Re: [AMRadio] Ranger driving SB220
>It is also easy for the modulator to over modulate because it doesn't need to deliver as much current. John, WA5BXO This is probably the main cause of trouble using an amp with a driver as described. I constantly hear crappy audio on the bands with the configuration. Many do not understand meter readings of Class A, AB and B amps anyway so they tend to overdrive them with audio. Not only that they do not monitor the output waveform. Additionally many do not know how to interpert what they see. So all in all, I believe, the best way to avoid hidden troubles is to operate an exciter or transmitter is near its design parameters and reduce power with the attenuator. Last night was a perfect example. One station who was using a solid state exciter to drive a tube amp was splattering all over the place and the person (s) he was in contact with could not hear the problems. If they did, they either wouldn't tell him or did not know what was happening. I was about 5 kc below and when I heard the buckshot tuned up to see who it was. They were all telling him that he sounded fine and what the meters should read. Wrong of course. All this assumes the exciter is operating properly. That can be a crap shoot with a lot of this old gear. Especially a transmitter pulled from a barn and put on the air with mimimual rework. Jim/W5JO __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Ranger driving SB220
Hi Jim, Yes, if you change the loading so as to draw less current in the final then the modulation circuit will see higher impedance. In this case, the change to a higher Z load for the modulator is not a bad thing. Audio out put stages will generally produce cleaner audio when they don't need to work so hard at delivering the current. It is easier for them to get the modulation audio voltage necessary for 100 percent modulation when the impedance they see is higher and less current is on demand. OTOH, lowering the voltage to the final (only the final) with out changing the loading will reduce current and voltage so that the load resistance that the modulator sees is the same as before. But less modulation voltage will be required to hit 100 percent of the new DC voltage. The thing to watch on tetrode finals is the screen current. As you reduce the loading on the plate the screen current will rise. This is not to bad (although worth looking in to) if the screen gets its DC and modulation from the plate supply point, but if there is a separate screen supply then you will need to adjust it down to prevent excessive screen current. All in all, the best way to reduce power for a driver /linear combo is to reduce the plate / screen supply voltage for the driver final only, via a dropping resistor or a separate power supply for that tube only. There are other considerations about reducing the load on a final, as the RF voltage at the plate of the tube will increase and may cause arcing of the plate tuning cap or some other component. It is also easy for the modulator to over modulate because it doesn't need to deliver as much current. John, WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Wilhite Sent: Tuesday, February 12, 2008 8:16 AM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] Ranger driving SB220 I see this discussion every so often and wonder something. If you lower the plate voltage or current the final (s) draw, what is happening to the impedance the modulation transformer sees? The design of a class C final looks at the plate load impedance of the final. If you alter that, the modulation transformer sees another impedance and may not work properly. Some instruction manuals point this out in them. The manual for my Globe Champ says to load to 320 ma. plate current @ 1kv. In another paragraph it says to load the plate current to no less than 275 ma. for the reason specified, plate load impedance. So it seems to me that one would want to load a driver to the proper output designed into the rig. If you need less driving power then dissipate with the attenuator like Johnson built or build an exciter for the power level you need. Another approach I have seen is to feed the transmitter into a dummy load with a T connector and use the other T output to go the an amplifier input. The HT 32/37/44 are low power and can be used easily to drive an amp. They only give about 25 watts out which is about right for most amps. The bad thing about sloppy modulation from an exciter is that a Class A, AB or B amp will just amplify it and you really don't want that going out over the airwaves. Jim/W5JO __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Ranger driving SB220
