The AM Forum

Just arrived today, waiting for me on the porch after work. Stuck a mic on it, wired up the receiver mute, plugged in the antenna, and voila! Full output on 3885. Had a nice QSO with W5XJ and WA5HRF with good audio reports. After a longish transmission, the transmitter still felt cold to the touch. I think I am going to like this box! A good way to start the weekend.
Doug

Do these transmitters have a FCC blessing? UL approval? Or is it even needed? i.e. Complies with Part XX.xx

There was a review and conversation on it.
Have not read all of it but am now.
http://amfone.net/Amforum/index.php?topic=33537.25

UL is not required to sell a product.  The reason firms get UL approval is that if their is an issue it buys the manufacture some degree of protection since they have gone through all the testing required to earn the UL mark.   

FCC is another matter.  They do required type acceptance since it must meet the harmonic standards as stated in the FCC for HF operation.   

Joe

Yep. I understand the significance of the UL mark on equipment. Almost all the AT&T packet switch equipment i managed on the end-user side had to submitted to UL, CSA, and the European equivalent before it hit the market.

What makes me nervous with the Super Senior stuff is that the 120 AC line goes directly to the full-wave bridge. There is no line isolation. If the diodes shorted in the bridge, you could have AC line voltage in all the wrong places. I would also worry about trouble shooting on your own and accidentally touching the wrong terminal while standing on a basement floor. Of course, the same precautions have to be taken with working with a transformerless AC/DC receiver. As far as the FCC stuff, I couldn't find any mention of it on the web site.

Direct rectification has been used for decades. Particularly in switching power supplies. Most home entertainment products now use it. Designed properly it poses no more threat than traditional transformer technologies.- Many commercial customers require a minimum of Class 2 insolation for indoor products and Class 4 for outdoor stuff prompting the mfg to seek UL recognition.

At work, any ODM supplies we market must have UL listing which requires a higher level of UL testing than recognition.

 

Also regarding FCC type acceptance, It's a transmitter, not a linear amplifier so perhaps different FCC compliance language applies. I'll have to look it up.

Glad your happy with it Doug.

So far, so good. Still dialing in the audio. Was over driving it a bit. Most of the old boat anchors I am used to have restricted audio, the Super Senior has the opposite problem and can be quite happy cruising along at more than 10kHz wide. Not friendly to the other users of the band. Got to watch the audio drive and bandwidth. Getting there.
Doug

Doug,

   I was listening to you yesterday on 7160 when your Super Senior cut out on you twice. I wonder what happened?

Are you using the K7DYY preamp/processor in the base of a D-104? If so, I wonder which version you have since I believe that are three separate designs.

With class D it is pretty important to keep the rig loaded close to a 1:1 SWR. Take a look at what Janis AB2RA says about that topic with here pair of Super Senior's:

http://wireless-girl.com/Projects/AMTransmitters/K7DYYtransmitter.html

Jim
Wd5JKO

DEFINITELY Pete,
One of the big draw backs of the (earlier???) K7DYY transmitters. I think he straightened that out. Maybe the newer transmitters are not wired that way. I had the little Class D 80M transmitter and I accidentally connected something to the PTT and it blew something out. Cost $90 to fix. Bruce said that it is mentioned on his web site that these units need an isolation transformer "or bad things will happen!!!!"
How are these transmitters built now?? Is there a warning to use an isolation transformer?? I think he was getting a lot of flak from buyers falling into that pit and maybe he reconfigured the circuitry.........dunno
I looked on Bruce's website and the latest super senior for 80/40 is not listed...I see the 160/80 for $1430

Jim,
It was faulting due to over modulation. I was running the mic preamp with the same settings I use on my AF68, but, of course, that's a high impedance tube rig and this is low impedance solid state. There is no way to monitor the modulation (no modulation meter or any other indicator) and my REA mod monitor software is on my work laptop, which I will put in line today. Sooo, learning experience time here, moving from rigs where everything is metered to one where nothing is metered and there is no visual indicator of anything except my peak reading Bird watt meter.

BTW, yes, I've read the Wireless Girl's comments. My SWR is fine, but I am aware of the issues involved, which is why I have a tuner in line. Once I have the modulation monitor running, I'll do some tests and see which carrier level and what audio settings give me the best results.

