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HF/MW/LW Equipment - For general and technical discussion of all receivers which cover the HF bands. For HF tranceiver discussion please use the Amateur Radio Equipment forum above.

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  #21 (permalink)  
Old 06-22-2013, 11:01 PM
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RE: SSB 'gurgling':
I noticed this also, on nights when real high noise levels were present. A couple nights ago, there was high noise on all the bands, and SSB was difficult to clear up, and CW had strange harmonic overtones. I could still read the CW but it sounded odd. SW AM broadcasts sounded normal, though.

So I wonder if maybe it's high noise levels that cause the 'gargling' noise you heard. They go above a certain threshold, it makes it more difficult to clear up.

Today I was tuning through the 20, 15, 40 and 30 meter ham bands -- because it's Field Day, the 20 meter band is wall to wall signals. And everything -- CW or SSB -- sounds great. Maybe 4 and a half hours of monitoring, it's all clear as a bell. Of course today I've noticed that the noise level on the bands has been very low.

So maybe the SSB decoder doesn't handle high noise very well.

I'll have to keep track of this and see if the pattern fits.

Other recent observations:
Tuning this radio with the tuner knob is a pleasant experience, it sounds eerily like analog tuning. And it's easier to bandscan with the radio using the tuner knob.

I can set it to 5 khz and using it I can scan through the maritime and aeronautical bands without hearing chuffing, or having to press the up or down buttons a gazillion times with my thumb (like I have to do with my DX-398). When I come across a signal, just press the tuner button in and slow down to 1 khz, or use the clarifier.
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  #22 (permalink)  
Old 07-05-2013, 3:08 PM
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Hello Boombox,

I'm more than satisfied with the Radio Shack 20-629. From here in Virginia, U.S.A., I easily get Shanwick, San Francisco, Gander, Halifax Coast Guard Radio, Hams on 160-meters, and of course New York Radio -- all with an indoor wire. There's nothing more I can ask of it. I think the SSB sounds better, more natural, than on the Tecsun PL-660. My guess is that the AGC is just right for sideband listening.

I see the 20-629 finally getting mention on the internet, but it's largely the sneering type of comments from the predictable crowd. What I'd love to say in response is: it ain't the radio's fault if you don't know what the heck you're doing.


Larry
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  #23 (permalink)  
Old 07-25-2013, 12:07 PM
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I hear ya Larry on the bad rep that some radios get.

One of my SW mainstays is a DX-390 and internet reviews on that radio range from 'atrocious' to 'it's a great radio'.

Every radio has its strengths and weaknesses; I've found that you just have to be aware of whatever weaknesses these portables have and work around them. They still will bring in good reception.

Even some of the best tabletops have their complaints: 'It sounds too muddy'; 'synch doesn't work right', 'not enough features', 'too many features', etc. etc.
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  #24 (permalink)  
Old 07-25-2013, 3:14 PM
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It's like automobiles (well, back when autombiles were automobiles):

You have an Oldsmobile, been driving it for years, then you buy a Chrysler. Well, the Chrysler feels totally different -- it isn't the exact same as the Oldsmobile you've loved, so you say the Chrysler is the worst car ever. Same with radios. Each has its own different personality, so to speak. I think critics make a mistake not understanding that.


Larry
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  #25 (permalink)  
Old 11-13-2013, 9:26 PM
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Did some accidental 'experimenting' with the Radio Shack Synthesized World Receiver 20-629 earlier this week -- I was tuning through the ham bands and the SSB sounded very clear, with no gargling noises whatsoever. But the volume level was lower than usual.

I checked the side of the radio and saw that I had left the DX-Local switch on Local by accident.

The 'gurgling' noises on SSB, which were mentioned earlier in this thread I think are the radio's BFO reacting to the AGC on strong signals. The AGC pumps a bit, and the BFO overreacts.

Switching in the attenuator (setting DX-Local to 'Local') cleans up the SSB when this happens, and there is enough volume left on the radio's volume control to compensate for the reduction in gain.

So anymore, when listening to 20 meters or 40 meters and the SSB signals are very strong, I just switch in the attenuator and turn up the volume control, and the SSB then sounds fine. Same with CW.