I see this discussion every so often and wonder something. If you lower the plate voltage or current the final (s) draw, what is happening to the impedance the modulation transformer sees? The design of a class C final looks at the plate load impedance of the final. If you alter that, the modulation transformer sees another impedance and may not work properly. Some instruction manuals point this out in them. The manual for my Globe Champ says to load to 320 ma. plate current @ 1kv. In another paragraph it says to load the plate current to no less than 275 ma. for the reason specified, plate load impedance. So it seems to me that one would want to load a driver to the proper output designed into the rig. If you need less driving power then dissipate with the attenuator like Johnson built or build an exciter for the power level you need. Another approach I have seen is to feed the transmitter into a dummy load with a T connector and use the other T output to go the an amplifier input. The HT 32/37/44 are low power and can be used easily to drive an amp. They only give about 25 watts out which is about right for most amps. The bad thing about sloppy modulation from an exciter is that a Class A, AB or B amp will just amplify it and you really don't want that going out over the airwaves. Jim/W5JO Ron, Yes, the VKII uses a pair of 6146s and it has a 6AQ5 adjustable screen clamp tube. I see no reason to wast power with an attenuator and there is a sweet spot in the final current thru the mod iron that requires a less than full rated final current to avoid saturation. It seems to me that a fine adjust here would allow power reduction for use with an amp and also enable fine tuning the final current without reducing optimum drive current when used barefoot. Just an idea. I like the ability of the DSB transmitters like the HT 37, FT101,etc to lower the output power without having to retune the final. 73, __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Ranger driving SB220
Thanks Bill I don't have a schematic of a VII but it seems rational to assume the same "type" of mod would work in it. Let me know what you end up doing. All the Best Ron Weaver W6OM www.qsl.net/w6om -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, February 11, 2008 7:48 PM To: amradio@mailman.qth.net Subject: RE: [AMRadio] Ranger driving SB220 Ron, Yes, the VKII uses a pair of 6146s and it has a 6AQ5 adjustable screen clamp tube. I see no reason to wast power with an attenuator and there is a sweet spot in the final current thru the mod iron that requires a less than full rated final current to avoid saturation. It seems to me that a fine adjust here would allow power reduction for use with an amp and also enable fine tuning the final current without reducing optimum drive current when used barefoot. Just an idea. I like the ability of the DSB transmitters like the HT 37, FT101,etc to lower the output power without having to retune the final. 73, Bill, KB3DKS -Original Message- From: W6OM Good question, I have not restored any Viking II's or set them up to drive an amplifier but as I recall they have a pair of 6146's in the final rather than just one don't they? All the Best Ron Weaver W6OM www.qsl.net/w6om More new features than ever. Check out the new AOL Mail ! - http://webmail.aol.com __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Ranger driving SB220
Ron, Yes, the VKII uses a pair of 6146s and it has a 6AQ5 adjustable screen clamp tube. I see no reason to wast power with an attenuator and there is a sweet spot in the final current thru the mod iron that requires a less than full rated final current to avoid saturation. It seems to me that a fine adjust here would allow power reduction for use with an amp and also enable fine tuning the final current without reducing optimum drive current when used barefoot. Just an idea. I like the ability of the DSB transmitters like the HT 37, FT101,etc to lower the output power without having to retune the final. 73, Bill, KB3DKS -Original Message- From: W6OM Good question, I have not restored any Viking II's or set them up to drive an amplifier but as I recall they have a pair of 6146's in the final rather than just one don't they? All the Best Ron Weaver W6OM www.qsl.net/w6om More new features than ever. Check out the new AOL Mail ! - http://webmail.aol.com __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Ranger driving SB220
Patrick Thompson wrote: How did you go about getting the RF drive from the Ranger down to a level usable by the SB220? [...] I thought about a homemade pad but that's a lot of heat to throw away. Maybe a 3db pad and turn the drive down a little? AE5AW/Bill, in San Angelo, TX, inserted a roll of 50ohm coax between the Ranger I and the grid input of his GU-76 amp. He gets around 6 watts of carrier out of it, and the station sure sounds good from out in West Texas! I could lower the screen voltage but it would be nice to have the rig full power when barefoot. You could wire in a big pot, to vary the screen voltage. -- Driving your AM Rig without a scope, is like driving your car at night, without headlights. (K4KYV) -- 73 = Best Regards, -Geoff/W5OMR __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Ranger driving SB220
