Elcom Synthesizers

23cm, 2.4/3.4/5.7/10/24/47 GHz and above - antennas, propagation, operating, etc. Includes Optical communications, with light,
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Elcom Synthesizers

Post by VK5ZD » Tue Oct 18, 2011 4:23 pm

Hi

Does anyone know how to program the frequency in an Elcom DFS-1301 synthesizer? I've tried the 'frequency x 3' method but it doesn't work. I've also tried all 32 bit BCD encoded numbers from 10000 to 99990000 (in 10000 steps) with no success. i.e. I've tried
  • 00010000
  • 00020000
  • 00030000
  • ...
  • ...
  • 99990000
The codes were sent at 1 second intervals to allow things to settle but none of them produced a lock. The output frequency just sits at about 13.6GHz. If I don't try to program the device it does lock at a default frequency of around 13GHz. I'm running out of ideas :cry:
All sensible suggestions welcome.
IMGP5585.JPG
I also have a DFS-1101 synthesizer which is also different from the 'frequency x 3' method. However, I've managed to work this one out :D
For this device, the code needs to be (Frequency / 5) +1024. e.g. For, say, a 10.61GHz output the code would be 0x31460000.
IMGP5586.JPG
73
Iain
73
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Re: Elcom Synthesizers

Post by VK5KK » Tue Oct 18, 2011 6:04 pm

Hi Iain

I ran into the same problem with my DFS 1301 which looks the same vintage as yours. These seem to be early ones that run off 6V (not 8V like later C series). Yes these seem to sit around 13.5 Ghz when out of lock

It turns out (after usual trial by error testing!) that the DFS-1301 Oscillator is multiplied X2 not X3 as in the DFS1295, 1201 etc in the various articles. E.g. the magic number in PIC asm file for G4FRE 12F675 mod to set PLL to 12660 MHz (for 1292 MHz up convert IF) = 25320. Lines in code ...

movlw 0x25
movwf f1_1
movlw 0x32
movwf f1_2
movlw 0x00
movwf f1_3
movlw 0x00
movwf f1_4

The VCO volts should rise to >5v (for 12650 MHz) in 3 seconds in lock initially with a "blip" in VCO volts a couple of seconds later when the PIC sends enable/clock & data and frequency changes. If the PLL gets a divider out of range VCO volts usually go to zero. I have a Verticom 11.4 - 12 GHz PLL, it works much the same (its X3) however have a CDFSL-1201 that isn't responding to data at all, I suspect there are a "custom" units amongst all of these

Cheers

David VK5KK

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Re: Elcom Synthesizers

Post by VK5ZD » Tue Oct 18, 2011 10:09 pm

Hi David

That works :D
Now I can get on with the rest of the 24GHz transverter.

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Re: Elcom Synthesizers

Post by VK3HZ » Sat Dec 24, 2011 12:09 am

Hi Matt,

I'm currently working on a 24 GHz transverter using an Elcom DFS-1201.

I've written some code for the PICAXE08M (based on the 12F675) to load a single frequency - in my case 11.38 GHz (code attached).

It wouldn't be that hard to adapt it to multi frequencies. Have a look at the VK3XDK PLL board code for example viewtopic.php?f=40&t=10047

If that all seems a bit daunting, I could do the mods for you if you tell me what freqs.

Regards,
Dave
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Elcom_DFS1201_Loader_v1.bas
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Re: Elcom Synthesizers

Post by VK5ZD » Sat Dec 24, 2011 8:50 am

Hi

I also have PICAXE code for the DFS-1301 used as a 24GHz LO.
Note that the 1201 only goes up to 12GHz, so the last frequency you need will be a problem.

73
Iain
Elcom_Synthesizer.bas
Picaxe code for DFS-1301
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Re: Elcom Synthesizers

Post by VK3HZ » Sat Dec 24, 2011 9:07 am

As Iain said, the DFS-1201 won't do the upper frequency. I've found they cover 11.15 to 12.05 which is handy because I have a x2 multiplier and can use one as a signal source on 24048 or thereabouts.

