Discussion in 'Ham Radio Discussions' started by KR2C, Feb 5, 2020.
Anyone who really cared could look at the IMD plots published in QST.
Which are 6 dB worse than reality.....I take it they fooled you also along with "others"
That is incorrect. The spectral plots show two tones and the resulting intermodulation products. The readers can decide for themselves what the reference level should be.
This isn't like redrawing a map with a Sharpie.
And the text clearly explains the testing method used.
HAW!!! Nicely done!
73 de Jim, N2EY
Ah yes! The original HW-29!
HW-29 used 50 MHz 5th overtone crystals - the operating frequency was the crystal marked frequency. Such crystals existed then but were quite expensive. There were only two advantages to this approach:
1) The transmitter RF section was very simple (a single triode-pentode tube, with the triode as overtone oscillator driving the pentode as RF amplifier)
2) Harmonics that could cause TVI were few and well removed from the operating frequency, since the only frequency present in the transmitter was ~50 MHz.
But the design was very unpopular, and the HW-29 was soon replaced by the HW-29A, which could use the much-more-common 8.33 to 9 MHz fundamental crystals, either new or surplus.
Heath offered a modification kit for the HW-29 that added a 6AK5 oscillator and permitted the use of 8.33 to 9 MHz crystals as well. There was a QST article that showed a similar mod to the HW-29.
73 de Jim, N2EY
Let me know when you can do that to test the touchscreen on your new computerized rig too.
Hi Jim, thanks for the Adult response.
The DX-35 wasn't my first nor only Heath exposure, and whether or not it was one of their better designs is of no consequence. The one thing those experiences taught me was....don't buy any more kit stuff. And yes I'm WELL aware that was 63 years ago.
The fact that National, or Hallicrafters, or Hammarlund, or any one else made poor design decisions has nothing to do with heath, they were simply poor decisions, made by others, and cerainly isn't any justification for heath's errors. Nor, do they deserve any boost in "street cred" because of poor decisions by others.
One forms their opinions on personal experience, and my experiences with heath kits weren't to my liking, and that was the end of the trail, so to speak. What they did after that, made no difference to me, because I was done with them.
And on the subject of opinions, in the final analysis, they are not unlike sphincters. Everybody has one, and they all have a tendency to stink.
By far, the biggest selling point for most of the kit pervayers, was that they were cheap compared to factory built equipment, at least made in U.S.A. factories, and, were so in every way possible. They had front panels, cabinets, and chassis that you could dent just by rapping them with your knuckle, finishes so durable you couldn't even use soap and water to clean them. They usually worked, more or less, and were "no frills" basic designs. If you had 5th grade reading comprehension skills, and knew which end of the Iron was hot, you could most likely pull it off.
You can work on any of the equipment from that era, and you don't need any more equipment than for kit designs of the same or similar performance level.
Now compare the quality of heath, or most any other kit outfit for that matter, to E.F. Johnson. E.F. Johnson also made and sold kits, but there is no comparison in quality of components or level of performance. Kinda like a Yugo vs a Ford.
As for Jim Silver's home brew efforts, on the surface they look to be well thought out, and inovative. He certainly doesn't have the resources that were at heath's disposal. Though not often, I HOME BREW stuff as well and its not very polished either.
The point I was trying to make is that, yes, Heathkit made some real design mistakes - but they also did some really great stuff. However, I can understand how bad experiences could sour someone on the whole company and concept. "Fool me once......."
I disagree somewhat. IMHO, if one is going to condemn Company A for a bad design, then if Company B has a bad design too, they should not get a pass.
In my experience, almost every company that makes ham gear has made design mistakes in one or more of their products. Doesn't make them bad companies.
IMHO, the intelligent person forms opinions on their personal experience, the experience of others, whatever other reliable information is available, and sound reasoning. For example, I don't need to have struggled with a DX-40 to know they have weak power transformers. Nor do I need to have wasted time and money on an NCX-3 to know they are useless on CW.
And, some opinions are more valid than others. An opinion based on facts and sound reasoning is more valid than one based on hearsay and a lack of sound reasoning.
I agree 100%. And that was a VERY big deal in the past, because anything electronic was quite expensive. For many amateurs of the past, even a basic station was a serious expenditure. A $500 station may not seem like much today, but in a time when the median income was $5000, it was serious money.
You're exaggerating more than a little, there.
Maybe - but, then and now, some hams didn't even have those skills. All one needs is a copy of QST from May 1957.
First check out an article called "Who's Afraid Of A Receiver?" starting on page 26. It describes a condition that was apparently common in those days: "Receiverphobia" - hams who were afraid to do anything inside their factory-built-and-aligned receivers, for fear of doing irreparable harm! Several pages of really, really basic info - but clearly it was sorely needed.....
