Grundig S450DLX Field-Radio

[nanZor]

Bummer - I have to do the same thing to my Tecsun PL-660, but don't feel like cracking it open.

Even though my 450 is spot on, on my 350, depending on if the bandswitch knob was sitting to the left or the right of the next detent (without actually switching) would move me 1k up or down (audibly, not seen on display). I used this "feature" as a super-fine tune. Behind those loose rotary bandswitch knobs are actually slide-switch contraptions. My 450 doesn't exhibit this same problem, but I wouldn't be surprised if there are unit to unit differences.

But like you say, perhaps it is just a bit of mis-calibration.

I found an interesting SSB bfo made for the 450dlx (and some others) on ebay, the "TG37 SSB BFO Adapter". Looks interesting, but I haven't tried it.

 

[ke9oa]

Grundig 450 Power Supply Noise

The problem with the power supply is that there isn't any kind of snubber network to eliminate the noise from the rectifier diodes. What we are running into is conducted emissions of the switching noise of the diodes as they rectify the AC voltage. The Kaito 2100 has the same problem. At the lower end of the AM broadcast band, there is a buzz that you hear. Since this is a conducted emission on the power supply wire itself, you cannot eliminate the problem by moving the radio further away from the power supply unit.
The cure? A 1uF non polarized film capacitor connected across the secondary of the power transformer. Use a cap that has at least a 50 volt rating. A tubular type is fine. Use either a good quality heat shring or spaghetti tubing on the capacitor leads to prevent shorting on the underside of the power supply's PC board.
The end result is a power supply that is dead quiet across the entire tuning range of the receiver.
I don't know why this technique wasn't implemented in the first place. The wall wart for my Yaesu FRG100 had the same problem, so it isn't exclusive to this series of radios.
This type of power supply bypassing has been used in test equipment for decades. I hope this helps.

Pete KE9OA

 

[nanZor]

That helps a LOT, Pete!

I was falsely blaming the supply noise to be due to a switching-type supply, when it might very well be a linear-type without a snubbing network for the rectifier diodes! I might have to take a hammer to it later.

I would run tests against various supplies by running the radio(s) from batteries, and then nearby would put the wall warts into a power strip and switch it on - not connected to the radio of course. Purposely trying to see if it was acting as an rf emitter with a short antenna.

The obvious switching-type supplies just threw out gobs of broadband hash while switching the power strip on and off. Most of my old-school linear supplies were totally clean, but a few smaller linear-types weren't, so I was scratching my head. (I put a small load on the test supplies to make sure that the rectifiers were actually doing something)

Thanks for the tip - that answers a lot of questions. Time for me to visit Mouser I guess!

 

[wizardb]

Just catching up on these forums after being away from the site for a coupe of months. Appreciate the review on the 450. I had read several bad reviews on this radio so I was very doubtful. I purchased a 350 some time back from ebay for $50. Was very disappointed in it and ended up selling it for what I had in it. I looked at the 450 the other day and liked what I saw but as I said was hesitant because of the reviews. Currently down to a Grunding G8 Traveller II. I purchased a Tecsun PL-390 that will be here sometime today. I like DXing on AM and this radio supposedly has a longer ferrite antenna. Also enjoy shortwave. The G8 does pretty good with a 50' long wire clipped to the tele antenna.

 

[nanZor]

I looked at the 450 the other day and liked what I saw but as I said was hesitant because of the reviews.

Reviews, and yes even my own should be taken with a big grain of salt.

Because these types of radios vary so much in quality and environmental conditions, it can be a crap shoot at times. If the reviewer has more radios that have been reviewed, you can kind of get a feeling for just general dissatisfaction, cheerleeding, or worse - corporate agenda.

The 450 I have works great, but that isn't any guarantee that if I popped into RS and picked up another one, it wouldn't be a dog.

But good luck with your G8! I had one, and really liked it. The knobs went the wrong direction for me, but that's not a showstopper or something to prompt a bad review.

And guys remember - this forum doesn't belong just to me....

 

[Zaratsu]

Just picked up a 450DLX yesterday from RS. Wanted to get a Sat 750, but funds are tight at the moment.

I'll edit this post to reflect my thoughts as I get used to this radio.


