Ham Radio

BENS BEST BENT WIRE

Due to the inherent rhythm in Morse Code, some stuff is just fun to hear. If you swing your Bug a bit or don't have the most perfect 3:1 DAH-DIT element timing it can sound even more interesting.

The old timers all know this stuff but for those of us new(ish) to CW there are still these little gems we keep finding... like how sending the words BENS BEST BENT WIRE sound in CW when they are all crammed together .

If you've never played around with rhythmic sounding words during your off-air practice just give it a whirl. If you do it on a bug with a bit of liberal timing it can be even more fun.

BENS BEST BENT WIRE

Play / Pause

Learn CW Online - LCWO.net -
Text to Morse Converter

So play around with it and if you have other interesting sounding texts in CW please comment or email them to me.

That's all for now...

So lower your power and raise your expectations

72/73
Richard, AA4OO

Unfortunate name for a Great key

The Junker D.B.G.M. is one of the finest telegraph keys ever manufactured.

In 1926, engineer and marine captain Joseph Junker, founded a factory in Berlin which made equipment for radios and submarines. He was the creator of the Junker telegraph key.

At the end of World War II, the factory was moved to Honnef just before Joseph died in 1946.

German precision - Micrometer gap adjustment

The phrase "German precision" is applicable here. Historically, German engineers seem to go above and beyond what is minimally required for a design and often "over-engineer" their products. This key is a perfect example. The Junker excels in the precision of its construction, and may have the most controllable gap adjustment of any straight key in the world, resulting in the ability to send very clean CW.

Ball-bearing plunger under the gap adjustment

The knob at the rear of the key moves in precise clicks controlled by a ball bearing plunger under the knob, engaging small detents underneath the wheel. Each click moves the gap one-tenth of a millimeter. That is "very" precise.

click stop gap adjustment

Unlike most straight keys when the gap is set at it's minimum it's calibrated to actually be a minimum gap and not allow the contacts to touch. I don't have a feeler gauge thin enough to measure the gap but it's there. It's so small, that I can't discern the lever actually moving when I operate the key, but it makes clean contact with zero mushiness and nearly effortless operation of the key.

gap at 2-clicks

The lever force, or tension adjustment is singular as well. The smaller knob on the left trunnion base moves a cantilever under the base of the key that moves a plate under the lever spring. So rather than compressing the spring from the top of the lever at it's narrowest, it is compressed smoothly from the base up into the lever. Just amazing!

Some Junkers came with an RF suppression coil comprised of a many turns of hand-wound, insulated wire tied into a tight loop and held with ties fitted up into a circular recess in the base of the key. My key did not have the RF suppression coil, which is fine, since I am not operating a high-voltage keying circuit that might benefit from the coil. I've read that some users have encountered problems due to the fine wire of the RF coil providing too much resistance and have bypassed it. No need here.

under the base of the key, notice the armature for adjusting the lever tension.

In use

Most straight keys I've used in the past two years employ a Navy-knob style grip that I've grown accustomed to. The Junker has a lower (about 2.5" above table), flat lever disc. It's odd how used to the Navy style grip I've become. I practiced for about 15 minutes trying various grips. I still operate with my arm in free-space and I imagine with this key I'm supposed to rest my elbow on the desk but I don't have room for that at my station so I operate with the key at the edge of the desk.

Anyway, I settled for now on sort of a loose fist style grip where I'm resting the first knuckle of my middle finger on the dish of the key while lightly gripping the disc. Seems to work and the more I operate the more comfortable I'm becoming with it.

The level of adjustment is truly amazing. Being able to quickly change gap adjustment during a QSO to relieve fatigue or just try a different spacing, without messing around with a set net, or worrying about actually closing the contact was novel and fun.

The demonstration QSO below was my first contact using the Junker after a few minutes of practice. I'm sending at about 17-18wpm. After a couple more QSOs and bit more practice I was easily sending at 20wpm which is faster than I'm comfortably able to operate my other straight keys.

A bit of refinishing

Not being terribly enamored with the rough appearance of the old key I removed the aluminum corrosion from the cover and the heavy handed brushed paint from the base with a bit of light sanding, and sprayed it with hammered silver. I also made a proper cable and plug for it. Now it's fresh as a German daisy.

A re-spray has spruced it up

Video

Following the introduction to the Junker is a full length QSO using the Junker on it's first Amateur radio QSO with W4PCA.

Compared to my other favorite key, Navy Flameproof

I'm looking forward to using this Junker and comparing it head-to-head with my Navy Flameproof. Initial impressions between the Flameproof and the Junker give the nod to the Junker. The Flameproof was previously the most controllable and precise straight key I owned but the Junker makes it feel mushy in comparison. I do prefer the grip of the Navy, so time will tell whether I become as comfortable using the Junker as I am the Navy Flameproof.

That's all for now

So lower your power and raise your expectations...

72/73

Richard AA4OO

http://hamradioqrp.com

FT8 hasn't killed CW yet

I'm not a contester but I enjoy listening to some amazing contestants pulling in those weak signals flying by at 30 wpm during CW contests. Today is the last day of the...

CQ WW Contest

Lots of CW stations grabbing those final contacts of the contest

I was listening via my SDRPlay connected to a short piece of wire in my garage. Even with this highly compromised "antenna" I was hearing wall-to-wall CW stations vying for a piece of the action. I listened to W4SO and other big-gun stations, pulling in DX contacts one after another.

I'm looking forward to the day when my brain can decode call signs at that rate. I need to spend more time with LCWO.net callsign trainer...

That's all for now...

So lower your power and raise your expectations

72/73

Richard AA4OO

Chrome browser extension for Morse Code

I'm always interested in finding new ways to practice my copy skills when away from the radio.