Do you have the programming cable for the PICAXE? From your question, I gather you're already set up for programming a PIC (not-AXE)?

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Re: Elcom Synthesizers

Post by VK3HZ » Sat Dec 24, 2011 11:25 am

Attached is the modified code. Note that I haven't tested it fully ...

So yes, the PICAXE08M (and M2) can do it. It only uses half the code space. I/O was a bit of a squeeze. The Programming output pin now does double duty as the Elcom data output. This means that you'll possibly need to unplug the programming cable for it to work properly - perhaps not.

Good luck!
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Elcom_DFS1201_Loader_Multi_Freq_v1.bas
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Re: Elcom Synthesizers

Post by VK4OE » Wed Sep 05, 2012 4:23 pm

Interesting thread, you fellows!

I am wondering if any of you (or other readers) has/have had experience with the option that some Elcom CDFSL synths have (two SMA connectors on the side) for use with an external reference. (CDFSL is a similar but more recent version than the DFS types.)

I have seen the data sheet that Elcom has on-line for these where it says that the -----E5 model number is for a 5 MHz reference and (you guessed it!) the -----E10 model number is for use with a 10 MHz reference.

Two of the Elcom CDFSL synths I have here have the SMA connectors but their model number, strangely, just ends with -----E. Free running, they output just a few KHz below 11.6 GHz (before re-programming) - just like the other non-external-reference models do.

I have tried injecting each of 5 MHz, 10 MHz or 100 MHz (GPS locked source) into the 'REF IN/OUT' SMA on the side at varying reasonable power levels but I have not yet been able to 'see' a jump to the precise 11.600000000 GHz as I would expect. I have also tried applying 'logic 0' or 'logic 1' voltages to the power connector pins that have remained unidentified, only to find that a positive voltage on several of these pins completely kills all output!

Does anyone know if there is a proper way or 'trick' to getting the synth to change its referencing from its internal crystal oscillator to the external reference signal?

TIA and 73,

--Doug Friend, VK4OE.

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Re: Elcom Synthesizers

Post by VK3HZ » Wed Sep 05, 2012 5:24 pm

Hi Doug,

I think that's the same one I use on 24 GHz. Unfortunately, the way it's mounted, I can't read the full number. It's got two SMA connectors on the side labelled Ref In/Out and Ref Out.

Internally, there's a 10MHz TCXO reference oscillator. This and the Ref In/Out run through a gating circuit (using (7Z00B) NAND gates) controlled by a PIC that selects which of them is used by the synth. Here I reached a brick wall as no matter what combination of command bits I sent to the PIC, it refused to switch across to the external reference. So in the end I traced the control line back to tthe uP and modified the circuit so it could be manually switched it.

Here are the notes I wrote on the mod at the time:
- cut track from PIC pin 12
- add pullup of 27K across cut (pin 12 will always remain high)
- remove component on pin 9 of J1
- link pin 9 of J1 across to gating circuitry line (i.e. other side of cut from pin 12)
- J1 pin 9 becomes NOT(Ext_Ref_Enable) - i.e. ground to enable external reference
- When Ext Ref is enabled, the circuitry powers down the TCXO (just an FYI note)

I suspect that J1 pin 9 originally was an EEPROM write enable line to perhaps allow a frequency to be permanently programmed. However, I wasn't game to try it in case it completely obliterated something.

Hope that helps.

Regards,
Dave.

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Re: Elcom Synthesizers

Post by VK4OE » Wed Sep 05, 2012 9:09 pm

Wow, thanks Dave!

It's beaut that you have shared the details your experience with modifying this synth for external reference. You've obviously traced the circuit through as far as you could go, so, in the absence of any information about external reference switching from the manufacturer, the 'cut track' final modification had to be the way to go.

And the modification that you eventually did is a whole lot more elegant than what many others of us would have done!

I have tried contacting the Elcom company by e-mail about the recommended/designed method of switching references but, as is often the case these days, they're apparently not interested in non-profit-making communications..... If I do eventually hear back (which I'm not actually anticipating will happen) I'll share what they say with this forum.