Last night on 3890 WA5CMI watched his pan adaptor while I adjusted things at 300 watts carrier. We got it in the ball park before he had to go. No more latch outs due to over modulation!

I'm so used to knowing everything that's happening in my transmitters that this is taking some mindset adjustment. But that's part of the fun, too!

Doug,

Found this on his web site for the Super Senior PS:

(http://k7dyy.com/images/supersenior/superpwm.jpg)

If you look further, the Audio input is isolated as is the RF output. So there is no "user" danger so long as you stay out of the internal circuitry. I sometimes work on switch mode power supplies at work, and most have the same design topology. They are isolated to keep the user safe, but putting a scope on the internal chopper is problematic. I use a battery operated Tektronix scope to allow me to do that, and do so safely.

http://www.k7dyy.com/sssch.htm

I would not be worried about those rigs being unsafe isolation wise. Still, any 1500 watt peak capable transmitter should be respected.

Jim
Wd5JKO

As per part 97.307(D)

(d) For transmitters installed after January 1, 2003, the mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency below 30 MHz must be at least 43 dB below the mean power of the fundamental emission. For transmitters installed on or before January 1, 2003, the mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency below 30 MHz must not exceed 50 mW and must be at least 40 dB below the mean power of the fundamental emission. For a transmitter of mean power less than 5 W installed on or before January 1, 2003, the attenuation must be at least 30 dB. A transmitter built before April 15, 1977, or first marketed before January 1, 1978, is exempt from this requirement.

This information is part of the data that one must present when getting a transmitter or external amplifier type accepted.   

Joe-GMS

In poking around the internet, it sounds like if it has a "FCC Label" it complies with their rules but reading some of this info can be confusing.

There is this info from the FCC:
Equipment Authorization Program For Radio Frequency Devices (https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CC0QFjACahUKEwi289K8_PTHAhWIrD4KHe57Aus&url=https%3A%2F%2Fwww.fcc.gov%2FBureaus%2FEngineering_Technology%2FDocuments%2Fbulletins%2Foet61%2Foet61.pdf&usg=AFQjCNEH6fA6MBYtbiTSGQ_BbvWkpTs0AQ&cad=rja)

Also this from the ARRL web site: http://www.arrl.org/part-15-radio-frequency-devices#Threats

I wonder if there is a list of type accepted transmitters and/or equipment available from the FCC. If there is, I couldn't find it but it might be buried somewhere on their web site.

You have two parts to getting a transceiver type accepted.  The receiver is a non intentional radiator and that falls under part 15.  In the case of a receiver, they want to make sure the L.O. does radiate back through the front end and out the antenna.   The transmitter is an intentional radiator and that falls under part 97 which deals with the purity of that intentional radiator.  Both part 15 and applicable sections of part 97 must comply before FCC type acceptance be granted.  If its not granted then the item cannot be sold.  When all requirements are met, an FCC ID number is granted. 

Joe   

So then, does anyone know if this transmitter has met the FCC requirements and a FCC ID numbered issued for it? Is a tag or label applied somewhere on the rig? None of my boatanchor transmitters have any FCC identification on them nor does my mid 70's Kenwood T-599D transmitter.

I think we need to broaden this topic to include other amateur radio equipment, or move onto something else.

This topic is explored and concluded here:
http://www.eham.net/articles/23327

As hams, and as AM'ers we are better off with this nice AM transmitter being on the market.

Jim
Wd5JKO

Its a valid question and in the process of asking questions we all can learn something.  Not trying to run down anything that may or may not be type accepted.  After looking at the design, I am sure it would easily make the grade!   

The law is the law and manufactures need to go by the rules. 

Joe-GMS   

There is no FCC type acceptance label on the back of my K3 which btw contains an optional 10in/100out watt linear amplifier.

There is a very prominent FCC label on the back of my Alpha 89.

On the back of my ASRock Atom computer is a ton of labels, UL, CEF, TUV, FCC type 15 and Chinese characters, you name it.

Same on back of Sony Laptop i5, SVE151 including FCC.

Most all of my other equipment predates type certification.

