Sunday, August 25, 2019

The Thrill of Making Contacts with a Homebrew Radio Station

The Station Here is Homebrew!

Yesterday I had the good fortune to have a bit of time to actually get on the air on 40 Meters. I was running a new homebrew transceiver (non-SDR) and it was such a buzz to be able to say that the station on this end was 'homebrew". In this case because of the specific topology of this new rig I even had to homebrew an electret microphone.

Now as to the other station -- he was running a FLEX6700 and a brand new FLEX KW Amplifier that he evidently had to wait months to receive. His antenna was not unlike mine ( a wire) but he also had a three element 40M beam. The other station was in Nebraska and I of course not too far from Los Angeles. It was early evening and the signals were quite strong. The general comment from the other station (not even acknowledging that I was ruuning homebrew or that he was looking at my signal on his large display) was that I was a solid 5X8 into his QTH. That I considered as positive. 

Don't get too excited -- I was not running QRP but my new homebrew rig was driving the SB200 to about 600 + watts into my dipole. So I am able to run with the big dogs using a homebrew station. 

Should mention that the new homebrew rig runs 5 watts with the IRF510 in the final and the intermediate amp is a "brick" (literally the size of a common red brick) came out of a defunct Atlas 210X. This amp runs 100 watts + and has been fitted to a small chassis and includes a fan for cooling the heatsink --so there is much homebrew into this piece of the station. The former Atlas 210X amp easily drives the SB200 to 600 watts +.

But back to the other station and a discussion about his new FLEX Amp. He described that there is circuitry in the amp much like a diplexer (my words) that takes out of band signals that are generated in the transmit chain and dumps them into a dummy load built into the amp. He is able to monitor the level of the dump and was telling me that it was close to 200 watts and he could even look at his output spectrum and all he could see was the primary signal power output.

This was not the first time I had heard of this. I believe over 10 years ago I saw  such a process in an article where this was done. It might have even come from someone with or formerly associated with Collins Radio (Bruene ?? or Sabin??). 

But something I have personally noted and watch for at my station when running QRO. I will briefly tune up a rig (at QRO) into my antenna to assure the SWR is 1:1. If I get on the air and I see the SWR pop up on voice peaks --I know there is something slipping through outside of the desired operating frequency and I immediately stop! If there is nothing coming through other than the desired signal then the SWR will not change. 

As described to me with the FLEX KW amp -- they are automatically terminating that out of band signal into an internal dummy load. Given that the other station mentioned it was 200 watts -- that is sizeable.

Now a few comparison comments on the new conventional filter rig. This new rig (notice I didn't say HDR since that is trademarked by N2CQR) is in a different class from my RADIG. I miss being able to see the energy in the incoming signals. I also miss tinkering with the filters and having a built in accurate S Meter. 

Don't get me wrong -- the new conventional rig does a yeoman's job (have had 6 contacts so far) but it is just that it is not an SDR transceiver. True it is small, does not require a computer and of course no computer screen so it is ideal for portable operation. It does however make serious contacts and most importantly runs with the big dogs. Isn't that really the overall determinant?

There is another important consideration and that is the ability to replicate this conventional filter rig. Few feel comfortable homebrewing any rig. An even smaller percentage feel at ease in fabricating an SDR transceiver. So this project would appeal to a larger set of potential homebrew constructors and is worth more than a look see as a potential winter project.

I must stress again if you are not a member of the GQRP Club -- you best get that done. Enough said.

I relish when I can say to a station running over $10K worth of hardware not including any antennas -- the rig on this end is homebrew and cost about $100.

73's
Pete N6QW

Friday, August 23, 2019

Experience with the OLED Displays -- Careful what you buy!

More Expensive and More Flash -- Not always the best course.


I have been evaluating two types of the 65K Color OLED Displays. One uses the SSD1331 application contained in the Ucglib Library and is a bit larger in size than the one using the ST7735 application. Frankly the colors and background on the SSD1331 is like uptown versus the colors and display size on the ST7735. The there is a 3:1 price difference too.

But you don't always get what you pay for! The SSD1331 display was so noisy when installed in a rig that it was useless without some major additional noise reduction techniques. The buzzing noise completely obliterated the signals. In looking at the backside of the SSD1331 there appears to be some sort of switching power supply right on the substrate! The high end color and sharp features has to come from somewhere!

Whereas the ST7735 just popped in the circuit and no noise issues. So what you have my friends is the high end call girl and the street walker --- the ST7735 which I paid $2.58 works perfect.

There is another advantage to the ST7735 and that is size --it is about 2/3 the size of the SSD1331 and should make for retrofitting into existing rigs a much easier task. 

Stay tuned as there is a N6QW application for the ST7735 OLED Display that will be forthcoming. But it comes with a price! If you are not a member of the GQRP Club --then you best get a subscription today. Enough said.

73's
Pete 

Saturday, August 17, 2019

Dress Up your Homebrew Rigs with these new Displays

Once again from the N6QW Leading Edge!



