eHam.net - Amateur Radio (Ham Radio) Community

Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net



[Articles Home]  [Add Article]  

Your Built-In Amplifier Pulser

Michael S. Higgins (K6AER) on December 30, 2009
View comments about this article!

It was with interest that I came across a recent review of the Pecker 3898 pulse modulator that pulses your microphone with a 30% duty cycle on tone and a 70% duty cycle off pause, while tuning your amplifier. This is to greatly reduce grid and anode dissipation time which it does by the factor of the above percentages. No rocket science there.

Several in the equipment review section had made references to a MFJ 214 unit that pulses your CW keying at the same percentage rate and some hams felt the tone is better than a CW signal. A pure tone in SSB will produce the same output as a CW key down signal. Another words, a single tone SSB 30 watt signal and a CW 30 watt signal will produce the same grid drive on the amplifier. There is no difference unless the tone is a duel tone modulation or the modulation has been backed down to produce lower output. CW or modulated tone will produce the same output on today's transceivers.

So how do we obtain the same keying ratio with today's modern radios? Easy, just program the keyer memory with a series of “E's”. The on ratio with the spacing ratio is about 30% on and 70 % off. This is the same as your aftermarket pulsed unit. Nothing to put in your mic. or key line. Just used the radios internal memory keyer.

Now pulsing your output to many high end amplifiers will not yield an easy tune up. Most modern amplifiers require you power to be brought up slowly until your TUNE and LOAD are in the right ball park or the amplifier will go into gain fault. Even with a pulser you will need to bring the power up is several stages until the tuning is right. Today's microprocessed HF amplifiers have very fast gain fault protection circuits. I know some will think this is a pain in the butt this is what is necessary to keep stupid at a minimum.

Member Comments:
This article has expired. No more comments may be added.
 
Your Built-In Amplifier Pulser  
by K6SGH on December 30, 2009 Mail this to a friend!
Excellent recommendation! I have also found that if I bring the XYL into the room and inform her of my plans to put up another antenna, the high pitched whine that typically follows can be put to good use as well.
 
RE: Your Built-In Amplifier Pulser  
by AA4PB on December 30, 2009 Mail this to a friend!
Some don't pulse, the whine is continuous :-)
 
Your Built-In Amplifier Pulser  
by KC7NOA on December 30, 2009 Mail this to a friend!
At what words per minute was the best??

Iv tried that with a FT-450 and was not completely satisfied with the results ... but did work to achieve a near max tune for output.

I think my issues might stem from using a HM-102 power/swr meter - its not all that fast for responding to strings of "E"'s ....
 
RE: Your Built-In Amplifier Pulser  
by K0BG on December 30, 2009 Mail this to a friend!
I'm in the minority. I'm all solid state, and the antennas are resonant. As a result, I don't tune.

Alan, KBG
www.k0bg.com
 
RE: Your Built-In Amplifier Pulser  
by W1NK on December 30, 2009 Mail this to a friend!
Excellent recommendation/reminder Michael!

I've set my keyer for about 40wpm and that seems to do the trick, for me.

Just to remind readers, if you are using an watt meter that reads AVERAGE power, it will look as if your amp's output is less than what it is rated for. Using a PEAK reading watt meter will give you a more accurate assessment.

Frank, W1NK
 
RE: Your Built-In Amplifier Pulser  
by N4KC on December 30, 2009 Mail this to a friend!
Good idea! I'm surprised nobody's thought of it already. Or maybe many have and just simply did not share it as Mike has.

I do have an alternative. I've trained the dog to howl at about 800 CPS. I can usually get a pretty good tune on the AL-811 before he runs out of breath and demands a treat.

Happy New Year and 73,

Don Keith N4KC
www.n4kc.com
www.donkeith.com
www.n4kc.blogspot.com
 
RE: Your Built-In Amplifier Pulser  
by N3JBH on December 30, 2009 Mail this to a friend!
Dog howling or Xyl about same result hi hi. Only benefit i seen is dog lays down and takes a nap after he gets his treat tried that with the xyl same result did not seem to work matter fact she howled much longer.
 
RE: Your Built-In Amplifier Pulser  
by W4VR on December 30, 2009 Mail this to a friend!
I've been using SS amps for the past 10 years. But, when I had tube amps I made my own pulser using an IC chip...it worked great using a peak reading wattmeter.
 
RE: Your Built-In Amplifier Pulser  
by N7BUI on December 30, 2009 Mail this to a friend!
Excellent idea Michael!
 
RE: Your Built-In Amplifier Pulser  
by WB2WIK on December 30, 2009 Mail this to a friend!
Good idea, and I've done this before.

