The AM Forum

After several months of thinking about it, I have today commited to K7DYY for one on his Super Senior AM Transmitters.  It should arrive in mid-February.

Does anyone have any suggestions about what to do, or not to do, while getting it set up and running on-the-air?  I have read all the messages in the archives here and am really hoping for some hints so I can be up and running with minimum hassles.

Tnx,
Craig WA8DRZ

 

What are your concerns?  Methinks this should be really straightforward.  It's a solid-state rig.  Just follow the instructions very closely and make sure it sees a 50-ohm load before keying it up.  Give it proper ventilation because I'm sure it generates a fair amount of heat being a legal limit transmitter.   

Craig you are our canary in the coal mine  ;)

Serioiusly, it seems to me that you just need to do the usual things--have a big dummy load, a wide response receiver for listening to your tx audio when you key the rig and modulate it into the DL, and an oscilloscope.   I'd watch the audio peaks and it's my understanding those rigs really like to work into as low a vswr as possible. 

Thats a really neat transmitter. They sound good too.  Dont worry about heat, Its class D. It runs cool.

Do you have plans for audio?

You can use the processor board that fits under a D104 and keep things simple. I use this and it really works great.  The board gives you a 600 ohm output to feed any rack gear or the SSR directly.

If you want even better sound you will want a studio microphone of some sort and a preamp.  Its hard to recomend a microphone as they really range in price.  My favorite is the Blue spark.  But lower end mics like the MXL also sound great. 

Most of these mics will need phantom power so you will need some kind of preamp that has phantom power built in to power the mic.  To get serious, you will want an EQ.

Dont forget the microphone boom.  I use the booms off ebay. They are great quality and cost about $60.

Rather then have an entire rack full of cables and gear for my audio setup, I got a voice channel.  Voice channels contain the preamp, phantom power, EQ, Compressor, limiter, expander all in one box. 

There are low end solutions like Behringer and higher end solutions from APHEX.  I use the ART voice channel and really love it. Its a good balance of price and performance.

You can use a transciever for the reciever with the SSR.  Its best to have a good reciever. The bands are crowded and your going to need it!

C

AXE the creator of the Senior AM transmitter if he has fixed the problem of isolation of the AC mains from the ins and outs of the TX.
Past creations were a big PITA if you did not use an isolation transformer and BAD things would happen if you connect external devices to the TX. Mainly the PTT lines. Audio and RF out seemed free of this problem.

The performance is outrageous!!! Great TX
I have an K7DYY 80 meter Class D TX. The entire 80M band, no tuning, and 180 watt carrier outpooot.
VERY nice TX audio
Fred

I have a friend here locally that run it. It sounds awesome and there have been no problems. Like anything else, read the instructions till you understand them completely.

Gentlemen, thank you for all the comments and tips.  Let me give a little more detail about my plans.
I have several R-390A receivers as well as two Ten Tec RX-330 commercial boxes, so I think that I am OK there.  I have a scope (USM-117, good to 5 mc.) and plan to use it - with a dummy load until I am happy with what I see.  My dipole shows an SWR of 1.7 on 3870; Bruce says 1.8 max, so I have an antenna tuner on the way to reduce it just to be on the safe side.
I plan to use a D-104 with Bruce's processor board in the base, at least as a start.  Other audio gear may follow.
I have tried to work some of the West coast gang on 3870, however my old Raytheon marine SSB xcvr is apparently not adjusted for AM as I get reports of very weak audio.  I will have to pop the cover and see if there is an adjustment that will help with that, if I get time before the Super Senior arrives.

73,
Craig WA8DRZ
Redwood City, CA

Craig, I wonder why you cant get the SWR on the dipole down by trimming it or other means.  Adding in a tuner is going to add alot of loss and many tuners on the market will not take Full legal limit AM.  At any rate, I hope you got one hell of a tuner comming.

C

Agreed that a lot of run-of-the-mill tuners will not handle AM.
We have a thread on AMFONE to build a HB tuner.

http://www.amwindow.org/tech/htm/160smallants.htm



And you can find more info about it and building details by searching "K1JJ TUNER"

If you have patience, you can find the old heavy weight tuners from DENTRON. MT 3000 or 3KA that will tune anything and handle AM legal limit. Several folks here, use Dentron. Then the old Johnson Matchbox ( 1kw) flavor.
The toy MFJ tuners will not handle legal limit AM.

ATTACHED is a good antenna that serves Frank "AHE" The Slab Bacon very well.

