Vintage Radios and Modern Headphones

I have a number of  pieces of “Vintage” Amateur Radio equipment that I have collected, repaired, and use regularly on the air.  A lot of my time on the air is on CW, or Morse code for the non ham readers out there, and I use headphones to copy weak CW signals from time to time.   Vintage headphones are not particularly comfortable to use and are hard to find and every harder to restore.  So I wind up buying modern stereo headphones to use on my newer equipment and also on these older tube type radios. That creates a problem.  These older radios are not the quietest things you want to hook to a pair of stereo headphones that have a wide frequency response.  There is high frequency hiss noises created in the tube circuits and 120 Hz hum from the unregulated power supplies.  Where modern amateur radio equipment has electronically regulated power supplies providing ripple free voltage for the circuits these older radios typically have a transformer with a full wave rectifier and high voltage filter capacitors to try to remove the ripple from the power that feeds the audio circuits.    That produces a small amount of hum in the speaker that becomes not so small when you connect a set of headphones to the radio.  So, what has that got to do with stereo headphones?  Well, first off they are stereo.  The older radios are all monaural, so some sort of plug in adapter is required to bridge right and left channels of the stereo phones to the monaural radio.  Second, there there is the hiss and hum, particularly the hum being a problem for me.  Modern stereo headphones are designed for very flat frequency response from below 50 Hz to 20,000 Khz.  I don’t want to be hearing all that directly coupled 120 Hz hum from my Drake 2-B into my new Koss headphones!

I hit upon the idea of putting a small audio passband filter in a 1/4 phone plug and build a passive filter for this application.  I cracked the books on basic filter design and came up with this circuit:


Click on the graphic to see a larger image

A passband filter is comprised of a Low Pass Filter and a High Pass Filter in series between the input side and the output side.  In this case I selected a low cutoff frequency of 400 Hz and a high cutoff frequency of 900 Hz.   I usually tune in CW signals at around 600 to 700 Hz so that makes the filter just right for CW work.  Since these are R (resistance) and C (capacitance) filters, I wanted to keep the resistor values low in this low impedance circuit to keep the loss of signal down.  Using the formula:


I selected 27 ohm resistors and calculated the capacitor values and then rounded them to standard values that I had in my parts box to get the circuit shown above.  The caps came out to be 6.5 microfarads for the Low Pass Filter and 15 microfarads for the High Pass Filter.

Not only did I want filter the audio I needed to convert from the typical 1/4″ Headphone jack that was used back in the day to a 1/8″ Tip/Ring/Shield that is commonly used on modern headphones.  I hit my local Radio Shack’s parts drawers and found a very old school 1/4″ plug that had a big fat pull handle on it.  It would give me plenty of room for my R/C components inside.  I did a bit of trimming on the ground side of the plug to give me a bit more room for the components, and everything fit nicely into the handle.  Here are a couple of pictures of the results:

Finished Filter Adaptor

Finished Filter Adaptor


Assembled Components

The results were quite good.  The hiss and hum is reduced by a considerable level making the copy of weak CW signals much better and reduces my fatigue by not having to listen to quite loud hum through the headphones.  All in all it was worth while project for a afternoon where it was too hot to do much outside!

RMS Express and the PK232

RMS Express is a program for sending Email via Amateur Radio via the Winlink network.  It has capability of sending Email over the internet, over a High Frequency (HF) radio link, or over a Very High Frequency (VHF) radio link via AX.25 Packet Radio.  This program is used by many of the hams that are in the Amateur Radio Emergency Service to send and receive Email messages while deployed in emergency situations.  The program works well, and its operation is almost automatic.  On HF it will use propagation prediction software select the best frequency to contact a radio gateway to the Winlink Network and send and receive email messages.

