Magnetic Loop Antennas

 I know absolutely nothing about Magnetic Loop Antennas! The OT's used to say if you want to make contacts then build a dipole, put it in the clear, up 100 feet in the air and you are there. The thought of a 40 inch in diameter copper loop sitting 2 feet above ground does not sound like a DX antenna, or any kind of antenna. 

Gulp! A $2500 Mag Loop from Italy sold by DX Engineering

The best analogy I thought of for those using a loop: Taking your cousin to the prom and convincing yourself... she is a YL; but in truth is sort of unattractive, not a 44DD and your cousin.

So, why Mag Loops? I did do a bit of research on Mag Loops and found in truth they do work and are good in high noise environments and where hams are subject to space limitations or HOA's. They are not a one for one substitute for dipoles in the clear, at 100 feet so don't get too excited!

Basically, a Mag Loop is really two loops with the outer loop being in the range of 10 to 15 feet in diameter with the better performing loops being at least 0.5 inch in diameter copper tubing with the ends connected to a HV Variable Cap. The best caps are vacuum variables. More on that.

The second loop is 1/5 the length (20%) of the main loop and this connects to your transceiver or transmitter. Now the configurations seem to vary but most common has the smaller loop at the top dead center of the larger loop, and the feed point at the bottom of the smaller loop. The Variable loop tuning cap is at the bottom of the larger loop. The larger Loop is supported at the bottom typically on a small stand or tripod often only a few feet above ground. One feature of the Mag Loop not easily done with a wire dipole at 100 feet... it is rotatable for nulling out noise.

Now for the shocker: the loops are Hi Q with a limited tuning range once set... like 20-30 kHz (or smaller range). So, if you QSY (move frequency for the BTE's) outside that range you need a retune. 

The other big shocker if you run 100 watts into the small loop, the circulating current in the big loop might be 10 to 15 amps and the voltage across the Variable Capacitor might be the close to 3500 Volts. That is the why of the large transmitting cap or vacuum variable. The reason is that the two loops form a step-up transformer where magnetic coupling (the Mag part of Mag Loop) connects the two loops.

VK3YE, Peter Parker had a good solution for the HV capacitor problem and that is a chunk of LMR coax. Coax cable has a certain capacitance per foot. His trick: Find an approximate length of coax to resonate the loop and solder each conductor at the ends of the outer loop and at the other end of the coax it is open. Two feet is maybe like 50 to 60 Picofarad. But this limits you to one band and one small tuning range.

Below are two you tube videos. I must have sampled about a dozen how to make it You Tube Videos and for someone unfamiliar with how to build one, these two seemed to hit the mark.

The second one answered a question for me. So, you got the expensive copper tubing, and now the problem how you make it into a perfectly round circle? His answer was he covered his dining room table with newspaper that was taped down. Then using a stick as a radius went around the newspaper with a felt tip pen forming a visual template. The final step has the tubing follow the pattern. Nice. 

Bozos has 0.5-inch copper tubing in a 10-foot coil in the $50 range. A 40 Inch in diameter loop is 40X3.14159 in circumference or 125.7 inches. Divide that by 12 and you get 10.47 feet. The open ends of the outer loop are connected to the capacitor, so you make that opening 5.64 inches (use an insulated spacer) and you have a perfect 40 inch in diameter loop.

Reference #1

Reference #2

So after watching the two videos most hams conclude that it is too hard to build one (only 1% of hams homebrew) and so what can you get for less than $2500. Here is one commercial loop that is about 20% of the Italian offering.

Here is a link to the Alpha antenna website. By the time you are done adding in everything to make it work likely you will have spent close to the cost of an ICOM IC7300 (earlier version). But the Mag Loop may be the only solution for those who have significant noise issues and where other antennas may be impossible to install, such as an apartment or where there are prevailing HOA restrictions.

Safety Precautions: That circulating current can cause serious RF burns. Keep your hands off the loop while transmitting. One install caused me to shudder. The loop was made of large diameter copper > 1 inch in diameter and was installed on the ceiling of a shack centered over the operating position. I saw a high risk of frying the operator's brain... well, I think he WAS from the W5 call area.

Them that know, now don't care if you know.

73's

Pete N6QW

The Regen Receiver

Predating the Direct Conversion Receiver was the "Regen" (Regenerative). Invented by E H Armstrong in 1912, it was a staple of ham shacks from then up to even today. Hams have described the "Regen" as evil, possessed by the Devil, a cause for alcoholism, diabetes, loss of hair, insanity, jock itch, infidelity, divorce and even pes planus. 

How can a marvel of electronics be described in such terms that serve to be like the highway traffic accident... as we pass by we all look for the dead bodies. The answer is while the Regen is simple in terms of circuitry, they are finicky to get operating. A special coil with a Tickler tap seems to be the critical path.    

There were two notable regens sold as kits by Allied Radio known as the Knight Kit Space Spanner and the Knight Kit Ocean Hopper. You can find these two on eBay today in rough shape, missing critical parts and rusted for about $150. The Space Spanner originally sold for $13.95 and the Ocean Hopper $10.95. In 1958, my dad bought me a Space Spanner.