(I particularly like the classic Gil cartoon with the caption "He tightened all the loose screws")
Next, flip to page 53 and read "The Careless Consumer (or, "Instruction Manuals Are Only For Beginners")". It tells fascinating stories of mistakes made by licensed hams, as told by the technical-service departments of various manufacturers of the day. All sorts of really dumb things done by licensed hams, usually with General or higher licenses!
Some of them pretty destructive. Others just silly. For example:
The ham who bought a receiver, hooked up antenna and power, plugged a microphone into the PHONES jack, flipped the SEND RECEIVE switch to SEND, and called CQ. Kept trying for two weeks and finally wrote the manufacturer asking why his set didn't work.
Other stories of hams complaining that their rigs didn't work, and then finding they weren't plugged in, or the RADIO-PHONO switch was in the PHONO position, or that an optional SSB adapter wasn't installed, etc. Also failure to understand meter readings on transmitters, failure to read instructions and remove packing material, failure to install tubes, and much more.
Kit manufacturers have all sorts of stories, too - the classic "spaghetti" one is in there too.
The article is from QST for May 1957. 63 years ago, back when hams were supposedly so knowledgeable.....
Work on? Maybe. Do a complete alignment? NO.
To do a complete alignment of a Heathkit SB-series HF transceiver requires a VTVM, 50 ohm dummy load, a way of setting the internal 100 kHz calibrator to WWV, and alignment tools to fit the adjustable cores and trimmers. Plus a key, mic, speaker, and power supply. And that's all.
To do a complete alignment of a National NCX-5 HF transceiver requires a VTVM, 50 ohm dummy load, a signal generator with output at 6.0218, 3.5, 4.0, 7.0, 7.3, 21.0, 21.5, 28.0, 28.5, 29.0, and 29.5 MHz, a "standard output meter", a sweep generator capable of sweeping 3.5 to 4.0 MHz at 60 Hz, an oscilloscope with response from DC to 30 MHz and at least 50 mV sensitivity (a Tektronix 545 with L plug-in is suggested), a receiver capable of receiving 9.72 MHz, a 1000 Hz audio generator, a way of setting the internal 100 kHz calibrator to WWV (the calibrator is an extra-cost option), and alignment tools to fit the adjustable cores and trimmers. Plus a key, mic, speaker, and power supply.
http://arizona-am.net/PHOENIX/W7CPA/National NCX -5_manual.pdf
See page 15.
A typical 1960s ham could probably afford the dummy load and VTVM, and the 100 kHz calibrator could be set to WWV or an AM BC station on a frequency that was a multiple of 100 kHz. The NCX-5 list, OTOH....
Quality of components, yes.
Level of performance.....maybe.
EFJ only made transmitters; Heathkit made an entire product line. And EFJ kits cost a lot more.
Compare the Heathkit DX-20 to the EFJ Adventurer. Both are 50 watt CW only Novice rigs. I've had both, the Adventurer is somewhat better. But, in their time, the DX-20 was $35.95 and the Adventurer was $54.95 - both as kits.
There is no "Jim Silver". The receiver in the linked pictures is one I built in the early 1970s as a poor college student. I put maybe $10 into it, mostly for the crystals and telephone toroids.
I did what was needed.
You've seen the threads about the Southgate Type 7 and the Southgate Ultimate Transmatch, I presume.
73 de Jim, N2EY
I see you have consumed the ARRL Kool Aid and dance to their mandated tune of protecting the advertisers and their often horrible TX IMD radios and amps.
IN REALITY the ARRL cherry picks the 700 and 1900 Hz test frequencies, while the commercial and military uses 800 and 1800 HZ. The ARRL 1200 Hz difference products BOTH FALL OUTSIDE the radios filter passband.
The real standard used for decades by commercial (not ham and CB) and military allows products to be within the filter bandwidth which is a more realistic test. While not emulating a human voice with all its frequencies it does give a more accurate idea than the ARRL method which deliberately hides that.
The commercial/military standard references the output intermodulation product to the power of a single tone. This is easily read on the spectrum analyzer as the difference in dB between one test tone and the IMD product.
The ARRL method references the intermodulation product to PEP, which is 6 dB above the single tone. If you want ARRL protocol, make the same measurement, but add 6 dB to the difference.
Here is some required reading for anyone doing the tests or contemplating published results.
What complete hogwash, the QST reviews give the readers no choice and many/most wouldnt have a clue how it is derived to start with. All they look at is pictures and numbers in the results section. I suggest you take your Sharpie and draw a smiley face on the Spectrum Analyzer display in the ARRL lab where you work. Use that to remind yourself of the con job being perpetuated on the readers every time you run an IMD test.
As was quite a bit of Nationals product line sold to non amateurs.
You forgot the Invader, Invader 2000 and Pacemaker. They also sold receiving converters, and electronic T/R switches.
Your always right there to criticize others; I suggest you do a bit more research.