While there's a growing number of mobile device apps for sending and practicing Morse Code, as well as excellent websites like www.lcwo.net, it's always fun to stumble upon a new one.

Morse Chrome is an extension for the Chrome web browser that allows you to select text on a web page, and send it as Morse Code.

After installing the extension, select text on a web site of your choice and right click (or in the case of a Macintosh, CTRL-click) and one of the options in the right-click dialog will be "Play Morse".

It will proceed to play the selected text as Morse Code.

The speed and pitch can be managed from your Chrome Extension options for Morse Chrome

The generated code sounds accurate to me but it is generated with a rather harsh ramp (possibly a pop) at the beginning of each element. I've heard other computer generated Morse sound similar so it may simply be a problem with the the audio API in the browser. I've played around with different pitch settings and can't reduce the pop. It may be better or worse on different computers.

The only real complaint I have is that I can't find a way to stop it from playing without closing the browser. So if you select a rather large block of text you'll have to wait for it to finish sending before being able to select another selection, unless you exit and restart your browser.

But it's another tool in the arsenal of practicing Morse Code practice so I'm glad to have it.

That's all for now...

So lower your power and raise your expectations

72/73

Richard AA4OO

http://hamradioqrp.com

CW - emergency communication ?

With the recent spate of natural disasters and dire warnings of impending doom, from terrorists and rogue nations alike, it got me to looking into my previous emergency ops participation.

When I was a newly minted amateur operator about a decade ago, I participated some in traffic nets and obtained FEMA certifications to participate in emergency operations. At the time I had built my go-kit, consisting of battery powered FM 2m/440 equipment and portable J-poles. It even had wheels and a pull handle, very spiffy. But I wasn't much concerned with CW.

With a re-kindled interest in QRP and CW operations, it got me to looking again at participation in emergency ops, and to my surprise there are few states that even list CW as a mode for emergency communication frequencies.

The following table lists the only pre-approved ARES frequencies I can find, designated for CW. There are 37 states missing from this list... If you live in a state other than those listed below; no CW emcomm for you buddy.

STATE	FREQUENCY kHz	MODE	SECTION DISTRICT	DESCRIPTION
AR	3,570.00	CW		MTN/OZ, KCW Traffic NET
CA	7,111.00	CW	SAC	(UP) NTS/ARES/Traffic/Calling, Daytime
CA	3,711.00	CW	SAC	(UP) Daytime
LA	3,673.00	CW	LA	NET
MI	1,812.00	CW	MI	Alternate Emergency Frequency (Winter/low flux)
	3,563.00	CW		Emergency
	7,068.00	CW		Alternate Emergency Frequency (Summer/high flux)
MN	3,568.00	CW	MN	ARES
MS	3,570.00	CW	MS	MS/AR CW Traffic Net
NE	3,540.00	CW	NE	Primary
NM	3,540.00	CW	NM	Primary
NC	3,573.00	CW	NC	Primary
NC	3,571.00	CW	NC	Alternate
OH	3,577.00	CW	OH
OR	3,587.00	CW	OR	Daily 1830 and 2200 Oregon Section Net
SD	3,578.00	CW	SD	net during an emergency/drill
WI	3,555.00	CW	WI

Excerpt from http://www.idahoares.info/resources_ares_frequencies.shtml I looked in a number of ARES/RACES sites listing nationwide frequencies and they appeared to have the same list

Why no love for CW?

I understand that CW is a slow mode of communication and not well represented by the amateur radio masses, but let's face it, CW has more efficiency at getting a signal through in marginal conditions than FM or SSB. When a disaster strikes and the electrical grid is down for hundreds of miles and gasoline for running generators is short, you won't be operating QRO stations or have power to run computers for digital modes. Powering a 12v battery with a solar panel may be your only option.

CW's power density is superior to any non-digital mode. A 5 watt CW signal packs as much punch as 100 watt SSB and let's not even discuss the inefficiency of FM or AM. In extended emergency conditions, using CW could mean the difference between getting a message through and not.

Operating CW in Emergencies

So if there were an extended emergency, shouldn't there be some fallback plan for use of low cost, easy to build and store XTAL controlled radios? Many home-built XTAL controlled CW radios use QRP watering hole frequencies for their center frequency; 3560, 7030 and 14060 kHz. Why not designate those frequencies using CW as standards for emergency communication?

Maybe CW is sinking so far into obscurity in amateur radio, this sort of thinking doesn't enter the consciousness of those in charge, but I don't think it should. Maybe CW clubs like FISTS and SKCC could partner with QRP clubs (who tend to be CW focused) to form a homespun group of emergency operators prepared to use CW when all else fails. It might be fun to organize, and who knows, it could save a life, or reunite separated family members.

That's all for now...

So lower your power and raise your expectations

72/73

Richard, AA4OO

http://hamradioqrp.com

Getting the audio right shouldn't be this hard...

I've spent a considerable amount of time lately creating machine generated Morse code videos for copy practice.

I've created videos of the top 100 Words, 500 Words and today, the top 100 most common words in a QSO, at different speeds. I'm machine generating rather than keying them by hand because I would make too many mistakes. I do this through my memory keyer connected to the computer via a terminal application and capture the text being sent along with the audio.

Getting the audio right has been hard. When I record screen captures on my PC it wants the audio to be recorded at 44 kHz but when I transfer that to a Mac to use my video editing software, it expects the audio to be recorded it 48 kHz, and converting the audio in the video just doesn't work well. I use an H2 USB mic for the recording. If I set the mic and the PC screen capture software to 48 kHz I get no audio. So I have had to record at 44 kilohertz on the PC. I'm sure there's better screen capture software that could be used on the PC but I haven't been able to find it for free. I guess I'm too cheap.