One of the most popular topologies today for the Regen is from a seminal QST article in September 2000 known as the Kitchin's Regen (N1TEV).

Sept 2000 QST

Of course, in typical QST fashion you have to have the article to find out how to build L1. This is all part of the evil aura surrounding Regens. I will try to find the info on L1. The follow-on text suggests a film can is the base for L1. You know like 35mm film cans --- that was before smart phones.

"A Simple Regen Radio for Beginners 

 Notes QST September 2000, pp, 61-64 

By Charles Kitchin, N1TEV  

Some readers have been asking for a more detailed circuit explanation for my beginner's regen radio project in the Sept 2000 issue of QST. This should answer most reader inquiries.  

A Detailed Circuit Description for "A Simple Regen Radio For Beginners" Project in the September 2000 Issue of QST.  

Although this circuit uses very few components, its design and operation are NOT simple. This project evolved through several (less effective) earlier versions and is the result of many years of experimentation and testing.

  

Coil L1 and capacitor C1 tune the input signal from the whip antenna. Regenerative RF amplifier Q1 operates as a grounded base Hartley oscillator. Its positive feedback provides a signal amplification of around 100,000. Selectivity is also increased as regeneration introduces negative resistance into the Q1 regenerative loop which reduces the positive resistance in L1 (and also the losses in C1). Since the Q of L1 is equal to XL/R, selectivity increases as regeneration is applied. The combination of the very low operating power of this stage, only 30 microWatts, with the use of a simple whip antenna makes this receiver extremely portable and prevents it from interfering with other receivers in the area.  

Q1 is a very high gain bipolar transistor. While it offers extremely high sensitivity, smooth regeneration control would not be possible without taking special precautions in the design. First, diodes D2-D4 are a simple voltage regulator that keeps the voltage powering Q1 very low, so that Q1 transistor operates at the bottom of its curve. I avoiding using a Zener here as I needed only 1.4V and I also needed to keep power consumption as low as possible (and silicon diodes are cheap and easy to find). Second, Resistors R1 and R2 provide a very large amount of negative bias which also helps to soften Q1's normally abrupt transition into oscillation. Finally, Potentiometer R2 controls regeneration and as R2 is adjusted to a lower resistance, Q1's gain increases (less bias) but at the same time R2's reduced resistance decreases regeneration by more heavily shunting the bottom portion of L1. These two opposing conditions help to linearize the otherwise highly exponential increase in regeneration as R2 is adjusted to a lower resistance. The resulting very smooth regeneration control is something not normally found with bipolar transistor regenerative circuits.  

Several important features of this design permit this circuit to have very good selectivity and also help preserve the high gain of the regenerative RF stage. First, a simple whip antenna is used. This does not load down the collector of Q1 and it also does not add any significant capacitance across C1 (which would otherwise reduce the tuning range of the receiver). Diode D1 and capacitor C4 are a "floating" detector that provides very high sensitivity with very little loading on Q1. Note that the relatively low back resistance of the 1N34 diode provides the necessary DC return path for the detector. The combination of a very high gain regenerative RF stage with a very sensitive signal diode provides a sensitivity equal to that of many superheterodyne receivers while only consuming about 16 microamps of power supply current (with R2 at mid position which is typically the threshold of oscillation).  

Volume control R5 sets the level of detected audio driving IC1, an LM386 audio amplifier. Capacitor C7 operates the LM386 at a gain of 200. In order to prevent any significant loading of Q1, both the bottom of the volume control, R5, and Pin 3 of the LM386 "float" above ground so that both inputs of the IC are AC coupled. This is very important. The LM386's output is internally biased at mid-supply. However, if the 100k Ohm volume control was DC coupled to the LM386 (bottom of R5 and pin 3 of the LM386 both grounded), the high input bias currents of a marginal LM386 device could cause a very large output offset to occur.....several volts of 

offset could easily occur as the LM386 has 50k input resistors referenced to ground and the LM386 has a typical input bias current of 250nA...250nA times 50,000 Ohms times a gain of 200 equals 2.5V (0.000250mA times 50k times 200). By floating the bottom of the volume control and pin 3 of the LM386, both inputs are now at the same DC potential regardless of the magnitude of input bias current (and both inputs "see" 50k to ground).  

Capacitor C5 provides low pass filtering that keeps RF out of the audio amplifier. Without it too much RF passes through the LM386 and into the headphones or speaker wiring then feeds back into the antenna circuit and causes motor boating on strong signals. C5 also improves the audio quality and slightly increases audio selectivity. Resistor R4 isolates the low pass filter from the detector circuit when the volume control is at the top of its range. Otherwise, the circuit would detune when the volume control was turned all the way up.  

Capacitors C10, C12 and C13 decouple the power supply line and isolate the RF and audio stages. Due to the long-time constant formed by R7 and C12, the detector will take approx. 7 seconds to start operating after the power switch is turned-on but operationally this is no big deal.  

Diode D5 protects the receiver if the battery is connected backwards. The coil, L1, is wound onto a standard 35mm plastic film can or 1 inch diameter pill bottle. I did not use a torroid here partly because it might saturate (and therefore detune) the receiver at critical regeneration but mostly because beginners want something that's easy to find and won't scare them off. Note that the selectivity is more than adequate (for a beginner's radio) using a film can coil form and therefore it is doubtful that a torriod would add any significant improvement here anyway (but it still might be interesting to try though).  