EDIT: I checked the K7DYY website and that is a lovely TX!!! WOW legal limit and hi-fi audio and continuous coverage on 80 and 160!!! Worth every penny.
Fred

Re: antennas
KE7TRP, yes, I could probably trim my dipole except that it would then have higher SWR on other parts of the band!
Fred: Thanks for the pointers on tuners.  I have a Ten Tec 238 on the way which both Ten Tec and other hams that have one say will handle the power. (I would not go near the likes of MFJ.)

Craig
WA8DRZ

assuming the load and feedline are unbalanced the 238 is okay except for your 375 w. on 160 m. where the fixed value caps are marginal disk ceramics that may struggle with the continuous current from your rig.   For my unbalanced loads on 160 and 75 I had to throw together an ugly L network tuner from a Unique Wire Tuner augmented with RF doorknobs and a bigger Cardwell cap.  The Johnson roller inductor is okay up to 5 A.  Some guys go into the 238 and modify it with doorknobs; I didn't bother with that and sold mine and made the one in the photo.  In radio no one sees how bad your gear looks (people here are um, battle hardened  :D )  You can try yours on 160 because it's possible you may not use the fixed value caps (unlikely) or, you may use all of them in which case the current gets divided across them and you may not see drift or heating.   I think most of the difficulty with them is with QRO continuous duty modes like RTTY so it's possible you may not have any trouble (I like overkill--next comes 1 MHz micas and a 10 A gates inductor).

My rememberance of a Ten Tec ??? that I had at one time. A little similar to the 238 was the fixed cap problem Rob mentions for 160M.
A 30 foot high full sized or zig zag dipole on 160M will draw a lot of RF amps through that tuner at 375 W.
Give it a try, even 150 watts of carrier is sufficient on 160M.
I don't know your layout for antenna. Height above ground is important!!

238 go boom.

C

I don't have an antenna for 160M right now so I will just start on 75/80.

By the way, the latest 238 has 3 caps in parallel at each switch position (for a total of 12) in an effort to reduce that current heating problem.

I'll report here when I get it all running.

I forgot TT makes a new and improved 238.  I don't know much about it except that I saw a bigger air variable cap in it.

Use as much air variable and as few disk ceramics as possible.  GL

OK FB
80M should be no problem.
I have a new wish list...............but do not have the $1400  :o

Fred

This is the gutz of my beefy-assed single-ended "hole in the wall" tuna.
It takes whatever I throw at it and never complains.

One more

Frank do you work for SHEETZ???

HUH???  ???  ???

The titles on your photos.........end in "Z". There is a popular gas-and-go place named SHEETZ and they add Z's to all of their advertising

http://www.sheetz.com/main/

I thing we need a major decoder ring to figure out what the MOP man is saying!!!!  New language?  CW is easier.... ;)
73,
Joe W3GMS

I see, said the blind man to his deaf wife
as he picked up his hammer and saw...............

I just wanted to say that I heard AB7KT out of nevada tonight on his new Super senior.  I can honestly say that rig is up there with the top 10 ten I have heard. Super clear, Super talk power.  Amazing for the size.  BC quality with more talk power then most. 

wa8rz did you get yours yet?

Still waiting...

Its going to be worth the wait!

  That was a rather common last name where I grew up in PA.

   Well, the Super Senior arrived yesterday; UPS dropped it off around 11 in the morning.  It sure is a light weight little thing.  You can literally hold it in one hand.  I bolted it in the rack and wired up a reciever to the antenna and mute jacks and thought I was ready to go.  (I had previosly received his processor board and mounted it in the base of a D-104 mike.)  Oops, the reciever did not mute and the feedback was horrible when I advanced the mike gain!  Turns out that I mis-wired the connector for muting on the Super Senior, but no harm done.  Another trip to the bench and few minutes of soldering  sorted that out.
   I fired it up first into a dummy load and adjusted the mike gain for 100% modulation with a scope.  OK, let's put it on the air.  it was too early in the afternoon for anyone to be on 3870 but I fired up there anyway, on my new 135' dipole.  All was well at first, then upon speaking into the mike the transmitter shut down with an SWR FAULT message!  What the heck, the SWR meter reads 1:1?  Reset, and back to the dummy load and all is well.  OK, try my other antenna a 90' NVIS dipole down in the canyon; it works fine.  Turns out that the balun in the new dipole can't take the 1500W PEP that the Super Senior puts out.  It must start arcing and the protection circuit cuts in quicker than the SWR meter can react.  That is a good thing!
   So I backed off the power to 200 watts carrier and it held together on the new, better antenna.  I enjoyed quite a few nice contacts on 3870 yesterday evening and again this morning on the early bird net.  Everyone gave me good signal reports and commented on the clear, punchy audio.
   I am a happy camper thanks to Bruce, K7DYY.
Craig

Time for a better balun.

Have fun with the new rig!

