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Post by Night Ranger on Dec 3, 2013 22:01:10 GMT -5
Videogate - Pennsylvania skip to South Carolina - 12/3/2013
Night Ranger
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Post by spitfire441 on Dec 4, 2013 7:13:23 GMT -5
This is the 'gate from my end. Spitfire441
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Post by Night Ranger on Dec 4, 2013 9:18:49 GMT -5
...and here is the videogate from Sandbagger's live feed in Pennsylvania.
-Night Ranger
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Post by BBB on Dec 4, 2013 10:31:05 GMT -5
Sounding Great Night Ranger. Is that front mic Cobra 148 GTL the later Chinese issue like the ones they sell now? Included a pic of the Cobra 150 GTL DX radio I was running:  When I first got it it did not sound good due to muffled audio with popping sounds on the peaks. Probably the reason the gentleman was selling it at the ham fest a few years back. Then I did the mod listed in the factory service bulletin that can be found on CB tricks. That fixed the audio and on low power it will dead key around 2-3 watts and swing to 12-15. High power doesn't sound as good but dead keys 12 and swings to 25 watts. Overall I think it's a very nice AM/FM radio and reportedly didn't have as many problems as the 200 GTL's had. If anyone's interested it looks like this shop has two NOS 150's for $250 each: www.deltaelectronicsonline.com/ProductDetails.asp?ProductCode=Cobra-150-GTL |
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Sandbagger
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Post by Sandbagger on Dec 4, 2013 11:02:22 GMT -5
Interesting to hear the same conversations from two different listening perspectives hundreds of miles apart. A capability we didn't have back in the day......  |
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Post by Sandbagger on Dec 4, 2013 11:28:10 GMT -5
Sounding Great Night Ranger. Is that front mic Cobra 148 GTL the later Chinese issue like the ones they sell now? Included a pic of the Cobra 150 GTL DX radio I was running: When I first got it it did not sound good due to muffled audio with popping sounds on the peaks. Probably the reason the gentleman was selling it at the ham fest a few years back. Then I did the mod listed in the factory service bulletin that can be found on CB tricks. That fixed the audio and on low power it will dead key around 2-3 watts and swing to 12-15. High power doesn't sound as good but dead keys 12 and swings to 25 watts. The most likely reason it doesn't sound good on high power is that you are out of modulation headroom. This is a dual final radio, but they normally run about 30 -35 watts PEAK power out. The carrier should not exceed 8 watts if you want the full 100% modulation capability. Also that radio has dual modulation limiter adjustments. One for low power and one for high. Make sure they are adjusted correctly. The high power adjustment will affect both, while the low power only affects low power. So adjust on high power first. |
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Post by Night Ranger on Dec 4, 2013 12:13:32 GMT -5
Sounding Great Night Ranger. Is that front mic Cobra 148 GTL the later Chinese issue like the ones they sell now? I bought that Cobra 148GTL brand new about a month ago, so it probably is the Chinese version. The sideband receiver signal strength is a little low. It seems to hear as much as my other sideband radios, but the signal strength is much less than my other radios. There is a mod to replace the front end transistor with a higher gain transistor, and since I already have those transistors I'm going to do it. The AGC looks like it is a fixed value, so there is no variable adjustment that I can find. That leaves playing with the emitter by-pass resistors to increase gain in the RF preamp and IF chain. Night Ranger |
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Post by Sandbagger on Dec 4, 2013 12:21:35 GMT -5
Sounding Great Night Ranger. Is that front mic Cobra 148 GTL the later Chinese issue like the ones they sell now? I bought that Cobra 148GTL brand new about a month ago, so it probably is the Chinese version. The sideband receiver signal strength is a little low. There is a mod to replace the front end transistor with a higher gain transistor, and since I already have those transistors I'm going to do it. The AGC looks like it is a fixed value, so there is no variable adjustment that I can find. That leaves playing with the emitter by-pass resistors to increase gain in the RF preamp and IF chain. Night Ranger There's something fundamentally wrong when you have to modify a brand new radio in order to make it perform like the older version..... |
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Post by "Doc"Hammer on Dec 4, 2013 13:05:36 GMT -5
Hey Sparky...I also have 2 NOS 150's ..New in the box, unmodified... I might list them in the for sale section......I also use one in my RV...not a bad rig....I also have a small supply of the caps to fix the recieve issue should it arise. So far, the one in my RV works great.
