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Two radios. One reaches, the other does not...

Smaggs

New Member
Apr 2, 2020
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I have two radios. I bought a DX2547 base back in 2006 and a DX979 mobile in 2011. I had both "peaked and tuned" Nothing clipped or bent. Just had a shop read them with a scope and bird meters to make sure they work and to make sure they weren't splatter boxes.

Well I've had the base radio in storage for a long time in my house. Just too busy working to use it. I got it out, because I'm off work due to the whole Covid 19 situation.

Here's the issue. My DX979 mobile radio really reaches, and my base station does not. My power meter really swings when I talk on the 979 and it doesn't move one bit when I read it on the base.

Had my girlfriend talk to me while I drove over five miles away. She could hear me like I was close, but I could only hear her when I was less than two miles away. Both radios have roger beeps, which those seem to punch through, but not her voice.

Same results if I switch radios in the house on the antenna on my roof... or if I switch radios in the car. So if I take my radios out and talk to someone on my mobile, they hear me great. If I swap for the base radio in my car with the same mic and antenna, it's like nobody can hear me. If I do the same test in the house... my mobile radio reaches for a little over 5 miles. There's a guy in my area with another base setup and I was checking with him. As the crow flies, we are almost 9 miles apart, but there is almost no obstruction between us. If memory serves, he uses an Antron 99 with ground plane kit that fits it.

I checked my variable resistors. My modulation is maxed (I double checked with a hand held Uniden radio to see which way is up and down on the pots). My AM low and high power pots are good. It's just like this 2547 isn't really working and isn't even hitting 4 watts. That's really annoying, because I paid over $300 for the base radio, but I can only talk for a mile before the signal fades.

Here are my setups.

For the house: 100' of RG8x coax. I temporarily have a wilson 2000 series antenna with a ground plane on my roof. I get less than 1.5:1 SWR. I have an Antron 99 antenna on back order. I used to have one, but must have lost it when I moved from Arizona to Pennsylvania.

For my car: Magnet mount Stryker SR10A antenna with RG8X coax. Same SWR readings. Super low.

If I put my DX979 on either setup, it really reaches. One local guy asked if I was using an amp, which I do not. I also use Ranger SRA 198 microphones. They're clear and passive noise cancelling.

I hope this info makes sense and hopefully I can gain understanding as to why a base radio with all this extra crap in it seems useless. It's basically a DX959 in a base case. Maybe I got unlucky and got a hunk of crap for hundreds of dollars?

Side note: I have a 20 amp 12 volt power supply. I might just buy another 979 for my car and use my old one as a base and get rid of the 2547.

Any suggestions would help. Has anyone else had trouble with a 2547? Has anyone had positive experiences with a 2547?
 

I don't have access to a trustworthy meter to see what's going on.

Is it possible that this 2547 is just a piece of crap? Is it possible I got lucky with my 979 and it just happens to be a better build quality?

When I key my 979 (no modulation) the PWR says 4 with the RF PWR fully counter clockwise. With the RF PWR fully clockwise, it shows around 15. On the 2547 the dead key reads 3 with RF PWR fully counter clockwise and barely above 3 (still less than 4) with the RF PWR fully clockwise.

Another test I've tried out is driving around with both radios. I parked in a Wal Mart parking lot and I was having an easy time hearing and talking to three radios... the reports I was getting back was that my 979 was "loud and proud" and no distortion. The 2547 only one of them could hear me, but it turned out his base station is really close to that walmart. The only thing I did was swap radios. Same cable, antenna, and microphone.

I'm pretty much just at the point where I'm going to give up on this 2547 and get another 979 for my car and use my old one as my base radio. The 979 worked great... brand new out of the box. Factory sealed. The "peak and tune" I got in 2011 or 2012 the guy that did it said not to let hack shops cut anything. He claimed he just made it so it modulates at 100%. He just set the pots inside to the proper levels using my microphone (Ranger SRA-198). Said it might PEP around 30-40 watts, but it's really much lower.

I'm also open to suggestion, if anyone knows a reliable place that I can send it to just to be sure I should even bother with it.
 
