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Author Topic: Receiver Question  (Read 9589 times)

Online skeezix

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Re: Receiver Question
« Reply #15 on: August 29, 2013, 0157 UTC »
In regards to the other half  if you have some advise on how to sneak a couple of Wellbrook ALA's by her.......

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Offline jazzjester

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Re: Receiver Question
« Reply #16 on: August 29, 2013, 0708 UTC »
In regards to the other half  if you have some advise on how to sneak a couple of Wellbrook ALA's by her.......

"Honey, this big ring only begins to show the amount of love I have for you."



!!!!

Offline jazzjester

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Re: Receiver Question
« Reply #17 on: September 03, 2013, 0709 UTC »
Thanks to everyone that offered up suggestions on the receivers. After three nights of DXing from the perch with the Icom, Kenwood and Sony I was very surprised by what I found. This was no scientific study but done just by ear. I tested all three units on a 71' random wire out of 20 gauge speaker wire, no ground, running from approx 30' off the ground at the end to 14' off the ground at the units. Test was conducted outside on the deck using a regular 120 wall outlet, no extension cords, surge protectors, power strips etc. The Kenwood and Icom were powered by their original power supplies and the Sony on batteries. All lights were off, no microwave, TV etc inside or out, so no interference. The random wire was plugged in to the clip terminals of the Kenwood and Icom but attached to the whip of the Sony with an alligator clip. The test station was Red Mercury Labs on 09-01-2013 beginning at approx 03:00 UTC over 6935 USB. I stumbled on Led Zep as broadcast via Red Mercury on the Kenwood 1000. The signal was faint but I could definitely ID the tune. Happy as hell with the Kenwood but thinking the Icom would make me want to plug into my tower speakers I ran inside, grabbed the Icom and plugged in. After trying every possible configuration of filters, preamps etc I was really shocked that the Icom wasn't nearly as adept as filtering out the background noise as the Kenwood. Hardly able to believe it I switched back and forth several times. Same result. Shaking my head I grabbed a clip and hooked up to the Sony whip and after adjusting the RF was further blown away to find the Sony even clearer. After this test and several others on USB over the weekend I could got similar results. All the options on the Icom are very cool and it does things neither of the other two can. Unfortunately at the present one of those things is not filter out the muck on USB.....
« Last Edit: September 03, 2013, 0843 UTC by jazzjester »

Offline BDM

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Re: Receiver Question
« Reply #18 on: September 04, 2013, 1716 UTC »
Interesting
Radios -- Perseus SDR // Icom IC-7410 // Tecsun PL-660 // Panasonic RF-5000A --Antennas-- Pixel Pro 1B loop - 82' fan-dipole at 40' - tuned MW/BCB 40" loop and 100' receive only dipole
-Brian--North of Detroit--MI-
1710/KHz the MW Pirate Clear Channel (not so much anymore "sigh")

Offline desmoface

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Re: Receiver Question
« Reply #19 on: September 04, 2013, 1754 UTC »
That sony is legendary, so I can't really say I'm suprised.  Kenwood is no slouch when it comes to building receivers, so I'm not really suprised that it outperformed the Icom.  All in all, I'd say you've got some keeper rig's there.

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Offline BoomboxDX

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Re: Receiver Question
« Reply #20 on: September 07, 2013, 1030 UTC »
The question here is what do you mean by 'noise'?  If it was absorbed through the AC line, the fact that the Sony operated on batteries could be a clue as to why the difference there.

I think the R75 comes from the factory with a 2.1 khz SSB filter, whereas the R-1000 came supplied with a wider, 2.8 khz SSB filter. That might have made a difference in what you were hearing.  I think the Sony 2010's narrowest filter is around 3 khz (from what I see on the 'net), so it would be even wider. 

The narrower the filter, the less audio information you're going to have -- which is fine for just voice or CW, but not so great if it's music.

Just a guess, anyway.
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Offline jazzjester

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Re: Receiver Question
« Reply #21 on: September 09, 2013, 0854 UTC »
The question here is what do you mean by 'noise'?  If it was absorbed through the AC line, the fact that the Sony operated on batteries could be a clue as to why the difference there.

