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Thread: Astro Spectra VCO Range2 jumper settings

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    Default Astro Spectra VCO Range2 jumper settings

    Does anyone have a range 2 vco that they can tell me which jumper are in and out thanks I'm in the process of converting ange one to a range two


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    From page 7-89 in the detailed sevice manual the range jumpers are as follows.
    Ju5641 in for range 1
    Ju5642 in for range 2
    Ju5643 in for range 3
    Ju5644 in for range 4

    According to the service manual (rev D) Page 7-92 these componants are not used at all.

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    Correct they are only for marking which range the board is. My guess is the OP has opened both units up and is now unsure of which board is which, been there done that.

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    I know which is which I was just going to try to mod a range 1 into a range to if it can be done I know I will have to change the cuts in the tuning strip allso

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    You should be able to make the changes. I think there are a couple of caps that need changing to bring the overall osc range up abit, then its just a matter of treaking the lock range.

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    That sounds about right I just need to narrow it down to them thanks Notarola

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    the caps are on the hybrid. You will need a steady hand
    part r1 / r2
    C9611 33p/30p
    C9616 11p/12p
    C9621 1.8p/2.7p
    C9622 15p/12p
    L9621 not used in range 2


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    I need the parts list for HLE6045 Range 1 and HLE6046 Range 2 all I got in my manual is HLE6000 Range3 HLE6041 Range 4 and for it it 3 jumpers and a resister

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    FWIW, it's much easier to convert a range 3 to a range 2. You can get a R3 cheap from some old 450 Analog spectra, then all you need to do is bridge the big microstrip accessible through the hole in the shield cover. You need to make the stripline a bit longer (like 1/4" or so) so put a solder dot on either side of the first laser cut, and bridge with wire-wrap wire.

    You can do this with a steady and and a very small very hot iron like a Metcal. This will allow the VCO R3 to lock below 442 MHz, usually it will go down to 436-438 MHz.

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    Quote Originally Posted by Alpha View Post
    FWIW, it's much easier to convert a range 3 to a range 2. You can get a R3 cheap from some old 450 Analog spectra, then all you need to do is bridge the big microstrip accessible through the hole in the shield cover. You need to make the stripline a bit longer (like 1/4" or so) so put a solder dot on either side of the first laser cut, and bridge with wire-wrap wire.

    You can do this with a steady and and a very small very hot iron like a Metcal. This will allow the VCO R3 to lock below 442 MHz, usually it will go down to 436-438 MHz.
    Or you can try the voltage shift trick, try putting a 100k on the VCO SL+ line, I don't remeber it off the top of my head(need to find it again, it's probably on repeater builder), but have sucessfully taken range 3 down to 450 and range 2 to 440.

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    OK, found it :
    http://www.repeater-builder.com/moto...z-vco-mod.html

    Works on all bands, you some times have to try different values to get the spread where you want.

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    Thanks Guys

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    The resistor mod works nicly. I just tried it on a VHF range 2 and on a freq of 135 mhz into a service monitor. I used a 330K resistor. I did lose top end to about 170. Im sure a multiturn presision resistor can be used to finetune the exact range ajustment desired. For safty I would have a 47k fixed value resistor in line to prevent grounding out the steering line.

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    Question - if it was required to steer the VCO lines in the other direction, would one simply put a resistor on the other (SL-) line? Repeater builder website says to add the resistor to the -SL line. The info above says its the SL+ lines.

    The 70cm band over here in Oz has the repeater inputs at 433MHz and output at 438-439.975 which is stretching the Range 1 ASTRO Spectras VCO just a little bit.
    Last edited by MattSR; May 22, 2012 at 06:48 PM.

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    Actually disregard the last - to increase the frequency i'll probably have to mod the resistive divider that feeds the -SL line to bring it down a volt or so. Will see how it goes.

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    Yes Matt you would have to adjust the divider to get the output voltage range desired. I would try changing R1 (r637 on rf board) to 100K, R2 (r640 on rf board) to 47k and the added resistor arround 75K. This might let you drop down to the range you want. If not your going to have to play with the VCO tuning stub (longer is lower lock range) then fine tune the resistors.

    Myself I would concider doing a course mod to the VCO strip allowint it to work in the section you want then play with the resistors to slide the window to the band edges you want.

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    I still think that you'll have an easier go of it taking an R3 (450-482) down. I made a 430-460 mod for a buddy so he can use a Spectra when he retires in a year or two and goes to Germany. The lock range was about 428 to about 465 after conversion.