This has caused my videos to have popping noises in the transferred audio. While I've tried to fix it during the editing process, it still sounds bad to me.

So, you may wonder why haven't I just recorded the videos on a Mac from the beginning rather than using a PC? Well, I haven't been able to get the OSX terminal application to talk to my 1990's MFJ Super Memory keyer via the serial cable. For some reason my Mac doesn't have a driver for the usb dongle I used to talk to the old memory keyer but my PC does. I searched a bit more and found a non-free terminal application that will let me connect to this serial cable. Now I connect from the Mac and capture the keyer output. I'll spend hundreds of dollars on ham gear but ask me to shell out $30 for computer software and I balk. And after all, I'm a software developer, shame on me.

So, starting today, my new videos should have improved audio and be at a higher resolution than previous videos recorded from the PC.

These practice Morse code videos seem to be popular with folks, so I hope they're helping people. They're a lot of work but I guess they're worth it.

That's all for now...

So lower your power, and raise your expectations

Richard AA4OO

http://www.hamradioqrp.com

Straight Key Night -- 2018

Don't forget January 1st, 2018 starting 00:00 GMT (7pm EST Dec 31) is the start of Straight Key Night 2018. Bring your tired, old equipment on-air and mash your favorite mechanical key. This is not a contest, just an opportunity to make lots of fun QSOs.

I'll be on the air with my 1977 Century/21 using my Junker Straight key and Standard Vibroplex Bug.

ARRL has details on their website... http://www.arrl.org/straight-key-night

Video from 2018 SKN

If you hang in there until the 2:08 mark you'll see my new, spiffy, dual camera angle recording method that I plan to use in all my videos.

So, lower your power, and raise your expectations...

72/73

Richard AA4OO

The trouble with DITS

KX3 Displaying some sent code and a Palm Single paddle in front, magnetically attached to a steel base

As I've learned the code one problem area, early on, was dealing with words that started with characters that were all DITS. I'm probably not alone in having my puny brain overloaded when I am trying to head copy words that start with DITS. I would panic because the all-dits character would fly by and I'd get fixated on trying to figure out what that was and miss the rest of the word.

To overcome DIT panic, I started training on the all DIT characters of E, I, S and H

Using https://lcwo.net/ I'd configure it to send only those characters, and practice them alone. Then I started creating words that began with DIT characters and I'd practice recognizing them.

After two and half years I still get tripped up on occasion but I'm doing much better.

I also like to practice sending DITS. The following sentence is fun to practice: "SHE IS 55 ES IS HIS SISTER"

So how do you deal with DIT overload?

That's all for now.

So lower your power and raise your expectations...

72/73

de Richard AA4OO

http://hamradioqrp.com

https://www.youtube.com/user/4gven

We aren't supposed to get this much snow in central NC

We received a remarkable amount of snow yesterday here in central NC, my antenna iced up and looked very pretty, then the wind picked up and my antenna fell down. Boo-hiss !

My homebrew OCFD antenna is constructed from donated, surplus, lightweight doorbell type wire attached to a 4:1 current balun in a PVC tube with threaded nuts to hold each end of the dipole on top and a coax connector on the bottom. An eyelet through the top of the balun suspends it all via some 10 year old dacron rope (dacron rope is amazing stuff), which is attached to the eave at the peak of my roof.

How, pray tell did I get the rope attached to the peak of roof 33 feet up in the air you ask, having no tall ladders or Spiderman abilities? I'm glad you asked... Well, the rope is tied inexpertly, using granny knots, to one side of an S-hook. I use a cane-pole fishing rod as an extension with a piece of masking tape on the end lightly holding the S-hook. Then I precariously lean out my 3rd story window eight feet under the eave (don't try this at home) and "fish" the S-hook through a loop at the peak of the eave, that was installed there by my nice painter, many years ago. Once the S-hook is in the loop, I tug on the fishing pole and the masking tape lets loose of the S-hook and the S-hook remains in the loop, holding a few feet of old dacron rope. QRP-indeed !

This incarnation of the antenna was first installed November 2015. In that time an ice storm drug it to the ground, and a tropical storm broke the mooring as well.

Amazing stuff, doorbell wire and old dacron rope.

That gleaming line of ice from right to left in the picture below used to be elevated a bit more

Even with my outdoor antenna down, I was able to make a contact on 80m last night using the 68'ish foot long doublet in my attic so wasn't completely incommunicado. It shouldn't be hard to get the OCFD operational again. A bit harder will be repairing the blueberry cage that collapsed under the weight of snow on top of the netting.

This antenna is designed to fail gracefully

I wanted to be sure that when the antenna was under stress it would relieve itself at the easiest place to repair. The rope on the long end of offset dipole runs through a pulley attached, with a zip tie, at the top of a set of sturdy, stacked fiberglass tent poles. The rope runs through the zip-tie attached pulley to a long, lightweight, spring (the kind used for a small fence gate) along with the pulley provides the strain relief when it's windy. The zip tie holding the pulley at the top of the pole is intentionally the weak link. When the forces become too much the zip tie breaks and the long, heavy side of the antenna falls across the garden. It's a simple matter to pull a section of the fiberglass pole loose, attach a new zip tie, and Bob's your uncle.

So when you design your next wire antenna, plan ahead for easy repair.

That's all for now...

So lower your power and raise your power... and antennas after they fall

72/73

Richard AA4OO

Too early to plan the Christmas QSO card?