I tried one more thing with each radio and maybe this will shed a little light?

DX2547: PWR position for the meter. If I key up it sits around 3 and barely moves toward 4 when I talk at 100% modulation.

DX979: PWR position for the meter. When I key up it reads around 4 and swings to around 18 when I speak at 100% modulation.

I'm wondering if this means I'm getting plenty of modulation with the 2547, but the carrier power is low for some reason.
 
Doesn't the 2547 have a way to be used in your Mobile?

I mean put the Base as Mobile out there and let the 979 be your base a the means to remove any doubt.

OR has that been tried already? (The Walmart things too "coincidental" to trust the effort as being a true test unless you were able to swap both and try with the XYL and even leave a Video gate)
  • - if you need to, do one off of one of a Smartphone and just play it back for direct head to head comparisons.
Else without a true power test, you may have more issues with the Network not quite up to snuff like the 979 is - they are nearly identical - but that means squat when you can take both out on the road and see one definitely overperforms the other. Then in this case I'd look into reflowing some solder and make some close up comparisons to both their networks.
 
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Doesn't the 2547 have a way to be used in your Mobile?

I mean put the Base as Mobile out there and let the 979 be your base a the means to remove any doubt.

OR has that been tried already? (The Walmart things too "coincidental" to trust the effort as being a true test unless you were able to swap both and try with the XYL and even leave a Video gate)
  • - if you need to, do one off of one of a Smartphone and just play it back for direct head to head comparisons.
Else without a true power test, you may have more issues with the Network not quite up to snuff like the 979 is - they are nearly identical - but that means squat when you can take both out on the road and see one definitely overperforms the other. Then in this case I'd look into reflowing some solder and make some close up comparisons to both their networks.

Yes I did try that. While sitting in the walmart lot, I swapped the radios ( the DX2547 has the 12 and 120 volt inputs) That's how I confirmed it was so quiet. I get lots of modulation, but it's like the carrier power is choked somehow.
 
I was advised on another forum to ditch my RG8x and go for 213 and to find a shop to check my alignment on my 2547. Seems legit, because my symptoms line up with having poor alignment.

I didn't realize RG8x had such high loss compared to 213 until now. That might not be as important, but I will heed the advice and try the 213 coax. Seems like getting a proper alignment, which I cannot do on my own, is the main issue.

I will post my results, but probably not for a while. Obviously can't get in for an alignment now and I don't know how long it will take to get the proper coax, given the current crisis.
 
I don’t agree about the RG-8x. It’s actually perfect for many applications.

As far as losses...with 100 feet of cable and a 1.5 SWR, you’d be dealing with the difference in 2.75 and 3 watts.

That means the difference on the other end would be effectively zero.
 
DX2547: PWR position for the meter. If I key up it sits around 3 and barely moves toward 4 when I talk at 100% modulation.

DX979: PWR position for the meter. When I key up it reads around 4 and swings to around 18 when I speak at 100% modulation.

I'm wondering if this means I'm getting plenty of modulation with the 2547, but the carrier power is low for some reason.

The difference in carrier is small. 3 vs 4 watts...but the 979 is modulating and the 2547 is not.

This isn’t a matter of one being better or anything like that. You just have one working radio and one broken radio.
 
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The difference in carrier is small. 3 vs 4 watts...but the 979 is modulating and the 2547 is not.

This isn’t a matter of one being better or anything like that. You just have one working radio and one broken radio.

Very good to know. I decided to order another 979, because I wanted a second one to leave in my car and another to put in my other big rig. I'll use my old 979 as my base radio for now.

What I plan to do is get the 2547 into a shop when I'm physically able to. I don't know how long I'll have to wait, but I will post my results here when I find out what happened.
 
Very good to know. I decided to order another 979, because I wanted a second one to leave in my car and another to put in my other big rig. I'll use my old 979 as my base radio for now.

What I plan to do is get the 2547 into a shop when I'm physically able to. I don't know how long I'll have to wait, but I will post my results here when I find out what happened.

What better solution than another radio :D

I like the way you think.
 

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