Icom AG-35 Preamp Question
I bought an Icom AG-35 preamp about a year ago. The fellow ham advertised it as virtually brand new and it was/is. I planned to use it this summer with a TS-2000 which doesn't supply 12v voltage to the coax to power a preamp as other xcvrs do. I used a Mirage KP2 unit to inject power to the coax to drive mast mounted the preamp. When I turn the power on there seems to be little or no noticeable difference in background noise and worse than that I cannot here any signals on FO-29 downlink, and I know the bird has been active. Any suggestions? Is the preamp fried? I can't even get the weather proof case off to trouble shoot, not that I'd know what to look for. Any suggestions on repair?
TNX 73 Rick W2JAZ
First, make sure that nothing else that might block DC is in line between the power inserter and the preamp. Then, have someone go up the ladder and listen as you turn the power feed on and off. They should hear a distinct click as the relays in the preamp engage. Tune to a distant repeater, and you should see at least a 2 - 3 S-unit increase when the preamp is on.
How much current is the KP2 capable of supplying? If it can't pull in those relays, the preamp will remain in bypass mode.
George, KA3HSW
----- Original Message ----- From: "Lawn, Richard" [email protected] To: [email protected] Sent: Saturday, August 11, 2012 5:29 PM Subject: [amsat-bb] Icom AG-35 Preamp Question
I bought an Icom AG-35 preamp about a year ago. The fellow ham advertised it as virtually brand new and it was/is. I planned to use it this summer with a TS-2000 which doesn't supply 12v voltage to the coax to power a preamp as other xcvrs do. I used a Mirage KP2 unit to inject power to the coax to drive mast mounted the preamp. When I turn the power on there seems to be little or no noticeable difference in background noise and worse than that I cannot here any signals on FO-29 downlink, and I know the bird has been active. Any suggestions? Is the preamp fried? I can't even get the weather proof case off to trouble shoot, not that I'd know what to look for. Any suggestions on repair?
TNX 73 Rick W2JAZ
Rick, I suggest you use a VOM or DMM to measure the current drawn on 12 volts going to the power injector. If everything is connected correctly It will draw 30-200 mA. Confirm that you have continuity in your coax. Some lightning arrestors have a DC block built in. It is best to test it with a short run of coax between the preamp and the power injector at the radio while listening to a local repeater to see if the signal increases when you apply power to it. If it operates then you can proceed to determine if there are problems with the coax to the antenna, not carrying the 12 VDC. 73 Art, KC6UQH
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Lawn, Richard Sent: Saturday, August 11, 2012 3:30 PM To: [email protected] Subject: [amsat-bb] Icom AG-35 Preamp Question
I bought an Icom AG-35 preamp about a year ago. The fellow ham advertised it as virtually brand new and it was/is. I planned to use it this summer with a TS-2000 which doesn't supply 12v voltage to the coax to power a preamp as other xcvrs do. I used a Mirage KP2 unit to inject power to the coax to drive mast mounted the preamp. When I turn the power on there seems to be little or no noticeable difference in background noise and worse than that I cannot here any signals on FO-29 downlink, and I know the bird has been active. Any suggestions? Is the preamp fried? I can't even get the weather proof case off to trouble shoot, not that I'd know what to look for. Any suggestions on repair?
TNX 73 Rick W2JAZ
_______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Hi All,
Somebody please clarify---I may be wrong, but I thought the Icom preamps did the following with Icom radios:
In receive, 12V is powered up the coax. Device is powered, preamp is ON. In transmit, the 12 power feed is stopped. Device is not powered, and it's bypassed during xmit.
If this is the case, it complicates greatly the use of Icom preamps on non-Icom radios (means there isn't a typical RF-sensed bypass circuit, which means it would be easy to blow in a non-Icom radio).
Am I remembering this wrong?
Mark N8MH
At 09:30 PM 8/11/2012 -0700, Art McBride wrote:
Rick, I suggest you use a VOM or DMM to measure the current drawn on 12 volts going to the power injector. If everything is connected correctly It will draw 30-200 mA. Confirm that you have continuity in your coax. Some lightning arrestors have a DC block built in. It is best to test it with a short run of coax between the preamp and the power injector at the radio while listening to a local repeater to see if the signal increases when you apply power to it. If it operates then you can proceed to determine if there are problems with the coax to the antenna, not carrying the 12 VDC. 73 Art, KC6UQH
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Lawn, Richard Sent: Saturday, August 11, 2012 3:30 PM To: [email protected] Subject: [amsat-bb] Icom AG-35 Preamp Question
I bought an Icom AG-35 preamp about a year ago. The fellow ham advertised it as virtually brand new and it was/is. I planned to use it this summer with a TS-2000 which doesn't supply 12v voltage to the coax to power a preamp as other xcvrs do. I used a Mirage KP2 unit to inject power to the coax to drive mast mounted the preamp. When I turn the power on there seems to be little or no noticeable difference in background noise and worse than that I cannot here any signals on FO-29 downlink, and I know the bird has been active. Any suggestions? Is the preamp fried? I can't even get the weather proof case off to trouble shoot, not that I'd know what to look for. Any suggestions on repair?
