RE: [AMRadio] GG 813 Linear in GE Ham News
I have an SB200 linear and on AM it is equivalent to a DX100. I increased the bias on it so to the point just beyond cutoff for AM so that it requires a little more to drive and it reaches negative 100% modulation slightly before the driver does. But this seemed to help the modulation linearity and efficiency just a little. That's an old trick that I first read about in a 1930's RADIO article. Overbias the AM linear to increase the negative peak modulation percentage. It also can have a distortion advantage, especially if the modulator driver stage uses grid modulation. Most grid modulated finals become nonlinear near 100% negative modulation, or are simply incapable of cutting the carrier off completely, so to maintain good modulation linearity, limit the modulation to 90% or less in the negative direction, then overbias the linear output stage until the negative peaks in the output reach near 100%. This will retain modulationr linearaty on negative peaks and reduce overall distortion levels.
RE: [AMRadio] Ever seen this?
I crank the VariAC down to 0V, apply excitation again, and "HOLY CRAP! WHAT'S THAT?" The recently installed 250TH, with just 35 or so watts of grid drive looked like an 866 rectifier, under full load! A translucent 'blue glow' appears all around the inside of the glass envelope, with grid-drive applied. What causes that? Is the tube good? This 250TH hasn't seen air in about 5 years (since I got it) and appears to be brand-new. Can't tell that it was ever inserted into a socket, before today. The 250TH is gassy. That's not uncommon with the Eimac type tubes that have been sitting idle for a number of years, even if the tube has never been used. If it is gassy enough to glow blue inside just from grid excitation, it it beyond hope. Don k4kyv
Re: [AMRadio] AM and FT-101E?
"Can anyone tell me the fundamental difference between an FT 101 EE and FT 101 F in 25 words or less?" I believe the F model has all the previous 101 mods and the F model has a different power regulator card. 73, Ken W2DTC
[AMRadio] AM Mods for FT 101 series
FT-101 Audio Modifications Transmit Modifications PB-1315: # Change R2 from 47k to 4.7 M for crystal mic (D-104, etc.) # Add 100 pF in parallel with R2 to bypass RF. # Change C2 from 10 uF to 150 uF. # Change R3 from 4.7k to 1.5k. # Change C5 from 1 uF to 10 uF. # Change C3 from 0.047 uF to 0.001 uF disc ceramic. # Change C7 from 1 uF to 10 uF. # Change C8 from 22 uF to 150 uF. # Change C9 from 0.01 uF to 0.001 uF. # Change C11 from 2.2 uF to 22 uF/35V . PB-1184A: # Change C12 from 0.22 uF to 2.2 uF (+ towards R7/8/9 )(use C11 removed from PB-1315). # Change C2 from 0.01 uF to 0.001 uF. # For high level auxilliary input from tape deck or other source cut L36 from pin 5 and connect to pin 4 of PB-1315 board. Receive Modifications First and foremost, the narrow SSB IF filter makes signals through the receiver sound very muffled. Fortunately, there is an aftermarket 6 kHz wide AM filter available for the FT-101/B/E/F series from: International Radio and Computer, Inc. 3804 South U.S. 1 Fort Pierce, FL 34982 Phone: (407) 489-0956, FAX: (407) 464-6386 The filter is the Fox-Tango #2011. Price as of January 1993 is $75.00 plus shipping. The filter is installed in place of the CW filter, with some minor circuit changes so that the 6kHz filter is in circuit when the mode switch is placed in the AM position. The SSB filter remains in the FT-101 and is used in the SSB and CW modes. PB-1315: # Change C45-from 0.1 uF to 10 uF/25V electrolytic (+ towards base of Q9). # Remove C39 0.047 uF. # Change C43 from 0.01 uF to 10 uF/25V electrolytic (+ towards Q9). # Change C44 from 220 uF to 750-1000 uF at 10V. # Change C40 from 33 uF to 150 uF. Cheers Ron W6OM
[AMRadio] AM and FT-101E?
Can anyone tell me the fundamental difference between an FT 101 EE and FT 101 F in 25 words or less? Thanks Ron W6OM
Re: [AMRadio] AM sensitivity value: FT-101E?