Glad you got the rig.  AB7KT's sure kicks #$@.  Super clear audio. He made it out to the east during the AMTR.  I cant wait to hear yours Craig.  I am sitting in the shack now listening to 75 phone.  3870 has west coast am with the texicans blasting in on SSB.  I am currently on 3880.  There is a very loud buzz right on that exact freq. If you are going to be on, let me know.


I would prob just run a Sleeve balun or nothing if you can. One less thing to get in the way.  Heavy wire and coax should be enough.  I like and use the Palomar Slip on baluns. They work very well.

C

 Craig,

I moved up from the K7DYY 160m & 75m "Senior" transmitters and have purchased a "Super Senior" as well. I'm luck in that Bruce lives only a few miles from my location. I've had my Super Senior for some time now and can't provide too much in the way of advice. The transmitter just flat works without too much adoo..

If you haven't done so, I would suggest that you also purchase one of Bruce's audio processors and a good D-104 microphone. That's really the only way to go.  The 'DYY processor board replaces the original preamp in the microphone base. Use a scope to set up the audio. Other than that, there's really not much else to do or be aware of, except for having a lot of fun on AM!  On mine I have set the carrier level at 375w indicated on my 'DYY AM Monitor.

I just moved the 'DYY Super Senior to a 3/4 size rack along with my Collins R390 (Not 'A' model) receiver. I just need to hook up a couple of cables and should be back on. Unfortunately, I discovered that the break-in function in my receiver is not working. I am a bit paranoid of running 375w of carrier with no muting of the receiver. Not sure if there will be some fried/melted coils in the front end. I will have to give that some consideration and meanwhile figure out how to get break-in working.

Good luck with your Super-Senior. I think you will love it. I certainly do mine. I find that Bruce, K7DYY, to be very friendly and helpful. If you have any problems or questions, I'm sure he would reply to email or snail mail. See you on the bands.

Best regards,

Gary, K7EK

Gary. I had that issue with my R390. Its almost always a diode that blows that prevents the Breakin from working. Its in the PS. Others can help with how to get at it.

If you do not want to fix the reciever you can simply use a coax realy and a pair of contacts to cut the neg speaker line.  I ran one like this for 2 years before someone told me about the diode failure.

That SS is one awesome radio.  BIG signal and very clear audio. 

C

Hi WA8DRZ:

I have a Super Senior on order, and I'm wondering if my antenna can take legal limit AM. I wasn't aware that the output power could be lowered with this rig. How did you lower the power from 375 to 200 watts?

ND9B

I saw one a couple weeks ago. It looks like a nice package.

Hi Craig,

Been hearing your SS over the past few days,  and on last night's AMI Net.  It DOES sound teriffic.  Big signal,  clean,  crisp audio that is very well-balanced.  I'd be very happy to own one,  but porb will try to build a WA1QIX  Cass E style transmitter,  altho there may not be enough years remaining on my calendar!

Sounds great!  Vic

Craig, I heard you last night on 3870. However, You where very weak into AZ.  The Texicans where on in full force so the Frequency was like a wasps nest.  From what I did hear, you sound great!

c

Steve k1mv just got his.  It came in last weekend and he brought it over to my place last Sunday after our usual Sunday AMer breakfast.  I did not open it up and peek inside..but we did put it through some modest testing.  We ran it from about 150W to 350W. 

We hooked it up to the QIX monitor and a dummy load.  I noted that when we started to drive it over 300W the power supply started to groan a little  bit affecting the audio in regard to distortion and I think head room.  So we set it up at 250W which seemed to be about right.  Good positive peaks in excess of 130%.  Very clean TX and audio. 

Not much to complain about the unit....it was amazing that such a small and light unit could put out this kind of power.  In looking over the prints, the obvious reason for the small size and weight is no power transformer.  The DC HV that feeds the PWM is directly off the AC line.  Normally that would raise a big red flag, but in this case the PWM supply is isolated from ground and takes care of any risk of a chassis shock. 

The unit has 8 fets...not what is shown on the website (only 4 there).  So it can certainly run at 250-300 watts no problem.  The is one annoying aspect of the radio....the fans are LOUD!  My mic was easily picking them up.  I was surprised the manufacturer used such noisy fans....there are quieter ones.  But this is not a major issue and there are some things one can do such as using remote PTT.

The VFO is a little odd.  Kind of clunky.  But it works and is very stable.

I think it is a good idea to run this unit through a tuna.  Kind of a class D feature.  All in all a very nice radio and Steve is very pleased I think.  For someone who does not want to build an E rig for whatever reason, this is a nice alternative for a 2 band AM TX.  Pretty much plug and play.