On VHF, using a Terminal Node Controller (TNC) and a VHF-FM transceiver the program will configure the TNC settings and make a connection to a gateway and send and receive emails with little intervention by the operator.  However, once you are done with the RMS Express software, and you want to go back to sending packet radio messages to other systems or to other Ham Operators, the settings that RMS Express had set in the TNC are still there.  Some of these setting need to be changed before you can perform keyboard communications.  This required typing a half dozen or so commands into the TNC, not a big task but none the less it has to be each time you open your terminal program after you have used RMS Express.

I wanted a way to reconfigure the TNC after quitting RMS Express.  I had the bright idea to set up a batch file in Winders to send the required settings for keyboard communications to the TNC via the Serial Port.  Well, I was able to get a batch to do that, but it didn’t work well.  I tried several different approaches in my batch file but I had no success changing the TNC.  The biggest of the problems was handling the carriage returns that are required for the TNC to process commands.  Each command string needed to be terminated with a carriage return (Enter Key).

Looking around the internet I found Plink, a add on to the PUTTY terminal program that I use for Keyboard Packet communications, but it is more geared toward automatically logging into remote systems than sending commands to a TNC.  Finally, I came across a utility called SerialSend at

Serial Send is a command line utility that will configure a serial port an send a string and control characters to it.  Just what I needed to do.  If you would like to give this utility a try, download the utility from the sight above and copy the serialsend.exe file into a folder that is in the system path.  This will make sure the program can be executed from any folder on the computer.  If you don’t know what your system path is, open a command window (click the start button, select the “run” command and type ‘CMD’ and press enter.)  and type “path” at the command prompt and press Enter.

Path Command Result

Path Command Result

You can see that the C:\windows folder is in the path, and that is a good place to copy the serialsend.exe file.

Once you have the serialsend.exe file in the C:\windows folder, test the path to the file, again from your command prompt, type “serialsend” to make sure the serialsend will execute.

Screen Shot 2016-04-30 at 3.27.16 PM

serialsend result

So now we have the program loaded test with a single command to the TNC from the command line.  Type:

serialsend /baudrate 9600 /devnum 16 /hex “alfdisp on\x0d”

This should open Com Port 16 (COM16), set the baud rate to 9600, and send the TNC command ‘alfdisp’ followed by a carriage return.  I am using the /hex option of serialsend to allow the insertion of a carriage return.  (hex 0D)  ALFDISP is the command to make the TNC send a line feed character to the terminal a the end of each line sent.  Check the command by opening your terminal program and type ‘alfdisp”, the TNC should reply ALFDISP is now ON.

Having success with one line, I put a series of TNC commands into a batch file to use serialsend to setup the TNC. Here is the batch file contents:

serialsend /baudrate 9600 /devnum 16 /hex “alfdisp on\x0dacrpack on\x0dmon 4\x0dmto all\x0dmfrom all\x0decho on\x0d”
c:\Users\Bob\Desktop\putty -load PK232COM16

There are three lines to the file. (note: on your screen the first line may be wrapped)  The first line invokes the serialsend utility setting the baudrate 9600 on COM16 and sending a string that contains hex coded characters.  The string is inside the quotes.  The next line starts my terminal program, PUTTY, and opens a profile named PK232COM16 with the -load command.  The last line, exit, will close the command window after the PUTTY program is closed.  Use Notepad to create the file above and save it as ‘packetsu.bat’ in your documents folder.

That’s it.  I can run RMS Express and do my emails.  Then run the ‘packetsu.bat’ and configure the TNC for keyboard communications and open the PUTTY terminal program.  Put a shortcut to the packetsu.bat file on your desktop and you can open the terminal and be ready to communicate with one click of the mouse!


Who’s on First?

Here is a really good explanation of how the Obama Administration counts unemployment.

COSTELLO: I want to talk about the unemployment rate in America .

ABBOTT: Good Subject. Terrible Times. It’s 5.6%.

COSTELLO: That many people are out of work?

ABBOTT: No, that’s 23%.

COSTELLO: You just said 5.6%.

ABBOTT: 5.6% Unemployed.

COSTELLO: Right 5.6% out of work.

ABBOTT: No, that’s 23%.

COSTELLO: Okay, so it’s 23% unemployed.

