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Author Topic: Best HF receiver with lowest noise floor  (Read 3655 times)
KD7RDZI2
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Posts: 135




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« Reply #15 on: January 02, 2017, 11:35:43 AM »

I also don't understand (or believe) the ole', "radio A can clearly hear signals that radio B doesn't even know are there". One of those radios is busted.
N4UE

I agree. Even cheap portables (Degen DE1103, Redsun RP2100, Tecsun PL660) do hear quite the same of tabletops. They have plenty of sensitivity just as super expensive transceivers. The main drawback in portables is the front-end. Bandpass filters usually are non existent or poor at best. When connected to big arial you hear a mess, but if you use RF bandpass filters or a good preselector you cannot hear much difference between a portable a tabletop, unless during a CQWWCW contest. What I cannot understand in the Ten-Tec 340 test is the extremely poor figures in the dynamic range and 100kHz Blocking published in the http://www.sherweng.com/table.html come on it cannot be worse than a RTL stick!
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K1VCT
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Posts: 49




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« Reply #16 on: January 02, 2017, 02:49:03 PM »

Totally agree that even the cheapest radio will generally "hear" and generally have a sufficiently low noise floor that it becomes a non-issue when other sources of noise are present.

I've personally had good results with the TimeWave ANC-4, but I've heard lots of good about the MFJ unit as well (can that be??!!).  There are a few online pages about easy mods to the MFJ, which seem to favor that unit over the TmeWave for that reason.

I dunno.  Just a thought.  I've got nasty noise here in the house, source yet to be determined, but the external (roof mounted) vertical has a good six S-Units less noise.   The ANC-4 can be set to phase out almost all of it.
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HFCRUSR
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Posts: 202




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« Reply #17 on: January 02, 2017, 04:51:58 PM »

+1 the ANC-4. I run my receivers through an AlphaDelta 4-way coax switch to a Wellbrook ALA1530s+ up on my roof. The loop is supposed to ignore a lot of electrical RFI but it isn't perfect (likely because I have it up 50' off the dirt), hence the deployment of the ANC-4. I have the ANC-4 running on another AD two-way coax switch with my scanner, to the D130j on the roof, so it uses that antenna as noise pickup for stuff beyond my QTH. The ANC-4 knocks out a ton of RFI the loop suffers, and when I work that unit with the receivers' NBs, NRs, and even in some instances, a little reverse gain and/or ATT., I can isolate all of the noise as if it were squelched while still getting the desired signals. It takes a little coordinating effort though Tongue
« Last Edit: January 02, 2017, 05:01:06 PM by HFCRUSR » Logged
AUSSIE
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Posts: 49




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« Reply #18 on: January 03, 2017, 04:15:04 AM »

When it comes to receivers they all perform different since i been the hobby for over 35 years never had a portable perform same as a desktop even with the same antenna in fact yesterday i was listening to 5643 usb auckland hf aircraft on my Icom R75 aircraft and ground controller was cleari switched receiver Grundig Satellit 800 could bearly hear the aircraft ground controller was clear maybe when it comes to listening to shortwave radio stations both desktop and portable will be very close as for the 2 wellbrook loops mine are in the garage not being used.

Regards Lino.
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W8JX
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Posts: 10389




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« Reply #19 on: January 03, 2017, 07:30:36 AM »

Quote
"I also don't understand (or believe) the ole', "radio A can clearly hear signals that radio B doesn't even know are there". One of those radios is busted.
SMH.....ha ha"
Yessir, and I  wonder by what mechanism all 1950s Collins military receivers are said to hear more on the AM BCB than modern radios?

Why do so many people believe this crap???  

I think it is because a lot of modern HF rig that cover BCB have there receivers padded with attenuation of 20 db or more on that band. 
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Ham since 1969....  Old School 20 WPM Extra
K0OD
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Posts: 2869




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« Reply #20 on: January 03, 2017, 01:12:19 PM »

True about the front end attenuators on many receivers.

Was curious so I flipped on my old analog TS-850 which has one of those 20dB BCB pads. Still AM stations were deafeningly loud even with the AF gain set on 2 (out of 10). So lack of gain isn't a problem with hearing weak BCB stuff with any kind of reasonable antenna. I'd risk blowing out the Kenwood's speaker and my eardrums if I turned up the AF to seven or eight.

Yes, many modders remove those attenuators but I've never seen a need. Also I figure that Kenwood engineers know more about the 850 than I do. 
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VA3VF
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Posts: 52




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« Reply #21 on: January 04, 2017, 07:35:22 PM »

The pad is there for a reason, and that reason makes most hamradio transceivers not suitable for AM BCB/NDB dxing, which is why some people remove the pad. It works for some people, but not for all. In your case, based on what you described, removing the pad would likely not be a good idea.

By the way, the 850 is very popular with LF experimenters, so it does have something else that other hamradio transceivers don't. Keep it, you never know where your radio interest might land you next.

73 de Vince, VA3VF


Yes, many modders remove those attenuators but I've never seen a need. Also I figure that Kenwood engineers know more about the 850 than I do. 
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K0OD
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Posts: 2869




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« Reply #22 on: January 05, 2017, 09:32:04 AM »

There's nothing remarkable about the longwave performance of the 25-year old Kenwood TS-850. Yes, I know a few SWLs say there is. Probably SWLs with 850s to sell! 

How do I know about the 850? Because I own one, and several other longwave-capable receivers. My preference is my Flex-5000 with Palomar VLF converter. The Flex has a panadaptor and a zillion modern features. I find its SAM mode very helpful for longwave reception. The Flex combo can tune down to 10 kHz versus about 100 kHz for the Kenwood.

But in terms of digging out weak signals, they're all about the same. On longwave especially, your enemy is EXTERNAL noise of various kinds and broadcast crud.
 
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VA3VF
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Posts: 52




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« Reply #23 on: January 05, 2017, 09:46:07 AM »

>>>Probably SWLs with 850s to sell! 

That's a possibility. I wish I had done a screen capture of a guy's for sale ad some time ago. It was the best radio ever made bla bla bla. A couple of days latter, he placed a review of said radio. It sounded quite different than the one he sold.  Roll Eyes

>>>My preference is my Flex-5000 with Palomar VLF converter.

I believe most hard-core LF/VLF people use converter's, at least before SDRs.

73 de Vince, VA3VF


There's nothing remarkable about the longwave performance of the 25-year old Kenwood TS-850. Yes, I know a few SWLs say there is. Probably SWLs with 850s to sell! 

How do I know about the 850? Because I own one, and several other longwave-capable receivers. My preference is my Flex-5000 with Palomar VLF converter. The Flex has a panadaptor and a zillion modern features. I find its SAM mode very helpful for longwave reception. The Flex combo can tune down to 10 kHz versus about 100 kHz for the Kenwood.

But in terms of digging out weak signals, they're all about the same. On longwave especially, your enemy is EXTERNAL noise of various kinds and broadcast crud.
 
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K1DA
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Posts: 709




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« Reply #24 on: January 07, 2017, 11:36:33 AM »

A quiet receiver is  going to hear the noise better.
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W1JKA
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Posts: 2044




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« Reply #25 on: January 13, 2017, 08:40:47 AM »

ICOM 7200
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