Thursday, February 11, 2016

HW-8 Adventures

At this writing, I am about mid-way through refurbing the HW-8 I got from WB6JDH. It was in beautifully shape (sort of) and worked just fine until I over-rotated the dial and pushed the rotor plates off the shaft. At that point, I was about to have a meltdown because I thought life for this radio -- as I knew it -- had come to an end. Surely, unless I found a scrap unit, the arcane VFO cap was a once-in-a-lifetime thing of the past.

Wow, was I misinformed! Turns out that there's a guy in Northern California who stocks and sells these beauties for $20 + 5 s&h. It might seem a little steep but, when you're the only game in town, you almost break your hand writing out the check. (There's also a factory that makes them and they also sell retail. After all is said and done, the price plus shipping is about the same.)

So, after waiting for the mailman about three to four days, I set about replacing the cap and, while not an easy task, it was do-able. But, you know me, Al. I kept running into kluged solder joints and inexpertly wired leads, and the odd mess here and there that just screamed to be tidied up.

Also there was the matter of the two upgrades I ordered from John Clements in Michigan. These were his non-pereil T/R switch and his audio board. The former is somewhat of a luxury but the latter is an absolute necessity if one wants to drag their HW-8 (or HW-7) out of the QRP stone age and convert it to use 8 ohm speakers and headphones. Both of these boards are stone cheap and come with the added benefit of superb customer support and the friendship of KC9ON, one of the nicest hams I have met in a long time. I will go into more detail in the description of the mods down below, but you need to seriously think about these two items as "must haves" for yoru "8". (Or "7" as well.) They will be a stock mod for any rig I now have or will acquire in the future.

Here are the mods and notes on tune-up I made for my "recovering" this radio.

REPLACING THE VFO CAP
{difficulty}
{caveat about the tensioner spline}

REWIRING THE AUDIO POT
{difficulty}

ADDING THE KC9ON AUDIO BOARD
{notes}

ADDING THE KC9ON T/R SWITCH
{notes}
{out-of-unit 12V sanity check}

ALIGNING AND TUNING UP THE HW-8
{transmitter}
{HFO}
{Receiver}
{using the HP3400 to peak receiver trim caps}

REBUILDING THE S-METER
{reason for rebuild; casualty of VFO cap installatin and rewiring}
{subsequent performance on 80 and 40}

ADDING THE K1EL K16 KEYER
{description}
{function switches}

SUMMARY


-72-










A new Jones: The Heathkit HW Series of QRP Rigs

Part I - Revitalization
Well, WB6JDH did it to me again! He infected me with another jones. I fell prey to the siren call of those who have fallen in love with the old Heathkit QRP radios, the HW-7, HW-8, and HW-9. And, true to the W6DQ maxim, "why buy one thing when you can buy two at twice the price", I stocked up big time by taking advantage of deals and opportunities that cropped up over the last three months (while I was wrestling with the &*^%$#*@! Cheap Chinese Crystal Checkers & [not] Counters -- dubbed "CCCCC" for short.
Siderbar: Dick is working on a small preamp circuit -- hopefully low-profile and cloned from a quad NAND gate 74HC00 or something. So maybe something will come of it anyway. If these can be made to actually count then maybe they can be used as cheap and reliable (well, cheap anyway) digital displays for older analog radios. But I digress..
Anyway, as I was saying, in short order I scored the following:
  • An HW-8 in good, clean working condition.
  • Two HW-7s, both working, one in sorry cosmetic condition.
  • A complete HW-9 station, rig, PS, power meter, antenna tuner.
More on the HW-8 and HW-9 later, but to titillate, I immediately broke the HW-8's tuning cap by over-rotating it and was able to replace same with a brand new VFO cap (they still sell them) and upgraded the T/R switch and audio board with absolutely marvelous products from KC9ON. Then, one early morning, I got up to take a whiz and was perusing eBay when I saw the HW-9 station pop. So I jumped on that like a dog on a bone and..well..more about those two later.

Staring with the HW-7s, I got them both from WB6JDH -- as I did the HW-8. One of them was good cosmetically but Dick said it may "have some issues". I have not fired it up as yet (see above re CCCCC and the HW-8 work) but I will do so soon. And, after reading all of the bag jobs on these HW-7s (great out of band short-wave station and AM band receivers because of their DC receiver and 40673 mixer, etc.), I am prepared to be under-whelmed. Still in all, there is something quaint about these radios and, indeed, all three of the HW series. It is something that reached out to the kid in me when I was first a Novice in 1961 and built my DX-40. Scoring a legit manual and all of the diagrams and drawing foldouts tends to make one fearless. Subsequent books, articles and notes like WB8VGE's HW-8 handbook series ((out of print, second edition alleged to be here) only emboldens one.

