range of the RTL-SDR so you can get a feel for things in a relatively short period of time. His video is about 17 minutes long.

Getting started with SDR# and an RTL SDR Tuner

Sunday, January 12, 2014

The QRP Diaries #2 - The X1M Platinum - Specs

X1M Pro - The New Platinum Edition
  • Improved Display
  • Improved Controls
  • Improved Components
  • Improved Filtering
  • Improved Performance
Frequency range RX & TX:  100 kHz ~ 30 MHz*
Modes: USB & LSB & CW
Power output: 5 Watts (4.5 Watts)
Operating voltage: 12 vdc
Operating current: 0.35 ~ 1.2 amp
Receiver Preamplifier:  Yes
Memory Channels:  100
RIT Function:  Yes
Automatic Internal CW Keyer:  Yes
Backlight On/Off:  Yes
Keyboard  lock:  Yes
Dimensions:   3-13/16 x 1-9/16 x 6-1/8 inches
Weight:   0.65 kg  ~  1.43 lbs
PTT Microphone:  Included
Computer Control:  Compatible with Ham Radio Deluxe (factory adapter required - Choose Icom IC-718 in HRD)

* Transmits continuous 100 kHz - 30 MHz via  Menu option.  Preset transmit range is the five US bands shown below.

Five Ham Bands are configured with bandpass filtering.  Transmitting on frequencies outside these ranges will require external bandpass filtering.

  • Band 1:    75/80m - 3.5 ~ 4.0 MHz
  • Band 2:    40m - 7.0 ~ 7.3 MHz
  • Band 3:   20m - 14.0 ~ 14.350 MHz
  • Band 4:   15m - 21.0 ~ 21.45 MHz
  • Band 5:   10m - 28.0 ~ 29.7  MHz

Receiving sensitivity: better than 0.45uV,

Frequency stability: better than 0.5ppm

Frequency accuracy: better than 0.5ppm

Operating voltage: 12.0 ~ 14.0V DC

Receiver Standby Current: 0.5A

Included in the package:
  • X1M Platinum Transceiver
  • Power plug (owner must build their own cable)
  • Keyer plug (owner must build their own cable) 
Available options:
  • Audio Filter for CW or SSB - Variable Center Frequency and Bandwidth
  • Computer Interface Connector Cable (TTL/RS232 to USB) - To Update Firmware & Operate X1M via Ham Radio Deluxe or other rig control or digimode suites.

Friday, January 10, 2014

The QRP Diaries #1 - Picking A Radio

I wish I could remember the trigger, the tiny thought that got me started down the road of buying a  QRP radio. If I think back to last year it might have been the release of the Elecraft KX3.

Elecraft KX3 - QRP Transceiver.
The KX3 got a lot of press and was featured in every magazine. It is new and cool, it is small and feature rich. Elecraft is a great brand name. My only problems with the KX3 was the cost. By the time I filled the shopping cart with the radio and the essential accessories it was well over $1000 US and that's a level of investment that requires justifications and approvals within my household. My wife the 'Budget Master' would not be happy. I can't tell you how many time over the last 12 months I surfed to the Elecraft site and filled up the shopping cart and then eventually walked away without clicking the final Confirm Order button. and not becasue I didn't really really want too.

My next inspiration came 4-5 months ago when a local ham posted a Swap & Shop ad for a used MFG 9420 QRP radio. My first thought was maybe the 'Rolls Royce' KX3 was overshooting the mark and I should be looking at Honda's or Ford's instead?  I've only been a licensed Ham since early 2012 so maybe I should broaden my knowledge and do some more research.

MFJ-9420 - QRP Transceiver
That's when I started a more extensive search for QRP radios of all makes, models, and types. I fairly quickly narrowed down to the feature set that would be most practical for me.
  1. Multi-mode - SSB and CW. I don't know code yet, so SSB and Digital are the only modes I currently use. CW is something on my to-do list.
  2. Multi-band - Most or all of the HF bands would be the most useful to be.
  3. Rig Control - Even if it's a tiny netbook, laptop, or tablet. Logging, digital modes, and CAT control are tools I really enjoy having.
Well in QRP there is a lot of variety; from total kits, to assemble yourself, to ready built radios. There were single band radios and radios just for CW. When I applied my entire shopping list not a lot rose to top.

The Yaesu FT817 seems to be the main horse in the race. Priced at $750 CAD it's still pretty pricey for my budget but it covers the wish list very well. Nice 3rd party accessories also exist like autotuners, etc.

Yaesu FT-817 - QRP Transceiver

Somewhere along the way I stumbled onto blogs and webpages talking about the X1M from China. This was originally a kit radio and had an extremely active community of owners and builders. The price was half that of the FT-817 at $349 USD and the word on the web was a next generation (v3) model was due for release soon and it would be ready built and contain a shopping list of improvements over the original two versions. The new model was going to be called the X1M Platinum and it was due for import into North America in Nov/Dec 2013.

 Xiegu Technology X1M Platinum - QRP Transceiver

I started reading owners blogs and posts, and I joined the X1M owners Yahoo Group. I found the Yahoo Group to be incredibly active, with upwards of 30 posts and replies every single day. There were Elmers helping new owners, Engineers designing and sharing upgrades and modifications, and almost every conceivable Question and Answer that you could think of.

Eventually I settled on the X1M based on it's price, features, and the overall excitement from the community. I figure if your gonna stick your toe into the waters of QRP, you might as well know that others are already in the pool.

The timing was great since Christmas was just around the corner and with any luck I might be able to leverage some holiday gift money into a new purchase. I got so excited that this was gonna happen, I ordered the radio on the credit card 2-3 days before Christmas and crossed my fingers...