The Shop Web Cam Page
"Life is too short for QRP, turn on the glow and QRO..."
Here is where I spend my time with Radios, HF Amplifiers and Tuners.
Note...The shop is for sale.
IF THE VIDEO IS NOT RUNNING YOU WILL SEE A BLANK WINDOW. THIS PAGE IS NOT LOCATED ON WWW.RFAMPGUY.COM
This is my place...a "man cave", not a "pussy basket" the fridge is full of 16 oz. soda and beer. There is 240 VAC laying
on the floor and solder spattered everywhere. Most of my tools can be classified as weapons. My "hammer" is a WMD...
Don't come here expecting to see Martha Stewart...she left the building with Elvis!! Get it on...
The main shop is dedicated to amplifier repairs with test gear that includes scopes, spectrum analyzer, several VTVM and
DVM, with several High Voltage probes up to 5KV. The use of a digital SSG and broadband receiver allows me to carefully
look at the final signal with full power drive applied. I use two 50 OHM dummy loads and a third, 3:1 load to test the amp RF
deck under load. My final tests are done on 40 Meters. I use a TS-520 and TS-180S to test drive the amplifiers in service.
There are several scopes, a hy-pot testing unit, amplifiers, computers, Wheatstone bridge, antenna analyzer, decade boxes,
audio generators (2), counters (2), GP signal generator, wattmeter (2), and all kinds of parts for repair work and building.
Yes, I also have "dummy load" equipment (3)...I do not test amplifiers into an antenna. That is simply ignorance...
All about using an amplifier:
Several items must be considered. Those include available AC mains, power handling capabilities of antennas, tuner and
the driving power from the exciter. Of less importance, but certainly a consideration, air flow around the amplifier and the
proper location on the desk or bench. I mention this because many desktop amplifiers can inject heavy 120 cycle hum into
nearby equipment. Microphone cables, audio mixers and even the exciter itself can be suspect to picking up the magnetic
fields of these powerful transformers, even though they are inside a cabinet and shielded. The SB-220 is one such cabinet
that tends to radiate 120 cycle hum into nearby equipment.
This is one reason why I like separate power supplies for amplifier and radio. Drake always had a better idea...
Parasitics can be traced using the spectrum analyzer and broad band receiver while monitoring frequencies up to and above
150 MHz. These little gremlins can cause un-announced arching and destroy tubes, components and meter circuits instantly.
They tend be more evident when running multi-tube amplifiers on higher frequencies above 21 MHz. The 3-500Z has been a
long time parasitic monster, but there is a TRUE fix for these problems and it is NOT only the parasitic chokes!!! Forget the
"fancy measures" way, just keep it short, simple and to the point. (KISS)
Most distortion products are a result of the exciter and not the amplifier. The single tube amps are better at controlling these
harmonics and spurious signals than multiple tube amplifiers. However a well designed amplifier with a good "Q" in the final tune
circuit can do more to control IMD than anything else. Since tube circuits are not "broadband" like solid state, it is highly
recommended that an antenna tuner be incorporated into the HF signal chain. This is more important when the station includes
an early amplifier that simply uses a ".01" capacitor to feed the cathode or grids (tetrode). Placing a small 100W tuner into
the CHAIN before the amplifier maintains a good SWR curve and insures the solid state exciter will perform properly. In many
of the older amplifiers the SWR would swing from 2:1 to as highs as 4:1. This swing will certainly shut down most solid state
radios. The alternative is a separate tuned input circuit. I custom build these for users of the Dentron, Gonset, Swan Mark and
most all that use the ".01" input circuits.
No matter what input circuit, the antenna tuner after the tube amplifier is a must for signal quality assurance.
ALC...I do not believe! I am sorry, but I laugh every time I hear some operator discussing ALC and a solid state exciter. Not
required...do not use the ALC line to a solid state radio. Perhaps it is time to think "outside" the box. Most "grounded grid"
amplifiers that were built 25 years ago simply do not support today's modern radios. The ALC circuit in the exciter will take
care of itself. Set the RF POWER out control to the desired drive and let the internal ALC do it's job.
If you have a monitor scope and you are not exceeding iG (grid current) there should be no problems. Every serious Ham operator
should have a scope in the shack, you can see that"flat top" pattern plain as day. This is generally caused by over-driving the amp.
In most cases, "flat topping" is a result of OVER-MODULATING. Over Modulation is a result of microphone settings and poor ALC
at the exciter level. Did you realize "compression" can, and often causes "flat topping"? Leave the power level where it should be
according to the amplifier specifications. and back off on the audio gain. Stop beating the snot out of your finals. You will soon
find out that you don't have to "over-drive" in order to be heard in Lower Tazmania.
Hey, you might consider replacing that G5RV with a real antenna. Next time try a loop...no traps, no kidding!
