May 31, 2024. Have you heard anything?

We just passed an important milestone and was just curious if you have heard anything important? Discount yesterday's ho hum news.

May is the month for the Dayton Hamvention and being kind of away from mainstream ham radio stuff -- what's up? It been two weeks since it was held and there seems to be a radio silence.

The one and only time I went to Dayton, FLEX Radio had a small booth with a laptop connected to a black box and I could see this was going to be big time stuff.

So, any new rigs being showcased? Any new innovative stuff being displayed? How was the flea market?

If I were dreaming about a month ago and pondering an expectation list my dream sheet would be like the following.

1. A US made real SDR radio with 15 watts output for less than $300.
2. A test instrument to rival the Nano VNA that really works and is not vapor ware.
3. A 100 MHz DSO for $199.95
4. A 13.8 VDC, 5 Amp Linear Power Supply for $35.
5. A small form factor Single Board Computer at 2.0 GHz with 8GB RAM for $45.
6. A high quality 40M Dipole costing less than $40.
7. An array of parts like IRF510's, J310's, 2N5109's, MC1496's, BF991's and FT-37-43 cores that are not counterfeit, priced reasonably and actually work.
8. A stock of reprint Solid State Design for the Radio Amateurs book @ $12 a copy.

I guess if you are a bratwurst aficionado, that used to be the place for a hookup or has that too taken a place in history.

73's

Pete N6QW 

34445

May 30, 2024. The Yaesu FT dx 100 an Amazing Radio for its time!

Another of my Boat Anchors, the FT dx 100. 

This is a truly remarkable radio given it is vintage dating to 1967 and likely a test market radio for its sibling the FT-101. 

BTW I think somewhere near 250K FT-101's were built. I have one of those as well.

This radio has been on You Tube previously but I thought it time to make another video of the FT dx 100. I am impressed with what they could do with Germanium transistors.

Also, impressive is the Linear Reading and Highly Stable Analog VFO. I think this same VFO was employed in the FT-101. 

The Crystal Filter frequency is not unlike that of the HealthKit's at 3.180Mhz (Heathkit = 3.395MHz). A caution for would be homebrewer's thinking about single conversion transceivers using these filters. The harmonics of the BFO or VFO are very close to the range of the Band Pass Filter. Think Double Conversion.

The panel layout with S Meter and VFO Dial Scale is common to many of the Yaesu offerings. 

The radio is a bit weak on the AGC control but hey this was 1967. [There is no waterfall or spectrum display like the FT dx 10 or FT dx 101. OK, I am just poking a bit of fun!]

Check https://www.jessystems.com for a look at how I fixed an earlier FT dx 100 I had. There is also info on that link regarding the radio that exits in few other places on the web. 

https://www.jessystems.com/FTdx-100_Troubleshooting.html

That said Yaesu gets an F for the build as there was no thought about how you service parts of the radio. The HV Filter Caps are located in the radio such that you have to remove wiring and many parts just to get access to their solder lugs. Other critical circuits are built into metal boxes that have been soldered shut and no hope of easy access.

If you are homebrewing a radio, then think about DFMA.

Always slightly ahead...

73's

Pete N6QW

34445

May 29, 2024. The $200 QRP Radio

Yes, today is filler content day and this time it is about buying a radio. Snooze time!

So, you were not born in the Pittsburgh area thus failing to receive a heavy dose of the toxic chemicals found in the drinking water and in the air. I attribute those vicious chemicals acting as a catalyst to spark innovation, creativity and pushing the leading edge. Thus, lacking those poison effects instead of homebrewing a rig you buy one.

Xiegu G1M

There is an allure to going to an outdoor park, setting up a painter pole dipole with a small radio attached and thence shouting POTA CQ POTA, Parks on the Air. The side benefits include actually getting outdoors and the endless possibilities for meeting YL's, after all Ham Radio is indeed a Chick Magnet.

So, moving to reality and setting a goal of $200 what would you buy for a rig? It seems like that number ($200) has become the "bar level" of what is hawked on eBay. Lots of junk, old and NIB, at that price point.  But what do you buy?

The Xiegu G1M (out of production and likely a predecessor to the G106C) caught my eye. It was the compact size and look that had curb appeal. I tried You Tube/eHam to get some reviews of the Rig and found two key points. 