Capacitor C1 can be any air variable capacitor with 100pF to 365pF maximum capacitance.

Frequency coverage will vary with the capacitor used but all should cover the 40 meter Ham band plus several international broadcast bands. Note that using a capacitor with a large tuning range (such as a 10 to 365pF) will make it more difficult to tune-in a station than using a smaller capacitor (such as a 10-150pF). Therefore, the optional fine-tuning control is recommended when using large tuning capacitors.  

By increasing C1's capacitance (or increasing the turns on L1), this radio will operate all the way down to the AM broadcast band (and probably long wave as well). But it is important to limit the total tuning range, so that it is still easy to tune-in a station. That is why I am specifying the max. capacitance of the air variable to 365pF. Operationally though, a 100pF or 150pF value is best. You can always just switch-in extra capacitance to move down to a lower band.  A fine tuning control may be added to the receiver using diode D6 which functions as a poor man's varactor. As the voltage from fine tuning control R7 is increased, the diode is reverse biased and its capacitance decreases. This fine-tuning control is cheap and easy to add but its added capacitance will somewhat reduce the maximum frequency range of the receiver. You can compensate for this by removing turns from L1 (but keep the same ratio of turns for the tap if you reduce the total turns by 25 percent reduce the tap turns by 25 percent etc.).  Note that an audio taper control is specified for R8. This should be connected so that turning up the control causes an increase in voltage driving D6. The use of an audio (logarithmic) control helps to linearize the otherwise exponential decrease in capacitance as the voltage across D6 is increased. Note that capacitor C15 should be kept very small: 10pF MAX. Large values will give a greater capacitance (fine tuning) change but D6 will then start to load down Q1 and decrease gain and selectivity.  

With a whip antenna and weak stations (during the day etc.) this receiver is easily detuned by hand capacitance changes. There are several simple cures for this. A one- or two-foot length of wire can be clipped to the metal front panel or an external antenna (any random length of insulated wire) can simply be wrapped around the whip antenna. Be careful not to overcouple the external antenna as this will also cause loading on Q1.  

73  

Charles, N1TEV " [Found on the Internet.]

Now you know, direct from the author. He seems to be telling us that it took him a long time to arrive at this configuration and hopefully did not endure pes planus in the process.

Or for $50 you can buy a Regen Kit from a supplier in the UK. (Spectrum Communications.)

Regen Kit from the UK

The website for Spectrum Communications is here and Antony sells many hard-to-find components like 9 MHz and 10.7 MHz SSB Crystal Filters. The 10.7 MHz Filters are an interesting find for use with a 10.245 MHz mixer stage (a standard computer crystal) where one of the outputs is 455 kHz. Here you could use a Collins Mechanical Filter in a 2nd IF. Dual Conversion BTE's. To see that scheme check the N6QW QRZ.com page and look for the KWM-4 rig. 

Them that know, now don't care if you know.

73's

Pete N6QW

Multus Proficio MKII, A QRP SDR Transceiver

Meet the Multus Proficio, a 5-Watt QRP SDR Transceiver from the USA.

The MK II sells for about $425 and I have the MK I which was a bit cheaper. I have had my radio for a couple of years now operating with HDSDR. It does a pretty good job. (Regrettably it will not operate with Thetis or SDR Console.) Add a 100-watt amp and a laptop and you have a nice functional POTA station ready to operate from some park.

Multus has a custom (homebrewed) Software Suite and also has tagged on to QUISK with a special CW Suite. Multus traces its roots back to the Peaberry SDR board which featured an on-board codec. No external sound cards were needed for the I/Q encode or decode for the Peaberry.

True you are 1/2 the way to an Icom IC7300 (non MKII, 7300) but the radio will give you lots of capability for 1/2 the price.

St. Louis

I did two tours of duty in St Louis totaling 11 years and it was all about the job. I was paid well and it was a good place to raise kids, but it had an unmistakable terrible mindset. That mindset was the basis of my saying St. Louis is a great place to retire from not to! In between tours was a job assignment in Mesa Arizona where the same saying applies.

The McDonnell Douglas plant was physically located at the Lambert St. Louis airport. I lived in St. Louis County and that meant a 35-mile commute one way. In wintertime it was a dangerous drive.

So back to the mindset. During the Gulf War, I used my drive time listening to the news. My thoughts were always with our troops and remembering my time in the Seabees. That was the problem: the local news (mindset). 

The local news program on FM radio would start out: There was a major battle today outside of downtown Kuwait and now for the ball scores! The rest of the program was dedicated to baseball, football and hockey stories and/or including sports injuries and trades. Satellite radio would have cured that but not available in the early 1990's.

I am not a sports fan but am sure interested in world events. My interest peaked as two of my boys were draft age at that time. What a vacuum it was. Arizona followed a similar template with the overemphasis on sports.

We have the same issue today with the focus on old what is his name with stories like he spent two hours on X after midnight ranting about revenge and fair elections. Do we really care about cankles and suggested cognitive decline. What really is involved is his shifting the focus from the economy and people out of work to dribble about subjects that cause agita like renaming buildings. 

