2970N2-High SWR

[The Mad Scientist]

that is correct. it is an important step that seems to be falling through the cracks lately.

 

[Kodiak_341 SE KY]

I recently purchased a new RCI-2970N2 and I cannot get the SWR down, 3.5:1, to an acceptable level. The radio was bought from Bells CB Radio. The technician at Bells has recommended a Low Pass Filter. My set-up is as follows: a new A-99 antenna 8' above my house, 27' of Belden RG8X cable, a new RCI-2970N2, 30 amp power supply. When a Galaxy 979 is connected the SWR is fine,1.3:1. Is a Low Pass Filter going to help? I have used two external meters and I get the same results. Again, the Galaxy works fine with the set-up. Help would be appreciated.
Thank You.
LDG

You're not the only one that has bought this radio from screwdriver at bells cb. my 2970N2 is the exact same issue. with amp off it runs beautiful match. turn amp on and it goes through the roof. also bought another radio from bells cb and having issues with the mal adjusted receive on my Galaxy 94HP , yet he was supposed to have done a receive upgrade... man has had two strikes and I am not giving the hack a third chance to screw things up on another radio.

 

[Limeybastard]

You're not the only one that has bought this radio from screwdriver at bells cb. my 2970N2 is the exact same issue. with amp off it runs beautiful match. turn amp on and it goes through the roof. also bought another radio from bells cb and having issues with the mal adjusted receive on my Galaxy 94HP , yet he was supposed to have done a receive upgrade... man has had two strikes and I am not giving the hack a third chance to screw things up on another radio.

How did you turn the amp off?

 

[nomadradio]

Small 2-pin plug just in front of the driver transistor. The two wires on it used to be brown and black. Newer-version radio may have changed the wire colors.

Pull the plug and you're barefoot.

73

 

[Limeybastard]

Small 2-pin plug just in front of the driver transistor. The two wires on it used to be brown and black. Newer-version radio may have changed the wire colors.

Pull the plug and you're barefoot.

73

any of these ones?

Small 2-pin plug just in front of the driver transistor. The two wires on it used to be brown and black. Newer-version radio may have changed the wire colors.

Pull the plug and you're barefoot.

73

Any of these cables?

https://goo.gl/photos/M6Ef4N4msU8bM3FM8

https://goo.gl/photos/xpZAGbpQmd7iAwMT7

 

[cbkidd1]

Mad Scientist,
I just bought a used RCI-2970n2 with black backlight and was looking up info on it. I asked the gentlemen I bought it from where he had got it and had the alignment done. Like the other gentlemen, This radio came from screwdriver at bell's. My SWR going from The radio over to the antenna tuner are 1.6.1. I tried adjusting l34 and l35 as you had suggested. But all that did was lower the wattage output. Yes, it did lower the SWR but at the expense of losing wattage output. I had also found that screwdriver had spread apart 3 of the four coils in the back of the radio. Not sure why? So is there any other way besides putting an antenna tuner between the 2970n2 and tuner to bring the SWR down? I don't have my amplifier inline yet. It has an input tuner that can be used. 73,

 

[Tallman]

Mad Scientist,
I just bought a used RCI-2970n2 with black backlight and was looking up info on it. I asked the gentlemen I bought it from where he had got it and had the alignment done. Like the other gentlemen, This radio came from screwdriver at bell's. My SWR going from The radio over to the antenna tuner are 1.6.1. I tried adjusting l34 and l35 as you had suggested. But all that did was lower the wattage output. Yes, it did lower the SWR but at the expense of losing wattage output. I had also found that screwdriver had spread apart 3 of the four coils in the back of the radio. Not sure why? So is there any other way besides putting an antenna tuner between the 2970n2 and tuner to bring the SWR down? I don't have my amplifier inline yet. It has an input tuner that can be used. 73,

You are very Harmonic rich! Some one tuned that radio for "Ghost Watts." They hook it up and tweak and deform coils just to get the watts up. If you hook that radio up to a Spectrum Analyzer you will see a lot of your power is up in the 54 MHz range. Totally useless and where the people you want to contact will never hear.

The Mad Scientist was last seen 1 year and 49 weeks ago.

 

[cbkidd1]

Hey, Tallman how are you doing? I pushed the coils back together. Got a few radio checks and was told it sounded fine. I set the dead key on low at 6 watts and high set to 40 watts. Doing around 220 on output. I still need to put the relay that was sent with the amp in for 10 meters. He told me to remove two of the 8 pins on the relay and it should work I hope. Here is a drawing of the relay pins. Think I will put it in tomorrow.

 

[Tallman]

That's the thing about the "Doofus Tune Up" It will sound just fine locally and on skip.
But the signal is dirtier than all get out. That's what I'm talking about tuning up for
"Ghost Watts". If you run an amp behind it, it gets even worse.
If you run an amp, one low pass behind the radio before the amp and one behind the amp before the antenna. Your neighbors and the radio community will thank you.

I don't know anything about the relay change. Tell me what does it do?

 

[Handy Andy]

Whoa Kidd!

Hi BTW...

Ah...Hey, did you happen to notice that if you REMOVE those Pins on the Relay, you also remove the INDEX - an orientation feature - an insertion "bot" will use to ensure the Relays contact and Coil connections are correct?

• MEANING: The Relay can be installed two ways. The 2 pins they tell you to remove are for INDEXING to keep it mounted and ORIENTED Correctly - this isn't a Simple IC with an INDEX notch to show Pin 1 location - it is purposely for orientation use.
• I'm only mentioning this to keep you from having the board sent back for repair and burnt foil traces are not considered Warranty covered work - Customer induced damage is how they interpret this.

Please - Please, review your ORIGINAL Relay pinout so you don't hook it up backwards and do even more damage. For if you hook up the wrong pins you'll blow the RF board (being on all the time) Or worse - the power supply feed? Follow Relay coil to Relay coil pins, and DPDT Normally Off to Normally Off layout - at least you should be ok...



IT's gonna' blow a fuse - but in taking that much current - Murphys law still applies - it will blow in the most expen$ive fashion possible - and in the worse possible way - to protect the 2 cent Fuse.