As for all my homebrew equipment including linear amplifiers with PI, ( not PI-L) output networks,  regenerative radios, etc.
 .... well they can come and get me.  ;D

Better watch it Rick with all that black market gear that you have around ;)....

In my modern station, which is the TS-590S and Alpha 8410 both are well marked!   No markings on my Ranger II !!  

Notice the early product announcements in QST on new gear saying it cannot be sold until FCC type acceptance is granted.

Joe - GMS    

 

The way I read the FCC doc and Part 97 (admittedly, a quick read), there is no requirement for "Type Acceptance" for a commercial transmitter in the amateur service.  But I'm rarely right ;)

In any case, I sent an email to Bruce and asked him about it.  Might as well go to the horse's mouth.

Grant NQ5T

Follow up:  Heard back from Bruce and also found other corroborating sources.  "Type Acceptance" is not required for transmitters used in the Amateur Service.  Amps, yes, per Part 97.  Transmitters, no.  We are considered to be technically competent enough (a stretch perhaps in some cases) to ensure that our transmitters meet the requirements of the rules — whether they are commercial or built on our bench.

How does one "ensure that our transmitters meet the requirements of the rules" with this transmitter in the discussion? I can't find any transmitter specs on his web site. Does he provide "test results before ship" with each transmitter he sells?

Why not simply email Bruce K7DYY yourself Pete, ask him your questions, and report back to all of us here with the answers.

From what I have heard of his line of transmitters and gear on the air and from online reviews, it seems to be a very good, well designed AM transmitter.


Al VE3AJM

So the 40 meter version is shipping now?

I would think these things would be boring, great in every way but not much excitement?
No meters, no glowing tubes...

    My take is that type acceptance, if required, just means I would not buy a transmitter so labeled. I am a builder, a tinkerer, and a modifier. If something does not work right, I try to understand it, and if possible fix it. Sometimes I go further and make it better than it ever was. If a rig is type accepted, wouldn't tampering with it affect the the type acceptance certification? This might even be illegal.

    At my work I repair commercial class E 13.56 mhz amplifiers. Once done, we keep a record of three pages of tests, and the unit is factory sealed. I don't understand why there are those in ham radio that want the same thing, i.e buy, plug in, hook up, talk...CQ CQ with no thought ever of what is inside that thing, or how does it work?.. I have resisted being an appliance operator all my adult life. That said, there is something in ham radio for almost everyone. But me, NO, I'll pass on that type acceptance, and the extra cost to purchase something so certified.

   Back to the thread, the K7DYY Super Senior is a pretty neat rig. Several people use them, and they love the things. They can be mated to an SDR receiver, or even and old Hammarlund Super Pro. Then add in the QIX modulation monitor, etc. to complete a station.

   Good Job Bruce!

Jim
Wd5JKO

"So the 40 meter version is shipping now?

I would think these things would be boring, great in every way but not much excitement?
No meters, no glowing tubes..."

********************************

But on the other end...  "OH, the audio."
  Tell 'em your using a Gates!

More thinking  (uh oh) on the dull no knobs or meters rig. 

Rack mount the DYY.
 In same attractive rack, mount your separate HB tuner with a lighted watt meter, another lighted SWR meter and a couple of lamps for various switch positions along with at least two tune and load knobs plus a band switch knob. Might even want lighted indices for same.

Also install another matching AC power input panel with exotic big boy switches,maybe even a twin breaker, separate aux. AC jacks, etc. along with a big sassy AC line voltage meter ( you do check your sag, don'cha )
Don't forget to add the essential Ip or I'd equivalent meter in the AC box, a big lighted AC wattmeter / power meter to show quiescent vs. quasi peak power differentials when modulated.

Now add another matching panel or two in the same rack for all your audio gear, starring of course the biggest, strappinest lighted VU meter you can find. Don't forget at least 10 knobs, another twenty sliders, and numerous switches with indicator lights.

All above for the retro man. If you go modern, wanna be the LED King, then sky's the limit.
 ;D

Oh and almost forgot the best. Another panel or rig top flasher modestly behind perf. shielding showing fluorescent blue modulation swing alom with with warm yellowish background glow to simulate those always-on pubes.
You know, trick it out like 27.185 brethren.