Anyway, now to the nut: the "other" HW-7 is kind of like the little puppy with a limp who follows you home and you affectionately adopt. While Dick says it "plays really well" you will see that it has definite cosmetic issues. I frankly dunno about some people. As Bob, WB3T (a great restorer of these radios) said of the former owner of an HW-8 he scored off of eBay:
I enjoyed HW-8 II so much, I decided to do another one (HW-8 III). This one was a real clunker when I got it. The mixer amplifier FET was in backwards, as were the internal trimmers in the receive circuit, which "ungrounded" the ground end. Most components were standing a half-inch off the PC board, the panel meter was shot, and the soldering needed to be completely re-done. (Some people by law shouldn't be permitted within 100 yards of a soldering iron!) It looked as though several people had tried and failed to get this one going over the years.
By the way, I recommend visiting Bob's web site and perusing his restoration work on the HW-7 and HW-8s he did. If anything, his video of the HW-7 during a contest -- together with the simplicity of the HW-7 -- make me eager to see if these can truly be turned from a sow's ear to a silk purse. (Also, his "King's New Clothes" take on Elecraft is interesting and refreshing. I love my K-2 but believe my romance with Elecraft stopped when the stratospheric prices came in and "bolt-together" radios came out. We're now "just good friends".)



So, here's pictures of the little puppy that followed me home. As you can see, someone went nuts with a power drill and rendered the simple-yet-elegant front panel a shambles. (I'd like to take a drill to that anal pore's nether regions, believe me.) As it stands, I am toying with cutting a new panel out of aluminum and doing OHR WM2-like stick'em labels. Or something..

..am open to ideas. Enjoy; kind of like looking at a traffic accident, innit?


























-72-

Tuesday, January 19, 2016

Two Pieces of Chinese Crap.. Interesting Developments! PIECE OF SHIT!


NEWER UPDATE
These are pieces of shit. Basically, the circuit for measuring frequency (not their goddam crystal checker circuit) doesn't work at all. I would not piss on the makers of these piles of fecal matter if they were on fire. As far as I am concerned, they can all die and go to hell with a hard-on.

That is my final word on the matter.

UPDATE
I need to do a retraction of sorts here. While I am still somewhat agitated by the lack of support by the seller of these items, I would like to go on record as saying, once revived, it appears these might actually be quite useful. Let me bring you up to date.

It seems -- after all my poking and prodding -- the second unit "woke up" and began working. Once that was in place it was a simple matter to debug the first unit -- which was truly moribund. Seeking and getting advice from Chuck Adams, K7QO, over on the QRO Tech Yahoo group, I swapped out out the PIC chip, trading the good board's chip for the bad board's chip. The fact that the good board performed correctly no matter which PIC chip was aboard revealed that BOTH chips were fine and dandy. Next, I timidly put the good board's chip into the bad board -- and yet it still slept with the fishes. Remembering back to my earlier debugging effort where checking the crystal operation on pins 15 and 16 revealed a nice clean 20 MHz trace (well, 19.997 MHz, actually) on the good board and bupkis on the other, I thought to swap out the crystal on the bad board.


Of course, these little guys are the "low-rider" HC-49/U cases and wicking out the one on the good board and soldering it into the bad board would have been dicey at best. So, reaching into my cavernous junk box, I grabbed a 16 MHz crystal (that I checked out in my PacifiCon crystal checker AND the good board's crystal checker first) and "welded" that in place.

Viola! The bad board awakened and began perking along nicely.

So I am forced to conclude it was a bad crystal all along. It cycled through the menu, saved offsets (more below) and, of course, the results of checked crystals were off by about 4 MHz. But all I had to do was get some ("Get some! Get some! Get some, baby!") new 20 MHz crystals and I'd be set.

I pulled the trigger on a local auction (to hell waiting a fortnight for some guy in a warehouse in China get around to sending me them), and was the proud owner of what I thought was six or seven 20 MHz jobbies. Sadly or happily, the quantity count turned out to be FIFTY!

Oh well.

Remember the 19.997 MHz comment above? Well the good board was off by 3 KHz so it seems as though a the 19.997 MHz may be causing the error. The price was right on the batch that I got, so I can wade through all fifty, find one or two of them dead on, and swap out the old crystals for the new accurate ones.

Another plus of the design is deriving the offset if this is going to be used as a frequency display for a radio. You merely go into menu mode, measure the IF of the radio in question and then press "ADD" or "SUB" to obtain the appropriate offset and call it a day. The VFO frequency will then be ADDed or SUBed to the stored offset and Bob's your uncle. I am guessing that you can also set the IF by using a signal generator. How the hell will the counter know?

