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Old 11-10-2012, 11:54 AM
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Exclamation 10m Woes

I have a President HR-2510 (25watt) 10m radio.

It's SWR is nearly 1:1 on 28.4Mhz, when I call CQ people seem to be able to hear me just fine but... when I get a reply they are so quiet and buried in noise I can't make them out, just that I hear them copy my callsign.

The antenna is an 18' 2" vertical mounted 12' above ground and grounded with a new 8' ground rod that is 7' into the ground.

The radio is powered by an ATX pc supply hooked into a line condition with a ferrite core in place on the DC side before going to the radio.

I do on occasion hear someone loud/clear but they are usually talking to someone else that I can't hear without blasting the radio....

With the gain all the way up the noise is at about 3 on the meter, I can hear people but they are so quiet even blasting the radio is not enough for me to copy them in the noise.


Is this just an issue of my antenna's height? I'm not sure whats going on.
oh, the radio is connected with RG-8X

Any help is very much appreciated.
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Old 11-10-2012, 1:17 PM
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I would try and find a good shop that can check your receiver sensitivity & selectivity, might not cost much if you take it in, then go from there. If it is within specs the you will have to get into checking for losses or problems with you coax & antenna. The grounding system should not affect your reception problems.
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Old 11-10-2012, 3:15 PM
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Uh oh, that's one of those illegal CBs which raises the question; has it been modified? If so likely it's been "tweaked and peaked" for CB which naturally messes up 10M. Truck stop chop shops with the technician wannabes are a dime a dozen, but good techs with proper equipment are hard to find since today's rigs are beyond most and are usually returned to the factory for repair. Good luck, not sarcasm, I mean it most sincerely.
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Old 11-10-2012, 3:31 PM
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I hear ya KB2VXA,

Yes, unfortunately it was indeed modified for CB :/
That being said other around me that also run 10m can indeed hear me in most cases.

I tested the power output on USB on 28.4mhz and its right at or slightly under 25 watts as it should be. It was previously owned by an Xtra ham who claims it worked fine for him.

I know his antenna is up about twice as high though, he also lives in an area with fewer homes in the way around him.

Thankfully it is a 10m radio though at least, rather than the CBs thats are modified down into 10m but still channelized... gah, I certainly avoided those.

EDIT

I heard someone from Arizona today (did not talk to him because he was up in the General range) but he was pushing 1200 watts on a yagi... Was crystal clear Arizona to Ohio.
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Old 11-10-2012, 5:18 PM
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I would look at a few things first.

Try an external speaker. This will tell us if the internal one is messed up.

After that, make sure you are not using some kind of split or have the bandwidth turned way down or something like that. I have not used one of these rigs for years, so I forget what all they had.

You also need to make sure (as has been said already) that you are correctly on frequency with both the transmitter and receiver.

I don't think it has anything to do with antenna or power supply or anything like that.

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Old 11-10-2012, 5:26 PM
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It is most likely not an antenna problem. I had a 2510 that acted very similar. One of the local guys begged me to sell it to him, I told him what it was doing. He still wanted it because it was the radio the "in crowd" used in his circle of friends. Few months later I asked him how it was working for him. "Billy Bob worked it over and it dead keys 45 and swings almost 75 on peaks." Fine but how does it receive? "It hears real good now, Billy Bob tweaked the receive too." As long as you're happy I'm happy.
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Old 11-10-2012, 5:42 PM
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I tune around very carefully once I hear someone to get them turned in.

I've called CQ on 28.4mhz just to see if someone can catch me rather than me tuning for them... Sure enough I immediately hear someone copying my call.. .but, again its so faint I'd never be able to hold a conversation. Couldn't even get his call

I just heard K.....R........I....V and I'd hear it repeat a few seconds later, so I'm sure someone, somewhere heard me and tried to come back.
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Old 11-11-2012, 11:16 AM
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I recently had the DSP noise reduction modification installed on my Yaesu FT-817ND. Wow, what a difference. Previously, I'd give up playing radio on days the noise was even moderate. It is just too fatiguing to listen through all that hash. Perhaps KR0SIV (great call) could look into a DSP solution.

Another thing to consider is that PC power supply and other local noise generators. Try using a battery, even if just for rx and see if the noise drops off at all. The two noisiest RFI generators in my house located to date are the battery charging circuit in my laptop and my lead acid battery charger. Both of these are unplugged before heading to the shack or I can't hear a thing.
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Old 11-11-2012, 11:18 AM
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"Billy Bob worked it over and it dead keys 45 and swings almost 75 on peaks."

That's rich, that looks like Dosy watts. Dosy CB and Amateur Meters Then there's that age old myth that upward modulation now called swing is good, properly modulated there should be NO carrier shift.

Just because the transmitter puts out rated power says nothing for receive. Back in the daze I gave people those "extree channels" and quickly found out receive falls off sooner than transmit. Technically speaking, sort of, transmitters are broader than receivers so it's like I said, diddling it down to 11M de-tunes 10M so your sensitivity and S/N ratio is suffering.

I don't know what to tell you BUT you might try a bit of reverse engineering. There are plenty of CB renegade web sites and on one you're likely to find the modification for your rig. At least that will tell you what was messed around with, just work backward and hope for the best.

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Old 11-11-2012, 11:53 AM
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If it has the 27 MHz modification performed to it then I would check the sensitivity under 28 MHz.

There is the possibility that the receiver pre-selector tuning has been optimized for the CB end of the band.

Even though your antenna is tuned for 28.4, MHz if you compare the receive noise at 27 MHz to that at 28.4 MHz is there any difference?
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Old 11-11-2012, 1:28 PM
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mm,

Just checked, the noise levels are the same...