Still, I wish this radio had an RF control, or the 'Local' setting had a bit less reduction.

FWIW the AGC works fine on AM modulation -- it doesn't pump like the AGC does on my DX-398.
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  #26 (permalink)  
Old 04-14-2014, 6:19 AM
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Default Review for Radio Shack #20-629

I'd bought a very cheap FM and MW/SW radio off eBay when I'd seen this model on sale on Radio Shack's website. Just like everyone else, I'd seen accounts that stated it was a re-branded Sangean. I think every indication on the 'Net says it's the ATS-505P. There is a chance it's an ATS-505.

Having said that, it didn't make sense to me that it was $60 versus $125 Sangean at Radio Shack. I literally jumped at the chance to get the same radio for half price, driving the 40+ miles into Tulsa. The first unpleasant surprise was that there was not an AC adapter nor any batteries included... or any other accessories. So I spent the $5.41 for 4 AA batteries from their store.

The first pleasant surprise was the sound quality. The second was picking up Kentucky hams on SSB inside the first hour. As someone stated previously, it does take a bit of finesse with you trying to pick up on the voice pitch on which way to tune or to move up or down 1kHz. For the first night, was slightly disappointed with MW reception but figured it could have been atmospheric conditions (storms in the outlying areas).

Out of excitement, rigged an indoor wire antennae with 1 vertical and 3 horizontals the next night. I did notice an improvement in reception but at the cost of additional noise. The following afternoon, rigged a simply long-wire outside and had my 2nd pleasant surprise... sounded great and picked up hams from Arizona, Missouri and one guy in St. Lucia!! Even some CB'ers.

The next time I'd used it, noticed some patter or thumping. I stopped using the wire antennae, turned off the radio or turned it down and it wasn't an issue. Then heard a bunch of rapid chirping sounds in one band (either 10 or 13Mhz, can't remember). Figured it was interference, so ignored the problem.. since it certainly did not exist on MW or FM. The following usage, found it was even worse, so I shut down every electronic device and computer in my room, still a problem. The next unpleasant surprise was when I switched to CW/SSB mode, if I changed the dial, it changed the chirps or patter in regular AM mode!!!

Again, the radio worked well on MW, even proving to have better reception than my first thoughts, since my lil cheapie came in and didn't match it's performance. This unit has a nice look, even if a bit cheap around the numbered buttons and even better feel due to it's size. The BFO tuner could have been a bit bigger and with more range. The next pleasant surprise was when I plugged in my headphones. WOW! The FM reception was already good, but sometimes it was unbelievably good, especially with an external wire.

But I shut the radio off, tired of hearing noise/interference/chirps/squeals and even a "different" sound of the reception with a background howling or sounding like it was inside a food can. Took it to work thinking again, it could be interference. As soon as I turned it on, same issue... repeated fast chirps or thumping patter. I took it back, even though I really loved the overall performance. I still find myself wanting to take a chance on another unit, but that would mean ordering it online from Radio Shack. And if it didn't work, it'd mean having to ship it back or take it to the same RS jerk that helped me with my last return (and that almost shorted me $5!!!).

Due to other issues that arose from that incident, it's certainly curbed my desire to shop at Radio Shack in any form or fashion, even though I'm an ex-sales associate.

I have still not found a suitable replacement, but am definitely hooked on the SSB. So it's either a Degen 1103 or a Tecsun PL-600. The Eton/Grundig G5's look awesome and have great features, but the problems with those seem rampant based upon reviews. I'd really dig having a Panasonic RF-2200 or an Eton/Grunding S350DL, but neither of those receive SSB.
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  #27 (permalink)  
Old 04-14-2014, 3:40 PM
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Boombox said...
Quote:
The 'gurgling' noises on SSB, which were mentioned earlier in this thread I think are the radio's BFO reacting to the AGC on strong signals. The AGC pumps a bit, and the BFO overreacts.