The price is up there, but any commercial product is expensive.  Some of the rice boxes cost as much as a small car...and can do a whopping 25 watts AM  ;D ;D ;D  So as far as watts/dollar this is a good deal. 

My .02...and worth all that.

73.....
~ps

Hello 'PS
I thought the K7DYY design might have changed by now with all of the problems of past units and no isolation transformer. Not from Chassis shock but from connecting other devices (usually the PTT) to the PTT lines of the K7DYY unit. There was always a warning that a relay needs to isolate the TX from a PTT line from the shack. "Or bad things will happen" from an UN-isolated TX. And it did to me. These things are always accidental and poof there goes the final and some other components and a $100 bill for repair.
Apparently the audio and RF are isolated from the AC side of the TX chassis.
 Are there warnings about isolating the TX????

Fred

I'm listening to you right now on 3870, talking to Mike, Mike, Jim, Bernie, etc. I'd break in but I have a cold and don't want to give it to you guys. If you read this in real time, give MS mike some grief from me. He just doesn't have enough pathos in his life.

Audio is just beautiful, very, very clean.

Congratulations

Jon

Yes - There is a small hole on the front panel, through which a flat bladed jewelers screw driver can be placed, to adjust a trimpot for carrier level. I don't think this is something you will want to regularly adjust as the pot in question will eventually fail. This is one of those set and forget types of adjustments.

It seems to me that it is time to invest in some gear (transmatch? antenna system?) that will handle the full legal limit. Why bother with a top notch transmitter if you are only going to cripple its output?  Time to dump the Mighty Fine Junque and the RG58 antenna feed line for something that will handle anything that one can throw at it.  K1JJ's Super Tuner and a antenna fed with "real" open wire comes to mind... A small investment, but pays major dividends...  Just my two cents  ;D

Best regards,

Gary, K7EK

 

I've had the SS for about a week now. As N1PS said it's set for about 250 watts out with 130% positive peaks.  I'm getting very good audio reports and with the help of Steve (QIX) made some adjustments on my Behringer VX 2000 and all seems fine.  I have had several shut downs when operating but believe I had the mic gain up too high.  After reducing the gain on my pre-amp all seems good.  I moved the unit away from my mic and that has helped with the fan noise.  Like Peter said it would be nice to have had quieter fans in the unit.  Peter is designing a relay for the audio out and thus grounding the unit.  It'll add a level of safety kinda like a belt and suspenders.  The only thing I have left to do is get my SDR radio to work consistently and then I'll have a 15#+ package that'll include the TX, RX and a computer.  The last time I carried my AR-88 receiver around was awful now my back is happier.

Bruce...thanks for a great rig!!

This fellow bruce must be a busy guy.  I Know about about 6 of this units on the air in the last month or so and several guys are waiting for units to arrive.  It seems expensive but then you consider that you get full legal limit AM and do not have to have a computer or an amplifier or on the other hand, You dont have to have a 600+ lb transmitter in the room.   Every one of these I have heard has been LOUD and clear!

C

Very impressive transmitter,  indeed.  DYY Bruce also makes a Mic Preamp/Processor board that fits in the base of a D-104 mic (forget if this has been mentioned above).

If interested,  Schematics of the SS:
http://www.k7dyy.com/sssch.htm

Care and use of the SS:
http://www.k7dyy.com/usingsupersenior.htm

Pic of the guts and rear panel -- scroll down:
http://k7dyy.com/

The slighest nit that I'd pick at is that the PLL steps at 5 Khz ... at times it might be useful to  have better resolution,  but this could be a fairly easy mod (external DDS??).

I have no interest in the company.  In the past,  have bought Bruce's Mic Pre/Proc board,  and it works well.  I do wish him great success,  he seems to have a winner,  Vic

Some comments after using the Super Senior for 2 1/2 weeks:
- Nothing major, it just works.  Flip the AC on and start talking.
- As noted above you can reduce the power with a front-panel trimpot.
- An antenna tuner is a good idea.  It likes a 50 ohm load.
- Yes, I have Bruce's audio processor in my D-104. It makes great audio.
- Below from a recent email to Bruce:
Complaints:  I miss waiting for filaments to warm up.  I miss watching five wiggling meters and seeing pilot lights glowing.  I miss the warm glow of the final tubes just before they blow up because the plate tuning had drifted off dip.  I miss the arcing and sparking of the 866 rectifiers and the arc-over because the mercury was not completely vaporized.  I miss the sizzling of the high voltage trying to find an alternate path to ground.  I miss the modulation transformer arcing when I accidently cough into my D-104.  (Above with tongue-in-cheek!)

73,
Craig WA8DRZ

Can you imagine the sales if he made a 10 though 160 version?

C