The media is to blame for the lopsided reporting on the latest antics. Stop reporting on the trivia and ask why so many layoffs in January. Big question: While shooting Americans seems like a new ice (ICE) sport what is the long-term path to citizenship plan? 

As Michael Douglas said in the movie The American President: "These are serious times for serious people." (This is not The Monty Python Clown Show!) Time to get serious and make your vote count in the Mid-terms. 

Them that know, now don't care if you know.

73's

Pete N6QW

BC-348 Receiver

 

BC-348 WWII Receiver

A ham friend who also grew up in Western PA shared his recent BC-348 video with me. He too dabbles in Boat Anchors... he has had more pass through his shack than me. I am in awe. He also reads the blog.

But three pieces of information for other blog readers and the 1st is the power supply. Many WWII vintage radios on eBay lack power supplies as the source of power especially those used in airplanes was a dynamotor. 

For those with a question mark on their face, a dynamotor was a small motor generator set running usually off of 24VDC that supplied all the operating voltages. Read noisy. 

The small ARC-5 receivers had a space on the back where the dynamotor attached. Often the filament string (transistors weren't invented as yet) was series/paralleled to operate from 24VDC.

The BC-348 had an internal space to install the dynamotor. The 1st important point the video shows how a $30 switching power supply from BOZOS can power the BC-348 and fits in the space where the dynamotor would attach. This power supply could be used for many other WWII surplus receivers.

The second point is the radio itself as it was as much electronic as mechanical assemblies (to switch bands). Keep in mind these radios were designed in the late 1930'w... No Internet, No Computers, No Nano VNA's and no Transistors or IC's. I marveled that the VFO had set points for various bands. In other words, you can calibrate the VFO at 5 MHz WWV and then a separate set point for 10MHz WWV.

The third point and that is radio tuned from 1.5 to 18.5 MHz, operated AM and CW and no band spread. Dial markings could be as much as a 100KHz apart. It struck me that the BC348 could be the principal receiver on a B-17 traveling across the Pacific and was the sole piece of long-distance communication receiving equipment. Good Luck!

Today's hams have no clue about WWII radios like the ARC-5, BC-348, HRO or ART-13's where 30 Hertz off frequency was routine. They have no clue that these radios were manufactured without using AI, Computers, sans solid-state devices or Nano VNA's. I guess the answer from this BTE set... who cares. 

Well in fact somebody cared as it was the shortcomings of these earlier radios that formed the basis of the designs we have today. 

Think about in the video how the 5MHz WWV set point was done. Now the military radios (SDR) have BITE (Built In Test Equipment). When the radios are placed in this mode there is GPS Disciplined Oscillator at 10MHz that readjusts all oscillators to that standard. A flick of a switch and in 1 second you are on frequency. 

Them that know, now don't care if you know.

Here is what Mr. Carlson did with a BC-348.

73's

Pete N6QW

17M ~ The Sneaky Band

The IF is 4.9152 MHz and the LO is 23 MHz

17M, the Sneaky Band.

Some 19 years ago, I built my 1st 17M transceiver and very much enjoyed working DX on that band. Several years ago, I revisited that rig and removed the crystal switched VXO and in went the Si5351 and Arduino. One of the reasons for the change was to give full band coverage. [Click on the link for ad nauseum details of the 17M Build.]

Center Area Relay Switched VXO 

Board Overview ~ 7X7X2 Inch Chassis

Non-Analog 2 Band VFO

The 17M band has a lot of charm as it is a DX Band. It is void of contests as it is considered a contest free sanctuary but has a very active FT-8 following. I call it a sneaky band because the CQ POTA, SOTA and IOTA aficionados frequently use the band as these are not considered contests!

In essence you avoid the 45 Minute Extra Class wonders trying to work contests; but will hear them shout CQ POTA. Given that the 17M antennas are modest in size it is a great band for portable operation while hiking or camping. 

One notable item is the homebrew diode ring used as the Balanced Modulator/Product Detector which has a panel mounted switch to unbalance the ring and used for Tune purposes. The RF Output device is a MRF260.

Attention Adults in the Room

The economy is in the toilet, and I hope the majority is happy with their choice. The massive Layoffs in January is a sure sign there is a huge problem. The hirings are pitiful and we now have more evidence of what needs to be done in the midterms. You might want to stop wearing your red ball caps.

Vietnam

To recognize our contingent of blog readers in Vietnam here is a partial translation. Side comment: Vietnam has a plethora of stunning YL's. I've seen them!

Băng 17M có rất nhiều nét cuốn hút vì đây là một băng chuyên săn DX. Nó không có các cuộc thi vì được xem như một “khu bảo tồn không thi đấu”, nhưng lại có cộng đồng FT-8 hoạt động rất sôi nổi. Tôi gọi nó là một băng “lén lút” vì những người chơi CQ POTA, SOTA và IOTA thường xuyên sử dụng băng này — do các hoạt động đó không được xem là thi đấu!