Switching in the attenuator (setting DX-Local to 'Local') cleans up the SSB when this happens, and there is enough volume left on the radio's volume control to compensate for the reduction in gain.
This has always been a problem with reception of SSB on 'domestic' radios. It's because SSB has no carrier for the AGC to work with, so the AGC tries to do it's best on the (very) varying SSB signal. It's constantly adjusting the gain in sympathy with the audio so you get the garbled effect.
Three solutions - put a larger capacitor across the AGC line so that the gain doesn't change so quickly - turn down the RF gain control if there is one - and (as you have found) reduce the signal with the attenuator so that the AGC action is not so prominent.
"Commercial" receivers (aka expensive!) derive the AGC from the audio signal, have tailored time constants (fast attack and slow decay) and product detectors to resolve the SSB to audio better.
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  #28 (permalink)  
Old 04-15-2014, 2:17 AM
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Thanks for the explanation, Martin. I figured it was the AGC overreacting somehow. This also would explain why pulse noise (like powerline hash, sometimes present on the ham bands) would also cause it to do the same thing.

Rancer: Sorry to hear of your bad experience with the Radio Shack receiver. It seems a lot of the modern digital portables have more QC issues than they used to. I was considering getting a Grundig G3 which was on sale a few months ago, until I read the reviews on a couple ham sites, mostly complaining about the bad quality control. It seems rampant in consumer radios anymore.
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  #29 (permalink)  
Old 04-15-2014, 7:53 AM
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Thanks Boombox. And thanks to majaco for pointing out where some of the problems may lie with the portable radios. Yes, it does seem like there are too many issues with newer models. I guess that's why dealing with reputable companies that back their products with great return policies makes a big difference. So if there were a model that was available through those, it'd be a hassle but at least there would be the upside of getting your money back or a replacement.

I probably should have waited to return it since a store return wasn't due in for another couple of weeks. Then could have taken it to some wide open spaces where there would be no electric/electronic interference. It's possible that with time and patience, could have figured out the "trick" to getting past the noise, overloading, feedback or whatever it was.

Was also just looking at G3's on eBay. They do look like nice units. I'm guessing they're general coverage?
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  #30 (permalink)  
Old 04-16-2014, 6:41 AM
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I am pretty sure the G3 is general coverage, and it may also have VHF airband.

The reviews I've read of the radio are generally good -- the MW and SW performance is good, the sync detection works well (and if it doesn't there is apparently an easy fix for it, on a thread on this site). One guy said he wasn't sure the tuning knob felt substantial, but had no problems with it.

So overall, it seems if you get a good one, they're good radios.

The main negatives I read about the G3 were the dud radios that people got -- having to go through one or two to get a good one. Maybe those QC issues have been fixed by now. The store I thought about buying one was a large retailer with several in stock, so I suppose dealing with a dud would be less of a problem if I happened to get one.
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  #31 (permalink)  
Old 04-16-2014, 10:22 AM
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Default Grunding radios

I'd gotten the same impression with the Grundig S450DLX radio, that if it wasn't a dud it was a very good radio. Was on the verge of buying one when returning the receiver I'd reviewed when the guy told me it was a few bucks more than what was advertised as the sale price on their website. I thought the prices were consistent from online and every single store but guess I learned the hard way.
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  #32 (permalink)  
Old 05-03-2014, 3:23 AM
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I just picked one up to play with, and think it is ok for the price range, but ultimately frustrating on strong ssb. No surprise there.

The dx-local switch provided too much attenuation, so in cases of overload growling, the easiest thing to do was to just retract the whip about half-way.

Still, nobody builds them like Sony did. My 7600GR blows the doors off it. Selectable usb/lsb, usable agc, variable attenuator and much more sensitive without overload. Audio quality, especially for weak ssb was also a big deal - when totally uncopy-able on the RS 505, the Sony handled weak sigs with no problem and good audio.

The problem is that once you get a taste of what used to be quality, you'll be disappointed by the current crop of cheap sw radios. The funny thing is that the Sony 7600GR is/was the "low end" of their line.

If being portable means a lot to you, I still recommend getting a Sony 7600gr, even with it's quirks. They are still out there new, although not currently in production.