Jose: Back in the mid 90s I talked to a guy in Pauls Valley, OK who had an FT 101E. He had made modifications to his for better audio, but I don't know if they mirror what you saw. Recently another friend in Amarillo, TX bought another transmitter and sold FT 101E. It also sounded very good on the air. I agree with Paul, they can sound very good with minor changes. 73 Jim W5JO - Original Message - From: "Jose HF Silva" <[EMAIL PROTECTED]> To: Sent: Thursday, October 06, 2005 12:43 PM Subject: [AMRadio] AM sensitivity value: FT-101E? Dear Paul, WA3VJB I took very seriously your references to the capabilities of improved FT-101E: "The older Yaesu FT-101E can also be made to sound very good, and the purchase price for used gear like this is less than $400. Here's Frank's example of the transceiver: http://www.wa3vjb.com/sound/WY3D-Demo.mp3"; and passed this to some colleagues over here, to inform them and convince them to join in and help to broaden the AM enthusiasm. But nobody believes that such a sound could be produced by a FT-101E! Is there some misunderstanding? Is this just a personal recordind of Frank speaking... or is it a real recording of Frank's modulation by his FT-101E being received by you (or someone else)? Please help us to come out of this kind of "hoax", saving the face and the real value of FT-101E ;-) Thank you 73 de José Silva CT1AXG
Re: [AMRadio] AM sensitivity value: FT-101E?
Jose, No hoax. With the proper mods, the FT-101E can produce great audio. With a small amount of equalization, the FT-101E can make HI-FI audio. I ran an FT-101EE for over a year with great audio reports. I recently switched to a Viking II, for no reason other than I wanted to make a change. 73, Ken W2DTC __ Ken Barber Middletown, NJ Radio Website: http://w2dtc.com Family Photos: http://kenw2dtc.home.comcast.net __ - Original Message - From: "Jose HF Silva" <[EMAIL PROTECTED]> To: Sent: Thursday, October 06, 2005 1:43 PM Subject: [AMRadio] AM sensitivity value: FT-101E? Dear Paul, WA3VJB I took very seriously your references to the capabilities of improved FT-101E: "The older Yaesu FT-101E can also be made to sound very good, and the purchase price for used gear like this is less than $400. Here's Frank's example of the transceiver: http://www.wa3vjb.com/sound/WY3D-Demo.mp3"; and passed this to some colleagues over here, to inform them and convince them to join in and help to broaden the AM enthusiasm. But nobody believes that such a sound could be produced by a FT-101E! Is there some misunderstanding? Is this just a personal recordind of Frank speaking... or is it a real recording of Frank's modulation by his FT-101E being received by you (or someone else)? Please help us to come out of this kind of "hoax", saving the face and the real value of FT-101E ;-) Thank you 73 de José Silva CT1AXG __ Yahoo! Mail - PC Magazine Editors' Choice 2005 http://mail.yahoo.com __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami
RE: [AMRadio] Eq sale
I have put an HTX-100 SSB/CW rig up for sale now on the website http://wa5bxo.shacknet.nu/mick-KAN%20stuff/ Please send your bids to [EMAIL PROTECTED] or [EMAIL PROTECTED] Thanks, John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John E. Coleman (ARS WA5BXO) Sent: Saturday, October 01, 2005 8:15 PM To: 'Discussion of AM Radio' Subject: [AMRadio] Eq sale Some of you may remember Mick, WA5KAN, who past away a few months ago. I have been asked to sale his equipment. I will be placing pictures and a text file on the server location below. There will be a separate folder for each piece of equipment. The first I have done is the Tentek transceiver that he was using. I will place more up as time permits. http://wa5bxo.shacknet.nu/mick-KAN%20stuff/ Please send your bids to [EMAIL PROTECTED] Thanks, John, WA5BXO __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net AMfone Website: http://www.amfone.net AM List Admin: Brian Sherrod/w5ami
[AMRadio] AM sensitivity value: FT-101E?
Dear Paul, WA3VJB I took very seriously your references to the capabilities of improved FT-101E: >"The older Yaesu FT-101E can also be made to sound >very good, and the purchase price for used gear like >this is less than $400. Here's Frank's example of the >transceiver: >http://www.wa3vjb.com/sound/WY3D-Demo.mp3"; and passed this to some colleagues over here, to inform them and convince them to join in and help to broaden the AM enthusiasm. But nobody believes that such a sound could be produced by a FT-101E! Is there some misunderstanding? Is this just a personal recordind of Frank speaking... or is it a real recording of Frank's modulation by his FT-101E being received by you (or someone else)? Please help us to come out of this kind of "hoax", saving the face and the real value of FT-101E ;-) Thank you 73 de José Silva CT1AXG __ Yahoo! Mail - PC Magazine Editors' Choice 2005 http://mail.yahoo.com
