"Donley" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Garey and all other Drakelist members,
Below are two quotes from previous emails:
'The letters are a color code for the Carrier Oscillator and BFO crystals in
the Tx and Rx. Ideally, the letters (and color stripes on the crystals
themselves, CHECK!) are the same in Tx and Rx.'
'I want to transceive with this pair so the color code is important. The
R-4B has a red stripe on a crystal next to the crystal calibrator under the
chassis. None of the other crystals are color coded. And the T-4XB has a red
stripe on one of five crystals under the chassis.'
I want to mildly disagree with the concept of these two statements. I say
mildly disagree because I am not completely sure of myself, but will list my
objections (there are only two).
I don't see the importance of matching the color stripe of the Tx and R. I
would think that the Tx or R unit would be tested individually for drift
(+, - or 0) and the appropriate TC compensating crystal would be inserted to
minimize that drift (- TC for + drift,+ TC for minus drift or 0 TC for 0 or
minimal drift). This would insure minimum drift in either unit. So shouldn't
any Tx transceive with any R?
Secondly, I can find no reference in the Drake manuals to the requirement of
matching Tx and R colors. In fact, I can find no reference to the color
stripe at all in the manuals that I have.
This concept would have put a burden on the seller and buyer of Drake 4B
series Tx and R to match the color designation at purchase. I don't recall
(remember it was 30 to 40 years ago) any mention then of this concept. I
have the 4B series Tx and R with two different color striped crystals, B for
the T-4XB and G for the R-4B and do not notice any problems in transceive.
I do recall seeing written information recently about the color coded
crystals, but I can't remember where. (I just found that article and it was
written by you, Garey).
I will bow to those of more expertise than I have and stand by for any
comments.
Remember, I said mildly disagree.
73
Dick
KC9UB
----- Original Message -----
From: "Garey Barrell" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, October 15, 2007 9:54 AM
Subject: Re: [drakelist] Any disadvantages to using R-4A with T-4XB?
Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist
gang
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Wow! Talk about decisions..... :-)
Both of your receivers are VERY "late" in their respective groups. Your
R-4A is close enough to actually count the tubes. It "should" have 13
tubes, and therefore the tube type PD, but Drake wasn't always "perfect"
when it came to model changeovers. So I'd be very interested in how many
tubes are in your R-4A, just for refining my data.
There is an article on the WB4HFN site, but that was also from 40 year old
memory also. I "think" the Red crystals were positive TC, the Green were
near zero TC and the Blue were negative TC. The same color in R an T is
ideal, but if I have the colors right you have a positive and zero
combination with the R-4B. The R-4A could be better or worse, since all
Drake did was characterize their standard crystals in-house, and we have
no idea what group the R-4A crystal would have fallen into! :-) I asked
Bill Frost at Drake about this a few years ago, and he had even forgotten
that they "had" color coded crystals....
Best is to set them up, and try them for a while. Depending upon how
stable your shack temperature is, and how long you let them warm up before
use, etc., you might not have a significant problem. You could try a
"want" for someone with a mismatched pair to swap your G for an R or your
R for a G if you find it to be a problem. A hint..... You can get an
Xcelite 3324 screwdriver which is long enough to reach the C61 adjustment
in the receiver without removing the cabinet top. If it's not quite long
enough, you can shave a bit off the blade end of the handle. After you
put it through the "proper" hole in the cabinet top, slip a piece of
aquarium airline tubing over the blade end and fit it to the C61 adjuster.
You can probably figure out why I did this 40 years ago!! :-)
My choice, assuming the general condition of the two receivers is similar,
would be the R-4B. The "above the belt" lettering on the A is difficult
to see in normal lighting at best, the same for the slanted kC dial, and
the PTO in use light is handy. The cabinet paint on the B is tougher
also. Actually, if it was me, I'd keep them both, which is why I have a
couple dozen 4 Line boxes........ :-)
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B & C-Line Service Supplement CDs
<www.k4oah.com>
Tom Bowman wrote:
Hi Garey,
Thanks very much for your complete answer. Here's what I found out:
First question is what is the serial number of your R-4A?
The R-4A serial number is 3956 with no letter behind it.
What is the letter at the end of the R-4B serial number?
The R-4B is 15359 with G behind the number.
What is the letter at the end of the T-4XB serial number?
The T-4XB is 10382 with R behind the number.
BTW, I want to transceive with this pair so the color code is important.
The R-4A has no color code on the crystals.
The R-4B has a red stripe on a crystal next to the crystal calibrator
under the chassis. None of the other crystals are color coded.
And the T-4XB has a red stripe on one of five crystals under the chassis.
The letters are a color code for the Carrier Oscillator and BFO
crystals
in the Tx and Rx. Ideally, the letters (and color stripes on the
crystals themselves, CHECK!) are the same in Tx and Rx.
My plan is to keep one of the receivers and sell the other. Will either
of these two receivers work on transceive without problems with the
T-4XB?
Thanks for taking the time to read and answer this.
Tom, WA3REY
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