I think the R75 comes from the factory with a 2.1 khz SSB filter, whereas the R-1000 came supplied with a wider, 2.8 khz SSB filter. That might have made a difference in what you were hearing.  I think the Sony 2010's narrowest filter is around 3 khz (from what I see on the 'net), so it would be even wider.  

The narrower the filter, the less audio information you're going to have -- which is fine for just voice or CW, but not so great if it's music.

Just a guess, anyway.


Thanks BoomBox. The noise being hiss and atmospheric static. The fridge was the only thing on and it was on a different breaker. I wondered about AC line noise as well. However it sounded similar on all units. I guess I would have to say the Sony seemed to have better ability to pull in the station at that time under the conditions.

In an attempt to limit "noise" this weekend I pounded in two 4' copper ground rods 20 feet apart and daisy chained 3-20 foot sections of wire to both rods and then to a ground terminal on the cabin near the breaker box. I hooked an MFJ 949E Versa Tuner to the Kenwood 1000 and ran the first 20' section of ground wire from the Versa Tuner to the first rod. I'm not sure if it made any difference or not but was picking up Red Mercury Labs and XFM really great using the 71' random wire. Didn't take the Icom this week and the signal from Red Mer especially was so good I didn't even mess with the Sony. Should probably post some new questions on the MFJ tuner and another on grounding. The more I research and play around the more freakin questions I have.....

Thanks for the research on the filters on those units! Taking the Icom next weekend. I have a Par Electronics EF-SWL should be here this week. Will make for some great testing I'm hopin'.
« Last Edit: September 09, 2013, 0857 UTC by jazzjester »

Offline BoomboxDX

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Re: Receiver Question
« Reply #22 on: September 12, 2013, 1519 UTC »
Well, I can't speak for tabletop receivers like the R75 or R1000, but of the portables I have, some just seem more impervious to electrical (and other) noise than other radios. That may be part of the case with your Sony.

My Panasonic seems to reduce noise more than my other SW radios.

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The usual Realistic culprits on SW (and a Panasonic).

Offline Lex

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Re: Receiver Question
« Reply #23 on: September 15, 2013, 0701 UTC »
Receiver noise and overall effectiveness are difficult to judge until you're in conditions that are relatively free of man-made noise.

Before the 2000s most household doodads had to meet FCC standards (which are still technically in effect but ignored for all practical purposes).  Any decent battery operated portable with a whip was good enough for broadcast shortwave listening indoors.

When I lived in a rural area the Uniden Bearcat DX1000 - a modest portatop receiver - was good enough for international DXing with only an inexpensive Radio Shack random wire antenna 20' off the ground.  My ground was just a hollow copper pipe knocked a couple of feet deep into sandy loam.  RFI was practically non-existent, so I heard everything within practical reach of propagation.

Back then I hardly every used my Sony ICF-2010 and Magnavox D2935.

Now that I'm in a typical suburban area a good receiver like the Palstar R30C is only as good as the antenna and man-made noise allow.  Often I get better reception by just walking 50 yards away from the nearest building and power lines with the Sony 2010 or Magnavox portable.  Walking on a few yards away can make a huge difference in apparent signal clarity. A directional antenna like a small loop to null out the worst local RFI can make a big difference too.

I'm occasionally tempted to give up the Palstar but portables tend to be makeshift solutions.  The Sony 2010 isn't ideal for sideband listening because the tuning increments are rather coarse - although it's excellent for AM stations.  The Magnavox D2935 uses a BFO so I can fine tune for sideband, but it's a little drifty and I have to continually retune every few minutes to keep music on pitch - although it's not that critical unless the sideband content is mostly music.  The Palstar is rock solid stable, bulletproof against MW breakthrough, and the narrow filters virtually eliminate breakthrough from opposite sidebands - there have been a few occasions when there were pirates on 6925 LSB and USB, and I could easily isolate one or the other without any QRM just by switching between USB and LSB with the narrow Collins filter.

But the main challenge remains man-made RFI, which varies depending on which doodads the neighbors have turned on at the moment.  Usually it's not bad at night.  But on the unusual occasions when the power goes out and I can use just a portable on batteries, I realize just how incredibly noisy a typical suburban neighborhood really is.
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