TNX 73 Rick W2JAZ
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
You are unfortunately correct and this was not clear in any manuals, at least to me, when I began to use an icom preamp for 435 on my TS-2000. Hence, a blown preamp! There is a guy I found on eBay that sells a switching box that plugs into the external control port on a TS-2000 and gives you a relay control RCA out cable for each of the VHF/UHF bands, even 1.2 if you have it. You can control either amps or preamps. I may look into this, once I figure out how to repair the preamp if it is even repairable, but I think it is. Thanks for all the input everyone. At the end of the day I wish I had my 847 as I feel it may be a more user friendly rig for sats at least for controlling external preamps. Rick W2JAZ
Sent from my iPad http://RickLawn.com
On Aug 12, 2012, at 8:39 AM, "Mark L. Hammond" [email protected] wrote:
Hi All,
Somebody please clarify---I may be wrong, but I thought the Icom preamps did the following with Icom radios:
In receive, 12V is powered up the coax. Device is powered, preamp is ON. In transmit, the 12 power feed is stopped. Device is not powered, and it's bypassed during xmit.
If this is the case, it complicates greatly the use of Icom preamps on non-Icom radios (means there isn't a typical RF-sensed bypass circuit, which means it would be easy to blow in a non-Icom radio).
Am I remembering this wrong?
Mark N8MH
At 09:30 PM 8/11/2012 -0700, Art McBride wrote:
Rick, I suggest you use a VOM or DMM to measure the current drawn on 12 volts going to the power injector. If everything is connected correctly It will draw 30-200 mA. Confirm that you have continuity in your coax. Some lightning arrestors have a DC block built in. It is best to test it with a short run of coax between the preamp and the power injector at the radio while listening to a local repeater to see if the signal increases when you apply power to it. If it operates then you can proceed to determine if there are problems with the coax to the antenna, not carrying the 12 VDC. 73 Art, KC6UQH
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Lawn, Richard Sent: Saturday, August 11, 2012 3:30 PM To: [email protected] Subject: [amsat-bb] Icom AG-35 Preamp Question
I bought an Icom AG-35 preamp about a year ago. The fellow ham advertised it as virtually brand new and it was/is. I planned to use it this summer with a TS-2000 which doesn't supply 12v voltage to the coax to power a preamp as other xcvrs do. I used a Mirage KP2 unit to inject power to the coax to drive mast mounted the preamp. When I turn the power on there seems to be little or no noticeable difference in background noise and worse than that I cannot here any signals on FO-29 downlink, and I know the bird has been active. Any suggestions? Is the preamp fried? I can't even get the weather proof case off to trouble shoot, not that I'd know what to look for. Any suggestions on repair?
TNX 73 Rick W2JAZ
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Hi Mark,
That is the way they're supposed to work. +12v receive - 0v on xmit.
It is fine with a Yaesu FT-736R using the built in preamp feed system - power up the coax. Just have to watch out for any DC block.
It also would work with a Yeasu FT-847 if it had 1296.....
I had one for a while. I found I had to open it up and retune as it was set for the low end of the 23cm band?!? My biggest problem was that it was only good for about 15 watts. I had to use it after my DL2AM 80 watt amp....
Mike
----- Original Message ----- From: "Mark L. Hammond" [email protected] Subject: [amsat-bb] Re: Icom AG-35 Preamp Question
Hi All,
Somebody please clarify---I may be wrong, but I thought the Icom preamps did the following with Icom radios:
In receive, 12V is powered up the coax. Device is powered, preamp is ON. In transmit, the 12 power feed is stopped. Device is not powered, and it's bypassed during xmit.
If this is the case, it complicates greatly the use of Icom preamps on non-Icom radios (means there isn't a typical RF-sensed bypass circuit, which means it would be easy to blow in a non-Icom radio).
Am I remembering this wrong?