The first is how to unbox a radio and the second is the lack of a serious technical review. You know does it put out spurs and does it have a distorted signal quality? Reminds me of when I attended real estate school. When asked does the roof leak you were to reply only slightly when it rains. Spurs and distortion -- only slightly.

The eHam reviews were bi-polar in that there were some 5 Star ratings as a super radio to the 1 Star piece of crap. Does this mean it has a 2.5 Star rating?

But if the G1M did pass the smell test as a POTA radio, it might be OK if you are patient enough to be a QRP operator. As a one and only rig for use at home and POTA -- likely a huge disappointment as a $200 radio is just that a $200 radio. The G1M is not an IC7300.

On the negative side for me is my FFS (Fat Finger Syndrome). Those tiny push buttons were designed with a dainty YL op as a model and would soon frustrate me. The menu crap would likely drive me nuts. But it does look nice and can be had for around $200 from a supplier with a 91% rating.

The bottom line is to use a process to evaluate a rig purchase to take it from the emotional curb appeal to the reality of a small box sitting in front of you that you actually want to employ making contacts. As a portable radio (assuming it does work to current FCC specifications) then likely OK. But if you cannot fill in the blanks with + comments then pass.

There! You have been given a daily dose from N6QW.

73's

Pete N6QW

May 28, 2024.Knowing about the Bilateral MMIC Amplifier Stage

The MMIC (Monolithic Microwave Integrated Circuit) is an excellent vehicle to represent the overall homebrew process from the Idea to the Design to the Finished result.

So, this posting is about a process and not so much about MMIC's specifically.

Several Blog postings ago I showcased a Bilateral MMIC Amplifier stage used in a SSB Transceiver and likely there are many blog readers who would like to "know" more before building one.

It all started over 15 years ago when I spotted a piece about MMIC Amplifiers. It might have occurred with something unrelated like hunting for packaged Double Balanced Mixers and a trip to the Mini Circuits website. It was an experience much like a kid in the candy store! 

While searching for SBL-1's I spotted the MAR line of MMIC devices. That info was tucked away in the grey matter. My brain is warped and several 3 AM Brain Awakening Realizations (BAR) said Pete you need to look more at MMIC's. 

Also, the craze at that time were bilateral circuits. (Although bilateral circuits go back to the mid 50's with the Cosmophone 35 and the early 60's with the SBE-33.)

About 15 minutes' worth of "noodling time" convinced me to pursue a Bilateral MMIC Gain Block. What convinced me? Well, for starters, minimal part count (engineering economics) coupled with high gain wide bandwidth, low cost (economics) and physically small size. Did I mention termination insensitivity at 50 Ohms in/out. It is like the pairing of a fine wine with some good old Italian Pasta!

More research turned up the company Tri-Quint which was in lock step with Watkins Johnson who made Commercial Military Receivers and was a former division of Tektronix. In researching their Catalog I found the AG303-86G MMIC device. 

I was not smart enough to scratch design a total Bilateral MMIC amplifier but smart enough to contact their Engineering Department. It turns out their Director of Engineering was a ham and so much needed help was forthcoming. A Key Point is to not be afraid to ask questions.

A reply from the Director resulted in this circuit.

 A better photo here

A couple of noteworthy points about this bilateral circuit with the 1st being Diode Steering and DC Power Switching to cause the Bilateral action. Each leg of the Amp is powered through a 5 Volt Regulator and is only turned on either in Transmit or Receive but not both simultaneously. 

Anticipating the issue that will be raised by the nerdiest of the Blog readers and that is transit time from power on to full operation. In practice for SSB and QSK at Moderate CW Speeds (25WPM) that is not an issue. For more demanding applications then another method may be warranted.

The power application via the 5VDC three terminal regulator not only powers on the MMIC but provides steering voltage to the 1N3070 didoes to route the signal as either an Input to the Gain Block or as an Output. 

Tri-Quint was specific about the 1N3070 not so much about the Voltage or Current capabilities as its RF properties. I bought a bag and at that time were pennies but now one unit is about $7. Luckily there is a cheap substitute a 1N4935T about 17 Cents. The same applies to the AG303-86G which is out of production thus the MAR-6SM+.