I  guess the present cost of the Super Senior, negates any fancy meters and whistles and bells.
Now exploding RF devices might be a little extra.
I hope Bruce can figure out what is going on and maybe beef them up a little, instead of running them close to design parameters.
I enjoyed the little Class D 80M transmitter. 125watts in the palm of your hand. It needed the isolation transformer, though.

Got the transmitter back last Thursday, while I was out of town. Hope to get it back on the air tonight. I'll let everyone know how I fare.
Really fast diagnostic from Bruce, and good communication. He burned it in over a couple of days, so everything should be good. In any manufacturing process things are bound to happen. A cracked FET case was the issue, and it was found, fixed, tested, and returned in record time and with professional, hassle-free courtesy.  Don't see how anyone could improve on that.

Doug

Best of luck with it Doug and hope it works out this time.  I do believe that Janis-AB2RA is still happy with her 80-40 DYY rig.   It sure sounds good on the air. 

Would appreciate hearing your feedback after you have been operating it awhile.

Joe

Been using it quite a bit, and it seems to be working FB. Good reports on the audio. Can't seem to get to 100%modulation at 375 watts, but that might be due to my audio preamp set up. Can get easily to 110% positive peaks at 315 watts carrier, does not exceed 100% negative peaks no matter what I do. I think I'm gonna like this little transmitter. Stays cold to the touch even after a buzzardly transmission.
Doug

Is your microphone in the proper phase? Or maybe there is a stage in your AF chain that is clipping on the hi peaks.

Al

Some of the successful users of the DYY xmtr have had to dial the carrier back to 200 - 250 watts to get that positive peak.  It may be you are hitting the 1500 PEP limit at 315 watts.  Try lower carrier levels and see if those positive peaks on the REA monitor start showing up

Al

PS: I did some calculations assuming the normal asymmetry of the male voice of 150% positive peaks, assuming proper mic phasing.  You might try running the carrier at 240 watts   You may be hitting the rig with as much as 1970 watts PEP which may be flat topping and perhaps stressing the output mosfets


PPS:  That may be why Bruce is recommending a phase rotator which would remove this asymmetry issue altogether and allow you to run 375 watts carrier is that's your "bag."

Thanks, Al.
Very interesting. Audio is not my specialty, RF is. I blush to admit I have never even heard of a phase rotator. I will do some research, and I'll dial back the carrier to 250 watts tonight and see what happens into my dummy load. My mic preamp does have a phase shift button, but it seems to have no effect with the DYY rig -- everything is the same no matter which position the switch is in, according to the REA modulation monitor. It does make a considerable difference with my Multi-Elmac AF68, though -- one position is very much louder and has less background pickup than the other.
Yes, at 375 watts, driving it over about 80% modulation results in visible flat topping on the modulation monitor. Nothing in the instruction sheet about that, so dialing this transmitter in is a learning process.
Don't really have a thing about needing to run 375 watts, just putting the transmitter through its paces to see what it will do. I've just joined the DYY reflector, so I will look for posts there about the audio characteristics.
Doug

Doug

Just remember that it's all about that 1500 PEP spec.  The problem with using a scope to monitor the PEP is that you need to be able to supply a 1500 watt CW source to calibrate the scope.  After that, you have to deal with the persistence of the scope to show all those tiny transient peaks that are hard to see.  The REA monitor is the best approach along with the ability to do the math to know where you hit the 1500 PEP value given the carrier power and an accurate way to measure the % modulation.

Exceed the 1500 watt PEP spec and you are asking for flattopping or worse splatter / failure.  The DYY can have a failure problem.  We still do not have a common failure that can be isolated.  It seems like there is a component quality issue with that rig from time to time.  We've discussed designing too close to maximum components used in the transmitter on this forum but Bruce also has to deal with a price point that is acceptable with the amateur radio community.

Gl to you Doug  and Bruce, Gl as you continue to keep this neat transmitter available to us.

PS: Bruce points to an article discussing the merits of phase rotation. 

http://www.w3am.com/8poleapf.html (http://www.w3am.com/8poleapf.html)

I have decided to eschew the whole messy audio chain thing with mine, in the interest of less stuff is better.  I have the new version of the D-104 processor with the phase rotator and a shiny D-104 to put it in.  

