| Author |
Message |
    
Cobra2000
New member
Username: Cobra2000
Post Number: 4
Registered: 6-2007
| | Posted on Sunday, July 08, 2007 - 11:05 pm: | 
|
Is anyone still manufacturing these varactor diodes? (NTE,ECG,etc). I need one for D35 in a Grant XL. Part numbers would be helpful anyway. I have a 10-turn 20K clarifier control. Maybe I can track down a NOS piece - crossing fingers. ;)
Thx,
Dan |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2581
Registered: 9-2004
| | Posted on Tuesday, July 10, 2007 - 11:12 pm: |
|
you are most likely not going to find one of those.
NOS or not.
they were specially manuafactured for a specific purpose and they are not made anymore.
the NTE612 can be used, but doesnt give quite the range that the super diode did.
really there is not much use for one.
without any mods to the circuit but cutting D52 and R44 (i think), and applying 8 volts to the clarifier from pin 1 of the MB3756 voltage reg.
you should be able to slide between 12-14 khz.
some will slide up to 17khz.
if you do the 10khz mod to the PLL, then you never need to slide more than 5 or 6 khz in either direction anyway.
one more trick for more slide is to add a 5.6uH choke to the banded end of D35.
just remember that the more slide you have, the more unstable the voltage is, and it can make you sound like crud on SSB.
best of luck,
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
|
Dale
Advanced Member
Username: Dale
Post Number: 986
Registered: 12-2002
| | Posted on Wednesday, July 11, 2007 - 5:31 am: |
|
alo makes it slightly hard to tune cause the the
slighesdt bump of the clarifer and off freq.
youll go.i like having a 10k swith with a clasrifer that slides 2-3khz.max slide of 5khz.
but thats just me
dale/a.k.a.hotrod
cef426
cvc#64
|
Cobra2000
New member
Username: Cobra2000
Post Number: 5
Registered: 6-2007
| | Posted on Wednesday, July 11, 2007 - 11:15 am: |
|
KV:
Basically, the radio comes stock with a NTE612 equiv. I read that you could run 2 of these in parallel to double the capacitance, thereby increasing the slide range, but I think that will just skew the slide too much one way...I could probably run a NTE613 and do the same thing.
I have 6K +/- now (total of 12 KHz) with a 20K ten-turn Amphenol pot, SSB is still very stable, I figured I could get a little more out of it...
the 10-turn is actually overkill at the moment.
I have the 5.6 uH choke, but didn't put it in. It has a tuning slug in it, but is a little on the large side. It came with the 10-turn pot.
I just like to experiment a little. ;) |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2584
Registered: 9-2004
| | Posted on Thursday, July 12, 2007 - 7:00 pm: |
|
i sure understand about the experimenting.
if you are wondering what is possible if you had all the right parts, i know of a guy who got almost 100khz of slide in his 2000gtl. thats no typo. 100khz.
he was a nut, but a very smart one.
i have personally experimented with the NTE612-614, and didnt notice much difference between them.
i will tell you that the radios with the big crystal in them slide about 5khz further than the ones with the small crytal.
it sounds to me like you have it just perfect right now. thats how i run mine.
nice to get a single knob from another 2000GTL to get the look right.
i dont find my 10 turn to be overkill at all.
the stock clarifier slid maybe 1.5khz in either direction. increase that to 6khz in either direction and you've got a very touchy control.
the 10 turn also makes the radio more stable.
have fun,
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
|
Dale
Advanced Member
Username: Dale
Post Number: 989
Registered: 12-2002
| | Posted on Thursday, July 12, 2007 - 9:12 pm: |
|
hey kv i gotta cobra 2000 over here im trying out for a friend of mine.it been channeled out
and pretty sure it has a 10turn clarifer.question is this it has a single toggle
switch up/down in aux jack flick it up and the
radio capable of .415-.995.with only 1 ch. below
ch.1.of clarifer.how was this capable it doesnt
skip many freqs. just a couple and ya can pick
them off the clarifer.can ya tell me exactly
what i got.and how they did the freq. mod cause
thisa is awsome
dale/a.k.a.hotrod
cef426
cvc#64
|
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2588
Registered: 9-2004
| | Posted on Wednesday, July 18, 2007 - 3:03 pm: |
|
sorry dale, i didnt see this until today.
sounds neat!
.415-.995 is more than 40 channels, so im not sure how they got that on one switch.
to me that doesnt sound possible.LOL
maybe a crystal switch or something.
what do you mean about below ch. 1?
take the covers off the radio, and follow the wires from the freq. switch back to the board and tell me what you find.
a separate PC board?
a relay?
a crystal?
do the wires go to the PLL (MB8719 or MB8734?)
im very curious about this too.
if you can take a pic or two and put them in the members pic area that would help alot.
interesting.....
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
|
Dale
Senior Member
Username: Dale
Post Number: 1003
Registered: 12-2002
| | Posted on Wednesday, July 18, 2007 - 4:26 pm: |
|
i sorry i forgot to mention it has a 10 turn clarifer.which actually picks up those skipped channels,.what i mean below ch. 1 is radio only
goes dowm to 26.9550 off the clarifer.which has
been modifed to a single knob pervious owner
marked as vfo.ill see if i can get radio back
again.i was testing it out cause my friend was in disbelief as you.he not allowed antennas so
i checked it out.i think the pll was MB8719
dale/a.k.a.hotrod
cef426
cvc#64
|
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2589
Registered: 9-2004
| | Posted on Wednesday, July 18, 2007 - 5:49 pm: |
|
AHA!!!!
i knew it would come to me.
i think the radio has what is called a "99er"
kit in it.
it was a kit sold over 20 years ago that gave the radio this exact freq. range, with 27.995 being ch.99
if i remember correctly, it also read these extra channels out on the LED display, so that .415 would be ch.41 on the display, and on up from there to ch.99.
if this is what it is, then you will find a small PC board somewhere in the radio, probably near the PLL somewhere.
it was a neat kit, and is somewhat like the mod i have done to my 2000gtl with the three LED's which read -79 to 108.
the A channels read out as 19A or 3A too.
very neat.
if you've not seen it, i have pics in the members pictures area.
sounds like your friend has a sweet radio!
tell him its not supposed to do that and its damaging the radio every time he turns it on.
then tell him you need a few parts out of it, and offer him 50.00 for it.LOL
JUST KIDDING!!!
later,
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
|
Dale
Senior Member
Username: Dale
Post Number: 1004
Registered: 12-2002
| | Posted on Wednesday, July 18, 2007 - 6:27 pm: |
|
the only difference is his 2 digit just show only 1-40 thats it.but freq. counter tells the whole story.so it works more like the export
type radio but without a band switch.from what he tells me the orignal owner did all the maintance and mods.was also a ham operator for over 30yrs.when he passed away his wife found it
while clearing out his stuff.she gave it to her
son in law who knows nothing about cbs so he
went to the flea market and sold it to my friend
for a unbelieveable price.he didnt think it worked anymore.couldnt find ext.speaker...lol
dale/a.k.a.hotrod
cef426
cvc#64
|
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2591
Registered: 9-2004
| | Posted on Wednesday, July 18, 2007 - 10:28 pm: |
|
oh man, what a find!
if this guy did his own version of the 99er mod, then he obviously knew ALOT about radios.
i would love to look inside that radio to find out what else he changed and/or improved on.
if you ever have the radio in front of you again, it might be fun to compare it to another 2000 or a 148 in close detail to see what else might be upgraded.
who knows, you may find a mod no one else knows about!
anyway, cool radio, wish it was mine.
take it easy,
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
|