ABBOTT: No, that’s 5.6%.

COSTELLO: WAIT A MINUTE. Is it 5.6% or 23%?

ABBOTT: 5.6% are unemployed. 23% are out of work.

COSTELLO: If you are out of work you are unemployed.

ABBOTT: No, Obama said you can’t count the “Out of Work” as the unemployed. You have to look for work to be unemployed.


ABBOTT: No, you miss his point.

COSTELLO: What point?

ABBOTT: Someone who doesn’t look for work can’t be counted with those who look for work. It wouldn’t be fair.

COSTELLO: To whom?

ABBOTT: The unemployed.

COSTELLO: But ALL of them are out of work.

ABBOTT: No, the unemployed are actively looking for work. Those who are out of work gave up looking and if you give up, you are no longer in the ranks of the unemployed.

COSTELLO: So if you’re off the unemployment roles that would count as less unemployment?

ABBOTT: Unemployment would go down. Absolutely!

COSTELLO: The unemployment just goes down because you don’t look for work?

ABBOTT: Absolutely it goes down. That’s how it gets to 5.6%. Otherwise it would be 23%.

COSTELLO: Wait, I got a question for you. That means there are two ways to bring down the unemployment number?

ABBOTT: Two ways is correct.

COSTELLO: Unemployment can go down if someone gets a job?

ABBOTT: Correct.

COSTELLO: And unemployment can also go down if you stop looking for a job?

ABBOTT: Bingo.

COSTELLO: So there are two ways to bring unemployment down, and the easier of the two is to have people stop looking for work.

ABBOTT: Now you’re thinking like a Democrat.

COSTELLO: I don’t even know what the hell I just said!

ABBOTT: Now you’re thinking like Hilary. So now you know why Obama took over Labor STATS from the LABOR Dept when he got in office.

Drake 2-NT Transmitter Re-Cap

I really love the older “Vintage” ham radio gear.   I especially like the Drake radios.  Drake produced some really fine radios, but went out of the Ham Radio business in the 1980’s. The radios are still great radios and perform nearly as good as some of the very latest ham radios made today.  In particular I find the 2-B to be an absolute wonderful CW (Morse Code) receiver.  There is something about the receiver’s AGC (Automatic Gain Control, also known as the Automatic Volume Control) that is just hard to beat on CW.  I have had three 2-B receivers over the years.  Not sure why I sold them but I did, and then I wind up wanting another one.  I will try to hang on to the one I have now.

Recently I acquired a “new” addition to the collection, a Drake 2-NT CW Transmitter.  I was always thought that these small “Novice” transmitters were very neat. One of the really nice features of the 2-NT is that it works well with several of the Drake receivers such as the 2-B, the 2-C, and the R-4 series of receivers.   It also has built in antenna switching, receiver muting, and CW Sidetone as well as being able to do semi-break-in keying.  All you have to do to send is hit the key and it switches to transmit and mutes the receiver for you.

Drake 2-NT CW Transmitter

Drake 2-NT CW Transmitter

I wanted to put together a vintage CW station, something that would be what a Novice station of years ago might be and it seemed that the Drake 2-B receiver and the 2-NT transmitter would be a great pair. I was using a Johnson Ranger with the 2-B for CW, but the Ranger is a very big and heavy transmitter for a 75 Watt (power input to the final amplifier stage) novice transmitter.  Plus, it was clunky to operate, it was not setup for semi break in keying.  Now, I like vintage, but let’s get real, I want to be able to actually use the rig the way I am used to working CW.

After checking out the 2-NT I found that there was a little hum on the transmitted signal.  This transmitter is close to 40 years old, and in these older radios one of the things that needs attention, besides the tubes, is the Electrolytic Capacitors.  The electrolytic capacitors are used as power supply filter caps, so when you see hum on the signal you can bet that the caps are going bad.  The electrolyte in the capacitors drys out over the years and the filter caps don’t do a good job of filtering the rectified AC power into pure DC voltage.  So I decided to “recap” the 2-NT with new, fresh, electrolytic capacitors.

