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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

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Old 2nd Jul 2020, 4:20 pm   #21
SiriusHardware
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Default Re: PCMA001S No Rx or Tx issues...

Conventionally, the 20.555 crystal is the one which generates the band immediately above 'Hi', i.e, the block commencing at 27.865.

I'm not sure whether that radio uses one crystal per 40-channel band or a combination of fewer crystals and PLL code manipulation via PROMs to generate all of its bands.

With the age these radios are now, if a decent one came into my hands I would actually restore it to its original channel / band range, whatever that was.
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Old 2nd Jul 2020, 5:40 pm   #22
VooDoo_Pete
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Post Re: PCMA001S No Rx or Tx issues...

Quote:
Originally Posted by SiriusHardware View Post
Conventionally, the 20.555 crystal is the one which generates the band immediately above 'Hi', i.e, the block commencing at 27.865.

I'm not sure whether that radio uses one crystal per 40-channel band or a combination of fewer crystals and PLL code manipulation via PROMs to generate all of its bands.

With the age these radios are now, if a decent one came into my hands I would actually restore it to its original channel / band range, whatever that was.
Hi SH,

ok the Nato 2000 has five crystals...

Frequency range:
Band A: 26.065 to 26.505 MHz
Band B: 26.515 to 26.955 MHz
Band C: 26.965 to 27.405 MHz (FCC band)
Band D: 27Л15 to 27.855 MHz
Band E: 27.865 to 28.305 MHz
Band F: 28.315 to 28.755 MHz

In some models, Band E is called "FM" and contains the UK CB band of 27.60125 MHz to 27.99125 MHz, with no Band F.

Band A. Adjust CT-1 for 19.655 MHz
Band B. Adjust CT-2 for 19.880 MHz
Band C. Adjust CT-3 for 20.105 MHz
Band D. Adjust CT-4 for 20.330 MHz
Band E. Adjust CT-12 for 20.555 MHz

Band E may contain the UK-FM band, in which case crystal is. 20.423 MHz.

Some models may contain only 3 crystals of 19.655 MHz (Bands А & В), 20.105 MHz (Bands C & D), and 20.555 MHz (Bands E & F)

The Nato 2000 has a unique channel selector from what I understand?

This radio is rough, cracked/broken/scratched fascia... missing knobs etc.

Definately not one a collector would be interested in... put it that way!

I can use the 10m band so would not feel bad about making it more useable for me.
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Old 2nd Jul 2020, 6:23 pm   #23
SiriusHardware
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Default Re: PCMA001S No Rx or Tx issues...

Really five crystals? I count six bands there, so there would usually be six loop mixer crystals.

The radio must also have PROM(s) to untangle the 'FCC' order of frequencies from the channel switch into a straight run of ascending 10KHz steps for the UK band - either that or an extra wafer on the channel switch dedicated to outputting 40 ascending PLL codes for the UK band.

The handful of Nato 2000s I ever saw all had the UK channels on the last band, but then all the ones I saw were UK examples. There are only two other sets I can think of which also had the UK channels straight out of the box.

The Commtron 'Nato CXX' was based on the standard Maxon chassis of the time with a large bank of crystals switched in and out to generate the consecutive frequencies of the UK band.

The Stalker 9F from Uniden also came in a UK specific version, on which one band had the UK channels.
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Old 2nd Jul 2020, 6:44 pm   #24
VooDoo_Pete
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Post Re: PCMA001S No Rx or Tx issues...

Quote:
Originally Posted by SiriusHardware View Post
Really five crystals? I count six bands there, so there would usually be six loop mixer crystals.
Sorry SH,

The A to F was to show what this board/chassis can cover...

The Nato 2000 is...

Band A - 19.655 MHz ~ L-Lows
Band B - 19.880 MHz ~ Lows
Band C - 20.105 MHz ~ Mids
Band D - 20.330 MHz ~ Highs
Band E - 20.423 MHz ~ UK40

Quote:
The radio must also have PROM(s) to untangle the 'FCC' order of frequencies from the channel switch into a straight run of ascending 10KHz steps for the UK band - either that or an extra wafer on the channel switch dedicated to outputting 40 ascending PLL codes for the UK band.
The Channel Selector has a specific wafer with the UK40/Roger Bleep add on board which has a Resistor pack that does the rest as far as I understand it.

Quote:
The handful of Nato 2000s I ever saw all had the UK channels on the last band, but then all the ones I saw were UK examples. There are only two other sets I can think of which also had the UK channels straight out of the box.
Yes, last band E is UK40 but is put on the band switch first...

labelled left to right = FM, A, B, C, D

Quote:
The Commtron 'Nato CXX' was based on the standard Maxon chassis of the time with a large bank of crystals switched in and out to generate the consecutive frequencies of the UK band.

The Stalker 9F from Uniden also came in a UK specific version, on which one band had the UK channels.
I've got a Stalker 9 here somewhere that I need to dig out and look at... Unsure what model but beleive it's the 9F-DX
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Old 2nd Jul 2020, 11:50 pm   #25
SiriusHardware
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Default Re: PCMA001S No Rx or Tx issues...

The 'UK' version of the Stalker 9 has a CB/27/81 logo screen printed on the front panel.
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Old 3rd Jul 2020, 6:19 pm   #26
VooDoo_Pete
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Question Re: PCMA001S No Rx or Tx issues...

Quote:
Originally Posted by SiriusHardware View Post
The 'UK' version of the Stalker 9 has a CB/27/81 logo screen printed on the front panel.
I need to find it, been a while since it was packed away!

Going back to the relay/capacitor mod... I'm wondering if it is something to do with the USB/LSB modulation?

From reading it seems these and the earlier boards suffered distorted/gritty sounding modulation?

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