Good question, I have not restored any Viking II's or set them up to drive an amplifier but as I recall they have a pair of 6146's in the final rather than just one don't they? All the Best Ron Weaver W6OM www.qsl.net/w6om -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, February 11, 2008 7:22 PM To: amradio@mailman.qth.net Subject: RE: [AMRadio] Ranger driving SB220 Hello, Would this one knob screen control technique also be a workable option for a VKII, etc, after proper loading/setup into a dummy load? Bill, KB3DKS -Original Message- From: W6OM Pat Leave the mic gain alone, just crank down the screen voltage via a pot inside. I can crank mine down to as little as 7 watts. When I want full power and no amp I open up the crystal socket door and crank it back up. Nothing else really needs to change. All the Best Ron Weaver W6OM www.qsl.net/w6om More new features than ever. Check out the new AOL Mail ! - http://webmail.aol.com __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Ranger driving SB220
Well, I'm telling a story on myself. I had looked at your page before and added it to a folder with Ranger related info from several places on the web and BAMA, etc. I've been fixing various things as I go through this rig. The latest item I was concerned with was the modulator current (way too high). So I was looking to see what other people had done and looked over the grid biasing for the modulator but missed the variable screen voltage power control (a future project). It used to be routine to try to get 120% positive modulation in broadcast AM service. Still not a bad goal. Thanks! Pat wa4tuk -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gary Blau Sent: Monday, February 11, 2008 9:39 PM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] Ranger driving SB220 It's a good place to start. Here's some more info: http://www.w3am.com/ranger.html You don't have to do anything other than the screen mod if you don't want to. This is just one option for you. g Patrick Thompson wrote: > Thanks to all who replied. > > If I go the route of lowering screen voltage is it enough to lower just the > screen on the 6146? And turn the mike gain down? > > I like the idea of hiding the control shaft behind the crystal cover plug! > > Pat > wa4tuk __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.2/1272 - Release Date: 2/11/2008 5:28 PM No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.2/1272 - Release Date: 2/11/2008 5:28 PM __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Ranger driving SB220
Hello, Would this one knob screen control technique also be a workable option for a VKII, etc, after proper loading/setup into a dummy load? Bill, KB3DKS -Original Message- From: W6OM Pat Leave the mic gain alone, just crank down the screen voltage via a pot inside. I can crank mine down to as little as 7 watts. When I want full power and no amp I open up the crystal socket door and crank it back up. Nothing else really needs to change. All the Best Ron Weaver W6OM www.qsl.net/w6om More new features than ever. Check out the new AOL Mail ! - http://webmail.aol.com __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Ranger driving SB220
It's a good place to start. Here's some more info: http://www.w3am.com/ranger.html You don't have to do anything other than the screen mod if you don't want to. This is just one option for you. g Patrick Thompson wrote: Thanks to all who replied. If I go the route of lowering screen voltage is it enough to lower just the screen on the 6146? And turn the mike gain down? I like the idea of hiding the control shaft behind the crystal cover plug! Pat wa4tuk __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Ranger driving SB220
Pat Leave the mic gain alone, just crank down the screen voltage via a pot inside. I can crank mine down to as little as 7 watts. When I want full power and no amp I open up the crystal socket door and crank it back up. Nothing else really needs to change. All the Best Ron Weaver W6OM www.qsl.net/w6om -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Patrick Thompson Sent: Monday, February 11, 2008 6:20 PM To: 'Discussion of AM Radio in the Amateur Service' Subject: RE: [AMRadio] Ranger driving SB220 Thanks to all who replied. If I go the route of lowering screen voltage is it enough to lower just the screen on the 6146? And turn the mike gain down? I like the idea of hiding the control shaft behind the crystal cover plug! Pat wa4tuk -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gary Blau Sent: Monday, February 11, 2008 7:45 PM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] Ranger driving SB220 You can lower the power in a couple different ways. Lower the screen, run the PA on the low HV, attenuate the RF, etc. If