Most of these older rigs used what were called “Can” capacitors.  The can contained several large value capacitors in a single chassis mounted aluminum can.  (I.E. the name Can Capacitors)  With the advent of solid state electronics these high voltage can capacitors have gone away.  They can be had from specialty suppliers like, but they can be pricey.  Since there was plenty room under the chassis for axial leaded capacitors,  I elected to go with them for this re-cap.  They work just as good and without pulling the bottom cover off the radio you would never know the difference.

Here is what we started with:


Before – Click on image to see a larger version

There are three capacitors in the can, a 60 uF for the “bottom” half of the voltage doubler for the High Voltage supply to the final, an additional 40 uF for the low voltage filter, a 20 uF for the screen voltage supply for the final.  There are a couple of axial leaded caps, one 60 uF 450V for the “top” half of the voltage doubler and a smaller 20 uF cap for the negative bias supply.   In shopping for caps, I found that you can’t always get the exact replacement.  I had availability of 80 uF for the HV and LV supply, (originally 60 uF) and 22 uF to replace the original 20 uF caps.  I ordered the caps from and had them in two days.

The can capacitor has lugs on the bottom that are very convenient for wiring, the leaded caps needed something to be wired too.  So, I added two terminal strips.  The first one I soldered to the chassis where the cap ground leg was soldered.  That strip had one ground, and three open terminals.  I moved the original wires from the can to the open terminals then wired the axial caps to them.   I added one more ground terminal under one of the screws for the power transformed and wired the ground end of the 40 uF and 80 uF caps to it.  The the final cap was the 22uF for the bias supply, the positive side goes to the ground on the 4 terminal strip and the negative lead to the circuit board where the original cap was wired.

So, after it is wired up this is what we have:

After - Click image to see a larger version

After – Click image to see a larger version

One final thing, on the cap for the “top” of the voltage doubler the capacitors case is at +300 Volts from ground.  The new caps have a very thin plastic coating on them and I felt that the coating my break down under that voltage where the metal clip holds the capacitor.  So, I trimmed a small part of the original cap’s cardboard cover and slipped it over the new cap where it contacts the metal clip.  Just to be safe…..rather than sorry.

I double checked my wiring, did a few checks with an ohmmeter tests just to make sure I had everything wired correctly and then turned it on.  It worked great.  The power supply hum was gone and it has a nice clean signal now.  The ole 2-NT is ready for many more years of service on CW.

Here is the “new” novice CW station:

Novice Station - Click on image to see a larger version

Novice Station – Click on image to see a larger version

On the left is the Drake 2-NT Transmitter, in the center is a Hallicrafters HA-5 VFO (late 50’s vintage), on the right is the Drake 2-B Receiver and the Drake 2-BQ Speaker and Q-Multiplier.  This novice CW station is much nicer than my original novice station back in 1965, which consisted of a Knight Kit R-100A receiver (that I built as a kit) and a homebrew (home built) 75 watt transmitter.  The transmitter had three tubes, was built into a black wrinkle finished Bud Box purchased from Allied Radio.  Looked right out of the late forties!

If you are into CW, check into the Sunrise Net on 7.123 kHz.  The Sunrise Net is a daily CW net that starts at 1300 UTC seven days a week.  QNI and say GM to the net!

Bill Clinton’s Loving Wife

Bill Clinton’s Loving Wife

By Dick Morris, former political advisor to President Bill Clinton

If you happen to see the Bill Clinton five minute TV ad for Hillary in which he introduces the commercial by saying he wants to share some things we may not know about Hillary’s background, beware as I was there for most of their presidency and know them better than just about anyone.  I offer a few corrections:

Bill says:  “In law school Hillary worked on legal services for the poor.”

Facts are:  Hillary’s main extra-curricular activity in ‘Law School’ was helping the Black Panthers, on trial in Connecticut for torturing and killing a ‘Federal Agent.’  She went to Court every day as part of a Law student monitoring committee trying to spot civil rights violations and develop grounds for appeal.