Add to the fact that the plastic case looks kind of nice -- much better than saving a few bucks and putting the display in some kludged-together pile of soldered PCB.

So, looks like the rain clouds are parting and the sun is coming out after all.

ORIGINAL POST
O.K., so there's only one in the picture. But I bought two of these units off eBay from a Chinese dealer in the mysterious Orient and it turns out that the only goddam thing that was mysterious about BOTH units was that they did not work when I assembled them.

What a waste of time and money. Oh, they do offer a money back guarantee but one has to go through the effort (and cost) of mailing the crap back to those pirates.

And, yes, I assembled them both carefully. And, yes, because the first one did not work, I MEASURED and TESTED each part I put onto the board of the second one. And, no, neither one worked.

But to be fair, the second one worked for a few minutes and then crapped out. And, when it did work, it blinked and gagged out some mysterious prompts via the display. Pushing the button only brought on more weird behavior and mysterious prompts before it finally faded into oblivion. Of course, I had given the dealer a positive rating when the packages arrived. And, of course. I sent the dealer a message telling him that his piles of Chinese crap sucked. (I was more polite than that. Next message will not be.)

But to my original cause for aggravation over these units: the single piece of toilet paper that the Chinglish instructions were written on. You know, the ones with the microscopic printing and faded, unintelligible diagrams. (I don't expect a damn Heathkit manual, but they could have invested a little more effort in the instructions, fer crissakes!) And as for operating instructions once these are up and running? Non-existent. Not a whisper of a hint of a breath of a word about how to measure frequencies or crystals or set the offsets.

Nothing!

..which is what these are worth.

Saturday, January 2, 2016

One Watter: Watt's up?

Just so you don't think my workbench is orderly and immaculate all the time..

The workbench in mid-crisis.
I was closing in on the finish and had added the final amp and output bandpass filter (actually completing the build) and was testing/aligning the radio when I hit a bump in the road. Try as I would setting the output power to one watt, I could not goose the little beast over 0.7W out. I peaked the bandpass filter over and over again. I check out the parts, solder joints, etc. but could not budge the output power past that level..

..at least that's what my OHR WM-2 watt meter was telling me.

My OHR telling me it's only 0.5W out.

But my trusty, rusty 7704 sang a different tune:


Consulting with my arch-friend, WB6JDH, and doing a little research, I came across a tour de force slide presentation entitled Math for the General Class Radio Operator that N9XH did for the ARRL and those sources cleared a lot up for me. Here are four salient slides from that presentation, right in the wheelhouse with respect to addressing this situation. They are self-explanatory:





So, extrapolating from the above,

(1) Determine total peak-to-peak volts:

4.8 divisions x 5 volts per division = 24 volts peak-to-peak

(2) Convert from peak-to-peak to RMS:

24 volts peak-to-peak / 2 = 12 volts peak x 0.7070 = 8.484 volts RMS

(3) Now solve I = E/R for I (current in amps):

I = 8.484/ 50 ohms = 0.16968 amps

(4) Now solve for P = I x E (power in watts):

P = 8.484 x 0.16968 = 1.440 watts

But Dick simplified this by using .3535 (half of 0.7070) and skipping the determination of the current and squaring the voltage. I will leave you to derive that, but it works out the same:

(1) 24 volts peak-to-peak x 0.3535 = 8.484 volts RMS
(2) 8.484 RMS volts squared = 71.918
(3) 71.978 / 50 ohms = 1.440 watts
Although it is good to know the derivation, I am going with Dick's method as it is shorter and handheld calculator friendly. Anyway, however you run the numbers, it works out to 4 divisions being damned close to 1 watt. (About 0.996 watts, actually.)

Now here's the rub. I went back and re-ran the calibration on my OHR WM-2 and it *still* came out around 0.7 watts when the 1-Watter output was set to 4 divisions (20 volts peak-to-peak) on the scope and I cannot explain away the difference. Trying a couple of other watt meters I had in on the bench, I found a some were "inaccurate", but a Diamond SX-200 was "dead on".

I guess it's why I call this "the man with two watches" syndrome. You know - a man with one watch knows what time it is; a man with two watches is never quite sure.

Failing a plausible explanation for the differences and trusting in my scope (a calibrated Tektronix 7704) as being the most accurate source -- AND since my other measurements of various circuit points on my 1-Watter substantially agree with those presented in K7QO's Phase 8 and Phase 9 videos, I deemed that the standard. And, actually, went back to calibrate the OHR WM-2 using the 1-Watter as a reference.