Isn't it amazing how, from a cold start and from an internal 10 MHz crystal oscillator as the reference, these synths start up at 11 or 12 GHz only about 3 or so KHz from their final warmed-up frequency? And after warming up, they are so amazingly stable? And their phase noise is fairly good as well - all pretty good features for surplus bits of gear!!!!

I presume that one of these is the LO unit you have been using for those record-breaking QSOs on 24 GHz!

Best 73 and thanks again,

--Doug Friend, VK4OE.

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Re: Elcom Synthesizers

Post by VK3HZ » Wed Sep 05, 2012 10:43 pm

No worries, Doug.

Doubt if you'll hear anything from Elcom. Others have tried and had no response.

Yes, I use the Elcom on the 24 GHz system. I suspect they may originally have been used with the Thales module in the 26 GHz link systems. They're being sold by the same people.

I haven't been able to measure phase noise performance, but the signals from Rex are quite clean on WSJT SpecJT when coming back from aircraft. Tropo spreads the signals as you may have experienced. I'll be trying one on 47 GHz too.

Regards,
Dave.

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Re: Elcom Synthesizers

Post by VK4OE » Sun Dec 09, 2012 10:59 am

Greetings to all readers!

I have been asked by a UK friend who doesn't have a VK-Logger profile (none other than Roger G8CUB!) to ask about collective VK experiences in programming an Elcom LCDFS-1101B unit covering 10.575-11.4 GHz.

Mostly this thread has talked about '1201' and '1301' types, but there is one mention in Iain VK5ZD's original post from 2011 describing his success in programming an earlier '1101' unit. This would suggest that Roger's desire to get to 11.100 GHz with his 'B' model synth should be readily achieved.

Any comments please.....

TIA,

--Doug Friend, VK4OE.

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Re: Elcom Synthesizers

Post by VK5KK » Sun Dec 09, 2012 8:22 pm

Hi Doug,

Just checked my collection (!) of Elcom's. Only have 1201 & 1301's (LCDFS & DFS models) as per previous posts, don't have the "1101" 10.575 - 11.4 or the "1295" 12.200 - 12.950 which the original G8CUB article refers to. Programming of the 1101 should be no different to 1201 & 1301, i.e. use the same PIC setup to preload the PLL. You just need to work out the multiplication factor required to program the PIC 12F675. I couldn't find reference for this on the 1101 but all the others are as follows ..

1201 Fo = 4 times Fosc
1295 Fo = 5 times Fosc
1301 Fo = 2 times Fosc

One way to find out is by trial and error and try different mult figures until it locks. Pick an obvious frequency that should work, this is how we found the 1301 was oddball with its times 2 scheme i.e it has a 6 GHz Oscillator whereas the other models have 2.5 - 3 GHz Oscillators! Or you could undo the 43 screws on the microwave side of the Oscillator and sniff with a spectrum analyser around the oscillator to see where it is. My guess if it is a later model LCDFS if could be times 4. I do have a Verticom MTS-1500-151 that covers 10.575 - 11.4 however (like most Verticoms) even though they are pin compatible with the Elcom's it uses a Oscillator is at the final frequency (not multiplied) so no clues from that. Hope this is of help

Cheers

David VK5KK

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Re: Elcom Synthesizers

Post by VK5KK » Sun Dec 09, 2012 8:22 pm

Hi Doug,

Just checked my collection (!) of Elcom's. Only have 1201 & 1301's (LCDFS & DFS models) as per previous posts, don't have the "1101" 10.575 - 11.4 or the "1295" 12.200 - 12.950 which the original G8CUB article refers to. Programming of the 1101 should be no different to 1201 & 1301, i.e. use the same PIC setup to preload the PLL. You just need to work out the multiplication factor required to program the PIC 12F675. I couldn't find reference for this on the 1101 but all the others are as follows ..