you're driving an amp there's no advantage to running full power in the Ranger. In fact, you give up a lot of potential positive peak modulation capability, if that's important to you. I vote for lowering the screen and making it adjustable. Second would be running the PA on the lower HV rail. There are numerous articles on line for modifying the Ranger to do these things. g Patrick Thompson wrote: > How did you go about getting the RF drive from the Ranger down to a level > usable by the SB220? I'm thinking about something similar to get to the > 200-250 watt carrier level (or 800 to 1000 pep AM). I'm guessing the amp > won't need much more than 10-15 watts drive (40 to 60 watts pep AM) leaving > a little headroom. > > I thought about a homemade pad but that's a lot of heat to throw away. Maybe > a 3db pad and turn the drive down a little? > > I could lower the screen voltage but it would be nice to have the rig full > power when barefoot. > > Can you get by with just lowering the drive and microphone gain? > > Pat > wa4tuk __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.2/1272 - Release Date: 2/11/2008 5:28 PM No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.2/1272 - Release Date: 2/11/2008 5:28 PM __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Ranger driving SB220
Thanks to all who replied. If I go the route of lowering screen voltage is it enough to lower just the screen on the 6146? And turn the mike gain down? I like the idea of hiding the control shaft behind the crystal cover plug! Pat wa4tuk -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gary Blau Sent: Monday, February 11, 2008 7:45 PM To: Discussion of AM Radio in the Amateur Service Subject: Re: [AMRadio] Ranger driving SB220 You can lower the power in a couple different ways. Lower the screen, run the PA on the low HV, attenuate the RF, etc. If you're driving an amp there's no advantage to running full power in the Ranger. In fact, you give up a lot of potential positive peak modulation capability, if that's important to you. I vote for lowering the screen and making it adjustable. Second would be running the PA on the lower HV rail. There are numerous articles on line for modifying the Ranger to do these things. g Patrick Thompson wrote: > How did you go about getting the RF drive from the Ranger down to a level > usable by the SB220? I'm thinking about something similar to get to the > 200-250 watt carrier level (or 800 to 1000 pep AM). I'm guessing the amp > won't need much more than 10-15 watts drive (40 to 60 watts pep AM) leaving > a little headroom. > > I thought about a homemade pad but that's a lot of heat to throw away. Maybe > a 3db pad and turn the drive down a little? > > I could lower the screen voltage but it would be nice to have the rig full > power when barefoot. > > Can you get by with just lowering the drive and microphone gain? > > Pat > wa4tuk __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.2/1272 - Release Date: 2/11/2008 5:28 PM No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.2/1272 - Release Date: 2/11/2008 5:28 PM __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] Ranger driving SB220
Thanks Pat & others who wrote concerning how I use a Ranger to drive an SB-220. Here is a list from my archives of things I tried. 1. The much touted pot to crank down the screen voltage. Simple, easy mod. Use a non conductive shaft, bring it out through the hole in the crystal socket and you can still insert a crystal, pot the cap back on and crack it all the way up when you want to. 2. Simply using less grid drive when tuning up the Ranger, bad idea, my linearity goes to hell. 3. Built a 3db attenuation pad with a hand full of one watt resistors, a couple of coax connectors a box and a switch. "Got way too hot" 6. Built a 6db attention pad with a hand full of 5 watt resistors, a couple of coax connectors a box and switch. "Found the sweet spot" 7. If you don't want to build an attenuator or mod the Ranger, surplus attenuators are plentiful and on eBay, Surplus sales of Nebraska and I am sure countless other places. All the Best Ron Weaver W6OM www.qsl.net/w6om -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Patrick Thompson Sent: Monday, February 11, 2008 4:37 PM To: 'Discussion of AM Radio in the Amateur Service' Subject: [AMRadio] Ranger driving SB220 How did you go about getting the RF drive from the Ranger down to a level usable by the SB220? I'm thinking about something similar to get to the 200-250 watt carrier level (or 800 to 1000 pep AM). I'm guessing the amp won't need much more than 10-15 watts drive (40 to 60 watts pep AM) leaving a little headroom. I thought about a homemade pad but that's a lot of heat to throw away. Maybe a 3db pad and turn the drive down a little? I could lower the screen voltage but it would be nice to have the rig full power when barefoot. Can you get by