Bill says:  “Hillary spent a year after graduation working on a Children’s rights project for poor kids.”

Facts are:  Hillary interned with Bob Truehaft, the head of the California Communist Party.  She met Bob when he represented the Panthers and traveled all the way to San Francisco to take an internship with him.

Bill says:  “Hillary could have written her own job ticket, but she turned down all the lucrative job offers.”

Facts are:  She flunked the D.C. bar exam, ‘Yes’, flunked it, it is a matter of record, and only passed the Arkansas bar.  She had no job offers in Arkansas, ‘None’, and only got hired by the University of Arkansas Law School at Fayetteville because Bill was already teaching there.  She did not join the prestigious Rose Law Firm until Bill became Arkansas Attorney General and was made a partner only after he was elected Arkansas Governor.

Bill says:  “President Carter appointed Hillary to the Legal Services Board of Directors and she became its Chairman.”

Facts are:  The appointment was in exchange for Bill’s support for Carter in his 1980 primary against Ted Kennedy.  Hillary then became chairman in a coup in which she won a majority away from Carter’s choice to be chairman.

Bill says:  “She served on the board of the Arkansas Children’s Hospital.”

Facts are: Yes she did.  But her main board activity, not mentioned by Bill, was to sit on the Wal-Mart Board of Directors, for a substantial fee.  She was silent about their labor and health care practices.

Bill says:  “Hillary didn’t succeed at getting health care for all Americans in 1994 but she kept working at it and helped to create the Children’s Health Insurance Program (CHIP) that provides five million children with health insurance.”

Facts are:  Hillary had nothing to do with creating CHIP.  It was included in the budget deal between Clinton and Republican Majority Leader Senator Trent Lott.  I know; I helped to negotiate the deal.  The money came half from the budget deal and half from the Attorney Generals’ tobacco settlement.  Hillary had nothing to do with either source of funds.

Bill says:  “Hillary was the face of America all over the World.” (LOL)

Facts are:  Her visits were part of a program to get her out of town so that Bill would not appear weak by feeding stories that Hillary was running the White House.  Her visits abroad were entirely touristic and symbolic and there was no substantive diplomacy on any of them.

Bill says:  “Hillary was an excellent Senator who kept fighting for Children’s and Women’s issues.”

Facts are:  Other than totally meaningless legislation like changing the names on courthouses and post offices, she has passed only four substantive pieces of legislation.  One set up a national park in Puerto Rico.  A second provided respite care for family members helping their relatives through Alzheimer’s or other conditions.  And two were routine bills to aid 911 victims and responders which were sponsored by the entire N.Y. delegation.  Presently she is trying to have the US memorialize Woodstock.

Here is what bothers me more than anything else about Hillary Clinton.  She has done everything possible to weaken the President and our Country (that’s you and me) when it comes to the ‘War on Terror’.

  1. She wants to close GITMO and move the combatants to the USA where they would have access to our legal system.
  1. She wants to eliminate the monitoring of suspected Al Qaeda phone calls to/from the USA.
  1. She wants to grant constitutional rights to enemy combatants captured on the battlefield.
  1. She wants to eliminate the monitoring of money transfers between suspected Al Qaeda cells and supporters in the USA.
  1. She wants to eliminate the type of interrogation tactics used by the Military & CIA where coercion might be used when questioning known terrorists even though such tactics might save American lives.

One cannot think of a single ‘Bill’, Hillary has introduced or a single comment she has made that would tend to strengthen our Country in the ‘War on Terror’.  But, one can think of a lot of comments she has made that weaken our Country and makes it a more dangerous situation for all of us.  Bottom line: She goes hand in hand with the ACLU on far too many issues where common sense is abandoned.

Share this with everyone you know, ask them to prove Dick Morris wrong.  Think about it – he’s (Dick Morris) said all of this openly, thus if he were not truthful he’d be liable for ‘Defamation of Character’ !

And you better believe Hillary would sue him.

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