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Barracuda
| | Posted on Wednesday, December 03, 2003 - 10:12 am: | 
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Does anybody know of any equivalent to the ECG583 Schottky diode. I have seen the NTE583 which seems to be the same, but they cost about $2.50 apiece. Not that that is such a problem, but I also saw reference to a 1N5711 diode, which to my relatively untrained eye scanning spec sheets seems the same, but at about $0.13. That's a huge difference in cost, so is the 1N5711 really a viable ECG583 replacement and if so, why the huge difference in cost. By the way, the prices quoted are from the SAME distributor.
Thanks,
Barracuda |
Bruce
| | Posted on Wednesday, December 03, 2003 - 2:43 pm: |
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ive got a supply of 5711 type diodes if you need one |
Barracuda
| | Posted on Wednesday, December 03, 2003 - 5:45 pm: |
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Bruce,
Thanks for the offer, but I ordered 10 of them on the assumption that they would work for what I needed. By the way, back in September, or so, you had mentioned in a post that you cleaned up the receive on a dx959. One of the items you mentioned was a replacement of the rf amp. Would you happen to remember the part that you substituted for the stock part. I'm doing a similar process on a dx959 I have.
The diodes are for the NB and dectctors, Channel Guard is on order and if the RF amp is replaced with a lower noise part that would be OK too. One last addition that I mentioned much earlier this year but never carried out is a replacement of the 1K pot used in the clarifier with a precision 10 turn unit to give more senitivity (mechanical) to the tuning. I don't expect it to change the function of the clarifier at all, just my ability to fine tune it.
Thanks again Bruce,
73
Barracuda |
Ss8541
| | Posted on Wednesday, December 03, 2003 - 9:53 pm: |
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the 5711 is not a replacement for the ecg, it is the opposite. the ecg is a replacement for the 5711. as for why it cost more, the subs always cost more than the originals. not sure why, but that is the case.
the rf amp upgrade is a 2sc2999. you can use an ecg/nte23, but they may go into oscillations. oh yeah you will have to cross the legs of the ecg/nte23 for it to work at all.
the 959, is a newer radio who's rx is pretty sensitive with its own two feet(regardless of the posts you may have read on forums). these upgrades do little for this radio, but you won't hurt it if you want to do them. |
Bruce
| | Posted on Wednesday, December 03, 2003 - 10:56 pm: |
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8541
convenance you get one in a bag and its ready i ordered 100 of them like 11 cents each and still have some around. the 959 i had was moded recive wise ( tinkered with ) because like your self of you can replace it with something better why not.
Results well i did get some and since i had 2 959's i could compair them that 2sc2999 / net23 is VERY unstable i tried 3 in that radio before i got one that worked right but it did make a improvement. I got rid of both replacing them with a grant lt which i simply like better
bruce |
Barracuda
| | Posted on Wednesday, December 03, 2003 - 11:07 pm: |
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Ss8541,
Thanks for the information. I find it interesting that I had problems finding the replacement ecg product when the original was readily available. As for the rf amp., I am not sure that I was even going to do that upgrade. I was curious about what Bruce had done. It would be interesting to hear what his experience was in terms of what difference changing the rf amp made.
I agree with you that the 959 is not a bad radio. I am fairly happy with it, but living in NYC makes it hard sometimes to pick out the signals you want from all the hash and trash of other radios and non-radio noise sources. As an example, the pedestrian walk/don't walk signals put out a tremendous amount of noise, short range. But when driving is residential neighborhoods were the streets are relatively short, the noise patterns overlap and form an almost continuous background noise that at times has completely drowned out the actual signals I wanted to hear. So this is a grand experiment to see if these mods will help or hurt. From all I've read and heard about them, the Channel Guard should help quite a bit too. We'll see.