Về cơ bản, bạn tránh được những “pháp sư Extra Class 45 phút” đang cố gắng tham gia contest; nhưng bạn vẫn sẽ nghe họ gọi CQ POTA. Vì ăng-ten 17M có kích thước khá nhỏ gọn, đây là một băng tuyệt vời cho hoạt động portable khi đi bộ đường dài hoặc cắm trại.

Một điểm đáng chú ý là mạch vòng diode homebrew được dùng làm Balanced Modulator/Product Detector, có một công tắc gắn trên panel để làm mất cân bằng vòng nhằm phục vụ mục đích Tune. Linh kiện khuếch đại công suất RF là MRF260.

German Translation for readers in Germany

Das 17‑Meter‑Band hat eine ganz besondere Anziehungskraft, da es ein echtes DX‑Band ist. Es ist frei von Contests, weil es als wettbewerbsfreie Schutzzone gilt, hat aber dennoch eine sehr aktive FT‑8‑Gemeinde. Ich nenne es gern ein „Schleichband“, weil die CQ‑POTA‑, SOTA‑ und IOTA‑Fans es häufig nutzen – schließlich gelten diese Aktivitäten nicht als Contests!

So entgeht man den 45‑Minuten‑Extra‑Class‑Wundern, die normalerweise nur in Contests auftauchen, aber plötzlich lautstark CQ POTA rufen. Da 17‑Meter‑Antennen relativ klein ausfallen, eignet sich das Band hervorragend für portablen Betrieb beim Wandern oder Camping.

Bemerkenswert ist auch der selbstgebaute Diodenring, der als Balanced Modulator bzw. Product Detector dient und einen frontseitigen Schalter besitzt, um den Ring zum Abstimmen (Tune) bewusst zu entbalancieren. Als HF‑Leistungstransistor kommt ein MRF260 zum Einsatz.

Them that know, now don't care if you know.

73's

Pete N6QW

Pot Pouree and Some Interesting Information

Half the world's hams are Japanese and yet no hams from Japan visit my blog... so maybe English is not a common language in Japan, so I had the blog translated to Japanese.

ブログ全文を自然な日本語に訳すとこうなります。

まずはブログの統計から得られた興味深い情報です。これは、アマチュア無線のイノベーションの中心がどこへ移りつつあるのかを示しているのかもしれません。

短期間での国別ブログ閲覧数はこうなりました。大半はアメリカですが、2位・3位・4位を見ると、思いがけない国々でホームブリューが行われていることが分かります。特に4位の国は、アマチュア無線機の自作が次に盛り上がる国を示しているのかもしれません。ベトナムとその低コスト生産力です！

誰が想像したでしょう？

RPi5 SBC の水冷

Digi-Key で約20ドル

ICE の活動

過去13か月間で、移民取り締まりに ICE がどれだけ費用を使ったか気になる人は多いでしょう。Copilot の推定では、およそ100億ドル規模のようです。

⭐ 総合推定：過去13か月で ICE は移民取り締まりに関連または直接関係する活動に約95億〜100億ドルを費やした可能性が高い。

その資金の一部は、契約業者の担当者へのボーナス支払いに使われたと Copilot は示唆しています。これは不法移民に対する「報奨金」のようなものなのでしょうか？分かりませんが、誰かは知っているはずです。

Simple SSB の話

Simple SSB のアップデート

修理作業と、他のバンドでの動作テストを行う必要がありました。まず、あの「船酔いグリーン」の16×4 LCD が故障したので、16×4 のジュリアノブルー（白文字）に交換しました。黄色いパネルとの組み合わせがなかなかクールです。

両方の LCD は外形寸法こそ同じでしたが、表示部の実際のサイズが異なっていました（ブルーの方が縦方向に大きく、横方向に小さい）。そこでアルミスペーサーと長いボルトを使い、ブルー LCD が開口部をまたぐように取り付ける方法を採用しました。これがうまくいきました！

次の問題は、最新の Arduino IDE が、IDE 1.8.5 で書かれたスケッチをコンパイルできなかったことです。20m や 17m など他のバンドをテストするために上限周波数の範囲を広げる必要がありました。そこで、1.8.5 がインストールされた古い Windows 10 マシンを使い、修正したスケッチを読み込むことができました。

BPF を 20m、次に 17m に再調整し、FT-8 信号を受信できました。これはかなり良いテストになります。実際、予想以上に良い結果で、設計の良さを裏付けるものでした。そう、これは私が設計し、製作したプロジェクトです。キットでもなく、他人の設計のコピーでもありません。これは本物のホームブリュー無線機です！リグのドキュメントへのリンクもあります。

さて、眠れる「犬」をそのままにしておくか、20m か 17m のどちらかの BPF を新しく作るか、決めなければなりません。

難しい作業ではありませんが、最新の Arduino IDE がこのスケッチと互換性がないため、余計に手間がかかりました。

ちなみに私の名前「Pete」の発音が難しい人は、これを試してみてください… Xochitl（ソチル） — 「ソ・チー」と読みます！

知っている人は、もうあなたが知っているかどうか気にしません。

73 Pete N6QW

必要なら、もっと自然な文体に調整したり、技術用語を日本のハム向けに最適化した訳にもできます。

First some interesting information from my blog statistics. This may be predictive of where the orb of ham radio innovation may be shifting.