No Tayloe Detectors or ADE-1's were involved in this  project and there are no LT Spice Simulations to pick apart. Just plain old hard work to get the displays to work.

I have seen many videos of the new Color OLED's but I have not seen any where they are actually used in a Homebrew Rig. So this may be a first. Most of the demo's involved taking the stock sample programs and just loading them on to an Arduino. This video was built from scratch!

Pete N6QW

Wednesday, August 14, 2019

The new 65K Color OLED Displays -- about 1 Inch Square

New Color Display Mania!

8/15/2019 ~ Yet Another Display
In today's mail I got two 65K OLED's that use the ST7735 Library and are smaller than the one I posted yesterday which is the SSD1331 type. These are way cool and I got the two for less than $6 including shipping! (160 X 128 pixels)


Comparison to the one of yesterday. About 2/3 of the size.

 Sorry for the dark photo.

73's
Pete N6QW

****************************************************
8/14/2019
Recently I discovered that there is a whole new crop of Color OLED Displays and by color I mean 65K choices. Below is a dummy display where I took the "Hello World" test program and did a bit of experimenting with how to place info on the screen and how to call up colors. Got the Splash Screen to Work -- a major breakthrough!!!!




We are a long way from having code written for use with the new transceiver; but I am excited about the possibilities. These are compact low power displays which should fit well with small low power QRP rigs. It only gets better. 

Mind you the display is less that 1" inch Square. There is a lot of info on that screen including which VFO is active and the Step Tuning Rate as well as the Mode. The code will have my standard Tune Function and when engaged the USB (or LSB) will be blanked out and the word TUNE will appear on the screen.

73's
Pete N6QW


Saturday, August 10, 2019

FT-8 with a Raspberry Pi2, 3 or 4.

FT-8 with a Raspberry Pi!

8/11/2019 ~FT-8 With a Raspberry Pi ZERO.

When the Pi Zero came out at a cost of $5, I bought one. I soon found it was useless! No wonder it cost $5. The reason for my comment was the slow speed, lack of RAM and no USB ports other than the single one that you had to have an adapter for! [Mine is an early version with no WiFi.]







So yesterday I wondered if it would work with my digital adapter and HDR rig for FT-8. Boom we now have a use for the useless Pi Zero. I also have a small powered USB Dock which I installed on the Pi Zero and that now gave me 4 USB Ports.

Using the NOOBS 3.2 and the WSJTX it will work doing FT-8. The slowness of the processor and lack of RAM is not an issue. That said -- it groaned when I tried to do QUISK. So for a compact FT-8 perhaps with a 5 Inch HDMI, the Pi Zero might just be the ticket.

BTW using my RADIG you don't need all of the extra peripheral crap (CRAP= Capacitors, Resistors And other Parts). The Digital Adapter is already in the hardware!

Pete N6QW 
 **************************************************
So why am I wasting your time as I already demonstrated using the RADIG ion FT-8. If you are now bored stop reading!



But many readers of this blog will never build a RADIG as it may either be in conflict with those who are ardent HDR guys or it just seemed to hard to connect all of the SDR bits (and bytes) together.

The subject of this post is that taking one of my conventional HDR rigs and using the N6QW designed Digital Adapter mated with a Raspberry Pi3 --I worked FT-8. Formerly I had to use a Laptop, Big Desktop or a Netbook to work the digital modes. But yesterday I asked myself --can this be done using just the RPi.

So for those HDR guys first you need a Raspberry Pi (in some form) then load NOOBS 3.2 onto an SD Card and then download/install the WSJTX software. The detail of the N6QW Digital Adapter was included on my N6QW website This adapter also utilizes the Sabrent Sound Card Dongle.

You can down load WSJTX from


Find the Linux form "arm.deb" and download that onto the RPi3. Once it is downloaded find it in the download folder and and right click on the file and one of the options is to install it right from that location.

You will also have to find the sound card settings using the drop down RPi menu under Preferences -Audio settings. If I have to further explain about selecting controls etc. stop here and proceed no further

Now you will have to setup the WSJTX and if you got this far then email me at n6qwham@gmail.com and I will send you some photos of what to put in the settings page of wsjtx. Otherwise get back to your ICOM7300 manual and read about the 10K settings you can make. Or open your QST to read about the latest contest or latest rig review.

So OK too hard to email Pete and being a BTE below your dignity...  Make your pages look like this for the wsjtx settings.







73's
Pete N6QW


Thursday, August 8, 2019

Contact Verifications -- AKA QSL Cards

QSL Cards --- Things of the Past


Today's subject is QSL Cards. So for the BTE's who just recently got their license via a subscription to QST, you perhaps are not aware of this bit of radio history.

There are many urban legends regarding how QSL Cards came into existence. In the early pioneering days of radio it was easy to say I worked the east coast from the mid-west on 80M running a type 27 vacuum tube five watt TPTG CW transmitter. Yeah Right! But if you had a slip of paper from that other station affirming that contact then that was confirmation and proof positive that you really did make that contact. That slip of paper often was a post card that on one side contained the contact exchange and the other side was the usual mail To From address format and a place to put a stamp. 

