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Author Topic: Improving Station for DX  (Read 1333 times)
KJ4DIS
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Posts: 23




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« on: May 04, 2009, 09:06:25 AM »

My main interest is HF SSB DX. I live in a restricted community where no antennas are allowed. I have a 22.5 ft "flag pole" with sixteen 20 ft radials in poor Florida soil with an automatic tunner at the base that allows 200W operation from 40 to 10 meters. I have a Kenwood TS-430S radio. I find that noise (natural and man made) and selectivity (QRM) are my biggest problems. As a next step to improve my station for DX, I see I have four choices:

1) Add more radials. However, I doubt that I can gain more than one dB with perhaps 24 radials and no more than 2 dB with a lot more radials. I understand that 2 dB change is just noticable, so this doesn't appear to be a great choice.

2) Install some type of stealth directional antenna to reduce noise. I can install it in the attic or flat on the roof. I would need a switchable pair at right angles to get full coverage, or a very small antenna with a rotor in the attic. However, its not clear that the  radiation angle will be low enough to compete with the vertical.

3) Add a SSB IF filter to the TS-430S to improve selectivity and live with the noise. This choice seems like a waste of money.

4) Upgrade my radio to one of the new entry level units or older used units that have DSP and improved selectivity. I'm leaning toward this choice.


How should these steps be ranked in importance? Have I missed some other potential improvement?
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WB2WIK
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« Reply #1 on: May 04, 2009, 10:32:02 AM »

>mproving Station for DX       Reply
by KJ4DIS on May 4, 2009    Mail this to a friend!
My main interest is HF SSB DX. I live in a restricted community where no antennas are allowed. I have a 22.5 ft "flag pole" with sixteen 20 ft radials in poor Florida soil with an automatic tunner at the base that allows 200W operation from 40 to 10 meters. I have a Kenwood TS-430S radio. I find that noise (natural and man made) and selectivity (QRM) are my biggest problems. As a next step to improve my station for DX, I see I have four choices:

1) Add more radials. However, I doubt that I can gain more than one dB with perhaps 24 radials and no more than 2 dB with a lot more radials. I understand that 2 dB change is just noticable, so this doesn't appear to be a great choice.<

::You might gain more than you think.  If you have the possibility to add more radials, I'd certainly do it: Very small investment for potentially surprising results.  However, an option you did not mention is simply adding more height to the flagpole vertical!  22.5' isn't bad, but 33 feet is better and will surely improve performance on 40m.  It will make 20m a bit difficult to match but if you have a very good auto tuner at the base, it should be able to find a match.

>2) Install some type of stealth directional antenna to reduce noise. I can install it in the attic or flat on the roof. I would need a switchable pair at right angles to get full coverage, or a very small antenna with a rotor in the attic. However, its not clear that the radiation angle will be low enough to compete with the vertical.<

::For transmitting, it won't.  It's very unlikely any sort of small indoor antenna will transmit better than the vertical outdoors; however, it might be useful for "receiving," which means you'd need a way to use two different antennas with your rig: The vertical for transmitting, and the indoor low-noise antenna for receiving.  A very good low noise receiving antenna is a mag loop; many designs are available on the net, or you could buy a commercially built one like the "MFJ Super Hi-Q Loop" product, which is very good.

>3) Add a SSB IF filter to the TS-430S to improve selectivity and live with the noise. This choice seems like a waste of money.<

::A narrower filter probably won't do much for "noise" at all, but might help QRM from ham stations operating very close together.  Overall, probably not a great investment for a TS-430S as the rig is quite old and lacks many features that are standard today.

>4) Upgrade my radio to one of the new entry level units or older used units that have DSP and improved selectivity. I'm leaning toward this choice.<

::That probably is a good choice.  You want not only improved selectivity, but improved noise blanking!  Some rigs are very good at this, some are quite poor.  The "entry level" rigs lack performance of the higher-end rigs, so a "high end" used transceiver is often a better deal than a new "entry level" one.

WB2WIK/6
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KB9CRY
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« Reply #2 on: May 04, 2009, 10:32:44 AM »

5)  Move
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AA4PB
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« Reply #3 on: May 04, 2009, 10:35:20 AM »

I think you are about maxed out on the antenna as far as making any significant difference. That leaves the radio. One of the newer radios with IF DSP may help with both the selectivity and the noise issue. You also may be able to eliminate some of the noise at its source. First eliminate anything that is coming from your own house. Next determine if any of it is coming from the power lines and see if you can get the power company to assist in eliminating it. It's probably difficult to get neighbors assistance in reducing noise comming from their houses if you aren't permitted to have any antennas.
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WA7NCL
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« Reply #4 on: May 04, 2009, 02:17:32 PM »

Switch modes to CW or PSK31.  Your signal to noise improves proportionally to the reduction in band width.   With a 100Hz bandwidth, your noise is reduced 20 to 30 times over SSB.  Thats a gain of 13 to 15 db!

For PSK 31 a hand me down computer running win95 or win98 will work just fine.