Now, here's an interesting factoid in this which lends to the mystery. About four weeks ago -- sometime around the first part of December 2015 -- wanting to give QRPp (QRP operation at one watt or less) a try, I got out my old NorCal 40A and set it to one watt using the OHR WM-2! Going back and measuring the NorCal 40A with the same WM-2 used to set it to one watt out, I got a similar 0.7 watt output reading. Netiher the WM-2 nor the NorCal 40A was touched in the interim.

Strange, huh?

Anyway, my final pronouncement on the 15 Meter 1-Watter is that it is a fun kit, very reasonably priced, and with Chuck and Diz's documentation, and excellent source of knowledge for the builder who wants to be much more than an appliance operator or "Baofeng Tech".

"Who knows what evil lurks in the heart of.."

"I do, old son.."

-72-

Friday, January 1, 2016

One Watter: Phase Four through Phase Eight..

I didn't necessarily blast through the middle and ending phases but I did not document them as thoroughly as I should have. (In fact, I did not document the first phases that completely either. Pretty much a bunch of pictures with comments. But then again, I did so for the following reasons:

(1) I was lazy.
(2) I was absorbed in the building process.
(3) I was learning as much as I could.
(4) Chuck Adams did a better job than I could ever do.

So here's up to Phase Eight -- the driver stage. Everything up through this stage checked out fine and I was set to sail through the last stage (the final and the output bandpass filter) when I hit a bump which I will describe in a final post. However, the bottom line was that the rig ultimately passed with flying colors and is waiting for a home.

So here's some pictures and comments for the last phases.

The T5 transformer on the 15m 1-Watter is wound on a BN-43-2402 binocular core and is actually pretty simple once one realizes that a complete turn is one pass through BOTH holes. (It is, therefore, possible to do a half turn.) If you follow the instructions re wire size and wind the 8-turn secondary first, it's a piece of cake.

T5 wound and ready to go. This one looks like the alien in Independence Day, don't it?

T5 in situ..

..ibidem.

Left is T4 (VXO circuit) and L1 or L2 (output bandpass filter). (They are identical).

Here is T4 along with L5 in the VXO circuit. Note L5 (left) was wound with 40 turns.

The primary windings of T2 and T3. They require a 1-turn loop for this secondaries.

The whole board just before adding the driver and final stages.

The completed driver stage with T1 in place. Note that this is an FT-37-61, the dull grey toroid.

Whole board up through the driver stage.


The tricky part is adjusting the pre-driver bandpass filter -- between C23 and C24 but that is only marginally nigglesome to adjust. For the transformers in this stage. Diz recommends an alternative of stripping the entire length of the one-turn secondary for each of these transformers but I opted to use semi-long pieces of bare clipped component leads I had lying around. They were more riggid and saves me the work of tinning, etc.

Also, be sure you get T1 and L4 wound on the correct core. T1 is wound on the FT37-61 core which is dull grey. L4 is wound on an FT37-43 which is blacker and more shiny.

..on to my final adventure!

-72-

Sunday, December 27, 2015

One Watter: Phases Two and Three

I continue my build of the 15 meter One Watter by Diz and Chuck Adams:

Phases Two and Three
I have taken Chuck's Phase Two and Phase Three and combined them into this post. Basically, he has you build then keyer circuit and install and test the chip. Additionally, the transmit keying circuit and receiver muting circuits are tested.

Project schematic completion.

Audio and keyer circuits.

Whole board including the keyer circuit and muting circuit.
While these two phases sound impressive and you'd figure that the testing would be extensive but it's really quite simple. Here, Chuck powers up the board WITHOUT a new chip inserted in a newly built section and tests for the proper DC voltage at the appropriate IC socket pin. This is also important because there are three types of voltage regulators in this project: a 78L05 for the audio circuit, two 78L08s for the receiver mixer and transmitter, and a 78L10 for the VXO and it allows you to double check that the regulators are installed in the proper places.

The Phase Three checkout involves setting the keyer into straight key mode and then keying the unit and measuring various places around the board to see it the keying circuit sends +12 volts when keyed.

Up next is Phase Four which tests the newly constructed demodulator to see if you can get an 8,064 kHz signal through U6 into the audio chain.

-72- 






Saturday, December 26, 2015

One Watt, a ton of fun..Phase One

As I posted re Breadboard Radio's Sawdust Regen kit, I have been on a building jag these past three to four weeks. I guess the main reason is that my boss at work is a hopelessly disorganized individual who invites chaos at every turn and has no compunction about spreading his quiet desperation around to others.