Ok, so it's only January but Christmas is just around the corner and I need help with a verse to go with my 2018 Christmas QSO card.

It starts like this...

We three keys from ham shacks are,
Sending code that travels afar,

. . .

That's all I got. Help me out.

Just a bit of silliness

So lower your power and raise your expectations

72/73

Richard, AA4OO

Oh Boy, what have I gotten myself into

TUBES

A few months after re-entering the hobby in 2015 I picked up a TenTec Century/21. It has been one of my favorite radios to operate and it is the most aesthetically pleasing radio I own. After working with it's older (circa 1977) discrete transistorized technology and debugging some of it's problems, I became interested in building kits to learn about electronics. I built a number of radio kits from different sources and some of the mini-module kits from Elecraft.

But I kept wondering about tube radios. I came to the hobby well past the tube radio era and although I've read a lot about valve technology I didn't have any first hand experience. I kept watching auctions for old Heathkits and Military radios and even bid on a few but lost the bids.

This past Christmas I decided that in 2018 I'd do something about this lingering interest. I knew I'd eventually want to operate one mobile because, well that would certainly make it harder. The power requirements of tubes are orders of magnitude greater than the QRP transistorized rigs I'd purchased. Not knowing what I was doing I figured I could re-work an old Heathkit HP-13 power supply to give me what I'd need for an old military radio like the GRC-9.

Heathkit HP-13a

Unsurprisingly, I was the only bidder and got one for $30 along with the odd grove power connectors that it uses. But I didn't do my research, and soon learned that the magic for these high voltage power supplies lies in the very specific design of their transformers. In the case of the HP-13 it is operated much like an old military vibrator power supply with two germanium transistors acting as the vibrator. Current is applied to to the core until it saturates and then a specific voltage determined by the number of turns is generated, the saturation drops the current to that winding and it starts over with the other transistor and the other winding. I couldn't easily, or practically lower the 800v high voltage down to 580v required by the military radio I wanted and even the low voltage windings produce 300v and 250v respectively which is far beyond the 105v needed by the military radio.

I was warned off actually purchasing a military vibrator power supply due to a number of issues so I decided I'd start out with the radio this supply was designed for, a Heathkit HW-101. All the electrolytic capacitors have to be replaced, and I plan to replace the diodes to be on the safe side as well. I'm hoping the old transistors are still serviceable as I can't find any information on direct replacements for those. I've ordered the replacement caps, diodes and resistors so I'll see how my refurb of this old power supply works out. Working with voltages that can kill me is a bit daunting and I'm being very careful with the limited power-up tests I've performed so far.

Heathkit HW-101

That brings me to the newest arrival. If you read my blog you know I like to do photography and it's no fun to photograph ugly radios so I kept watching auctions for HW-101s that were in good cosmetic condition. I knew I'd have to do a good bit of refurbishment on whatever I ended up with but at least I could start with a "looker".

Heathkit HW-101

I plan, of course, to use it primarily for CW. I'm aware that this radio is NOT particularly pleasant for CW due to the clacking relay as well as the poor filtering, but I've gotten accustomed to hearing lots of CW stations at once while working with my Century/21 so I think I can adapt. All my other radios have full break-in so this will be a challenge to deal with, but I'm up to seeing what it was like for old time hams.

Crystal filter

While it has a crystal filter, 6dB of filtering at 400Hz will not offer much rejection to the out of band signals. I guess I'll see.

Admittedly this is far from QRP radio but I will endeavor to operate mobile at least a few times just for the experience. I plan to operate at QRP levels to the extent I'm able. There's just so much for me to learn.

If I don't maim myself or burn my house down, be on the lookout for posts as I resurrect the power supply and the old girl and get it on the air. I have some ideas for photography involving glowing tubes that I think will be fun to figure out. My bigger challenge is that I have no room for this thing at my operating position, so I'm trying to figure that out as well.

So drop me a line if you have restoration experience with these rigs. Of course I'm reading what I can and look forward to learning how to align the transmit tubes and all the things I've had absolutely no experience with in the world of transistorized radios.

That's all for now

So warm up your tubes and raise your expectations

72/73

Richard AA4OO

Resurrecting a Heathkit HP-13

As seen in my previous post I've taken the dark plunge into the world of tube radios. I want to start restoring my Heathkit HW-101, but before I can do that I must be able to power it. As I previously wrote, I taken the road less travelled and got an old (circa 1965) HP-13 mobile power supply because I thought it would be nice to power the radio from a 12v source rather than mains.

Unrestored HP-13 with broken solder joints and trashed capacitors

Well there seems to be a reason these don't seem very popular... I'll get to that.

I found a very nice article from RDF-Electronics regarding modernizing the HP-13 power supply. That document includes the components and part numbers for everything you will need to restore your HP-13. My parts arrived from Digi-key and I began snipping and desoldering the old component off the PC board. The replacement electrolytic capacitors are all much smaller and have radial rather than axial leads. That makes placing things on the board require a bit more creativity.

HP-13 Schematic

The only truly problematic components to replace was replacing the twin positive axial lead electrolytic (C11) with two electrolytic capacitors (space issue) and replacing the C1 and C12 due to the tricky wiring around the transistors.

The orange cap on the left under the Q1 (C1) was tough to replace with a much smaller radial lead capacitor

The article suggested replacing the original 100 uF/50 V capacitor with a 4,700 uF/35V to better control ripple. The article goes into quite a bit of detail concerning his testing of ripple using an oscilloscope. Finding room for that big cap and it's accompanying filter disc required a bit of creativity as seen below, where it's laying on its side between two of the rectifier caps.

I will glue all the caps to the board before I put the power supply into service.

