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