A first piece of "knowing": what is a MMIC Amplifier and what is inside of the amp? This is the MAR-6SM+

Basically, a MMIC is a block amplifier and for the MAR-6SM+ is two transistors, Darlington connected for higher gain, along with the usual bias resistors. The MMIC Transistors typically have materials Like Gallium Arsenide or Gallium Nitride or even a Combo Silicon Germanium or just plain Silicon. 

The Gallium variants are especially liked by the military as they work in the Microwave region and tend to be RAD hard (Survive Electro Magnetic Pulses from Nuclear explosions). Better processes now make Silicon OK for the higher frequencies of operation but not RAD hard. The MAR-6SM+ is a Silicon device.

What are the Specifications for the MAR-6SM+? Essentially DC to 2gHz, 50 Ohms in/out, 20dB gain and 2.3dB Noise Figure. Not bad for less than $2 in single lots. 

Smaller than a pencil eraser, they present certain challenges for mounting and installation. If you have not graduated to Big Boy Pants and only deal with glue down Manhattan pads, then stop here. These devices need a carrier board or custom PC Board. Fortunately, K7TFC has a mounting board including the device in the works. So, start reading again.

That leads us from a MMIC device to a circuit diagram to a working module. In our travels we did the upfront engineering evaluations and considered carefully our application. No, we are not doing microwaves, but this unit has such great specs at HF and has low part count, no tuned circuits, is 50 Ohms and Termination Insensitive -- what other evidence do you need. Soon there will be a board from K7TFC --so no impediment from a mounting perspective. 

I know just because it appeals to me and has for some time does not make it a clear choice for all. Will your well-worn bag of 2N3904 devices work in an amp circuit? Why of course they will. But the MMIC devices have so much more capabilities. Sure, when you were a kid, you could talk to your neighbor using a string and two tin cans. But to have a QSO today, across the globe, takes some more sophisticated hardware.

The 1uH chokes at the input and output ports have an impedance close to 90 Ohms at 14MHz and provide a DC path to ground for the Diode Steering. (2*Pi*F*L)

Always slightly ahead...

73's

Pete N6QW

May 27, 2024. When You Know Stuff, You Can Do Stuff.

Memorial Day Observance today. Local time 7 AM and I just hoisted my flag and unlike one Supreme Court Justice, it is flying in the proper direction. A solemn time to remember those who gave their lives for our freedom. 

One Memorial Day I will never forget and that was in 1965 at Chu Lai in South Vietnam. I had a concern that I would ever celebrate another Memorial Day. Here we are some 60 years later, and I consider myself indeed fortunate.

Has my famous saying been hijacked? This captioned photo would lead you to believe that.

The crass suggestion here is that it does involve something more than homebrewing Ham Radio projects. I guess someone is claiming Freedom of Speech.

[As of Sunday (5/26), Logbook Of The World has been down for 12 days. That can't be good for the ARRL. Wonder when it will once again be the resource for documenting QSO's. Maybe it is connected to some sort of ransomware. ]

I was presented with an observation regarding my published works and what I build, and it has to do with WYKSYCDS, the Homebrew Ham Radio version. 

Basically, that statement is mathematical expression defining an equality but also like My Dear Aunt Sally (MDAS) which lists the priority of operations. MDAS is Multiply Divide Add Subtract in that order. There are two parts to my axiom like statement: Knowing and Doing and the order starts with Knowing is first.

The observation presented me was that many notable hams with large followings and many you tube videos (I only have 319) spend a good deal of time in sharing the Knowing part. Whereas my stuff is more focused on the Doing part. Likely many who are new to homebrewing want me to spend more time sharing the Knowing part so that the Doing part has a clear technical basis and removes the "well everyone knows E=IR" from our math process. 

Thus, with a reflection on another truism ~ all information is good information, I will endeavor to include more of the Knowing part in any future presentations on this Blog.  

Funny, I thought I was doing that but a hard look in the mirror causes me to have a greater appreciation of the audience and why they read the blog. Hopefully I am presenting opportunities for a learning experience and to the fullest should include the detail, rationale and basis for what I do. Simply saying you can build it will fall short of the mark.

73's

Pete N6QW

May 26, 2024. The Pipsqueak -- A Really Crappy SSB Transceiver from N6QW

In my active marketing of my building skills I often say when you know stuff you can do stuff. This Blog and my several Websites show the after state with some really clever ideas that have been shared. But you have to have the knowing part of the equation from the outset and when everything goes south.