But most of the time I just tune up on the fly, e.g., while I'm talking on SSB, or while I'm calling somebody on CW. Using a true PEP meter it's pretty easy. The only things I ever look at are output power and grid current. When the output hits max and the grid current is low, I'm happy -- and can usually do this in the course of just calling somebody.

Without a PEP meter it's a lot harder.

:-P
 
Your Built-In Amplifier Pulser  
by WA1RNE on December 30, 2009 Mail this to a friend!
I never had trouble with my built-in pulser: my foot

Proper tuning procedures and some experience are all you need - no fancy keyers required.

Tune your antennas at low power with the exciter, then tune the amplifier.


...WA1RNE
 
RE: Your Built-In Amplifier Pulser  
by K5END on December 30, 2009 Mail this to a friend!
"I'm in the minority. I'm all solid state, and the antennas are resonant. As a result, I don't tune.
Alan, KBG"

Oh c'mon, Alan.

Where is your sense of adventure?
 
RE: Your Built-In Amplifier Pulser  
by W3ATM on December 30, 2009 Mail this to a friend!
I use a wood whistle and it works great. I just blow into it and tune to the min SWR with the linear bypassed at low power but read the Palistar Manual Tuner Peak power/SWR meter and then turn on the linear and it is perfect.
 
Your Built-In Amplifier Pulser  
by KJ4EED on December 30, 2009 Mail this to a friend!
"E E E E"...
Thank you.
I like reading the comments.
 
Your Built-In Amplifier Pulser  
by K6ZSR on December 30, 2009 Mail this to a friend!
Hi Mike:

I set up my keyer like you said but when I went to tune up my Acom 2000A, I could not find the Tune and Load controls! ;-)

Mike
 
RE: Your Built-In Amplifier Pulser  
by W7ETA on December 30, 2009 Mail this to a friend!
Nice article.
Nice prose.

I cheat.
I wrote down the setting on a 3X5 card; one for the xmitter and one for the amp.

Maybe I could enter the digital era and record OOOOOOOOHSHAAAAAAAA on my computer and play that thru the mic to tune up?

Hi hi
73
Bob
 
RE: Your Built-In Amplifier Pulser  
by KC7NOA on December 30, 2009 Mail this to a friend!
Wow ... 5,500$$$$ for an amp .... the last car i bought - i paid only 120$$ for.

Bet that Acom 2000A is no effort at all to use.
 
RE: Your Built-In Amplifier Pulser  
by AD7VH on December 31, 2009 Mail this to a friend!
KC7NOA,

I bet it cost as much (over the of a course of a year) to feed that horse, uh... I mean dog that you have, as it does to buy a good amplifier!

John, AD7VH
 
RE: Your Built-In Amplifier Pulser  
by KC7NOA on December 31, 2009 Mail this to a friend!
lol no, and i happen to have 2 of them !!!!
 
RE: Your Built-In Amplifier Pulser  
by WG7X on December 31, 2009 Mail this to a friend!
Easy enough to do, if you have the right equipment.

I used to use the two-tone generator in my monitor scope to do the last tune up.

Now I set the built-in keyer in the rig to max (60 wpm) and use that.


Like Steve said, using a PEP meter helps, and I've also done just what he does, tuning up on-the-fly..

Not recommended but possible.

73 Gary
 
Your Built-In Amplifier Pulser  
by K6ZSR on December 31, 2009 Mail this to a friend!
KC7NOA:

Actually, the new cost today of an Acom 2000A is over $7,000. When I bought mine 4 years ago, they were $5500.The price on Eham.net reviews is way out of date.

So Let's do the math: $5500 divided by 4 equals $1375/yr. Which equals about $114 per month. My enjoyment and daily use of this amplifier, makes the $114 cost per month a bargain. Also, Each year my net cost of owning this beauty keeps decreasing! But the big difference is the quality & enjoyment keeps on going. I would bet that I will keep on enjoying this electronic marvel long after your $120 automobile is in the scrap heap.

Think value & quality, little grasshopper.
 
RE: Your Built-In Amplifier Pulser  
by K0IZ on December 31, 2009 Mail this to a friend!
I like the pecker circuit and built my own. Use with vintage KWM2A and LK800 Amp. The circuit has been around for 30 years or so.

Pulsing carrier, or sending dits, will also give a reduced duty cycle, as stated above. Fairly common to hear on the bands. However there is one difference as compared with pulsing audio: To send dits the radio must be in CW mode. Some radios will have different output in SSB mode vs CW. In such cases the pecker circuit will be a more accurate way to tune up, since radio will be in the SSB mode.

I personally prefer the pecker.
 
RE: Your Built-In Amplifier Pulser  
by WB6PWD on December 31, 2009 Mail this to a friend!
K0BG is all solid state?!? No carbon based metabolic activity at all? If he has a 555 timer he could probably duplicate any pulse required. OOPS! That could be taken more than one way. You're welcome ladies.
 
