Elcom Synthesizers

[VK4UH]

My penny worth

Col VK5DK is using a elcom synthesizer in one or both of his 24 GHz systems. Russell VK3ZQB has designed a programming/control interface for the 11 GHz version. From memory Col does not use 432 as IF (a good thing anyway) but higher up at I think 438 which allow operation from an 817 without modification. (428 MHz is outside normal Tx range of 817)

We had better ask them both for more info

Kevin VK4UH

[VK2OMD]

Russell VK3ZQB has designed a programming/control interface for the 11 GHz version.

Another option may be http://vk1od.net/module/PllLdr/index.htm .

It is a generic solution for PLL and DDS devices that use SPI (as does the Elcom), with capacity for 1/16 channel selection using a 4 bit binary code, 1/10 using BCD, or 1/5 using a 1/5 code (on 4 wires, 0/4 or 1/4 really).

I have tested it with several PLL and DDS chips, not tested it with an Elcom, but I think it ought to work.

If someone want to test it, I can loan them a prototype to try.

Owen

[VK4OE]

Greetings to all.

I haven't seen this point described before so I thought it should be added to the information about these remarkable units that is here on this Forum thread. It relates to the fact that Elcom 'CDFSL' synths do come with two different types of DC and programming connection.

The older ones have a 15-pin 'D' type connector whilst the newer ones have a 10-pin single-in-line 'header' protruding out of the back panel.

Regarding users' desire to connect powering and programming facilities to these synths specific information is not available about the pin-for-pin interfacing that has to be done. Moreover, from available on-line information, the data enable pin is called 'EN' on the newer unit and by 'LOAD' on the older unit.

The following table may be of assistance to some experimenters:

Code: Select all

PURPOSE     10-pin in-line            15-pin 'D' socket
-------------------------------------------------------
 +8V              pin 1                   pin 15

 +12V             pin 2                   pin 7

 Ground          pins 3 & 4            pin 8

 Data             pin 5                   pin 3

 Clock            pin 6                   pin 10

  'EN'             pin 7                   pin 11

 Lock             pin 8                   pin 14

 Unused         pin 9

 Signal Gnd     pin 10

Based on the information in this table, I have made up a simple patch lead that enables a programming board designed to plug into a 10-pin header to be connected to the 15-pin 'D' socket on the older CDFSL units (of which I have several) and it works just fine! (Many thanks to David VK3HZ who assisted me in getting these connections right.)

Cheers and 73,

--Doug Friend, VK4OE.

[VK4REX]

For those interested the Elcom ILCDFSL-1201 has the VCO running at 2320 Mhz (approx) depending on the programmed frequency. It uses a x5 multiplication to get to 11.61Ghz.
At the VCO frequency the phase noise is -103dBc at 10Khz offset - see attached screen shot.
Rex

[VK4REX]

Got frustrated today trying to work out how these things programmed via the existing interface. I decided to reverse engineer the PCB and find the actual control signals for the ADF4252 synthesizer chip and talk directly to the chip.
This allowed the direct control of the frequency plus other parameters (charge pump current, phase detector frequency etc) so the system could be optimized for this application. I can now set the frequency to a required frequency eg 11814Mhz so I am not stuck with the 10Mhz or 3.33Mhz channel spacing. I have to still make the lock detect function work. I am seeing the signal on the ADF4252 but it's not on the external connector so it some sort of wiring issue.
Once sorted I will document the changes and the software if others want to gain the added flexibility of these units. I will most likely get a PCB made for the controller PIC so if others are interested I will likely have some spares as I have to get 10 made. Using a 16F628 will also allow multiple frequencies to be programmed into the unit and switch selected.

[VK4REX]

Completed the modifications to the Elcom synthesiser model ILCDFSL-1201 to enable more useable frequencies to be selected (within the constraints of the loop filter).
As I have found out there are many variants of these units, and this document only applies to the model listed.
Added an OCXO for better stability and finer frequency adjustment.
Added Internal/External frequency reference selection.
Constructed a controller board to load the frequency data and other parameters and to monitor the synthesiser lock detection.
The internal 16F73 micro-controller is no longer used but left in place so the modifications can be reversed.

I have also been working on mods to a CDFSL-1101M-E and have the unit working on 10.368Ghz. This unit uses a totally different PLL chip (ADF4113) requiring software changes to the loader program, and instead of multiplying a VCO by 5 to get the final frequency the CDFSL-1101M-E uses a 2.300Ghz VCO multiplied to 9.2ghz and then has another PLL operating in the 1.3 to 2.3Ghz region that mixes with the 9.2Ghz signal to get the 10.5Ghz signal. Totally different scheme to the original and I suspect there may be many more different ones out there.