So far, it is absolutely smoking my Sony 7600GR on all bands just on whip sensitivity. The sony can't keep up with its roll up antenna attached either. Very little electrical noise on the batteries. Just a little buzz on am occasionally. MW performance isn't what I had hoped for, but still better than the 7600G? FM is very nice. Sensitive And clean. The mono setting cleans up any remaining static from FM Dx nicely. On SW, the filter helps a lot too.


Not much extra noise on the AC adapter it seems. Also, the IF noises reported elsewhere are absent on mine for the most part. My radio is from 07/2011, and noted as "version 11" on the box.

I also grabbed the grundig loop antenna. This really helps the MW, but weak stations are still tough to lock. MW is not the least bit fatiguing using to listen to.

Buttons and dials are a very cheap feeling. I think that they will be the weak point in ultimately determining the lifespan of this radio. At least the tuning dial is fairly nice.


Sound is very good. Seems to get better with volume. At lower volumes, it sounds a bit thin, but most will be very happy with it.

The Lack of SSB is not a huge loss, but I'm going to get the TG37 SSB adapter for it from eBay. Even after this, I'll have less than $150 into this radio setup. I'm interested in decoding software and DRM.

Only real gripe is can't shut off all of the key beeps. And the key beeps play even if you have headphones plugged in. Woke up wifey at 3a.m, playing with it on bedstnd. Ooops:lol:

Pretty happy camper here. Understand that I don't have a lot to compare against, but pretty sure that this will be a stepping stone if I decide to go further with this end of the hobby. I'm probably better off with this than the sat 750 anyways. I'm intending to move this from room to room, and outside on the deck. Would like to eventually get a Sat 800, or even a Sat 650, but for now, it's my main unit, and a LOT more fun than my 7600GR

 

[nanZor]

Buttons and dials are a very cheap feeling. I think that they will be the weak point in ultimately determining the lifespan of this radio. At least the tuning dial is fairly nice.

I agree. At least they have a good "feel" during rotation. Those rotary switches are a bit funky too, but so far so good. The radio is definitely not an heirloom, but I really like it overall. It is kind of a shock when first dealing with this generation of build quality these days.

The Lack of SSB is not a huge loss, but I'm going to get the TG37 SSB adapter for it from eBay.

I'd be VERY interested in how this goes. I have a 750 as well, but didn't want to invest in the TG37 for the 450 - so please let us know how you like it on ssb.

Only real gripe is can't shut off all of the key beeps. And the key beeps play even if you have headphones plugged in.

You can disable the keyboard beeps by holding the SNOOZE button down for more than about 2 seconds on the top of the case. To toggle them back on, just hold the snooze button down until you hear a beep. It's a life-saver. Of course you can use it a snooze for an alarm, but I didn't think of trying that at first to kill the keyboard beeps.

Overall, I think the 450 is a great value. My unit was far better than some of the other reviews I've seen make it out to be. Have fun and I'm dying to hear about the SSB bfo adapter!

 

[Zaratsu]

I agree. At least they have a good "feel" during rotation. Those rotary switches are a bit funky too, but so far so good. The radio is definitely not an heirloom, but I really like it overall. It is kind of a shock when first dealing with this generation of build quality these days.



I'd be VERY interested in how this goes. I have a 750 as well, but didn't want to invest in the TG37 for the 450 - so please let us know how you like it on ssb.



You can disable the keyboard beeps by holding the SNOOZE button down for more than about 2 seconds on the top of the case. To toggle them back on, just hold the snooze button down until you hear a beep. It's a life-saver. Of course you can use it a snooze for an alarm, but I didn't think of trying that at first to kill the keyboard beeps.

Overall, I think the 450 is a great value. My unit was far better than some of the other reviews I've seen make it out to be. Have fun and I'm dying to hear about the SSB bfo adapter!

Hertzian,

Will do! It's going to be another month or two because I blew the TG37 BFO budget on a Tecsun PL-380. I couldn't bear it any longer after reading reviews on the newest generation DSP receivers. Six filter widths on all bands on one chip! Really want something hot on FM for the office.

Once I get that done, I'll order the BFO and give a full report.

Also, fooling around with homebrew antennas. Looking forward to laying out 100ft of wire out on the beach next weekend.