Over a short period of time this is the number of views of my blog by country. The bulk is from the USA but #'s 2, 3 and 4 offer a view that there must be homebrewing going on in unexpected places. The #4 entry may be signaling the next country to go big on building ham radio gear ~ Vietnam and its Low Cost of Production! 

Who Would Have Thought?

Water Cooling for an RPi5 SBC

Digi-Key ~ $20

ICE Activities

Any one wonder what is being spent by ICE over the last 13 Months on immigration roundups. Wonder no more as copilot suggests perhaps in the range of $10B

⭐ Combined Estimate: ICE likely spent between $9.5B and $10B on activities that include or directly support immigration roundups over the past 13 months. 

Some of those funds as suggested by Copilot were to pay bonuses to contractor personnel. Is that like a bounty on illegal immigrants? Dunno, but somebody knows.

Simple SSB Stuff

Simple SSB Updates

I had to do some repair work and run some tests on other possible bands of use. For starters the seasick Green 16X4 LCD died and I had to install a 16X4 Juliano Blue with white letters, which is cool looking with the yellow panel. 

That was a bit of an effort as the overall footprint of both LCD's was exactly the same but their actual display electronics was different (the Blue needed a larger opening in the Y direction but was smaller in the X direction). My solution was to use aluminum spacers and longer bolts so the Blue LCD straddles the opening. That worked!

The next issue was the latest Arduino IDE would not compile the sketch written in IDE 1.8.5. I needed to open the range of the top frequency to test other bands like 20M and 17M. Using a decrepit Old Windows 10 Machine which had 1.8.5 installed, I was able to load the revised sketch.

I retuned just the BPF to 20M and then 17M and I could copy FT-8 signals which is a pretty good test. Actually, the results were better than expected attesting to my good design. Yes, I designed and built this project. It was not a kit and not a replication of another's design. Folks this is real homebrew radio! Link to documentation on the rig.

So, now I must decide whether to leave the sleeping "dawg" lie or make a new BPF for either 20M or 17M.

It is not hard work, but the task was made more difficult because the latest Arduino IDE is not backward compatible for this sketch.

In case you have trouble pronouncing my name, Pete, try this one...  Xochitl --- It's "So Chee"! 

Them that know, now don't care if you know.

73's

Pete N6QW

Simple SSB Transceiver

This 40M SSB transceiver was a project designed to produce a minimum part count rig, and the result was that only 10 Transistors were used. A follow-on project, the P3ST, got the part count to a mere 7 Transistors.

Simple SSB

The IF is at 9 MHz and uses the Plessey Topology (2N3904 and 2N3906 Bilateral form factor). It has two LO's and the 2nd LO boots up on 40M FT-8. It is USB/LSB selectable and has a 16X4 LCD display.

Full construction info can be found at my n6qw.com website. This rig was built in 2019 and subsequently chosen by the Vienna Wireless Society (Vienna, VA) as a club project.

It is a spare design but packs a lot of punch and feature rich capabilities. This is a great starter transceiver project.

When I pulled this out of the storage box the other day, I got a light bulb idea. Because the way in which the Band Pass Filter was designed, unsoldering two fixed capacitors and retuning 5 small trimmers shifts the BPF to 20M. I don't think I ever checked how this design would work on 20M so this would be a good evaluation.

Then I checked the range on the LO, and it would only tune to 9MHz, the top end stop frequency.  A simple one number sketch change would fix that and move the stop frequency to 15MHz. Pretty simple... 30 seconds with a soldering iron and about a minute with the Arduino sketch.

That is when the fun began! Several months ago, my Windows 10 machine died, and I bought a refurbished HP machine with Windows 11 Professional. This entailed loading all sorts of new software (Thetis, HPSDR and Arduino IDE 2.36). When this rig was built all of the Arduino Sketches were done in IDE 1.85. Never the twain shall meet. I now find that many of the old sketches, in this case about 7 years old have issues compiling in the later IDE.

I do have a Linux computer with the older IDE and will try a reload using the changed number so I can test this radio on 20M. If that works OK, then I will change out the W3NQN LPF and make this a 20M only radio. In the final analysis why isn't the IDE backward compatible?

Them that know, now don't care if you know.

Much discussion in the media about cankles... what is that?

A “cankle” is a slang word. It describes when a person’s calf and ankle appear to have no clear separation, creating one continuous shape. The word blends “calf” + “ankle.”

It’s not a medical term — just casual, sometimes teasing language about leg shape. It appears the media focus on cankles is a diversion from the Jeffrey Epstein drama. Just think if he was still alive and could finger those most involved. Better said: in lieu of finger, identify.

73's

Pete N6QW

Techie Stuff!

So, if you are a contester or just plain operate only, time to zone out because today I want to cover a steerable 4.9152 MHz IF module. So, this post translates to Techie Talk. 

Bored? As an alternative you could try to locate the Ham Radio Chick's You Tube channel, where she will update you on her latest POTA adventures following her 8-day sprint to an Extra Class License.