Hope this may assist others in playing with these great units.

Rex

[VK2EM]

The CDFSL-1201...

VK3HZ wrote...
It's programmed with Fo * 3 in 3.333 MHz steps

VK5KK wrote...
1201 Fo = 4 times Fosc
1295 Fo = 5 times Fosc
1301 Fo = 2 times Fosc

AND...
VK4REX wrote...
For those interested the Elcom ILCDFSL-1201 has the VCO running at 2320 Mhz (approx) depending on the programmed frequency. It uses a x5 multiplication to get to 11.61Ghz

OK, fellas! Which one is the correct statement?!

Or, are you talking about three different versions of the same thing?

[VK3HZ]

Which one is the correct statement?!

Correct - which one of the Elcoms .

Looks like the Elcoms are custom made - the label includes Purchase Order No., Frequency, Customer Part No., Model, Cage Code (?) and S/N.
So, it seems there's more to it than just the Model number.

In my case:
- 3 of the ILCDFSL-1201 - 2 with external 10MHz connections
the one in front of me - PO: FP26062/3, Cust P/N: ED-0702-0 and Cage Code 1UWV0
all require "x3" programming

- 1 of the DFS-1301 - PO: FP06670/0, Cust P/N: ED-0068-1 and Cage Code 1UWV0
requires "x2" programming

So, when you come to programming it, seems some experimentation may be required.

Regards,
Dave.

[VK4REX]

That's the point. These all appear to be custom made so you need to find out whats happening inside your unit. Ignore the "custom programming" and get down and dirty and find out what your unit is. I took the approach to ignore Elcoms custom program and actually find out what they were doing, this allowed me to program the unit with my requirements not their pre-programmed solution. If you modify the unit you can program it how you like not limited to some preset solution. Happy to discuss how this is done and happy to assist anyone with modifying their units to allow custom
programming.

[VK4APN]

Rex - are you going to publish your sensational elevation Compensated/ true north/magnetic north Compass Module with 4 line LCD readout in real time. I saw your excellent video demo. It would seem to be the perfect adjunct to microwave antenna systems to allow for absolute accuracy in aiming even the narrowest dish - as a starting point at least for line of sight. It would take a lot of guesswork away and would remove the obvious shortcomings of GPS alone.

That's the point. These all appear to be custom made so you need to find out whats happening inside your unit. Ignore the "custom programming" and get down and dirty and find out what your unit is. I took the approach to ignore Elcoms custom program and actually find out what they were doing, this allowed me to program the unit with my requirements not their pre-programmed solution. If you modify the unit you can program it how you like not limited to some preset solution. Happy to discuss how this is done and happy to assist anyone with modifying their units to allow custom
programming.

[VK3HZ]

Rex - are you going to publish your sensational elevation Compensated/ true north/magnetic north Compass Module with 4 line LCD readout in real time.

Do tell - it's something I've been looking at for a while. Perhaps a new Subject might be appropriate, though.

Regards,
Dave.

[VK4OE]

Greetings to all again!

In one of Rex VK4REX's recent postings he referred to the many and varied iterations that exist for Elcom CDFSL synth units:

"I have also been working on mods to a CDFSL-1101M-E and have the unit working on 10.368Ghz. This unit uses a totally different PLL chip (ADF4113) requiring software changes to the loader program, and instead of multiplying a VCO by 5 to get the final frequency the CDFSL-1101M-E uses a 2.300Ghz VCO multiplied to 9.2ghz and then has another PLL operating in the 1.3 to 2.3Ghz region that mixes with the 9.2Ghz signal to get the 10.5Ghz signal. Totally different scheme to the original and I suspect there may be many more different ones out there."

It seems to me that many folk have acquired the newer units that have the '10-pin header' type of DC and programming input, whereas I have a majority of ones that use a '15-pin D connector' at this location - reference my posting about pin-for-pin equivalents between these two connection systems.

Rex and I have 'pooled' the results of our investigations of these dual PLL Elcom units and this posting is about the successful modification of a CDFSL-1201 (Customer P/N: ED-0189-0) to have it locked to an external 10 MHz reference signal. I hasten to point out that this report is only relevant to CDFSL units that have the same internal design as the one I modified! It may be of assistance to some other folk who want to experiment. This report should assist folk who have this same type of CDFSL unit which has a 100 MHz temperature controlled crystal oscillator and associated divider chain delivering an internally generated 10 MHz reference that is was probably acceptable several years ago, but not so these days. Both of the on-board VCOs (on the RF side of the synth with so many screws to undo - but there should be no need to go there) are referenced to this internal 10 MHz signal.