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Post by Night Ranger on Dec 6, 2013 0:02:41 GMT -5
I bought that Cobra 148GTL brand new about a month ago, so it probably is the Chinese version. The sideband receiver signal strength is a little low. There is a mod to replace the front end transistor with a higher gain transistor, and since I already have those transistors I'm going to do it. The AGC looks like it is a fixed value, so there is no variable adjustment that I can find. That leaves playing with the emitter by-pass resistors to increase gain in the RF preamp and IF chain. Night Ranger There's something fundamentally wrong when you have to modify a brand new radio in order to make it perform like the older version..... I think the fundamental that is wrong is the re-issue Cobra 148 GTL may not be made by Uniden. Interestingly enough my 1977 Cybernet built PLL02a Midland 79-892 40 channel sideband is still rock solid frequency stable and has a more sensitive receiver than the re-issue Cobra 148 GTL. I've noticed one other quirk with the new re-issue Cobra 148 GTL. When I plug an external speaker up I can hear my voice coming out of the speaker on AM transmit. I put an RF choke on the speaker leads and the power cable and it made no difference, so I don't think it is an RFI issue. It's not a bad radio, but the Uniden made Realistic TRC-451 toast it. I think I'm going to go through the receiver chain and align it just in case the factory screwed that up too. Night Ranger |
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Post by Sandbagger on Dec 6, 2013 7:15:33 GMT -5
There's something fundamentally wrong when you have to modify a brand new radio in order to make it perform like the older version..... I think the fundamental that is wrong is the re-issue Cobra 148 GTL may not be made by Uniden. Interestingly enough my 1977 Cybernet built PLL02a Midland 79-892 40 channel sideband is still rock solid frequency stable and has a more sensitive receiver than the re-issue Cobra 148 GTL. I've noticed one other quirk with the new re-issue Cobra 148 GTL. When I plug an external speaker up I can hear my voice coming out of the speaker on AM transmit. I put an RF choke on the speaker leads and the power cable and it made no difference, so I don't think it is an RFI issue. It's not a bad radio, but the Uniden made Realistic TRC-451 toast it. I think I'm going to go through the receiver chain and align it just in case the factory screwed that up too. Night Ranger While the basic design is almost the same as the original Uniden-made Cobra, it hasn't been made by Uniden in quite a few years. More likely it's an adjunct factory of RCI. |
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Post by Night Ranger on Dec 6, 2013 12:16:06 GMT -5
I think the fundamental that is wrong is the re-issue Cobra 148 GTL may not be made by Uniden. Interestingly enough my 1977 Cybernet built PLL02a Midland 79-892 40 channel sideband is still rock solid frequency stable and has a more sensitive receiver than the re-issue Cobra 148 GTL. I've noticed one other quirk with the new re-issue Cobra 148 GTL. When I plug an external speaker up I can hear my voice coming out of the speaker on AM transmit. I put an RF choke on the speaker leads and the power cable and it made no difference, so I don't think it is an RFI issue. It's not a bad radio, but the Uniden made Realistic TRC-451 toast it. I think I'm going to go through the receiver chain and align it just in case the factory screwed that up too. Night Ranger While the basic design is almost the same as the original Uniden-made Cobra, it hasn't been made by Uniden in quite a few years. More likely it's an adjunct factory of RCI. I re-aligned the receiver this morning without touching the S meter adjustment. The signal strength did come up one to one and a half S units. I have not done the transistor upgrade yet. -Night Ranger |
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