For CW you will need to train the brain.....
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N4KZ
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Posts: 594




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« Reply #5 on: May 05, 2009, 06:13:36 AM »

I agree with WB2WIK that adding more radials might yield more improvement than you think. Years ago, I saw significant improvements with my ground-mounted Butternut multiband vertical as I went from 8 radials to 20 then to 40 and finally to 60.

And some radios have better noise blankers than others. As much as I like my Icom Pro 3, its noise blanker is nothing to write home about. I have three other lower-end, cheaper radios in the shack -- all Yaesus, by the way -- and their NBs are more effective than the Pro 3. I can recall one ARRL 10 meter contest in which a leaky neighborhood transformer was so bad that I had to switch from the Pro 3 to a FT-857D to continue working the contest. The power line noise was that bad and the Pro 3, which is otherwise a great radio, simply didn't get the noise blanking job done while the much cheaper 857D did. If you can arrange it, get some face time with different rigs to check out their NBs before making a purchase.

73, N4KZ
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KB1NXE
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Posts: 301




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« Reply #6 on: May 05, 2009, 08:28:16 AM »

KB9CRY,

   I've read your drivel and negative comments on altogether too many post.  Grow up, find a hobby that makes you happy or commit suicide.  Did you miss the lesson on playing well with others and if you have nothing good to contribute - shut up?  If you did, here they are again for your learning pleasure.

Thanks.


To the rest of the readers, I apologize.  I'm sure he'll make some comment about 'changing the channel'.  At least his call fits his personality.
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KB9CRY
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« Reply #7 on: May 06, 2009, 05:50:55 AM »

I just answered his final question:

Have I missed some other potential improvement?

5) Move
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KB1NXE
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Posts: 301




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« Reply #8 on: May 06, 2009, 06:34:34 AM »

There was no question 5.  "Move" is an unreasonable and completely unnecessary comment.

Your motive appears to be to incite strong emotion and controversy.  There is no need for that.  We try to be helpful.  Not inflammatory.  You, on the other hand, almost always try to incite an emotional reaction and do it in a negative means.  This is normally called "Trolling".  It results in you being disregarded and laughed at.  If this is your goal, congratulations on it's achievement.
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W3LK
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« Reply #9 on: May 06, 2009, 07:17:51 AM »

Ignore him, Phil. Some people can't handle non-politicly correct answers.

73,

Lon - W3LK
Naugatuck, Connecticut
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A smoking section in a restaurant makes as much sense as a peeing section in a swimming pool.
NI0C
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Posts: 2383




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« Reply #10 on: May 06, 2009, 09:00:06 AM »

"Grow up, find a hobby that makes you happy or commit suicide. Did you miss the lesson on playing well with others and if you have nothing good to contribute - shut up?"

Wow, those kinds of remarks sure aren't very exemplary!

I thought Phil's advice concerning moving was pretty realistic in this case.  Steve also presented another good idea concerning a bigger antenna. Otherwise, QRX for more sunspot activity.  

73,
Chuck  NI0C
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NN4RH
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Posts: 304




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« Reply #11 on: May 06, 2009, 03:29:51 PM »

Quote

Your motive appears to be to incite strong emotion and controversy. There is no need for that. We try to be helpful. Not inflammatory. You, on the other hand, almost always try to incite an emotional reaction and do it in a negative means. This is normally called "Trolling". It results in you being disregarded and laughed at. If this is your goal, congratulations on it's achievement.


Actually YOUR posts are the only ones in the thread that seem liked Trolls to me.  

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KJ4DIS
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Posts: 23




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« Reply #12 on: May 07, 2009, 07:51:58 AM »

Let's call a truce and get back to the issues. Thanks for your suggestions.

A couple of you have suggested that there might be a better stealth DX antenna than a vertical. I have reviewed the AARL Antenna Book and have not found a stealth antenna that appears to out perform a vertical - low radiation angle signal and S/N ratio. Please let me know if I have missed anything in that area.

Others have suggested that an older radio might have improved performance over one of the current entry level rigs. Suggestions for specifical models would be appreciated along with why you believe it is a better choice.
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W3LK
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Posts: 5644




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« Reply #13 on: May 07, 2009, 08:11:38 AM »

There's nothing basically wrong with your antenna installation. It's fine for DXing just like it is. Your rig, I would replace with something a lot newer, however. I have a 430 myself and it's a far cry from the newer rigs and it has spent the last 10 years sitting in the garage.

QRN is electrical noise or atmospheric noise. Find the source of the electrical noise and deal with that.

QRM is man-made interference, generally other radio signals, and the best cure for that is a more selective rig with better filter options.

73,

Lon - W3LK
Naugatuck, Connecticut
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A smoking section in a restaurant makes as much sense as a peeing section in a swimming pool.
NI0C
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Posts: 2383




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« Reply #14 on: May 08, 2009, 05:30:10 AM »

You may wish to check out ways to improve your antenna (or build another one) through top-loading. A good book with some practical advice on this is Jerry Sevick's (W2FMI), The Short Vertical and Ground Radial: Design, Theory, and Construction for HF systems that work, published by CQ Communications.  

He even has a 40 meter vertical disguised as a beach umbrella.

73,
Chuck  NI0C
 
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