New capacitors and diodes

I replaced all the electrolytic caps and diodes. The diodes might have been ok but they are blocking over 300 volts each and a single failure would let the smoke out for sure.

Out with the old

In with the new

All the resistors except one 100k 2 watt were ok. So I only replaced that resistor. The 1.6kv disc caps even measured ok.

The internals look a bit different now with the new caps standing up where the old, larger axial lead components laid flat.

Ready for testing

Testing

After performing resistance and continuity checks I buttoned it up for the test.

The Noise

I had no idea how audibly noisy this power supply would be. The switching that occurs in the transformer creates a very loud whine. I understand why hams would install these in the trunk. There's no way you'd be able to stand this for long if it was sitting next to your station.

I have a longish intro in the video. Skip towards the end to hear it powered up... turn your volume down when you see the "hearing protection" sign come up in the video.

Conclusions

This was a good learning experience. I learned about high voltage transformers and got some practice restoring older equipment. I practiced electrical safety and didn't kill myself, so I'm pleased about that.

I now have a power supply I could use from a sturdy 12v source if I needed it, BUT due to the noise in operation I'm going to look into restoring a HP-23 which runs off house mains (AC) and is mostly silent.

I'll keep this on the shelf waiting for a day that I need to run the HW-101 mobile.

That's all for now

Richard AA4OO

Breath new life into a Heathkit HP-23 power supply

My recent interest in restoring a 1970s Heathkit HW-101 tube radio, is leading me down quite a winding path.

Before I can even test the HW-101 I must be able to supply it with power. Vacuum tube radios need multiple voltages for the different tubes in use. In the case of the 20 vacuum tubes used in the HW-101, it needs the following voltages to operate, 800v, 350v, -130v and 12.6v.

If you've followed previous posts you'd read that I thought I'd be clever (as if), and restore a Heathkit power supply that runs off of 12v so that I could use it mobile or from my 12v linear supply in the shack. Well, I restored a HP-13 and if you read that post and watched/listened to the video you and I now both understand why operators only used those power supplies out of earshot, like in the trunk of their automobile, or in the next county. It makes way too much audio racket to be at my operating position.

So, pouring a bit more money into this effort, I bought a AC/mains powered supply; the Heathkit HP-23B... but alas it has old components and also needs to be restored.

Heathkit HP-23B

No direct replacement capacitors

Those large capacitors in the first photo have no modern equivalent in terms of the pin-outs and the HP-23B chassis used some phenolic wafers that are rather fragile after this many years, to hold those capacitors. There are some videos showing how to adapt modern capacitors to fit and that would help maintain it's classic look, but it seemed a bit fiddly to do. Also, you can see that in the base of the power supply there are numerous other axial caps and resistors that need replacing and it's a frightening mess of wiring in there given the voltages present.

Old Heathkit Parts to the rescue

This is such a common issue with these power supplies, that K8GNZ designed a PCB compatible with modern electronic components that would replace that tangle of wiring. It can be ordered from Old Heathkit Parts for a reasonable sum and comes with a CD listing the components that need to be ordered as well as instructions for building the PCB and wiring it up with the HP-23B.

This board gives you one convenient place to populate all the components and hookup the wiring in the HP-23 chassis.

HP-23D PCB

The 3w 100k resistors go on the bottom mounted 1/4" off the board so they don't burn the board (they get hot)

Partially populated board

All done, ready to wire up to the HP-23 transformer and choke

Note how much smaller the 4 new 450v caps are than the ones they replaced in the photo at the top of the post.

The next step is to tear down the old HP-23B and prepare for this board to replace its innards. Maybe this weekend.

Gotta get the power from the supply to the radio

The power supply has 8 connections to the radio and Amphenol 11-pin plugs are used for the connections. I purchased a wiring kit on eBay that I'm not really pleased with so I won't provide a link to the seller. It works but there were some compromises. If I need another cable I think I'll just find a used one.

Power cable

I also added an amp-key line out from pins 5 (ground) and 11 (relay) for future projects. I terminated it into a female RCA plug. I have previously used the amp-key line from my Ten-Tec Eagle to trigger the protective relay on my SDR, so I may use it for that, or something else. I figured as long as I was soldering 16 connections in those plugs I could solder a couple more.

Amp-key line out

I've also purchased an additional NOS female Amphenol 11-pin chassis plug that I plan to wire up from the Grove connector on the HP-13 so that I can just use the HP-23 cable with the HP-13 if I wish to in the future.

So just a few more hours of work and I should be able to light up the old HW-101 for the first time in decades.

The smell of hot tubes awaits... or magic smoke... I hope it's the former

That's all for now

72/73

Richard, AA4OO

Ah, the sweet smell of hot tubes and resistors

Heathkit HW-101 after it's first QSO under new ownership

I completed my rebuild of my Heathkit HP-23B power supply this morning. There was a bit of frustration on my part as I followed the instructions because they only have photos of a HP-23 which has adjustable bias and no LV switch.

It left me scratching my head a couple times, and I had to locate a schematic of a HP-23B to complete the work.

Heathkit HP-23B Schematic

I really need to learn more about electronics

In the midst of the rebuild I thought I had a problem with the transformer. Both low voltage winding taps (275v and 350v) showed very low resistance (about 5 Ohms) to chassis ground, which led me to believe there was a short in the transformer.

I called my mentor in all things Ham radio, Paul AA4XX, and described the issue. He walked me through the schematic and had me unsolder a couple points to confirm his guess that all was well. That double tap, low voltage winding presents very low resistance to ground but it is not a short in the world of AC. I continue struggling to wrap my head around the differences in AC and DC, but I'm slowly learning and fortunately haven't caught anything on fire yet.