Here is an example where the final product basically stinks! So now the knowing part has to be challenged as to why it is subpar. What do you think?

All ideas are good as a starting place but most never satisfy the smell test. Here is one of those that failed.

73's

Pete N6QW

May 25,2024. Other Radios with MMIC's

Following along with K7TFC's MAR6+SM board announcement, I had almost forgotten that the Peashooter Radio uses the MMIC Amplifier blocks. The Micro-20 also uses a bilateral MMIC Block.

[BTW I just checked the LOTW status, and it is still down! That must be one serious hack as this is now heading towards 11 days without that service. Field Day is about a month away and that is the next big hurdle. Hmmm, just thinking those paper QSL cards are in a box somewhere in the storage locker.]

Proof they exist!

 

Does Your MMIC Sound like this?

 

MMIC IF Stages Relay Steered

There was a time when I did have time to play with the electrons, but now, I can only think back to projects of the past. 

There is not tomorrow but only today! So, sign up for K7TFC's newsletter and watch for the boards for the MAR6+SM and build yourself a MMIC transceiver. Remember, they are inherently TIA.

Happy homebrewing!

73's

Pete N6QW

May 24, 2024. Forget that TIA Stuff!

 Bi-Lateral MMIC Module

Todd, K7TFC in his recently published Newsletter announced work being done on providing a board that will house the MAR6+SM MMIC device. The beauty of that jewel is the low Noise Figure of 2.3dB, gain to 2GHz, rated at 20dB and 50 Ohms in/out thus termination insensitive!

In 2010, I published my very 1st QRP Quarterly article which involved a 20M SSB Transceiver employing six MMIC devices in a bi-lateral configuration.

20M MMIC Based SSB Transceiver

For me having a 1st published article this was huge, but more importantly it proved the viability of the MMIC devices as a building block for homebrew ham rigs.

Below is a you tube video. The rig worked great but the Varactor tuned VFO was crap. The published article had a Si-570 PLL and I have never looked back. 

The Surface Mount issue some 15 years ago was a pox on more widespread duplication of this project. A bridge too far and how many hams have a CNC machine in their garage?

The 20M rig used the AG-303-86G MMIC which is now obsolete. But the MAR6+SM would work as a substitute. K7TFC's in work board mount will now make it possible to duplicate the radio. 

The MAR6+SM needs but two caps, a dropping Resistor and a small RF Choke. In the 1st photo is a layout for a bilateral circuit using the AG303-86G (similar MMIC) but that same layout will work with the MAR6+SM. The 2nd photo is the bilateral schematic.

The unit cost is $1.83 from Digi-Key and for most hams the Surface Mount would be a constraint. But a Board for the device in work from Todd will remove that mounting impediment.

Three such Bilateral Amp boards as in the 20M MMIC SSB would fill the need for a combo Rx RF Amp and TX Pre-driver, with a second set of two bilateral boards providing a bi-lateral IF module. Roughly less than $11 will provide 6 units. 

I used 5 VDC on board regulators to power the devices and simply powering on a unit is all that is needed for bi-lateral operation.

It is with regret that my time is so limited as I would love to rebuild that 20M MMIC using some of the newer devices (Xiao RP2040) and technologies. K7TFC's efforts will now make it possible for you to do that.

Always slightly ahead...

73's

Pete N6QW

May 23, 2024. Another Homebrew 20M SSB Transceiver

 

The LOTW has been down for 8 Days. Is the ARRL being held up for Ransom?

For those who belong to the ARRL, sounds like your membership fees may soon see a huge spike.

This is a follow-on post to yesterday's blog entry about the modules and boards available from Todd, K7TFC.

20M HB SSB Transceiver

Of note this is a two VFO, two Filter SSB radio on 20M. The VFO's have memory and it puts out 5 watts.

I was thinking of the array of K7TFC's modules and how the modules in this radio could be directly replaced with the stuff available from K7TFC.

• The ADE-1's for the RxTX Mixer and the PD/BM
• The J310DGM seen in the video
• The W3NQN LPF
• I used the Plessey Amp, but the TIA boards are a drop in
• I used two filters but easy to convert to one filter from Todd.
• Mine has an Arduino/Si5351 bit the Xiao RP2040 Board would work FB
• My audio amp is the 2N3904/LM386, but the new audio amp board is a drop in.
• K7TFC's op-amp board could become the Mic Amp
• Lots of possibilities for the BFR106 module.