The reason for covering this module again is because in less than 10 square inches you have a powerful piece of technology to wit:

Transmit and Receive mixer (SBL-1)

1st IF AMP using J310's as a DGM

Homebrew 4.9152 MHz 4 Pole Crystal Filter

2nd IF Amp using J310's as a DGM

Product Detector/Balance Modulator (ADE-1)

Audio Filter on the Out/In of the PD/BM

Ride along 4.9152 MHz BFO

The DGM Amps have trim pots to balance the input and output signals to achieve low distortion and good signal and noise handling.

The 1st IF Amp is a Tuned Amp and the 2nd IF Amp is broad band (No this is not Ina Rae Hutton's all girl band). The signal path through the 1st and 2nd IF Amps is always in the same direction and two small on-board relays steer the IF Module input to either the SBL-1 or ADE-1 depending on whether in Receive or Transmit. (Something 1st seen in the EAQRP Club "Pilgrim" radio.)

This was an earlier You Tube Video of this rig. Yes, it had some warts, but the plan is to fix those hiccups. That is a fun aspect of the hobby for me. 

Yes, there are few I can hardly hear you, but you are 5X9 comments to be heard while you build stuff. So, if you need an hourly dose of 5X9 Park 160079... that does happen during rig fabrication.

Also needed for a complete rig is a digital LO, a display, a steerable (Rx and Tx) RF Amp, a Band Pass Filter. Low Pass Filter and TR. Not mentioned as yet the Transmit Driver and Final Amp.

Them that know, now don't care if you know.

73's

Pete N6QW

The Weird, the Strange, the Arcane

A Tri-Band "Hot Water" SSB Transceiver

Back in the day when hams were more than appliance operators and delved into the circuitry of many of the radio models, they always were looking for an opportunity to upgrade their radios.

Heathkit struck gold when they produced the Mono band SSB radios. The individual kits cost about $100. Often hams would want additional bands and thus Heathkit sold more product. 

But enter the ham entrepreneurs who found ways to modify a Heathkit mono band unit to add more bands. I do know there were commercial kits sold to do this on a limited run basis. The above photo shows a tri-band Hot Water. This is an eBay listing, and I am uncertain if this is one of the modifications kits or the radio was modified similar to the kit.

I see the potential of ripping out the VFO and installing a ESP32 and Si5351. Maybe even the JF3HZB circular dial. 

Lots of possible improvements/modifications using the low-cost technology sold at Bozos. (BoJack + Bezos).

The Fox Hole Radio Set

It doesn't get any simpler... a rusty razor blade (iron oxide) a safety pin, a coil, some antenna wire and a set of headphones. This was a staple of many WWII "ground pounders" as it requires no electricity, something to fit in your 782 Gear (USMC term for a knapsack) and could be something that provided entertainment. 

For those who wonder the term 782 Gear comes from the USMC and the 782 refers to the form (form number) each "grunt" must fill out to validate that he or she received a knapsack and if you lose it, the form is evidence at a court martial. The Marines assure accountability. Thus, the form number became the name for the equipment.

The Rusty Razor Blade is a cousin to our galena (iron pyrites) crystal detector.

Cognitive Decline is real and is readily visible.

Them that know, now don't care if you know.

73's

Pete N6QW

Ugly Weekender

When I first heard the term Ugly Weekender, I thought of the young ham guy who went out partying Friday night and through an unfortunate incident of beer goggling* awakes the next morning to see a YL like this next to him. That had the makings of a true Ugly Weekender.

*Beer Goggling

C'mon guys it's somebody's Grandma!

We are not covering that kind of weekender but one that highlights that seminal W7ZOI project involving a CW transceiver. The Ugly Weekender was mentioned in yesterday's blog and the link has a you tube video.

Ugly Weekender

There is an elegance to the W7ZOI design in that it is a Direct Conversion Receiver with a tunable analog LO and that LO serves as the frequency source for the Transmitter.

For those ashamed of being an Amateur Extra and don't own a soldering iron or have never built anything, this is a project for you. 

The reason I suggest that is that you can build the receiver first and listen to how good a DCR can sound and then you can add the transmit side. 

Now there are many DCR receiver projects including mine or the N2CQR/KK4DAS effort and certainly both will serve you well. BUT building the W7ZOI version inextricably connects you to the great W7ZOI.

The Ugly Weekender (UW) involves no beer goggling and is a sparse design meaning you can do it cheaply. The UW also affords an opportunity to eventually rip out the Analog VFO (get it working with what is designed first) and then add a Nano and Si5351. 

Thus, the UW is a steppingstone project that builds ones CV (Curriculum Vitae) by bridging the Analog world with the Digital world.

It is a project like this from the father son team (Wes and Roger) that embodies the true ham radio hobby. Keep in mind before you can contest or operate... somebody had to design, build and test a radio.

A cute definition I heard regarding the term "cognitive decline" which is where an older person pisses his pants, doesn't care, blames others and covers over the spot with make-up. There are some clever people out there working overtime.

Them that know, now don't care if you know.

73's

Pete N6QW

Implementing a W7ZOI Design

Anyone who has been a licensed ham longer than 45 Minutes knows Wes Hayward, W7ZOI.