All is not lost however, - My 7600 has been rotated back to operational status, and the RS faux-505 is now serving as my RF-sniffer for local interference tracking.
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  #33 (permalink)  
Old 05-03-2014, 8:18 AM
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I hear ya on the SSB frustration.

I use my World Receiver more for SW Broadcast listening, and for MW (I use a loop with it on MW, the selectivity is very good. I have no idea which ceramic filter it's got, but it works well).

I've heard good things about the Sony 7600. Never tried one, though. Only Sonys here are an SRF-59 and SRF-42 -- both headset radios that work well, the SRF-59 being more usable -- a remarkable value for the money ($19).
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  #34 (permalink)  
Old 08-08-2014, 3:14 PM
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Radio Shack has this SW receiver on clearance now. With the current promotion of an additional 25% off they can be purchased for under $25.00.

Not all stores have them but I saw them this weekend. I bought a bunch of other crap but passed on this portable since I already have DX398 and a Grundig G3 for portables.

Still wondering if I should grab one to leave in the garage.
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Old 08-11-2014, 2:31 AM
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I have one works good with short wire for antenna jack pretty good on mw too got mine for 30 bucks but it doesent do well on the whip
Ssb is ok I listen to Cw with it alot
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Old 08-11-2014, 4:53 AM
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Quote:
Originally Posted by NYG View Post
Still wondering if I should grab one to leave in the garage.
For that price, go for it. I bought one a few months ago, and have it at my bedside. I have a random wire clipped to the whip, and listen to GHFS with it.

I have been impressed with the FM BCB performance.

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Old 01-02-2018, 7:33 PM
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Well, after a year or so of not using the Radio Shack 200629, I fired it up on SW. SSB worked as per usual, but on SW broadcast stations it puts out a phase shift sound on strong SW stations (which there actually were a few this afternoon). It sounds like the passband is whooshing or something -- like during fadeups, the frequency is moving across the ceramic filter or something. Almost like it's going through a variable speed phase shifter.

I re-set the radio -- does the same thing. Obviously, it's not very stable on SW for some reason -- something messed up in the circuits. It wasn't this way before.

MW is normal, though (uses a separate circuit for MW -- the ATS-505 is set up like a standard boombox or transistor IF chipped radio -- antenna directly to the IF chip).

It was nice while it lasted. Back to the shelf it goes. I don't really feel like digging into it to see exactly which surface mount part is messed up.

I still may use it on MW from time to time.
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  #38 (permalink)  
Old 01-05-2018, 12:40 PM
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^^^^clarification of what I said about MW and SW on the 200629 and ATS505:
On this radio the SW circuits run through a separate IF chain -- several FET's and filters before hitting the IF chip.

The MW goes directly from loopstick antenna to the IF chip -- which is similar to most boomboxes and standard AM radios.

Because I'm seeing issues on SW and not MW, it obviously is a component gone haywire in the SW circuits.... Hence, MW is unaffected...
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Old 01-28-2018, 12:53 AM
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Does the FM BCB follow the same path as the SW?

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Old 01-28-2018, 2:45 AM
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Quote:
Originally Posted by krokus View Post
Does the FM BCB follow the same path as the SW?
No.

FM goes through an FM front end chip (a TA7358 RF-IF amp), and then through an FET amplified IF can into the main IF chip (a TA2057). Just like a boombox, clock radio, etc., except the FET may add to the FM reception. Many boomboxes just go from the front end chip to the main IF chip.

FWIW, Longwave is separate also -- it goes directly into the main IF chip the same way that MW does. I've heard that this radio can do OK on Longwave -- some guy in Maine or New England somewhere claimed to hear European LW stations on his ATS-505, even without an external loop. Might have been conditions were really good, but it shows that it might be able to do a few things aside from LW.

I found the 200629/ATS-505 good on MW, but a loop was needed. The loopstick is a bit thin, and if you're in a low signals area like I am, an external loop is needed.

I found my 200629 a good radio for FM. Some guy in my state uses the Sangean version for DXing FM. I know the FM sounds pretty good through headphones and it seems to pick up fringe FM stations well. Not being an FM DXer, that's the extent of my observations.

Hope this helps.
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