Believe me I had to work hard to come up with all of the boards including the design, LT Spice Simulations, general layout etc. Perhaps not all who read this blog could see how Todd's Boards would simply plug into my design, but I sure can. Bottom line -- a lot of the heavy lifting has already been done for you!

Always slightly ahead of the curve.

73's

Pete N6QW

May 22, 2024. New Stuff from K7TFC at mostlydiyrf.com.

Todd, K7TFC has dropped a new issue of his newsletter and if you are into homebrewing then this is a must see.

newsletter

There are many new products that cover the realm from Circuit Modules to Circuit Protection and finally Test/Measurement tools. 

A General-Purpose Audio Amp

The above audio amp module is for those who must see all the components to consider anything as homebrew and who loathe the idea of using a LM-386 or LM-383 or LM-380.

G3URR Test Oscillator.

Following along is the G3URR test oscillator for evaluating crystals prior to fabricating a homebrew crystal filter. This oscillator is like the gold standard for crystal evaluations.

There are also some boards he showcased that are in development including this one for the W3NQN Low Pass Filters.

LPF Boards

What K7TFC has done is to select an array of modules and tools that are current technology and made it in a form (Boards) that can be easily integrated into your project.

I can shout all day long about the capabilities of various bits like J310 DGM's or the BFR106 or the MAR-6+SM MMIC device (in the future queue). However, there is a huge chasm between that device and a circuit board to use those devices. Todd has provided a bridge over that chasm.

Incidentally if you missed out on ordering the P3ST SSB Transceiver kit another round has been opened up for purchase.

P3ST SSB Transceiver Kit

The next batch of P3ST's includes some upgrades from the original that were developed as a result of customer feedback from the first build.

Lest I forget there is also a Digital Attenuator and boards to clean up your dirty power supplies.

Sign up for the Newsletter and Happy Homebrewing.

73's

Pete N6QW

A bit of a disclaimer: I am not directly involved financially or otherwise with Todd's venture. I do however share with him projects I have done that may be something that other homebrewers could use. From there Todd does his magic to turn that into kits/boards/modules for sale. The P3ST and J310 DGM are two such examples.

May 21, 2024. The Forgotten Element.

Many hams frequently forget that their station is a "system" comprised of major elements. These elements include the Rig, the Operator and the Antenna. The hierarchy places the most emphasis on the Rig with the Antenna not given much thought. [Our forgotten element!]

Today's posting started with a trip down the old rabbit hole.  I subscribe to just a few reflectors including Ten Tec and SWAN. I have several radios each from these two categories.

So, it was a bit of a surprise to see on the Ten Tec reflector that they had a booth at Dayton. I thought they had folded their tent and were just a name from the past. That led to a trip further down the hole to the Ten Tec website. Something caught me completely off guard which was a product evidently introduced in 2023.

This photo leaves you in the dark a bit, but the product is a continuously tunable Dipole, where the dipole length is adjusted to the operating frequency. Think of the StepIR, only this is a dipole whose length is changed from the shack. The product is called the Ten Tec Tune - A Tenna.

This would be a good compromise if you live on a small lot and can have but one antenna. Essentially, I think the portion of the antenna not used as a part of the radiator now is part of the feedline. 

It is not clear how you get it to lengthen once retracted but I suspect some heavy fishing weights on the ends would use gravity to do that job. This sort of approach certainly would keep the dipole from drooping. When I had the extended Lazy H antenna, I used a bucket full of stones to keep it taut. 

I did not see any pricing for this jewel but certainly those with the knack employing Arduinos plus stepper motors with some take up spools could whip up something in their back yard.

Collins Radio back in the day had a product called the Tape Dipole, Model TD-1, which essentially were two tape measures where you could precisely spool out 66.2 feet and be on 40M.  This is same concept except using the Armstrong method of deployment.

I was totally unaware of the Ten Tec antenna or if they were still in business making things. True this is just an item on their website so is this just vaporware. Regardless of the current status you caught my attention and if I had some time, I would whip up something for my use. Immediately I thought of "completing the triangle" and as I did with my Dipole and turned it into a Delta Loop.

If any blog readers know about this product drop me a line at my QRZ.com email.