SSB 1-3 on the meter
AM 4-5 on the meter

Doesn't matter which band I'm on its about the same....

I'm listening to 28.4mhz now, I hear some... no idea who, he hasn't bothered to give his call in quite a while... but, he seems to be working people like crazy, I can't hear anyone except him.
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Old 11-11-2012, 2:36 PM
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Quote:
Originally Posted by KR0SIV View Post
I have a President HR-2510 (25watt) 10m radio.

It's SWR is nearly 1:1 on 28.4Mhz, when I call CQ people seem to be able to hear me just fine but... when I get a reply they are so quiet and buried in noise I can't make them out, just that I hear them copy my callsign.

The antenna is an 18' 2" vertical mounted 12' above ground and grounded with a new 8' ground rod that is 7' into the ground.

The radio is powered by an ATX pc supply hooked into a line condition with a ferrite core in place on the DC side before going to the radio.

I do on occasion hear someone loud/clear but they are usually talking to someone else that I can't hear without blasting the radio....

With the gain all the way up the noise is at about 3 on the meter, I can hear people but they are so quiet even blasting the radio is not enough for me to copy them in the noise.


Is this just an issue of my antenna's height? I'm not sure whats going on.
oh, the radio is connected with RG-8X

Any help is very much appreciated.

While it can't be repaired over the net it sounds like an AGC problem. i have several of them all modded and function well.
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Old 11-11-2012, 8:40 PM
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Oh dear, you can't check receiver sensitivity with noise because most of it is generated by the receiver front end itself. To do it right you need a Station Monitor (professional radio shop equipment) but a crude method is to inject a weak carrier and observe the S meter reading. That means the injection level must be the same across frequencies and that's where the Station Monitor comes in, they're specifically calibrated for the purpose.

"...he seems to be working people like crazy, I can't hear anyone except him."

Sounds like a band opening and that's no way to judge receiver performance. The strong station is coming to you via sky wave and the others are in a skip zone. The word "skip" is often misused and misleading, you can't hear skip because the signal is skipping over you.
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Old 11-11-2012, 9:42 PM
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i can't remember if the 2510 has an Attenuater switch or not....i think it does...check...if it does, turn it OFF....

then, like someone else suggested, hook up an another external speaker or headphones.....it may be your internal speaker is acting up...//also check AGC.....

check to make sure you're on USB too....

sounds like much of what you report may be poor band conditions....hard to diagnose with your terminology...sorry.

HR-2510 is a nice radio...it has a SHARP receiver with great sensitivity.....i used it during the 2001 sunspot cycle as a QRP rig running page after page of JA's on cw......had a much better RX than my FT-101E.......

good luck
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Old 11-12-2012, 12:09 PM
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Since no-one else has mentioned this....

Try a different power supply! Computer power supplies are huge noise generators.
Try an analog supply or even a battery temporarily.
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Old 11-12-2012, 7:02 PM
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Quote:
Originally Posted by smason View Post
Since no-one else has mentioned this....

Try a different power supply! Computer power supplies are huge noise generators.
Try an analog supply or even a battery temporarily.
This is great advice, as good now as when post 8 was written
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Old 11-12-2012, 10:33 PM
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Quote:
Originally Posted by JnglMassiv View Post
This is great advice, as good now as when post 8 was written
LOL oops. Sleep deprivation (puppy) that's my excuse and I'm sticking to it.
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Old 11-12-2012, 11:31 PM
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What kind of antenna are you using, a multiband? That 18'2" vertical isn't going to be a 1/4 wave (or a 1/2, or 5/8) on 28.4 Khz, no idea why you see a SWR as low as you are. Since it's not close to being resonant it doesn't surprise me that you hear little and aren't being heard. How did you come up with that particular length?
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Old 11-13-2012, 12:02 AM
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Quote:
Originally Posted by LtDoc View Post
What kind of antenna are you using, a multiband? That 18'2" vertical isn't going to be a 1/4 wave (or a 1/2, or 5/8) on 28.4 Khz, no idea why you see a SWR as low as you are. Since it's not close to being resonant it doesn't surprise me that you hear little and aren't being heard. How did you come up with that particular length?
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Because 8' 2" is a 1/4 wave Vertical and is resonate at 28.4Mhz (not khz, not sure where you got that...)
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Old 11-13-2012, 12:08 AM
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Quote:
Originally Posted by barefootdipole View Post
i can't remember if the 2510 has an Attenuater switch or not....i think it does...check...if it does, turn it OFF....

then, like someone else suggested, hook up an another external speaker or headphones.....it may be your internal speaker is acting up...//also check AGC.....

check to make sure you're on USB too....

sounds like much of what you report may be poor band conditions....hard to diagnose with your terminology...sorry.

HR-2510 is a nice radio...it has a SHARP receiver with great sensitivity.....i used it during the 2001 sunspot cycle as a QRP rig running page after page of JA's on cw......had a much better RX than my FT-101E.......

good luck
I'll look into the ATT, but I didn't see one anywhere on the unit.
I'll look into an AGC issue and external speakers, I am on the Upper Side-band of course.

Some people have suggested poor band conditions, its possible... I've only worked HF once and I was along side an Xtra so I really don't have a sense for HF yet.

I thought we were at the peak of the Solar Cycle and the band was supposed to be at its best.. am I missing something here?

As per someone mentioning the supply, I'm working on a better one, right now I've moved it as far away from the rig as I can and added a ferrite core to the DC end of the supply.

EDIT

I also wanted to mention again.. While I'm working on getting my antenna higher its currently mounted at 12' from the ground.... 13-14' from the ground to my RX radials. I'm trying to get it another 10' off the ground but.... with winter rapidly approaching that is going to become difficult.

Last edited by KR0SIV; 11-13-2012 at 12:11 AM..
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