If I can sell my house, get moved, and get an antenna up in a new place, I'll have my 80/40 back on at some point in the next few months.

While I had the 80/40 on the air, I ran it at about 300 watts carrier.  For no particular reason other than there's no point in pushing it.  100% modulation (on the REA) with no signs of flat topping.  I did have a phase rotator in line, and didn't really experiment with how the SS behaves with asymmetrical audio.

The SS will do 375 watts carrier 100% modulated.  So if you run it at the limit and try to modulate over 100% on peaks you can expect it to flat top.  I suppose the same would be true if you ran it below 375 watts, and tried to modulate with 100++% that attempts to push it beyond the limits of the transmitter.

Grant NQ5T
Double Oak, TX on the way to Savannah, GA

I understand that you are using the REA monitor to see your positive peaks. I am using the REA monitor too but I still prefer to look at the carrier through a little RF sampler and the good 'ole scope.
I think the TX might not like slammin' the negative peaks if you are seeing excessive white baselining in real time using a 'scope
Fred

Just an update on the Super Senior. It's working FB now, and it has become my go-to transmitter on 75 and 40. I have installed the K7DYY audio board in the base of one of my Astatic mic stands, and I have tried it with several different heads -- JT-30, 77, D-104, DR-10 Crystal, DR-10 Dynamic, and a couple of others (you may have gathered that I collect vintage Astatic mics). Nice to be able to just switch heads and do A/B comparisons. On-air reports indicate the 77 and the DR-10 Crystal sound the best, with the DR-10 coming out on top. Full, rich audio, and it has a switch on the back that shifts the curves from low emphasis to high emphasis (Astatic calls it the "crisp" setting) that works really well for times when the bands are noisy and I need more punch on the high end.

The DR-10/K7DYY board combo replaces an ART TPS II tube preamp, 31-band EQ, and dbx266xs gate/compressor. Reports are that it's smoother than the audio chain setup, which probably means I have too much compression dialed into the dbx, but what the hey, it's a simpler set up and takes up no space, so I think that's what I'll go with in the future. I do occasionally still trip the safety on over modulation -- it's the most sensitive I've ever used -- but very rarely now.

Happy camper. Someone comes out with a rig like this at the power level this one has for all the hf bands, and I will buy it.

Doug

Thanks for the report Doug.   Its appearing to play well for you and that's great!   

I believe that rig is rated for 375 carrier output.  Have you confirmed that and if so under what positive modulation percentage are you able to achieve. 

I believe the new pre-amp board for the D-104 uses a phase rotatory to make the human voice audio symmetrical.  If so, that should reduce stress by limiting the positive voltage during positive peak modulation on most voices which are non symmetrical.       

73,
Joe-GMS 

It will do 375 watts, in fact, it will do more, although Bruce warns against trying that. FETs are pretty unforgiving, so pushing things beyond the limit is not wise. Moving from 80 to 40 meters requires a readjustment of the carrier level. The setting that gives 325 watts carrier on 80 produces over 400 on 40. That's how I know it will put out more than 375! The carrier-adjust pot is a subminiature pot mounted on a circuit board and accessed through a TINY hole in the front panel using a miniature screwdriver. A knob brought out to the front panel would be more convenient, but I guess you can't have everything. Thinking about how I can mount some type of adjustment external to the front panel, but not there yet.
I cannot seem to get 100% modulation at 375 watts carrier. I can get it at 340, though, and I usually run the transmitter at around 325. As the rig is used a bit (it never feels even warm to the touch, just not ice cold after some use -- I don't call that warm), the power output tends to rise slightly, so why stress things, and the difference between 325-340 watts and 375 is not even noticeable on an S meter. I may ask Bruce why I can't seem to get 100% modulation at full power output one day, but for now I am having too much fun.

I am using a Bird 43 watt meter and REA modulation monitor.

Doug

I think for the DYY rig the phase rotator is an almost must.  This 375 watt carrier as a "spec" for legal AM operation is a myth.  I repeat my earlier comment "it's all about the 1500 watt PEP spec"  If you run the phase rotator then you will, hopefully, see symmetrical modulation.  That being the case then the relationship between 375 watts @ 100% modulation & 1500 PEP is intact.