Several years ago, I had a couple of QSO's with a ham in 4-Land where on our initial contact he was running a Kenwood TS-2000 and a chunk of wire on the floor of his garage. He shared with me that he wasn't making many contacts so a QSO to the left coast was DX. Several weeks later another QSO and he proudly announces he upgraded to a ICOM 7850. 

That is a 5X increase in investment from $2K for the TS-2000 to $10K for the IC-7850. He lamented that while the 7850 had more bells and whistles, the number of contacts had not improved. 

So, what were his expectations using the same chunk of wire on his garage floor? For a lot less money he could have kept the TS-2000 and put up a decent dipole. Any dipole even up at 15 feet would be a marked improvement over a random chunk of wire on the ground!

Always slightly ahead of the curve...

73's

Pete N6QW

May 20, 2024. "Pot Pouree"

Today's Blog posting is an admixture of several subjects, but they all have a relevance to our beloved hobby.

The ARRL was Cyberattacked and essentially put the Logbook of the World out of business. I also believe the attack impacted their email systems where lots of hams use the ARRL for communications outside of on the air contacts. I heard about this on the air yesterday and sit here astounded, amused and amazed. 

This event conjures all sorts of questions like why did it happen? Was it to spite the shift by ARRL to digital delivery of QST? If the ARRL systems were attacked that could impact the digital delivery system. Was it for financial gain i.e. held for ransom? Is there more than meets the eye beyond denial of service in that personal data like your credit card info was stolen? Was the ARRL caught with their antenna exposed?

One must also ask what security ARRL had for their Computer System(s). Was it regularly tested for any potential breaches? As advanced technically that ARRL would have you believe they are -- someone built a better mousetrap.

That leads us to who would do this. I don't know how you would go about pulling off a Cyberattack but it likely was someone more than some unhappy ham living in a basement in the 4, 5, 7, 8 or 9 call areas. Was it from a hacking group in Russia or China.

Will the Science and Technology Committee in the House of Representatives call for an immediate investigation? Two heavyweights on that Committee are Darrell Issa and Ryan Zinke names well known for pushing such investigations. MTG is not on that committee so it might take a while to see an ad hoc sound bite about it being linked to Joe Biden.

Astounded that our hobby to got hit. Amused that the ARRL response will likely be tepid at best and definitely pale by comparison to a response should NASCAR get attacked. Amazed that it took this long to happen.

One must ask was this all a conspiracy timed to occur during the same time as the Dayton Hamvention and FDIM. That precise timing is more than just a coincidence!

A Follow Up on my tale of woe. Short story: not much of a connection to the braid.

Yesterday's post discussed the bad solder job on a coax connector. It was worse than I imagined. I was able to pull out the shield sheath without any desoldering.

A 6-foot built RG-8 cable assembly complete with PL-259's is about $44 from DX Engineering. This is a huge incentive to repair the old one. 

Finally, a bit of the homily from yesterday's mass. Thank God for You Tube as my local Catholic church live streams mass on Sunday morning. I manage a twofer -- time with the XYL at the Board and Care and attending mass.

Our priest talked about gifts we receive in the form of skills and capabilities. He shared that he was quite good at baseball and got close to signing with a semi-pro ball club. But he also confessed that at one parish he was encouraged to not sing along with the choir. Baseball gene's Yes, but singing gene's No. 

This was a good example for us all. Not everyone can design, and scratch build a SSB Transceiver and some of us do a really crappy job of soldering coax connectors!

73's

Pete N6QW

May 19, 2024. Another Tale of Woe.

I have an extremely limited time budget and when something that appears as a mystery (eating into that time) it creates a sense of terrible frustration. I had such events over the past couple of days.

All of us have seen the phenomena where you connect the antenna, and the atmospheric noise is present. Disconnect the antenna and the noise goes away. In fact, that is a simple test once you have homebrewed a rig to see if the receiver is working even when the band appears totally dead.

I have also noted that when connecting the coax cable that when the center pin 1st hits the connector lots of signal but upon full engagement you only hear the band signals for that band.

At times with the Arduino and no antenna connected you faintly hear the clock noise as the code cycles through the loop. Connect the antenna and magically that faint noise disappears. 

Now the tale of woe. Using the Ten Tec 150A described earlier on this blog, with the antenna connected I could hear the Arduino and connecting the radio to the antenna OR the dummy load there was no change in the background noise -- we still heard the code cycle. Now how could that be?