You'll see from the following pics that I have removed the 100 MHz crystal (it was held by hot melt glue in the 'space' there at the bottom LH corner) plus all oscillating inductors and semiconductors, as well as removing the temperature regulating electronics above the crystal space, plus the two frequency dividing chips. A new SMA socket plus a short piece of coax to feed in the external 10 MHz reference signal is featured in the pics. This feed-in point is where the output of the 74AC191 divider chip used to be - IC pin 1 coax braid to ground, and IC pin 2 coax centre conductor signal input.

I am happy to report that, with a clean 10 MHz reference signal applied, the synth works perfectly with the output accurate to +/- 1 Hz at 11.81 GHz. And the whole 'shooting match' is now only drawing about 600 mA total current, much less than the 800 mA it was drawing before (after warming up at even higher current).

Another good thing is that the modified unit happily withstands 'hot' removal and reinstatement of the reference connection - a potential reality of life in the type of service that we amateurs are likely to put the unit to.

So, with this older style of Elcom synth, such a modification for external 10 MHz input is feasible, effective and relatively easy.

Phase noise, as far as I can determine with my 'reasonable' HP spectrum analyser, is not too bad (carrier 50+ dB above noise pedestal in a very slow, very narrow sweep), but I have seen better. However, given that this is at 11.6 GHz (the default frequency) or at another programmed frequency nearby (11.81 GHz in my case), it's better than I have been able to achieve in LO chains with a variety of multiplication stages. [Crystal oscillators definitely being better than the earlier types of VHF or UHF PLL.]

Another interesting point is that the PN became a little better 20 KHz or so away from the carrier when I increased the main DC supply voltage from 10.1 to 12.5 Volts. Just one of those things.....probably caused by an internal voltage regulator getting noisy as its drop-out voltage was approached.

I hope that this report may be of value to some folk who have these interesting units!

Cheers and 73,

--Doug Friend, VK4OE.

[VK2OMD]

... This unit uses a totally different PLL chip (ADF4113) requiring software changes to the loader program...

A lot of these synth / DDS chips use one way SPI and are somewhat generic in interface (with some variations in maximum speed, polarity, number of registers, word size etc).

I took the approach of writing a generic firmware that reads a EEPROM data structure that flexibly supports many of these chips, and the approach works fine.

Owen

[AF4JF]

Gentlemen,

I saw several remarks made about CDFSL-1101 M-E synthesizer made by Elcom. We have several of them and tried to get them to 10,800.00MHz (LO for 10,368 with 432MHz IF and Upper Side Injection).

I see that VK4REX has it working on 10,360 .... how did you do that? I am trying to use the PIC controller and programming done by Dave G4FRE / WW2R.

Thanks,

Herbert, AF4JF

[VK4REX]

Hi Herbert

I don't use the G4FRE software/controller as it only talks to the internal PIC micro inside the elcom. I wanted to be able to program the synthesizer chip directly so I could get any frequency and not be limited to the 3.33 or 10Mhz steps.

This is all VERY dependent on the internals of the Elcom - as they say oil's ant oil's and neither are the various incarnations of Elcoms. Any that use the ADF4252 synth chip my mods should work for, but there are variations like the 1301 that use a Siemens chip and totally different topology.

Rex

[AF4JF]

Rex,

I understand that your controller talks to the chip directly. I have downloaded the files you have posted earlier and will take a look at them. However, you also stated that DFS-1101 uses ADF4113 .. I see that I will have to open my unit and check that.

I have seen other post earlier on this logger where was stated that DFS-1101 worked with code calculated as "frequency/5 + 1024", so for my 10800 ~ 31 84 00 but that doesn't work either.

Thanks for quick reply,
Herbert

[VK4REX]

I had problems with the previous code suggestions also that's why I went my own way. I have to stress that my mods will only work with units containing the ADF4252 PLL chip. I am still working on the 1301 type unit sorting out the code changes needed to talk to the Siemens chip. The units that contain the ADF4113 can be modded but the code has to be changed as it's register structure is different.

[RA1OGS]

Hi colleagues on the southern hemisphere of the earth.
Sorry I do not speak English.
I purchased synthesizer LCDFSL1201.
PIC controllers for external bootloader code frequency whilst in transit. I write on ATtiny13A loader code.
Please tell me what should be the duration of the pulses CLK and bit length DATA, so the synthesizer to receive data without errors.
I hope for your help.
Yours faithfully, Vasilij (RA1OGS)

[VK4OE]

Greetings to all!