Thanks for your tip on the snooze button. However, I should note that if you spin the dial to either end of the band spread (i.e. SW1, 2, or 3) it will still beep audibly even if the snooze button has muted the other keys.

 

[K3DRQ]

Just bought the S450DLX from Universal-Radio. With all the portable-sized modern SW radios, I wanted a radio next to my bed (replacing my Radio Shack SW-100 which finally bit the dust) which I can easily control in the dark. The S450DLX is only slightly smaller than the RS SW-100 I was using, and had lights and a digital display, so I was happy to find it.

Had all the same noise probs too on lower half of AM and various portions of SW with the included wall wart. Using D batteries instead solved the problem completely.

They also gave me the MINI400 portable radio free with the purchase, will have to check it out soon. Also ordered Tao Qu's TG37 off eBay the other day, should be here in a few weeks.

 

[wizardb]

Congrats on your 450. The free m400 is a nice compact portable but I will tell you that I had one for a while and it eats batteries like they were candy. I have a Tecsun PL 660 on the way. Will be excited to try it.

 

[wizardb]

Well yesterday I sold some extra guitar equipment so I had some money to burn. This morning RS had the S450DLX on sale for 75.00. I've looked at it before an liked the looks of it but was hesitant because of all the mixed reviews. I've only had it a few hours but I think I got a good one. Tuning is dead on. I really like this radlio. Everything works as it should. I'm usng it from batteries. It has a build date of 8/2011. Of course, I had to put up with a few comments from wifey--how many radios can you listen to, how many ears do you have(all depends on who I am listening to). Oh well, goes with the territory. Will be interesting to see how it does on distant AM stations tonight. I'll try shortwave later this week. I currently have a Tecsun PL-390, Tecsun PL-660, a Sangean DT-400W (great for hunting AM and a great weather radio) and the new S450DLX. I also have an RCA 3.5" digital television which I really love. Wife is not in good health and retires early. so I can do a lot of listening through the ear phones without disturbing her.

 

[nanZor]

Side Switches are labeled wrong!

It appears that the silkscreen for the side switches are in error - at least on my 450. I've been operating it with an external antenna and have been going by feel so I didn't notice it.

The top switch is truly the dx/local attenuator switch. BUT, the silkscreen label shows it as being the antenna selector.

The middle switch is truly the internal/external antenna selector, but it is labeled as the "am sense" switch.

At least on mine, the labels seem backwards!

Since there is so little isolation in the real antenna switch (the one in the middle) when you attach an external antenna to it, it might be easy to miss as the external just swamps the unit no matter what position the switch is in.

I could see this being a frustrating point if a new owner mistakenly took "dx" to be the external antenna, and "local" as being the internal whip. Don't sweat it - it's just the top and middle *labels* that are wrong.

 

[nz5l]

Grundig S450 DLX

I recently purchsed this radio, and am delighted with the general level of performance, particularly on AM and FM. I had hoped Ten-Tec still had their inexpensive little BFO kit, but, alas, that has been discontinued, so will have to cobble something - does anyone know for sure what the IF freq is on this radio? would hate to invest effort in a 455KHz bfo if this is an oddball. Thanks for any info, 73 Norm/NZ5L

 

[Kc9fje]

It appears that the silkscreen for the side switches are in error - at least on my 450. I've been operating it with an external antenna and have been going by feel so I didn't notice it.

The top switch is truly the dx/local attenuator switch. BUT, the silkscreen label shows it as being the antenna selector.

The middle switch is truly the internal/external antenna selector, but it is labeled as the "am sense" switch.

At least on mine, the labels seem backwards!

Since there is so little isolation in the real antenna switch (the one in the middle) when you attach an external antenna to it, it might be easy to miss as the external just swamps the unit no matter what position the switch is in.

I could see this being a frustrating point if a new owner mistakenly took "dx" to be the external antenna, and "local" as being the internal whip. Don't sweat it - it's just the top and middle *labels* that are wrong.

Mine is dated as 20110801and the labels are correct on the side. I'm suprised they let one slip through mislabeled.
That said mine usually only gets pulled out for camping trips. I've also used it as a station monitor when I operate AM a time or two to make sure my settings on my icom were good to go.