On the scope.  I'd like to respectfully disagree with whoever posted their preference of the scope over the modulation monitor as there are some transient spikes that just will not be picked up by a scope but will be detected by the modulation monitor.  In any case, how is one going to calibrate the scope for 1,500 watts carrier using the K7DYY transmitter to calibrate the scope so that it will be accurate.  Just a friendly disagreement. I've included an attachment to show my calculations of the above mentioned mathematical relationship.

Regards, Al VTP

In my case, I care mostly about over modulation in the negative direction and a scope shows that for sure, at all power levels and there is no calibration needed.
My scope sits on the iF outputs of the home brew receivers, and it tracks with the mod monitor on positive and negative, I adjust it to 4 divisions (or 40, depending on how you count, and when the carrier gets closed down its VERY easy to see.
When I hit 8 divisions its 100% positive or close enough.

This is a sine wave, but works the same with voice:
(https://n2dts.smugmug.com/Ham-radio/i-XjX39zC/0/L/PC180152-L.jpg)

My mod monitor seems to be 5% off, it was showing 95% at this point...

A good friend of mine bought one about 3 weeks ago. It let go last weekend. I think he's going to return it for a refund.

Darrell

I hope he will rethink things and just ask for it to be repaired

Al

From the K7DYY site:

 160m/80m * 80m/40m
The SuperSenior covers two of your favorite bands. It is available in TWO models, one covering 160 and 80 meters and the other covering 80 and 40 meters.


Legal Limit
The SuperSenior provides LEGAL LIMIT output with up to 375 watts of carrier (adjustable from front panel) and audio peaks reaching 1500 watts, no time limit!



So what is the deal with these things, if speced as above why won't it do it without breaking?

Why not just run the thing at 300 watts carrier?
No one can tell about the extra 75 watts of carrier at the far end.

    Doug,

   Glad your having fun. I suggest you scrutinize that preamp output with a scope, especially as you try different Mic elements. I own 2nd generation K7DYY pream pcb. This one had one pot, and no phase rotator. My two MC-320 elements would both overdrive the processor if spoken closely into the screen. I had to cut back the drive to the processor, and then as a result I needed to adjust the noise gate so it did not chop up my speech. I made it pretty decent, but it still would clip during the processor attack time. I ended up with a post processor clipper that only clipped when the processor output had a big spike during the attack time.

   I wonder if these processors when overdriven are part of why some of the Super Seniors go through a melt down?

The picture attached was the stock preamp with a close talked "SSSSSSSSSSSSS". I was able to correct that as described, but the brief spikes during the attack times remain.

Jim
Wd5JKO

Now, that is interesting. My board is the latest one with the phase rotator. Peaks look symmetrical on the mod monitor. Haven't looked at it on a scope yet, but will.

The only adjustment is the output. I would like to be able to adjust the noise gate a bit, though. It takes a couple of seconds to settle down when first keyed, then works fine, eliminating all background noise. Faster attack time would be good so there is no blast of fan noise on key-up until the gate kicks in.

But these are quibbles. The rig is not perfect, but it darn sure is very good at what it does. First comment I always get when I make a new contact is " you sure are loud," followed by "outstanding audio." 

My Super Senior failed right after I got it as well. Sent it back, and Bruce repaired it and burned it in for a couple of days before returning it to me. Been working FB ever since.

Doug

Folks:

The K7DYY Super Senior (160m/80m model) at the W1ZZZ palace can create a 240 watt carrier under full +125% dense modulation (using external broadcast processing). As the carrier is brought up, the positive modulation is clipped earlier. We have never been able to 100% modulate a 375 watt carrier.  In the end, this is not much of an S-meter difference.

Bruce works aggressively to resolve technical issues and has repaired Peter's transmitter multiple times at no charge.

73,
Dan
W1DAN

Sounds like fun.
Since these things run cool, I suppose its a voltage spike that takes things out?

None of the usual mic compressors would work fast enough to prevent big spikes hitting the transmitter.
Best to run low compression I suppose.

If you need labels on the gear, let me know and I'll print you some.

I have a special sale on "Official FCC Approval" labels at the moment

John K5MO

 :-X