Wow, we had a Ghost in the Machine. So how to attack this problem? The first step in the fault tree analysis is to separate whether the problem is the Radio itself OR Everything beyond that. Step 1 is to disconnect the coax at the radio. The atmospheric noise disappeared, and the only noise was the faint clock cycle.

The conclusion was that the problem was everything else. The fact that you could hear the atmospheric noise suggests that we have an open connection somewhere in the coax.

We have the classic PWP event! PWP = Problem Was Pete. If you look at this coax connector soldered by me, you will see pieces of braid not soldered to the shell. In a couple of other holes, the solder was a cold joint and actually broke away from the hole. 

I found this by accident as I bumped a short piece of coax when connected to the dummy load and the radio went quiet. A bit of wiggling and I could make the noise appear/disappear on demand. That was the problem -- bad solder connections by me.

It has been hard to tell how long it has been this way but sure showed up with the Model 150A. The Coax is RG-8 (real stuff) and hard to solder and not very flexible. A replacement with a short chunk of the smaller diameter RG8X is a temporary fix. 

The very astute blog reader would ask how come you are just now finding this issue? The answer is I have two operating positions and a two-position coax switch. Most of the time when I build and test stuff it is at the other bench. This bad piece of coax is located at the secondary position which is not used as much as the primary one. 

Lesson learned: check all of your coax connectors and recognize you may have a lot of skills but soldering connectors to RG-8 is not one of them. Let's see, type in DX Engineering and whip out the plastic. RG-8 previously bought at Amazon sucked big time!

SHOCKER: This is like getting hit in the cajónes with a bowling ball. A 6-foot length of RG-8 built with connectors is about $7 a foot from DX Engineering. This might be a good time to improve my coax soldering skills and fix the connector. Nothing like a dose of reality to improve one's mind! 

73's

Pete N6QW

May 18, 2024. Any one have one of these?

With a price point of about $250 you would think this is like hitting the lottery. Any blog readers have one of these?

This is the Xiegu G106C currently being sold at various places for about $250. Two reviews of this radio are bipolar ranging from very negative to very positive comments. That sure makes it hard to make any informed purchase decision. 

Certainly, at a price point of 25% of an ICOM IC-7300 it has to have some compromises like QRP power levels and not all of the whistles and bells. So, while the price is highly attractive are you wasting precious resources.

That is where taking your time to fully evaluate the product is job #1. You also need to evaluate the evaluator. Do the reviews cover the functionality of the radio and its attributes including the warts. Or is it just a rant following a bad purchase decision.

For $250 my take is it should not be the main station radio. But for something for use in the field where it is occasionally operated then that is a different paradigm. 

Caveat Emptor.

73's

Pete N6QW

May 17, 2024. Caveat Emptor

Any blog readers own one of these jewels? It is the uSDX, an Arduino + Si5351 driven SDR transceiver. 

This particular unit was hand built by me about 3 years ago. At that time, buying a bare PC Board and hand stuffing it was the only option. Now kits and finished units abound. Much like the Nano VNA prices are all over the place and many clones are evident. Another critical Nano VNA connection many of the variants simply don't work.

Amazon sells various units at varying prices. The original SDX work was done by Hans Summers and piggy backing off of that effort DL2MAN (Manuel) and PE1NNZ (Guido) did a lot of work to provide many features and of course SSB and CW capabilities resulting in the (tr) uSDX. Their offering is about $140 at Amazon who is one of the official sellers of the (tr) uSDX. 

These two hams now offer a unit which is a 5-band unit. Many of the clone units being sold are 8 Band units. Missing is 15 -- 10M on the (tr) uSDX

There are some amazing innovations in the design and the Arduino is packed to the gills with code. New firmware from Manuel and Guido yields a limited window spectrum display. The (tr) uSDX fits in the palm of your hand! It can run off of 5 Volts via the USB port and put out 0.5 watts. At 12VDC you get 5 watts.

I was disappointed with my final result with the version I built. (3 years ago) It worked OK on receive but sounded awful (like crap) on SSB. The Opposite Sideband Suppression on the (tr) uSDX is only 30dB down so not near what is possible even using a homebrew 4 pole crystal filter.