Out with the old, in with the new

Old components

Testing High Voltage

My Multi-meter can only measure up to 600v, so in order to measure the 800v output I used two 3 watt 100 kOhm resistors in series as a voltage divider. When in use, the MM will read half the voltage.

Voltage divider for measuring the high-voltage output

With the voltage divider the HV power measured 401v which works out to 802v undivided

Completed upgrade

The kit places all the components in the base and the holes that the old big filter capacitors used to be in are now just ventilation. I need to put a wire shield over those holes because high voltages are present just below, as well as some really hot resistors. With the top cover back on it, there shouldn't be a problem but the wire mesh shield is still recommended, especially if it's to be used inside a Heathkit speaker, where the top cover is not used.

With the PCB board, all the components are out of sight in the base except the big resistors

The old radio now has power

I replaced the old paper 350v 20uF electrolytic capacitors in the HW-101 and then connected the power cable and switched it on via the switch in the HW-101. I didn't hear any audio at first and thought something was wrong. Silly me, those tubes need a bit to warm up. After a minute I was hearing audio and used the built-in crystal calibrator to check the VFO dial. It was pretty close to spot on.

I ran through some initial checks according to the Heathkit manual. Receive worked well. I listened to some SSB and then dropped down to the 40m CW portion of the band and listened to CW. I waited about 30 minutes for the tubes to warm up. I didn't hear any drift on CW stations I was monitoring.

I found an open frequency, checked the plate current and then tuned up, outputting only about 10 watts because I don't know what state of alignment the finals are in yet. This is the first time I've tuned a tube rig and that was interesting. You have to peak the preselector in receive mode first, then when in tune mode, quickly work back through the preselector, final tune and load levers to peak the RF output. It reads more complicated than it actually is. My OCFD antenna has about a 1.7:1 SWR on 40m so it didn't need much tweaking from the initial settings.

I tuned around and answered N4PGJ, Ron in NY, and had a brief WES exchange. The relay control time set by VOX delay needs to be bumped up a bit as it was dropping between every word break, but other than that it worked like a charm.

I'll make a video soon, but initial impressions are positive. The audio quality was astoundingly good, and the CW filter really did a much better job than I expected. It has a very pleasant sine-wave sidetone rather than the raspy square wave sidetone of my Ten-Tec Century/21. I really think I'm going to enjoy using this old rig.

That's all for now

So lower your power and warm up those tubes.

72/73

Richard AA4OO

The inside of a Heathkit HW-101 is too interesting not to photograph

The glowing filaments and grids of tubes are a sight not often seen in today's transistorized world of amateur radio. I hope you enjoy the images...

Video with CW QSO

Brief video ending with WES exchange CW QSO. Listen to the old girl in action...

That's all for now

Oh my, what have I done

Don't take away my QRP CW card.

I picked up an old, high impedance Heathkit microphone having the appropriate 2-pin connector. One pin is the mic line and the other is for the PTT switch. The shield is common.

I set the mic level to indicate some movement on the ALC and peaks were occurring around 100w. QRP SSB will be tough to achieve.

I worked a few stations on 80m and they delivered great reports and offered their own stories of Heathkit radios.

The old rig is certainly a conversation starter.

That's all for now

So... well, my QRP saying doesn't go with this post, so... warm your tubes and smell the cooking resistors

Richard AA4OO

Get a remote signal report via WebSDR

I've been making modifications / upgrades to my old Heathkit HW-101.

I've had a good number of CW QSOs and a couple of phone contacts with it so far and received good reports. One concern I had, regarded losing the first DIT of a letter on initial relay closure. There is an upgrade article for the HW-101 with a section describing a fix for losing the first DIT of a letter on the initial close of the relay. The modification involve replacing a resistor with a lower value that triggers the VOX. It's a resistor change from 470k to 1k which seems kind of extreme to me.

According to the article you will hear the initial DIT in the sidetone but above 20wpm that DIT is not transmitted due to a delay of the relay closure because it's driven by a VOX circuit.

This test is difficult to describe to a remote CW operator.

I recalled that webSDR stations usually offer a remote recording facility. I found a webSDR station that was within propagation on 40m today and sent my CQ with my call while recording from that remote station. My call, of course, begins with the letter A, which begins with a DIT. I paused for the VOX delay to timeout between sending my call-sign, thus causing AA4OO to be sent with the relay closing at the beginning each time. I started the recording before my call and stopped when I was finished and downloaded it.

remote webSDR station recorder

I confirmed, that although the initial DIT was shortened a bit above 20wpm, it was still being heard and didn't affect copy of words that began with a DIT on relay closure. So I've decided to not do that modification at this time. I previously used DEOXIT on the both sets of relay contacts in the HW-101, because there seemed to be some corrosion present that was affecting receive at times, and that has cleaned up the performance of the relay considerably.

So if you're wondering how to get a remote signal report without another operator involved use the facilities of a remote webSDR station.

NOTE: The HW-101 doesn't have a precise VFO readout, even after calibrating it with the built-in crystal calibrator. I use the reverse beacon network to spot me and take the frequency reported by remote beacon to enter into the frequency of the webSDR station to find my signal.

This works for getting a SSB report as well

This is also useful for determining how your SSB signal sounds. So if you want to hear yourself from a remote station, try using a remote webSDR station recording capability for checking your rig.

That's all for now

So lower your power and raise your expectations

72/73

Richard, AA4OO

High voltage indeed

The Meter on my Heathkit HW 101 stopped displaying ALC (dropped down to the negative stop). So, I opened up the old rig to have a look. I found that the B+ voltage was reading 33 volts higher at one of the test points than it should. Ultimately that voltage didn't turn out to be the problem with the alc meter instead the meter switch had become dirty and needed to be cleaned. But in the process it got me to studying the way voltage is regulated in the Heathkit and I learned a bit about voltage regulation tubes like the OA2 used by Heathkit.