with just lowering the drive and microphone gain? Pat wa4tuk -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of W6OM Sent: Monday, February 11, 2008 12:10 PM To: 'Discussion of AM Radio in the Amateur Service' Subject: RE: [AMRadio] Using Heath SB 610 Monitor Scope to monitor modulation on AM transmitter John The SB 610 monitor scope is one of the best all around performers for the money you can still buy today. I have two, one connected to the plate of the 2nd IF on an NC 300 for monitoring the incoming signals and for transmit it monitors a Ranger driving an SB 220 on AM. No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.2/1272 - Release Date: 2/11/2008 5:28 PM __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Ranger driving SB220
There was a great article in Electric Radio (Issue 139, Dec 2000, page 25) on modifying the Ranger screen voltage with a variable control, and even access from the front panel, without drilling any holes in the front panel. Works great. Pete, wa2cwa On Mon, 11 Feb 2008 19:44:53 -0500 Gary Blau <[EMAIL PROTECTED]> writes: > You can lower the power in a couple different ways. > Lower the screen, run the PA on the low HV, attenuate the RF, etc. > > If you're driving an amp there's no advantage to running full power > in > the Ranger. In fact, you give up a lot of potential positive peak > modulation capability, if that's important to you. > I vote for lowering the screen and making it adjustable. > Second would be running the PA on the lower HV rail. > > There are numerous articles on line for modifying the Ranger to do > these > things. > > g > > Patrick Thompson wrote: > > How did you go about getting the RF drive from the Ranger down to > a level > > usable by the SB220? I'm thinking about something similar to get > to the > > 200-250 watt carrier level (or 800 to 1000 pep AM). I'm guessing > the amp > > won't need much more than 10-15 watts drive (40 to 60 watts pep > AM) leaving > > a little headroom. > > > > I thought about a homemade pad but that's a lot of heat to throw > away. Maybe > > a 3db pad and turn the drive down a little? > > > > I could lower the screen voltage but it would be nice to have the > rig full > > power when barefoot. > > > > Can you get by with just lowering the drive and microphone gain? > > > > Pat > > wa4tuk __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] Ranger driving SB220
You can lower the power in a couple different ways. Lower the screen, run the PA on the low HV, attenuate the RF, etc. If you're driving an amp there's no advantage to running full power in the Ranger. In fact, you give up a lot of potential positive peak modulation capability, if that's important to you. I vote for lowering the screen and making it adjustable. Second would be running the PA on the lower HV rail. There are numerous articles on line for modifying the Ranger to do these things. g Patrick Thompson wrote: How did you go about getting the RF drive from the Ranger down to a level usable by the SB220? I'm thinking about something similar to get to the 200-250 watt carrier level (or 800 to 1000 pep AM). I'm guessing the amp won't need much more than 10-15 watts drive (40 to 60 watts pep AM) leaving a little headroom. I thought about a homemade pad but that's a lot of heat to throw away. Maybe a 3db pad and turn the drive down a little? I could lower the screen voltage but it would be nice to have the rig full power when barefoot. Can you get by with just lowering the drive and microphone gain? Pat wa4tuk __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
[AMRadio] Ranger driving SB220
How did you go about getting the RF drive from the Ranger down to a level usable by the SB220? I'm thinking about something similar to get to the 200-250 watt carrier level (or 800 to 1000 pep AM). I'm guessing the amp won't need much more than 10-15 watts drive (40 to 60 watts pep AM) leaving a little headroom. I thought about a homemade pad but that's a lot of heat to throw away. Maybe a 3db pad and turn the drive down a little? I could lower the screen voltage but it would be nice to have the rig full power when barefoot. Can you get by with just lowering the drive and microphone gain? Pat wa4tuk -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of W6OM Sent: Monday, February 11, 2008 12:10 PM To: 'Discussion of AM Radio in the Amateur Service' Subject: RE: [AMRadio] Using Heath SB 610 Monitor Scope to monitor modulation on AM transmitter John The SB 610 monitor scope is one of the best all around performers for the money you can still buy today. I have two, one connected to the plate of the 2nd IF on an NC 300 for monitoring the incoming signals and for transmit it monitors a Ranger driving an SB 220 on AM. No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.20.2/1272 - Release Date: 2/11/2008 5:28 PM __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