1201 Fo = 4 times Fosc
1295 Fo = 5 times Fosc
1301 Fo = 2 times Fosc

One way to find out is by trial and error and try different mult figures until it locks. Pick an obvious frequency that should work, this is how we found the 1301 was oddball with its times 2 scheme i.e it has a 6 GHz Oscillator whereas the other models have 2.5 - 3 GHz Oscillators! Or you could undo the 43 screws on the microwave side of the Oscillator and sniff with a spectrum analyser around the oscillator to see where it is. My guess if it is a later model LCDFS if could be times 4. I do have a Verticom MTS-1500-151 that covers 10.575 - 11.4 however (like most Verticoms) even though they are pin compatible with the Elcom's it uses a Oscillator is at the final frequency (not multiplied) so no clues from that. Hope this is of help

Cheers

David VK5KK

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Re: Elcom Synthesizers

Post by VK5ZD » Mon Jan 28, 2013 7:30 pm

Hi

Has anyone had any success programming the frequency for a LCDFSL-1201MS synthesizer?
If so, how is it done?

73
Iain
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Re: Elcom Synthesizers

Post by VK3HZ » Mon Jan 28, 2013 9:48 pm

Hi Ian,

The LCDFSL-1201MS, with the two 10 MHz REF IN/OUT connectors, is the one I have been describing above.

It's programmed with Fo * 3 in 3.333 MHz steps.

Regards,
Dave.

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Re: Elcom Synthesizers

Post by VK5ZD » Tue Jan 29, 2013 6:54 am

Thanks Dave

I've since discovered the frequency doesn't change when you send the data to the enable input and the enable signal to the data input :oops:

Iain
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Re: Elcom Synthesizers

Post by VK4GHZ » Wed Jun 05, 2013 11:53 pm

I was getting excited about these Elcom synthesizers for use as an LO for a 24 GHZ system (with 432 IF), but from what I have learned tonight, they may be unsuitable.

As Dave originally advises, eBayer art-in-part has many of these available.

Would I be correct in saying the 1201 variant (11.2 - 12.0 GHz) can only be set to 3.333 MHz steps?
With every 3 steps equating to a 10 MHz step.

My understanding is for operation on 24048, we require an LO on 11808, which obviously is not obtainable with a 3.333 or 10 MHz step.

What am I missing here? :oops:
Or is operation on 24050?
Or do others use a 428 MHz IF with an 11810 LO?

My alternative train of thought would be to employ a ZL2BKC PLL, operating at 3936 MHz, followed by a MiniKits 10 GHz tripler kit.
So next question would be, has anyone had success going down this particular path?

Noting that MiniKits warn of:
3x 3000 to 4000MHz with much lower output no guarantee.
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Re: Elcom Synthesizers

Post by VK3HZ » Thu Jun 06, 2013 1:01 am

Hi Adam,

I use an Elcom on 24GHz and get excellent results.

Yes, they are limited to 10 MHz steps (unless you want brain failure trying to calculate a 3.333 MHz offset). As well, the LO is doubled in the transverter mixer, so it is really 20 MHz steps.

Operation is on 24048 MHz and I use a double-conversion setup with first IF at 1288 MHz. Output is at 144 MHz (using an XDK PLL board for LO).
If you're using a 70cm IF, then avoiding 432MHz is probably a good thing. 428 MHz would work fine.

I'd be a bit worried about phase-noise with a PLL multiplied up that far. The Elcom is less than half the cost, and a proven performer.

Regards,
Dave.

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Re: Elcom Synthesizers

Post by VK4GHZ » Sat Jun 08, 2013 10:58 pm

Hi Dave

Thanks for the info.
Might have to pick your brains at GippsTech, but one of these Elcoms and running a 428 IF sounds like good advice.
art-in-part seems to have quite a few of these on hand, so perhaps no immediate rush.
I was around at VK4OE's a few days ago, and Doug was very impressed with the Elcom... which lead me to doing a search here.

Have just heard tonight that a 24 GHz Kuhne is heading to Brisbane (not mine!), so the need to keep up with the Schraders has just ramped up a notch! :wink:
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