OA2 tube

OA2 in action at the right rear of the Audio board, notice the glowing gas inside

More Glow...

Look at the pretty violet glowing gas in the OA2

The OA 2 is actually not a vacuum tube it contains a gas that ionizes and in the process of ionization acts as a voltage regulator. In a vacuum tube, if you see glowing gas inside the tube that means it's leaking and has become "gassy", that's a bad thing. In the case of a gas filled tube like an OA2 you expect to see glowing gas and if you do not, then there's a problem.

In this case The OA2 regulates voltage to 150 volts and current is limited by the two high-wattage resistors connected in circuit to that tube (seen beside the OA2 in the photo above). Those resistors are dissipating a lot of heat. I measured over 300F degrees with my IR temperature gauge (ouch).

Tube Testing without a tube tester?

I emailed one of the members of my local club, Joe WA4GIR to ask about tube testing and he sent me the following, which he gave me permission to post:

The lack of a tube tester is not a limitation. You can tell a lot about a tube test by looking at the voltages in the circuit. If the filament goes out, the tube is dark and does not conduct. That one is pretty obvious. If the tube cathode loses it's ability to emit electrons, the voltages dropped across the cathode resistor and any resistors in the plate or screen grid circuits will change (the voltage drops across those resistances will drop). A good tube tester will measure the ability of the tube to vary the plate current for changes in grid voltage, and you can see this with a scope by looking at the AC voltages on those elements, at least for the audio circuitry. Probably not so much for the RF circuits as you are affecting the circuit when you probe it. The best way to check for a suspect tube is to replace it with another. I have 0A2's new in the box. I may have the other tubes pulled from radios but it takes longer to look through those as sometimes the numbers are hard to read. Hint. to bring out a faded number, rub it on the hair on the back of your neck-- better if it's oily.

A lot of resistors in old tube-type radios were 20% tolerance so don't expect the voltages to be that precise. Tube rigs had much more variability than modern solid state circuits. For the unregulated voltages, the precise voltage will depend component tolerances, tube health, and line voltage. The line voltage here is about 125 when where I lived in Raleigh it was around 110. You can do the percentages but that alone will account for some of the variation you might see. I don't think that any of your tubes were damaged by overvoltage. If they are drawing too much current, they will get hot, and in severe cases, the plates will glow red. That's a concern. Much less than that, the life might be reduced but I don't think you will see any short term effect. When I've run tubes too hot, you might see signs of the tube going gassy, which is indicated by a blue low in the space inside the tube that is supposed to be a vacuum.

If you want to see the plates of a tube glow red, operate the final mistuned so it is drawing too much current. They will glow red, haha.

The voltages out of the 0A2 are different -- they should be held pretty closely to 150V. I don't know the exact tolerance. It might be a few percent. So in your radio, 150V supply and any that are derived from it are the only ones that would have a tighter tolerance. The 0A2 has an operating current range of 5 to 30ma, and an operating voltage of 150V. The supply voltage should be at least 185V to get the tube to "fire" but once "on", the voltage feeding will drop to the 150V level and be regulated there by the action of the tube which causes the voltage drop across to change (like zener diode regulators). The regulation comes from the fact that a very small increase in the voltage across the tube results in a significant increase in the current so the resistor values are chosen so that the current through the tube remain in the 5 to 30ma range as the input voltage and the current draw of the regulated circuits varies for whatever reason. Remember the current draw when you first turn on the rig will be low because the tubes don't conduct until the cathode gets heated so the designer must account for that in the selection of the input resistors to that circuit.

More to learn about hollow state

As a young-ish ham I certainly have a lot to learn about old tube radios but I'm enjoying the journey. Just the thought of transistors operating by thermionic emission, tossing their electrons across empty space, being attracted to a plate with more positive voltage is fascinating to contemplate.

That's all for now

So lower your power... or at least regulate it with a OA2... and raise your expectations

73
Richard, AA4OO

Ionization is a beautiful thing

A reader asked me to video the pulsing of the OA2 voltage regulator tube in action.

OA2 VR tube glowing beautifully in back corner

I turned the room lights down to capture the OA2 in its glowing gas glory and noticed a problem with the V15 6EA8 tube that creates the sidetone oscillation and Vox control. A patch inside was glowing a brilliant violet color when the CW switch was engaged. Glowing gas inside a gas filled tube is pretty but glowing gas inside a vacuum tube is a no-no. I've noticed my sidetone volume (which is unadjustable) going a bit soft over the past week and now I understand why. The vacuum tube has developed a leak and has "air" inside. That "air" is mostly nitrogen which ionizes with this brilliant violet color.

Tbis 6EA8 should not be glowing violet

Lots of flagellant tubes

After I saw that I started looking and noticed I also have an 12AX7 beginning to go gassy as well so I ordered some new tubes from www.findatube.com

So let's keep the gases where they belong.

Solved a bit of a mystery tonight

I had a problem that I've just tracked down. Most boat anchor guys would probably already have known how to solve this but it a new discovery for me.

My audio was occasionally scratchy with a bit of popping. Sometimes when working CW the other stations signal would jump around slightly in frequency, like 20Hz - 50Hz.

I'd already re-seated most of the tubes, re-tightened screws, DeOxit'd switches, etc.