(As a sidebar, he is almost universally disliked by his charges who almost openly ridicule him and make jokes about this foibles. But this gives me little comfort and the confusion he causes leads me to seek an orderly, constructive existence elsewhere. It would seem, psychologically speaking, that this building is an effort for me to bring order back into my life. Hopefully, I shall be retired by this time next year and never, ever have to deal with incompetent management and disorganized assholes for the rest of my life. But I digress. Sorry to burden you further.)

In any event, I discovered W8DIZ's One-Watter single-board kits. Diz operates Kits and Parts Dot Com and who, in response to Chuck Adams' request for a rig that could be used by people as an inter-room, over-the-air code practice device helped Chuck develop a single-board transceiver that was so superior in design and concept that many are using it to further their QRPp endeavors. I could go into this in detail but Chuck Adams prepared a 10-video series on You Tube and describes the project in the initial installment:


In any event, I tumbled for two of these kits -- 20 meters and 15 meters -- and am enjoying a Christmas/New Year's holiday off from work (and my boss) building these.

Truly relaxing.

Chuck's methodology is to build and test segments of these radios as his video series will point out. So, I thought what more fitting way to embark on this adventure than to follow in Chuck's footsteps -- and his videos -- and build the 15 meter rig in phases. Also, by way of adding to the pantheon of knowledge regarding these kits, I would offer notes about my travails and triumphs. Probably might be a good idea to intersperse these with some other facts about the One-Watter phenomenon and other sanguine comments.

So here goes:

Phase One
Started out this project by organizing my work area to implement Chuck's methodology. He likes to mark a full-page schematic as he installs parts and I opted to do the same. In addition, Diz's kits uses the infamous 1/8th watt resistors and my eyes are becoming too feeble to discern colors -- even to the point where my magnifiers will not help. (See the problems I had with the resistors in the Sawdust Regen kit in the previous post.) Consequently, I found the cheapie Chinese component tester I got some months ago to be an indispensable tool for identifying resistors. Guessing that device will never leave my side for future projects.

As Chuck explained in the video above, Phase One consists only of ensuring that 12 volts negotiates the reverse-polarity 1N4007 diode and arrives at the proper pin of the LM396 socket. Also, the LM386 audio amplifier circuit is checked out to see if it working. I was skeptical of this because of my experience with the QST version of the WBR regen receiver and Chuck's comment about the speaker volume being faint. However, I was pleasantly surprised that the circuit provided a lot of volume and am led to believe that the unit will be perfectly suitable for unamplified speakers when put into operation. Pictures below:

Workplace. Not as gloomy as it seems just the flash didn't fire. Note component tester.

Phase One completed with audio circuit.

Audio section.

Radial 100 nF cap substituted for 100 nF SMT cap at C36.

Close up of same. Solder flux has been cleaned away. Cap will be lain flat when board completed.

Phase One schematic progress. Note R12 installed to facilitate C36 replacement.

I would add these notes to my Phase One effort: pay special attention to where Chuck says to go ahead and install ALL of the the SMT caps first if you want to. He mentions it and I pestered Diz who confirmed that installation of same would not adversely affect the "Build and Test" paradigm. Also, note Diz's correction in the addendum (and my pictures above) wherein he recommends NOT installing the C36 SMT cap but rather putting in the axial cap from one of the C36 pads to ground. I asked Diz about this and he says that there was an error in the PCBs dated 09/03/2015 ~~ see the "20150903" below the DC connector holes in the upper right. To quote Diz:
Hi Bill,

Take a look at C36 on the schematic....it connects from ground to the gates of Q8/Q9. Now look at the PCB...it connects C36 from the gates of Q8/Q9 to pin 4 of U4.

The PCB is in error...also known as a royal screw up. Easiest way around the error is to solder an axial 100 cap on the bottom of the PCB. The PCBs is error are silk screened with 20150903.

See http://kitsandparts.com/1watter15u.php

Any PCBs after 20150903 are corrected.

See http://kitsandparts.com/1watter30u2.php

73, Diz, W8DIZ

Parting comment on the LM386 audio amp circuit: I had a spare LM386 N3 rattling around on the bench from my WBR effort and plugged that in when doing Chuck's audio test. (I was too lazy to go rooting around in the kit parts bag.) The audio -- with headphones -- was more than adequate. When I swapped in Diz's kit-provided LM386 N4, it was almost ear-splitting. Again, this leads me to believe that this little rig will perform just fine with in a room with a speaker -- provided the room is not Carnegie Hall.

Anyway, all seemed to check out just fine. On to Phases Two and Three.

-72-