NOTE: There is an external ALC circuit that can be added at the output of your amplifier. It works more effectively and does not
use amplifier ALC lines. The unit is a home brew project.
ESSB Audio...These are the same guys who bitch about you being 4 KHz wide when they open up their radios to 6 KHz wide audio.
The rule, according to the FCC is no more than 3KHz wide or 1 to 3000 cycles of audio spectrum on either side of the passband.
That should cover all the different types of voice impressions from childhood (innocense) to adult male (high end ego) and all the YL
operators in between. So what are you gaining from ESSB?? Nothing is the correct answer. You are simple creating splatter, IMD
and spurious harmonics all over the radio spectrum. You have gained nothing...not one ounce of power, not one pound of HI-FI. You
see, the average Joe operator on the other end has his radio set to 2.7 KHz wide USB or LSB, depending. That means he is listening
to the "upper" or "lower" end of a 6KHz wide receiver bandpass. He does not hear all of your 6KHz signal. You push out that audio
and he hears only half (1/2, .5, 50%) of the result. You don't believe me(?) well look at it on the scope (there is that word again).
A scope will tell you what some of us already know. Audio is controlling the RF output. If you push out 6000 cycles and I filter out
3000 cycles of it, I am hearing you "half as loud" as you really are. Does that explain it Bunky? Unless Joe can open up his receiver
to 6KHz wide, he ain't going to hear those "hissy fits" or "thumping blows" as they were adjusted to when you cranked up the knobs
on your fancy EQ. It is not going to happen (period). Oh, while I am at it...what do you do with those pots that range from 7000 to
20,000 cycles? I mean, write me and let me know how effective they are on SSB. ESSB is for IDIOTS!
What you should do is work for a "flat" (average Joe) response from 200 cycles to 2800 cycles. Get the most out of that spectrum
so the final stage output can deliver all your energy into the receiver on the other end. Why do you piss away half your power?
Ignorance would be my first thought. Stop trying to put 10 pounds of shit into a 5 pound bag. believe it or not, if you have not
changed the IF filters from the standard 2.8 to 6.0, well the radio is not putting out 6 KHz anyway, no matter how you try.
The device is a BALANCED MODULATOR and that means half upper and half lower...by 2.8 KHz or less. Remember the old Drakes
at 2.4 KHz?
Oh, FYI...God gave you your vocal cords. Some were born with "Walter Cronchitis" others were born with our diapers way too
tight. Believe this, there is no EQ anywhere that is going to fix your God given voice...stop trying...be yourself, adjust to your voice
and take advantage of the cords you were blessed with. Otherwise...try some hormone pills, that might get the job done.
Over-driving...Take a minute and understand this if you can...a "grounded grid" amplifier generally speaking is about 55% efficient.
You can't get much more than 55% out of a glass tube. You can't do much better than 65% out of ceramic tubes unless you prep the
amp for a "narrow band" (high Q) application. That means a tuned input for every band, not just a freekin' .01 cap. Same goes for the
output stage. The one coil two cap, Pi-Net output tank is not effective for more than 60% max. So stop trying to get more out of the
amp than the manufacturer implies in the owners manual. Most amplifiers are better suited at 40 meters. The RF deck is tuned
by design to operate above or below 7 MHz, it is a compromise. Don't expect 1KW out of an amplifier on 10 meters if you can't get
1200 out on 40. Hell, even the best solid state amp can't do that if it is tuned as a "broad band device". This leads me to this single
comment "stop over driving"...it won't make a damn difference on the other end if you put 20 more watts into an amp that is already at
This is why I say...use a TUNER and monitor with a SCOPE. You will tune the amplifier more efficient and have better results
and increased tube life...
Tune up procedures...First rule of thumb: Don't start with full power. Set the exciter to the maximum drive you intend to use on your
amplifier. Now tune the antenna tuner so the SWR is flat. If you don't have a tuner behind your amp...get one. There is little loss in
an antenna tuner and it does wonders on the receive signal to noise ratio. But I digress...now that the SWR is flat, turn down your
exciter level to 10 or 20 watts. Key up in CW and tune the amplifier using manufacture specifications. Forget that "dip and load"
bullshit you learned from some website, tune the PLATE variable quickly and watch the SWR meter in the FORWARD position. Now advance
the ANTENNA tune variable for an increase in power. Stop advancing when the output falls off, then readjust the PLATE variable. You are
tuning for MAXIMUM linearity. This is easily done while monitoring your RF output on a scope (oh no not again). Ok you have how much
output? Want more? Advance the exciter output...watch the FORWARD power while watching AMPLIFIER GRID CURRENT. Stay within the
specified directions as given in your users manual for the amplifier. Now flip to SSB and talk...have fun.
One thing to remember...if iG is too high, try adding some more LOAD into the PA. If you cannot add LOAD, back off ANTENNA TUNE and
then increase LOAD.