Mark N8MH
At 09:30 PM 8/11/2012 -0700, Art McBride wrote:
Rick, I suggest you use a VOM or DMM to measure the current drawn on 12 volts going to the power injector. If everything is connected correctly It will draw 30-200 mA. Confirm that you have continuity in your coax. Some lightning arrestors have a DC block built in. It is best to test it with a short run of coax between the preamp and the power injector at the radio while listening to a local repeater to see if the signal increases when you apply power to it. If it operates then you can proceed to determine if there are problems with the coax to the antenna, not carrying the 12 VDC. 73 Art, KC6UQH
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Lawn, Richard Sent: Saturday, August 11, 2012 3:30 PM To: [email protected] Subject: [amsat-bb] Icom AG-35 Preamp Question
I bought an Icom AG-35 preamp about a year ago. The fellow ham advertised it as virtually brand new and it was/is. I planned to use it this summer with a TS-2000 which doesn't supply 12v voltage to the coax to power a preamp as other xcvrs do. I used a Mirage KP2 unit to inject power to the coax to drive mast mounted the preamp. When I turn the power on there seems to be little or no noticeable difference in background noise and worse than that I cannot here any signals on FO-29 downlink, and I know the bird has been active. Any suggestions? Is the preamp fried? I can't even get the weather proof case off to trouble shoot, not that I'd know what to look for. Any suggestions on repair?
TNX 73 Rick W2JAZ
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sorry guys, thought you were talking AG1200, not AG35....
73, Mike, N1JEZ AMSAT 29649 "A closed mouth gathers no feet"
----- Original Message ----- From: "Mike Seguin N1JEZ" [email protected] To: [email protected]; "'Lawn, Richard'" [email protected]; [email protected]; "Mark L. Hammond" [email protected] Sent: Sunday, August 12, 2012 8:57 AM Subject: [amsat-bb] Re: Icom AG-35 Preamp Question
Hi Mark,
That is the way they're supposed to work. +12v receive - 0v on xmit.
It is fine with a Yaesu FT-736R using the built in preamp feed system - power up the coax. Just have to watch out for any DC block.
It also would work with a Yeasu FT-847 if it had 1296.....
I had one for a while. I found I had to open it up and retune as it was set for the low end of the 23cm band?!? My biggest problem was that it was only good for about 15 watts. I had to use it after my DL2AM 80 watt amp....
Mike
----- Original Message ----- From: "Mark L. Hammond" [email protected] Subject: [amsat-bb] Re: Icom AG-35 Preamp Question
Hi All,
Somebody please clarify---I may be wrong, but I thought the Icom preamps did the following with Icom radios:
In receive, 12V is powered up the coax. Device is powered, preamp is ON. In transmit, the 12 power feed is stopped. Device is not powered, and it's bypassed during xmit.
If this is the case, it complicates greatly the use of Icom preamps on non-Icom radios (means there isn't a typical RF-sensed bypass circuit, which means it would be easy to blow in a non-Icom radio).
Am I remembering this wrong?
Mark N8MH
At 09:30 PM 8/11/2012 -0700, Art McBride wrote:
Rick, I suggest you use a VOM or DMM to measure the current drawn on 12 volts going to the power injector. If everything is connected correctly It will draw 30-200 mA. Confirm that you have continuity in your coax. Some lightning arrestors have a DC block built in. It is best to test it with a short run of coax between the preamp and the power injector at the radio while listening to a local repeater to see if the signal increases when you apply power to it. If it operates then you can proceed to determine if there are problems with the coax to the antenna, not carrying the 12 VDC. 73 Art, KC6UQH
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Lawn, Richard Sent: Saturday, August 11, 2012 3:30 PM To: [email protected] Subject: [amsat-bb] Icom AG-35 Preamp Question
I bought an Icom AG-35 preamp about a year ago. The fellow ham advertised it as virtually brand new and it was/is. I planned to use it this summer with a TS-2000 which doesn't supply 12v voltage to the coax to power a preamp as other xcvrs do. I used a Mirage KP2 unit to inject power to the coax to drive mast mounted the preamp. When I turn the power on there seems to be little or no noticeable difference in background noise and worse than that I cannot here any signals on FO-29 downlink, and I know the bird has been active. Any suggestions? Is the preamp fried? I can't even get the weather proof case off to trouble shoot, not that I'd know what to look for. Any suggestions on repair?
TNX 73 Rick W2JAZ
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (5)
-
Art McBride -
George Henry -
Lawn, Richard -
Mark L. Hammond -
Mike Seguin N1JEZ