Thanks again,
Barracuda |
Bruce
| | Posted on Thursday, December 04, 2003 - 8:16 am: |
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the channel guard will help but in some radios will cause problems with blanker but get rid of the joker 5 ch away on my grant im playing with a radio shack DSP filter ....the audio one worked wonders. |
Scrapiron63
| | Posted on Thursday, December 04, 2003 - 10:07 am: |
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Bruce, here's something you need for your old Caddy.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3063137166&category=1501
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Barracuda
| | Posted on Thursday, December 04, 2003 - 12:22 pm: |
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Bruce,
I wish that I only had to contend with jokers 5 channels away. In some areas in Brooklyn and Queens there are commuter van drivers that use CB to communicate, that must think they are talking to people on the other side of the earth. They run quite a bit of power on the AM side of their splatter boxes. So much so that sometimes I hear them across the entire 40. One particular set of these guys operates on 34 AM. Whey they get going 38LSB is useless. |
Bruce
| | Posted on Thursday, December 04, 2003 - 2:16 pm: |
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the channelguard will help but any trash realy on the channel will still be there i found on my grant a large reduction of about 20 db using my ifr gen to simulate the strong station .... if the stations signal was clean that will help get rid of some Now that helps the clean ones the best way is to pin coaxes of the others .... |
Barracuda
| | Posted on Thursday, December 04, 2003 - 3:56 pm: |
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Bruce,
I wish I could pin their coax. But that gets pretty tough to do on a mobile. By the way, I'm sure you'd get a kick out of the antennas these guys use. Most of them are either k40 or wilson mag mounts on top of full sized vans. What is funny about them is the way that they are bent and twisted and "pretzelized". Then there are the guys who don't understand much about radio who mount an antenna on a ball mount on the flat side or rear of the van, way down low so the tip of the antenna is below the roof line, and about 2 inches away from the sheetmetal . One guy in particular made me laugh because he must have gotten tired of the antenna banging into the side of his van so he screwed a metal bracket into the side of the van that the antenna is stuck through about half way up the antenna. I'm not sure how it works but it can't work terribly well. To compensate he probably runs extra power. |
Allagator
| | Posted on Thursday, December 04, 2003 - 6:36 pm: |
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Now that is a idea !!!!
anyone got any pins i can use ???
LOL |
Barracuda
| | Posted on Friday, December 12, 2003 - 4:22 pm: |
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Guys,
The verdict is in. I changed the 4 diodes from 1N60P types to 1N5711 types. I was expecting to have some difference in the receive, but I was not expecting the tremendous difference I got. Prior to the change I had a pretty solid background noise level across the band. Tuning the band on AM yielded few, if any, voices heard. On SSB I had much the same performance as well. With the mod in place, now I hear voices across the entire band on AM and can receive SSB much better on both usb and lsb. I never knew there was so much activity on the band and much of it was not local.
I haven't yet received the channel guard yet, but am anxious to see what difference it will make.
I'll post another update after I make that addition.
73
Barracuda |
Barracuda
| | Posted on Friday, December 12, 2003 - 8:35 pm: |
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Another quick note on the performance change. Previously with the high noise level the signal squelch was useless. Now with the mowed down noise it has become effective at last. This should help when the XYL is in the car. Maybe I'll no longer get the "how can you listen to that thing with all that noise...". |
Mr_Rf
| | Posted on Friday, December 12, 2003 - 10:17 pm: |
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Barracuda, u gotta understand...most XYL's don't know the definition of noise. While we the Om's define it as speaker activity the XYL's define the lights being ON as too noisy!!! hehehe |
Barracuda
| | Posted on Friday, December 12, 2003 - 11:10 pm: |
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Mr_Rf,
Yeah, that sounds about right. By the way, I also get it from my daughter. Sometimes in stereo.
Barracuda |
Barracuda
| | Posted on Saturday, December 13, 2003 - 5:53 pm: |
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Now the channel guard is in. We'll see how that works or what it does, maybe tomorrow on the net.
Talk to you all then
73
Barracuda |
Bruce
| | Posted on Saturday, December 13, 2003 - 8:28 pm: |
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Barracuda it will add about 20 db of rejection at 1 channel and more than 30 at 4 ch away not the 60 they clame but 30 db is 5 "S" units. |
Barracuda
| | Posted on Saturday, December 13, 2003 - 9:07 pm: |
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Bruce,
The acid test is the commuter van gang. We'll see Monday.
Maybe I'll catch you on the net tomorrow, though I haven't heard much North-South skip lately.
73,
Barracuda |
Barracuda
| | Posted on Monday, December 15, 2003 - 11:06 am: |
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Well, I ran the van gauntlet this morning and I have to say that it was like having a completely different radio than the one I had before. The channel guard was able to keep the splatter of all but the worst splatter boxes to 1 channel. Combined with the increased sensitivity of the detectors, I was able to hear stations on 38LSB throughout the entire ride. By the way, I was getting strong N-S skip, picking up Florida, Arkansas, Georgia, etc. Haven't heard from those states in months.