So, if anyone has a later version that actually works on SSB, please drop me a line at my QRZ.com email address or if that is too hard then use this email.

craponthebench@gmail.com

The (tr) uSDX is a really small unit and assuming it works OK on SSB would be ideal for the usual SOTA POTA adventures. 

73's

Pete N6QW

May 16, 2024. Another Conversion of a Commercial Radio

Today's topic is a Conversion of the Hallicrafters FPM-300, a 1970's Hybrid Transceiver into an all solid state QRP Transceiver.

 

The Original FPM-300

Long story short about 7 years ago (maybe 9 years) I bought a deal on eBay -- a Hallicrafters FPM-300. That deal turned into a nightmare! The Original FPM-300 was marginal -- the unit I bought was beyond fixing.

It drifted, it oscillated, and the rubber band switch assembly kept getting out of sync. [There was a rubber band toothed drive belt that when you engaged the band switch controlled several switches.] Think of the crappy dial string mechanism on the S-38E.

In desperation I pulled the solid-state main board and S Meter and sold everything else -- net loss was $20.

Not willing to let well enough alone, I designed a QRP Rig around the Main Board and S Meter. This is what we are showcasing today.

Yes, this is an older project, but I thought in light of the Matchbox Transceiver episode on the recent hackaday this is right in line with those of us who like to roll their own. I doubt any of those lurkers could pull this off.

Yesterday I had the Ten Tec Model 150A on the air during my noon break from the Board and Care and checked into the Jefferson Noon Net. 

They have a question of the day. Boom, yesterday's question: Where do you buy your ham rigs. I couldn't resist -- my answer is that I build them, and you are listening to one right now. 

That got some responses like who builds radios these days? Very few of us... WYKSYCDS!

73's

Pete N6QW

May 15,2024. Opportunities for Converted Radios

 Could a Hackaday Lurker pull this off?

I have always had penchant for Ten Tec Radios and when I spotted a Ten Tec Model 150A commercial radio an idea came to mind. Why couldn't this 8 Channel, 2-12 MHz SSB/CW transceiver be modified for the lower ham bands? I found one on eBay and the cost was $99. Heck if it was a bust the parts alone would be worth $99.

This is not a project where you can simply heat up the iron and solder a few parts and you are there. It is a project where you need the manual, and you need to understand how the radio was designed and intended to work.

The stock 150A covered 2-12MHz with a 12MHz IF and operated USB. The BFO/Carrier Oscillator was at a fixed frequency and to add LSB requires a second filter. Drake (and others) did this in the TR-3/TR-4. I could not find the LSB filter so with a bit of Arduino/Si5351 magic I was able to use a single filter.

I ran across a ham who worked at Kachina and he had a set of 16MHz USB/LSB filters which he suggested using in the TT 150A. I tried that approach but the 16MHz scheme would need a bit more work on the internal networks. Since the Model 150A already had much of the heavy lifting done, I stuck with the single 12MHz Filter.

My study of the circuits clearly showed that it was not just a simple matter of ripping out the Crystal Oscillator circuits and popping in a boring Si5351 for there were Tuned Networks that required modification and adjustment.

Let me explain. In addition to the 8 Channel selection switch there was another 8-position switch to select the proper range of low pass filters. In between were certain other filter networks to assure that what was selected was indeed transmitted. 

In this posting I included the LT Spice Simulation of the network following the Receiver/Transmit Mixer stage. I was blown away that one network could pass such a broad band of frequencies. Try that with your precious Nano VNA. It appears that the network is a cascaded Low Pass and High Pass Filter that results in a really wide range Band Pass. 

The 1st problem with this network was that it indeed cuts off at 12 MHz, so we had to play with the circuit constants to extend that to slightly beyond 14 MHz. 

Copy this circuit as someday you might want a wide range band pass filter -- like on a front end of a receiver. 

In passing the Drake TR-7 uses a similar cascaded LPF/BPF approach with a twist. On receive they are connected directly, but on transmit the High Pass which comes 1st is connected to the input of the RF Brick and the output of the high-power stage is connected to the input side of the Low Pass Filter. Some very expensive high power PIN Diodes do signal steering!

 

 

 

 

I am posting this because of what I have seen with those hackaday lurkers that make disparaging comments about individual projects. This conversion took engineering skills and the ability to look beyond a GitHub listing. So, hackaday lurkers let us see your work!

Always slightly ahead of the curve.

73's

Pete N6QW