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Message |
    
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2505
Registered: 7-2004
| | Posted on Friday, March 03, 2006 - 7:08 pm: | 
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after returning from PA last week, noticed my XL's s/rf/cal switch was loosening up from the chassis. had some spare time so i removed it from the truck took apart the radio & tightened it up. while apart, i replaced the 'stock' clarifier control with a (cheap, mostly plastic) 10 turn 100k ohm pot i purchased on an auction to experiment with. i had never placed a 10 turn pot in THIS particular radio, & had opened the clarifier & redone the mod several times, to be sure to be able to obtain 'A' channels. i never put a 10kc switch in this particular radio, either, so i went with the W I D E open clarifier. needless to say, when COLD, it was 3-4 kc's off, & after 30 minutes, was relatively stable. i had gone back & forth between that mod, & a 3-5 kc mod several times because of the drift. but, 'A' freqs got the nod.
well, i put this 10 turn pot in, not sure what to expect because 100k ohms is a little more then normal for this mod. after 3 days, once the radio/truck interior is up to temp, drift is practically non-existant-on my 6 digit counter. AM, even SSB, 30 minutes later, the guys are still on the same freq, i don't have to move 1 kc to find 'em.
the pot is kinda cheesy feeling, the hole in the chassis needs to be enlarged, & while the physical size of the part is intimidating, it slides neatly into place without any difficulty. it does not have the notch in the shaft like the stock piece, but by removing the insert in the knob, it fits tightly. 2 for $9 was a cheap price to pay to 'test' 'em out, & i have been more then happy with the results thus far.
also, after tightening up the loose switch, some hash & trash i'd noticed 'bouncing' in & out of the radio the last few days disappeared. |
Hollowpoint445
Senior Member
Username: Hollowpoint445
Post Number: 1116
Registered: 6-2004
| | Posted on Friday, March 03, 2006 - 8:07 pm: |
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100K is 5 times the value of the normal clarifier - that's more than a little larger!
By W I D E open do you mean that there is no resistance in the circuit other than the potentiometer?
Do you get frequency adjustment throughout the entire 10 turns or is there lots of adjustment in the first two turns and it drops off after that? |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2506
Registered: 7-2004
| | Posted on Saturday, March 04, 2006 - 10:41 am: |
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yup, the 10 turn pots that were available years ago(& while PROBABLY better constructed, cost 20 bucks EACH!) were 20k ohm.
i'm sure you're familiar with the various clarifier mods for these radios, the standard 'cut D & R, jump R & move voltage to XMIT'. as i said, whenever i had that mod done, i'd realize i needed more room. so, i'd change another D (35, possibly) & add inductance to it, usually around 4.7uh to get total slide of around 25kHz(17 down & 8 up). W I D E referred to THIS mod. and yes, it can be sloppy. when ICE cold, the radio can turn on 3-4 kc's HIGH, when the air temp is 60 or above, turn on is usually only about 1kc high. within 15 minutes(when warm out) to even more then 30 minutes when COLD, it stabilizes-pretty much. with 6 digit counter, it could occasionally use a 'nudge' when on SSB, even when HOT. on AM, it never really amounted to any problems.
it is consistent when tuning through 10 turns. no longer does a 'nudge' change a persons tone completely, but i get less then 3 kc's per turn. sitting for 11 hours last night, outside in 18 degree temp, when i started truck, i was on 27.0261, from 27.0250 at shut down. MUCH BETTER then before. & in 15 minutes you could watch 100 Hz click down almost every minute. once it got on freq, it stayed there. just ran out to truck now, 25 degrees, but sitting in sun for 2+ hours, cab temp has to be 55 or better, & radio turned on dead on 27.0250. i have also noticed i am tuning closer to 'dead center' then i have been in recent months when on SSB. some people that i tuned 300-400 up or down for, are now on '0', or '1' at the worst. (when i tuned to them, even @ 400 hz off, they never said my xmit was off, so i guess i can assume it was something with the W I D E tune instability, & not that i was truly 'off freq').
no, the feel is NOT the same as the stock pot. nor is it the same as the old 10 turn pots made for this purpose. not that i've really looked, but i haven't seen those for sale in, maybe 6-7 years or even more. and, yes, a 10kc SWITCH & the normal 6-7 kc mod would work just as well. i think it'd be really 'cool' with the lesser-slide mod!
for the price, & performance i've seen, i'm more then satisifed. even if i do get around to adding the 10 kc switch-in any form-i'd probably leave the W I D E slide & 10 turn pot intact... |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1254
Registered: 9-2004
| | Posted on Saturday, March 04, 2006 - 9:10 pm: |
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pat, not sure if you already know, but you can still get the 20K 10 turn pots.
i got mine from the local Fry's Electronics.
made by NTE.
cost about 8 dollars.
i did the same clarifier mod, but left a bit of reisistance to ground in the circuit.
i replaced the stock varactor diode with an NTE612, and i get 15 khz of slide.
about three up and 12 down.
i cant comment on the freq. stability, as this is on my base radio, which always sees a good temp.
mine seems very stable; only fluctuating between .0049 and .0050 for a few minutes upon turn on.
of course, i dont need more than 6 kc's of slice because my radio has all the A channels in it, and even reads them out on the channel display!
HA, HA!!!
j/k,
matt |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 2509
Registered: 7-2004
| | Posted on Saturday, March 04, 2006 - 9:26 pm: |
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hmmm, i have NTE part #'s for several models, but have been told they are no longer in production, so never searched farther. $19.99 is the last price i have on them, NTE's retail list price...
i think the added inductance in mine is what adds the extra 10kc's, and instability-at least with the stock 3/4 turn pot. actually, the XL was only supposed to be temporary, so i never really 'dug into' this one...11 years ago  |
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