Commercial radio broadcast radio stations in the 1920's liked receiving such cards as that gave them proof positive of their broadcast coverage --especially the clear channel stations like KDKA in Pittsburgh.

Then the ARRL stepped in and created awards for collecting cards like Worked All States or DXCC (100 countries) or the coveted worked all radio call areas  world wide. In the old days one had to send the confirming QSL cards. The use of the post cards made that pretty easy; but you did have to purchase the post cards from the post office and have printing placed on them or you had cards made. Whole new industries came out of the QSL Cards. BTW before QRZ.com there was the Radio Call Book Publication (The Flying Horse) where you could look up the call signs and addresses. Frequently the radio publications would have address info of some of the exotic stations.

The mailing of domestic  post cards was pretty easy as you either used the post office variety card and after filling out the info simply popped them in the mail or added a stamp to the other form cards and into the mail box. 

But another twist was added and that was the QSL Bureaus where you could bulk mail say a whole slew of cards to the bureau and then there was a process where cards for the station or for you were then distributed to the intended ham. For a small fee I have a bunch of envelopes on file at the W6 QSL bureau and periodically they mail me a batch of cards.

But if you wanted that very special DX card then you had to QSL direct and that often required sending IRC's (International Reply Coupons) so that the cost of sending you back a card was covered. But often it was extortion as the required IRC to send you back a card was less than the minimum you were told  was needed. Then there was the phrase "green stamps" only. Green Stamps = US Dollars. Who would do that ?? -- Well if you wanted a card from Bhutan, you did!

This meant that you had to send dollars to get a card back. There was a trick to this as often the mail would be rifled at the foreign country post office and the dollar bills stolen. Here was the trick. You used the front of one QSL card and the back of another then you carefully folded like a $5 bill and inserted it between the front and back cards and with a thin bit of Elmer's glue around the edges you pasted the cards together.  Some trick.

So what prompted this post. Two days ago I received an envelope with a QSL Card inside and the first thing that caught my eye were Amateur Radio Postage Stamps that are vintage 1970 on the primary envelope. The second thing was that the actual QSL card was a 1 Cent (penny) official US post card with the blank side printed with the exchange information. Man it has been a long long time since I saw a Penny Post Card let alone a Ham Radio Stamp. Someone must have a stash of these.

But as technology has moved on, the QSL process has changed too -- we now have Log Book of the World and e-Cards so that the US mail is being cheated out of revenue. But cost is an issue. I can remember that in the mid-1970's as I was pursuing DXCC I choked as I saw that one day I spent $45 on cards, postage, IRC's and Green Stamps just to get a few cards back. I stopped sending cards!

A bit of a note on a secondary aspect of the QSL process. Hams in foreign countries would email me direct and I should add I never asked for green stamps or IRC's. But they did send envelopes with colorful stamps. A fellow employee where I worked at that time was a stamp collector and I would provide him the envelopes so he could collect the stamps. He was ever so grateful as many of the stamps added significantly to his collection.

A bit of history came back to me as I opened that letter the other day. My printer is out of ink and today I need to get a new cartridge so I can print up a return card. The reason I like the homebrew card is that I can change the photo depending on the rig I am using. My process after printing is to then laminate the card as it is only typing paper. 

This makes for a durable card --and slipping a $5 bill between the front and back then laminating makes it hard to steal the $$$. The second card is from Midway Atoll (improperly called Midway Island as it is actually Midway Islands) where I was custodian of KM6BI. Keep in mind 3000 US Navy personnel and 6 single women (school teacher's). Three of the six were over 45! While I was stationed there, it was like being in prison for 13 months!

73's
Pete N6QW







Tuesday, August 6, 2019

Sunday, August 4, 2019

More Old School Analogue Stuff

More Old School Analogue Stuff !


Want to build this rig --see the above link for complete details? This project shows how there is a mix of Bipolar, IC and MMIC technologies to produce a rig that will rival a Paraset! 

Worse still, why suffer with a Pixie or single FET transceiver? Who needs a regen when you can have this amazing rig? Yes today I would build it differently perhaps with Arduino's and color TFT's maybe even SDR; but 10 years ago --this was leading edge. Yes folks I was building super slick stuff likes this a decade ago. 

A couple of changes. I repurposed the original SBL-1 for another rig I was building and I replaced it with an ADE-1. The IRF510 was smoked and was simply removed and the Driver stage rebuilt using the original  2N5109 but fitted to my 2N2219A design. I easily see about 600 Milliwatts with this stage. With a bit more design tweaking the 2N5109 might hit 1 watt to the antenna. I also have now included the LPF on the top board in the space formerly occupied by the IRF510. 

With an outboard amp keyed by a relay connected to Pin #3 on the NE555 we have 30 watts+ to the antenna. That is way better than QRP! If I want QRO -- the SB-200 will hit 300 watts to the antenna! If you moved the LO to 8.875 MHz and changed the BPF's and LPF to 14 MHz then you would have this jewel on 20 Meters.

Pete N6QW





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