Then I noticed that V1's tube shield was not bonded to the tube socket finger thingy (sorry don't know what it's called). The other tube shields were soldered and I hadn't noticed that this tube shield was new and looking at the socket spring thing appears it had never been soldered. After pulling that tube and its shield I scraped the paint from the shield where the socket spring presses onto it and cleaned the socket spring as well. Apparently those tubes leak RF and the tube shields catch the stray signals and send them to ground. Without proper bonding the tube is spraying RF around.

That turned out the be the problem, now all is good. Received signals are rock steady and the audio is very clean.

Tube shield needed to be grounded to the socket spring

This problem had been periodic and was driving me a little nuts. I'd read that grounding the tube shields was important but somehow I'd missed that this shield was not properly bonded to the finger thingy.

On the positive side, I am growing a tube collection by purchasing replacements that are not needed :)

That's all for now

So lower your atmospheric pressure and raise your B+ voltage

Richard AA4OO

Tektronix 475 Oscilloscope and Android Signal Generator App

When I was debugging problems with my Ten-Tec Century/21, and especially my problematic one-watter kit, I needed to see more than DC voltages. I carried my problem stuff to my friend Paul to see what his scope and signal generator revealed.

Why would a ham need a scope? Audio and RF are both AC (alternating current) and a voltmeter alone doesn't offer much insight into that world of voltage across time and phase.

I almost bought an inexpensive digital scope last year, then thought better of it. Then I almost bought a featured digital scope and checked my wallet and thought better of it. A good digital scope in the 100 Mhz and up range from reliable sources costs upwards of $500. On the other hand, older professional scopes that have been well maintained and kept in calibration are excellent choices and will last a lifetime. You do give up handy on screen cursors for measurements, so you have to count divisions by hand and do the math. You also don't have digital storage in a digital scope, but smart phone cameras and video can make up for that.

When I saw this recently calibrated Tektronix 475 listed in the classifieds on eHam.net for a nice price, I decided it was time to step into the world of visualized AC.

Watching a capacitor charge 250 times a second
The lines are a bit wide because the signal source was noisy

Tek 475 Specs

The Tektronix 475 is a portable (30 lbs), dual-trace oscilloscope with dual time-bases similar to the 465, but with 200 MHz bandwidth and a maximum vertical sensitivity of 2 mV/Div. It is all solid-state except for the CRT. It was introduced in November 1972.

This scope cost $3,000 when it was new. Now you can find them in good condition for less than $200.

Bandwidth -- 200 MHz (475), AC cutoff 10 Hz, switchable BW limit 20 MHz
Rise time -- 1.75 ns (475)
Deflection -- 2 mV/Div to 5 V/Div, 1-2-5
Cascaded mode -- 400 μV/Div, 50 MHz with CH1 input connected to CH2 VERT SIG OUT
Time base -- 10 ns/Div to 500 ms/Div, 1-2-5, and ×10 magnifier
Input impedance -- 1 MΩ // 20 pF
Triggering -- 0.3 Div (int) or 50 mV (ext) to 40 MHz, increasing to 1.5 Div/250 mV at 200 MHz; AC coupling >60 Hz; LF REJ >50 kHz, HF REJ <50 khz="" li="">50>
X bandwidth -- 3 MHz
Z axis input -- 5 Vp-p, 50 MHz
Calibrator -- 1 kHz, 30 mA / 300 mV square wave
Outputs -- CH2 Vert Signal Out, 20 mV/Div into 1 MΩ or 10 mV/Div into 50 Ω; A and B +GATE OUT, +5 V; Probe power jack
CRT -- 8 × 10 cm², P31 phosphor (P11 opt.)
Power -- 110, 115, 120, 220, 230 or 240 VAC ±10%, 48-440 Hz, max. 100 W

Real knobs and switches

One advantage of an analog scope is that there is a labeled switch or knob for every function. No need to dig through menus to figure out how to do something. To me this is the a true advantage to finding a well calibrated, analog scope.

An oscilloscope needs a function generator

An scope let's you visualize AC within a circuit, but when you testing something you often need to inject AC into that circuit. That's the role played by a function generator. Function generators allow you to choose a frequency and a wave type (sine, triangle, square, etc.), or sweep across frequencies.

In general, the higher the frequency they support the more they cost.

If you have a mobile device you can get one that uses your headphone jack as output up to 22 kHz for free...

For a free app it is very nice. It outputs sine waves very well, triangle waves are a bit soft pointed and square waves are for entertainment purposes only. But it is free so I won't complain. In the image below you can see the oscillations as it tries to generate a square wave but the audio amplifier of the mobile device just doesn't have that kind of control.

Frequency Generator App set to 1 kHz

Square Wave?

Square waves are not

Reduce the time base to zoom in

Yea, square wave.... not so much

The square wave is bad but sine and triangle waves look good until the frequency get's near the top of the range or the amplitude is raised too high.

Sine Waves look good

Triangle waves are on as well until you go up in frequency

The free app is inadequate for bench testing

While I appreciate that this would be a useful, portable signal generator for testing audio circuits, I'll be ordering a purpose-built function generator because generating clean square waves is an important test signal to be clean. I also will need a generator that works above audio frequencies, hopefully up the the IF frequencies of the some of the equipment I'm testing.

Only the beginning

Having an oscilloscope is a new adventure for me. I have another 1-watter kit ready to build that I've been holding off on because I wanted a scope for troubleshooting. In the meantime I'm using the scope to watch transistors trigger and measure the timing circuits I'm building and learning how to control the scope. The Tektronix 475 is a feature-rich analog scope. If you plan to fix your own equipment or do some homebrew electronics work a scope can come in handy.

That's all for now

Sow lower your power and sample it with a scope

72/73
Richard AA4OO