The NB is still not where I would want it, especially for street signals and other vehicles ignition systems in close proximity. But all, in all, I am much happier for having done these modifications and additions, and would recommend them to anyone with a Galaxy DX type radio. BTW, I have looked at the schematics for DX radios other than the dx959 I have and they are all pretty much the same in the receive front end and IF strip. So the mods I made should be applicable to them as well.
73
Barracuda |
Ss8541
| | Posted on Monday, December 15, 2003 - 12:58 pm: |
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barracuda,
don't take this as me raining on your parade. in ssb the detector diodes are useless. those diodes are only used in am detection. the rx signal does not even flow through these diodes during ssb rx. so this did/will not increase ssb sensitivity.
the only diodes that you replaced that are active in ssb rx are the ones you replaced in the n.blanker.
adding the channel guard to these radios lessens the effect of the n.blanker, so this is probably why the n.blanker isn't working as well as you would like.
but, the c.guard does block a lot of other ••••, and this does end up making the radio 'hear' better in real world usage. |
Bruce
| | Posted on Monday, December 15, 2003 - 2:52 pm: |
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8541
The noise blanker problem seems to vary from radio to radio but a cg does effect most of them. Now like most things in life we have a traid off here be splattered into ablivin or lose some noise limitting and be able to hear... I bought a DSP adapter for my ft-840 it has a noise blanking posision on it and does a fair job of limiting noise BTW your right on the diodes i still have a bag of them .....sell you a few CHEEP! HE HE HE.
Bruce |
Barracuda
| | Posted on Monday, December 15, 2003 - 2:53 pm: |
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Ss8541,
Information is always gladly accepted. I ask these questions and post the follow-up specifically to get commentary from people who know more than I do. I appreciate the information you posted above because it increases my understanding. Besides, I have always viewed this excersize as an experiment. I kept all the parts removed and appropriately labeled to place back in the radio if I did not like the outcome or if I wanted to do further experimentation.
As far as the NB, it still is much better than it was before. I had an opportunity to test the radio after the diode change but before the Channel guard as well as after both and the percieved (read, to my human ears under the conditions prevalent at those specific short tests) was not that different.
The end result is a radio I am much happier with and now an increased understanding of why. A Win-Win in my book.
Ss8541 and Bruce, my hat's off to you for your input on this project.
Enjoy your holidays gentlemen.
73
Barracuda |
Barracuda
| | Posted on Tuesday, December 16, 2003 - 6:01 pm: |
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Ss8541 and Bruce,
I was curious about the question of the effect of the CG on the NB so I was doing some reading and looking at the dx959 schematic. Correct me if I'm wrong, but the point at which the rf signal is siphoned off into the noise blanker is immediately AFTER the point in the circuit where the CG is installed (in place of C61). Now, if I read and understood properly about the concern of a steep skirted filter in the MIDDLE of an NB circuit causing a timing issue between the two signal paths, then would that not be a problem here since the filter is ahead of the NB entirely? First, did I get the NB concept correct. Second is my reading of the schematic correct and third is my final assumption correct? If no to any could you please put me straight?
Thanks much,
Barracuda |
Bruce
| | Posted on Tuesday, December 16, 2003 - 11:02 pm: |
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The noise blanker needs a virgin signal to work with. Every time you process a signal either through a tunned coil or worse yet through a crystal array you distort it. The rise and fall time of noise pulses is also distorted because every tunned ckt adds some phaes shift and by its nature frequency limiting and noise pulses nature to be very fast rising and falling they get " flatened out" and the rise/fall time increased and you no longer have a true noise pluse. I have found the channel guard does cause a problem with the noise blanker but in some radios it is not too noticable and the decrease in spaltter is so gteat that it becomes liveable. Placeing the filter after the noise blanker is the ideal place but would require a major rewire of the radio. I just bought a audio DSP filter for my ft-840 it DOES help with noise you might concider a DSP ( NOT CHEEP ) if your noise problems dont go away.
bruce |
Barracuda
| | Posted on Tuesday, December 16, 2003 - 11:24 pm: |
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Bruce,
Thanks for that explanation, it fills in some of the blanks, pun not intended. I have considered the use of DSP. I have even considered experimenting with DSP Eval boards and doing some of the programming myself (did I ever mention that I do that kind of stuff?) I just don't have the time at the moment to undertake such a project. And I really would like to approach it that way rather than store bought (nothing wrong with that, just not my preferred way), maybe a kit. We'll see. Maybe next year when the house is done.
Again, thanks for the input.
73,
Barracuda |
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