RE: Your Built-In Amplifier Pulser  
by N6AJR on December 31, 2009 Mail this to a friend!
I run the orion into the alpha 87 a and that goes into the steppir. no tune necessary, all resonant.

the pegasus runs into an als 600 and a LDG AT-1000 into the husstler 5btv so again no tune up but I do have to manually changes bands on the als600.

the ts2000 feeds into a TL922 and that does require a tune up into usually either the 5btv or the gap voyager.

the 746 pro goes into an IC-2KL and a AT 500 so it is also a no tune and no band switcher, but only a max of about 800 watts.

the ft 990 runs into an als 1200 and this does require a manual tune, and is the one I usually use for my second operator when doing a multi multi operation. this usually feeds either the 30/40/80/160 sloper or the steppir, what ever the orion is not on.

the ft 847 in th truck is feeding barefoot into a DK-3 so it is tuned by the antenna.

the ft 857 in the car feeds an ATAS 120 and it autotunes the antenna so again no tuning necesary.

I guess I am about 50/50 on tune / no tune setups, and I also reccommend a noe for low middle high for the settings on the amp and or tuner for the different antenna setups. notse get you close fast and then peak while operating.
 
RE: Your Built-In Amplifier Pulser  
by N6AJR on December 31, 2009 Mail this to a friend!
I run the orion into the alpha 87 a and that goes into the steppir. no tune necessary, all resonant.

the pegasus runs into an als 600 and a LDG AT-1000 into the husstler 5btv so again no tune up but I do have to manually changes bands on the als600.

the ts2000 feeds into a TL922 and that does require a tune up into usually either the 5btv or the gap voyager.

the 746 pro goes into an IC-2KL and a AT 500 so it is also a no tune and no band switcher, but only a max of about 800 watts.

the ft 990 runs into an als 1200 and this does require a manual tune, and is the one I usually use for my second operator when doing a multi multi operation. this usually feeds either the 30/40/80/160 sloper or the steppir, what ever the orion is not on.

the ft 847 in th truck is feeding barefoot into a DK-3 so it is tuned by the antenna.

the ft 857 in the car feeds an ATAS 120 and it autotunes the antenna so again no tuning necesary.

I guess I am about 50/50 on tune / no tune setups, and I also reccommend a noe for low middle high for the settings on the amp and or tuner for the different antenna setups. notse get you close fast and then peak while operating.
 
Your Built-In Amplifier Pulser  
by KC2POU on December 31, 2009 Mail this to a friend!
"However there is one difference as compared with pulsing audio: To send dits the radio must be in CW mode. Some radios will have different output in SSB mode vs CW. In such cases the pecker circuit will be a more accurate way to tune up, since radio will be in the SSB mode.

I personally prefer the pecker."


What he said. ^
 
Your Built-In Amplifier Pulser  
by WA7PRC on December 31, 2009 Mail this to a friend!
Just turn the Carrier or Power level control down on your rig... no pulser needed for initial adjustment. For best linearity (on SSB) during the final adjustment step, use a two-tone generator + oscilloscope.

Many hams who don't use a 'scope with their amplifiers would be surprised to see how awful their signals look from improper (insufficient) loading. W8JI touches on it here: http://www.w8ji.com/loading_amplifier.htm

73,
Bryan WA7PRC
 
Your Built-In Amplifier Pulser  
by ZL3AG on January 5, 2010 Mail this to a friend!
Sending a series of fast "E's" is a good method for pulsing your amplifier to keep the peak to mean ratio down for grid and plate current. But the ratio is 1:1, as in 50% not 30%. Using a rigs built in keyer, the E is a dit and the spacing between dits is the same length as the dit, so 50% duty cycle.

I have used the dits method and is fine but also have bult a 555 keyer with a 30% dutry cycle and it is better. The methodolgy only works if you have a true PEP capable power meter.

73
Eion
ZL3AG
 
RE: Your Built-In Amplifier Pulser  
by KD1MA on January 17, 2010 Mail this to a friend!
You cannot beat the 3898 Pecker for tuning up on SSB. Period! The rest are fine for CW.
 
Email Subscription
You are not subscribed to discussions on this article.

Subscribe!
My Subscriptions
Subscriptions Help

Other Recent Articles
WIA: Temporary Reassignment of Commercial Services into 70cm:
Army MARS at the ARRL Convention:
Skywarn Warriors: Radio Buffs Work Front Lines for National Weather Service
Amateur Radio Operators Descend on Civic Center for Annual Hamfest:
Ham Radio Users Could Be Vital Resource In Emergency: