help i need to know what freq these are!!!

cajoseph05 · Post by **cajoseph05** » Tue Apr 04, 2006 2:36 pm

the one crystal says

45435.00
KXN6235
MOTOROLA
R8703

the other crystal says

17.9
45J03
(M)
D8634

can anyne tell me what these nu,bers mean and what freq. they are?

k2hz · Post by **k2hz** » Tue Apr 04, 2006 3:17 pm

The KXN6235 is the channel crystal but I can't find the formula to determine the channel frequency for the VHF Minitor. If I find the info I will let you know.

The 17.9 crystal is part of the IF circiut and does not affect the channel frequency.

k2hz · Post by **k2hz** » Tue Apr 04, 2006 3:43 pm

I think the channel frequency is (45.435 x 3)+ 17.9 = 154.205

Post by **VE9MP** » Tue Apr 04, 2006 4:50 pm

I have a RF deck ganked from a Keynote I'd like to know the carrier frequency for

43706.66 with a 17.9 IF

k2hz · Post by **k2hz** » Wed Apr 05, 2006 9:00 am

VE9MP wrote:I have a RF deck ganked from a Keynote I'd like to know the carrier frequency for 43706.66 with a 17.9 IF

I don't have any info on the Keynote but several model Motorola pagers from that era used the X3 multiplier and the single conversion 17.9 IF.
So that would be 149.020 for your frequency. I do see some hospital systems and others that appear to be one way paging listed in your part of Canada for that frequency.

EEnerd · Post by **EEnerd** » Wed Apr 05, 2006 9:17 am

What frequency crystal would an Advisor need to be on the old Arch frequency of 454.450?

k2hz · Post by **k2hz** » Wed Apr 05, 2006 9:50 am

EEnerd wrote:What frequency crystal would an Advisor need to be on the old Arch frequency of 454.450?

I don't have specific info on the Advisor but if it is one of many that used the 17.9 IF, the multiplier for UHF was x9 so the the formula was:
(f-17.9)/9.

454.450 crystal would be 48.50556 if that formula applies to your Advisor.

EEnerd · Post by **EEnerd** » Wed Apr 05, 2006 12:59 pm

Are pager crystals generally marked by their primary frequency or their intended-use overtone frequency?

k2hz · Post by **k2hz** » Wed Apr 05, 2006 2:11 pm

Motorola normally marks only the crystal frequency and their part #. Most aftermarket crystal providers usually mark the channel frequency along with an "t" or "r" indicate transmit or receive application. Sometimes the channel frequency is marked on top of the crystal and the crystal frequency on the side.

EEnerd · Post by **EEnerd** » Thu Apr 13, 2006 10:10 am

Ok sorry to drag this old post up again but I pulled the receiver board from an (original, old) Advisor labelled 454.150mhz on the back (I'm 95% confident that's the real operating freq). There's 3 xtals on the receiver:

1- Micro rectangular (sorry I forget the xtal shape designations):

45.0
20J19
TAIWAN
(M)9330

where (M) is the motorola symbol

2- Micro rectangular

51143
750
X6301
(M)9330 <- Hard to read last line due to rubber xtal cover but I think it's just a date code anyway

3- Micro cylindrical

Impossible to read due to rubber xtal cover, need to cut it off or desolder the xtal to read.

Is #1 a 45mhz IF crystal?

Does #2 tell you anything useful?

k2hz · Post by **k2hz** » Thu Apr 13, 2006 2:37 pm

I don't have specific info on the Advisor but some Motorola UHF pagers use the xtal formula (f-45)/8.

454.150 - 45.000 = 409.150/8= 51.143750

Which fits perfectly with your crystals.