If you have SSDRA (the better) or EMRFD (the lesser) or built a Direct Conversion Receiver or a Crystal Filter or a TIA amp or the Competition Grade CW Transceiver or the Ugly Weekender... That is the handiwork of Wes W7ZOI.

In December 1989 and January 1990, Wes had a two-part article in QST which documented a 20M, QRP Solid State, SSB/CW Transceiver. Quite a feat at that time or any time. This project was beyond minimalist as fully built out it had multiple Crystal Filters. It actually was a trans-receiver which shared a common LO and BFO, thus separate filters in the receiver and transmitter. 

A link to the 2-part article

I could not resist replicating W7ZOI's project save for the hinky way he did CW and the Analog VFO sans VFO Stabilizer. It was a challenge I took on.

My implementation added Break-In CW and the use of the EI9GQ PIC based (16F84) VFO stabilizer. Most of the rest of W7ZOI's design remained intact with the exception of the IF stage/AGC which was a suggested change from W7ZOI. My only contribution was the break in keying and the addition of the Digital Display and VFO Stabilizer from Ed, EI9GQ

I had been in contact with Wes, and he said maybe you would like to try this IF as it uses 3N209's which he sent me as well. He asked if I tried it to give him feedback on how it worked.

The Revised IF Amp from W7ZOI. Empty Sockets = AGC

Replacement AGC

Ferrite Beads on the Gates

A View of the Innards

Essentially, I was Beta testing what would eventually become the HYCAS IF. The AGC seemed to hang up for me, and I Installed a different board. When all done, I shared my results with Wes. As those who homebrew know the final HYCAS did not use the 3N209's.

The XF-9B is an 8 Pole, 9 MHz Crystal Filter from KVG in Germany. OT homebrewers know this was once the ne plus ultra of Crystal filters. So, the newly minted 45 Minute Extra asks where is that filter in my IC7300. Didn't the test answer guide cheat sheet explain about different SSB generation technologies?

My build ended up with a big and heavy homebrew box. Yesterday afternoon I worked an HI7 station in the DR. 

My receiver uses the 8 Pole KVG Crystal Filter and the transmitter a 6 Pole from the G-QRP Club Sales. The receiver design is by far one of the best I have seen. 

This project required an advanced amateur to fabricate and not for someone who knows nothing about electronics.

Note: No Manhattan or Ugly construction here.

News Flash: Bozos selling the Baofeng UV5R for $16. Such a deal Vinny!

Them that know, now don't care if you know.

73's

Pete N6QW

The B and B of Ham Radio

No, we are not talking about some cutesy cottage with great food in a corner of New England (or maybe even Connecticut) but the B and B of Ham Radio.

Finally, you guessed it: a Bitx4o and the Baofeng UV35. I suspect the newly minted Extras may have had to struggle with the B&B since those are not rigs on the memorization list.

Up front I own one of each. The Bitx40 you see in the photo is no ordinary unit as it was gifted to me from friend N2CQR as a Tech Special. Bill often receives units like this (broken) and will occasionally pass some on to me. I think he does this with a twinkle in his eye... a chance to drive me nuts chasing down problem rigs.

I say this is a special Bitx40 as I figured out how to add USB to an otherwise LSB only radio. Of course, USB on 40M has only one use and that is FT-8 (or to talk to the group that only uses USB on 40M).  The solution was not to supplant the BFO crystal with one of the opposite sideband frequencies but instead change the LO frequency.

The Bitx40 as stock used a High IF Frequency (12 MHz) and a low LO Frequency (5 MHz) and with the BFO chosen this results in LSB.  Now if we place the LO above the IF Frequency (19 MHz) and subtract the IF from the LO, we get USB. So, a single BFO frequency will give both LSB and USB.

A second Bitx40 Tech Special from N2CQR was converted to 17M. I had to change out the BPF and LPF and create a digital LO at 30 MHz (30 -18 =12).

The other huge hill climb was the Digital LO as this leverages the excellent Bitx topology into a highly functional, stay on frequency, dual mode (USB/LSB) POTA capable radio.

I sure hope the BTE's were awake during this techie talk.

The plastic case for this Bitx was originally intended for first aid supplies and was waterproof. Time deteriorated the plastic and so it was a good idea gone bad.

The next B in the B&B duo is my Baofeng UV35.

N6QW's UV35

This Baofeng UV35 was acquired 13 years ago when I moved back to California. As luck would have it I have a ham friend who lives 500 feet from my QTH. When I 1st moved here, I spotted his antenna and you know the deal. Upon our 1st meeting he showed me his Baofeng which I think could be bought with some accessories for about $25 at Bozos. I bought one right away.

Then I heard stories it might not be legal with spectral purity. But it had some other features like a flashing light, a siren and FM radio. For a while I took it walking with me and used the FM radio to listen to NPR. I think I made one contact with the radio, and my report was scratchy and not full quieting. Now when I walk, I just use my smart phone and either listen to my stored music or internet radio.

So with 1/2 the total US ham population being Technician class likely lots of Baofeng's are on the air and they now might be legal and good for 10 watts.

Them that know, now don't care if you know.

Some people in high government offices seem to be thrown under the bus as that is in vogue today. Reminds me of the Circus Maximus and the throwing of people to the hungry lions.

73's

Pete N6QW