    All I did was:

    1. Start with a 450 VCO that had a very small resonator stripline to start with; i.e. the 1st laser cut was very near to the base of the strip so there was a LOT cut off to work with. You might have to go through a few different old analog Spectras to find a suitable one.
    2. I put several solder dots along it in between the 4-5 laser cuts there where there was a solderable surface. (Again, a Metcal REALLY helps here!)
    3. Connect the dots. Use stripped #40 kynar wire-wrap wire to bridge the dots so you have effectively restored the entire length of the strip.
    4. Test it out. I made a test codeplug with channels set up with freqs every 1-2 Mhz at the low end (420-440 MHz) and every 5 MHz to about 460, then every 2 MHz again up to 490, so I can see where it gives up and loses lock at both the low and high ends of the band. (Yes you have to use appropriately mod'ed CPS for out-of-band programming).

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    Hi Alpha, thanks for the info, but we have an abundance of 403-433 models here (as in theres several thousand of them out there), so thats what I'm focussing on.

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    Hehe, I know I have boxfuls of the damn things too, we get them as Gov't surplus units here in the USA. I understand. I did a hack on one a while ago, and I was able to get it to lock up to about 448 or so. Unfortunately the front end was so horribly deaf at that frequency, I finally gave up on it. It's probably rotting in my basement somewhere

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    Hopefully they work acceptably at 439MHz with mods to the preselector.. will just have to see how it goes!

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    Resurrecting an old thread... Is it my understanding that with the change of a handful of components; you can change an 800 RF board to a VHF? Narrowband? Wouldn't the radio have to be re-flashed to tell the CMOS on the RF board to tell it that it's now a VHF? I studied the service manual and noticed the similarities and component changes. Is this pretty much it in a nut shell? Will it do narrowband VHF, since the 800 board is already narrow? Any experience, thoughts, or ideas?

    Thanks!

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    Quote Originally Posted by 4n6inv View Post
    Resurrecting an old thread... Is it my understanding that with the change of a handful of components; you can change an 800 RF board to a VHF? Narrowband? Wouldn't the radio have to be re-flashed to tell the CMOS on the RF board to tell it that it's now a VHF? I studied the service manual and noticed the similarities and component changes. Is this pretty much it in a nut shell? Will it do narrowband VHF, since the 800 board is already narrow? Any experience, thoughts, or ideas? Thanks!
    NO, the 800 RF board has the same filters as the VHF and UHF, 5 kHz.

    The Spectra RF board, actually a IF/Synth board, can be changed to VHF, UHF, 800 or 900 with a couple of jumpers, actually 0 ohm surface mount resistors. These jumpers control the divide by to get the VCO signal into the correct range for the Synth section, and a couple of different resistors and transistors in the frontend of the IF section on the RF board that feeds voltage to the RX frontend board.

    Yes you can use a 900 RF board in a VHF or UHF radio for narrow band receive. The radio will not do some of the newer 'splinter' frequencies because the Synth section is the same as the stock VHF Spectra, even tho it is a 900 board. Actually the 900 board works well with narrowband receive on VHF, and UHF.

    NO re-flashing required, or possible. The'CMOS is the same on all Spectra RF boards.


    Been there, Done that, and have radios that work.....

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    As usual; "You 'da man!" Thanks for the information. So; my ill-fated experiment to convert the wideband VHF's to narrowband was flawed from the start? Are there commercially available filters that I could purchase to accomplish this? I have a friend who cannibalized a number of 800 Astro Spectra Plus' and has a lot of 800 RF boards. If it were a reasonable proposition; I was hoping to make them into narrowband VHF's since there seems to be a shortage of narrowband VHF boards - with me needing at least three to build some Frankenspectra's from older analog units. Was also DREAMING of having him make the 800 vocons from the Spectra Plus' into VHF or UHF - which is what I need mostly out here in Hillbilly Hell. (Insert The Drool Factor) Poor man's way of upgrading...

    Thanks again!

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    Plenty of 900 Spectras out there, well maybe not down in Texas.


    You could change the two 450 kHZ filters in the second IF, part no.91-80297K03. And change R 327 to 620 ohms.

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    Yeah; God only knows how many door stops we have in Texas. Actually TXU, Oncor and a lot of rural utility companies use 900 systems, but I have no idea what radios they use. Nearly the only good use (no offense, fellow hamsters) for a 900 Spectra is to keep a couple on your passenger seat to throw out the window at tailgaters. "Can you Hear Clear me now?" Although; now, Astro Spectra's are only slightly more useful than a 900 analog Spectra - according to whether you're talking to a Motorola sales person, or know the difference between your nose and your... Uh; Shoulder blade - Yeah! Shoulder blade!

    Thanks for the update. I'd have to defer to your wisdom before I attempt to undertake such measures after my last embarrassing Foxtrot-Union. I still think it would rock ass to be able to either modify, or convert some of the Spectra RF boards for TRUE narrowband compliant use.

    Thanks, Will. If anybody knows; you do.