With reference to my posting over a year ago (with pictures) regarding practical introduction of an external 10 MHz reference signal to an Elcom CDFSL-1201 synth, Rex (VK4REX) and I have discovered that a small further modification is required to the particular synth models that I was working on to achieve phase locking and proper operation at 'normal' 10 MHz input levels. Actually the ones I worked on all tested OK a year ago, but I can't explain why because the following additional modification has been found to be required.

By 'normal' level of the 10 MHz reference signal, I mean in the 0 dBm to +10 dBm range. I found that the synth was needing +13 dBm to make it lock reliably using a 'sine' wave reference signal fed to the coaxial input described last year.

As you can see from this image, the solution was straightforward:

1. Remove the 47R resistor (marked '470') going to Pin 9 of the 74AC04 Hex inverter chip. This is on the same side of the synth as the coaxial connector that was added.

2. Solder a capacitor (value not greatly critical - somewhere in the 10 nF to 100 nF range) where the 47R resistor was.

3. Solder two resistors (value not greatly critical - somewhere in the 4K7 to 22 K range) to the extended Pin 9 input PCB land. Shorten the leads somewhat before soldering. [I used 0.125 W resistors to keep them small, but normal Jaycar 0.5 W resistors will do just fine as well.]

4. Shape and solder the other end of one resistor across the chip and solder it to Pin 7 (Gnd).

5. Shape and solder the other end of the other resistor along the side of the chip and solder it to Pin 14 (V+).

6. Test unit and replace cover.

Some Elcom synths already have SMD resistors in place somewhere on the board that transform this input inverter gate to a sine-to-square converter, with V+ and Gnd points close to the input so SMD components can be used, but the particular synths I was working on did not have these points available - hence use of the axial lead resistors.

Rex and I trust that this modification may be of assistance to other folk experimenting with this model of Elcom synth.

--Doug Friend, VK4OE.

[VK4OE]

Greetings again to all readers!

The model '1101 Elcom synthesizer (10.575 GHz to 11.4 GHz) in its various guises is used far less by radio amateurs than the '1201 model, so comments about it and descriptions of experiences with it have been few and far between.

I have recently acquired an LCDFS-1101-B (Rev.C) and I have attempted to get it going on frequencies in its range that I needed. [Along the way I found that, even though my unit looked fresh and clean, there were at least two components that needed replacement before the DC and RF portions of the unit could work properly!] I also removed the internal 10 MHz TCXO and installed an SMA connector on the back panel for an external 10 MHz reference signal to be used, as shown in the following picture:

Knowing that, in an earlier posting on this thread, Iain VK5ZD had reported a programming 'trick' using an externally located PICAXE with the different model Elcom (DFS-1101) that he has, I started trying to adapt that idea to my use of the G4FRE PIC controller design. After failing to get anywhere with that, I commenced correspondence with Iain and that has led to his realization that his original posting of a programming algorithm was not correct - it should have been [(Frequency/5) - 2048]. In other words, for the DFS-1101 unit that he has, and given that the unit multiplies its VCO by five, the frequency programming data relates to the integer number of MHz that one fifth of the output frequency is above 2048 MHz. This should be the way forward for folk wanting to program their DFS-1101 units.

After finding that this principle simply did not work for my LCDFS-1101-B model Iain and I realised two interesting things: (a) that the 'default' frequency (the stable frequency it runs on when not being programmed) for the DFS-1101 model is 11.335 GHz whereas for the LCDFS-1101-B model it is 11.000 GHz; and (b) that the DFS-1101 multiplies its VCO by 5 whereas the LCDFS-1101-B multiplies its VCO by 4 to arrive at the final output frequency. Thus, even though they have the same 'quirky' output frequency range, the two models are internally very different from each other!

The following picture is the internals of the RF side of the LCDFS-110-B unit:

[A large 'unused' area is there because these synths do not 'mix' two frequencies before generating the final output frequency - they only multiply the VCO - whereas many other models need this space on the RF side to generate a second signal before mixing it with the main VCO signal.]

So I felt that I was 'on my own' regarding adapting the G4FRE power and PIC board to the LCDFS-1101-B synth. David, VK3HZ, was very helpful in offering possible approaches to try, but nothing seemed to be successful in moving the LCDFS-1101-B away from its default frequency of 11.000 GHz.

Then I realised that, considering the plethora of possibilities for programming schemes, the easy first thing that I should do was to start in a 'dead simple' way and adjust the first two pairs of frequency-determining digits in the G4FRE .ASM file so as to directly represent the two desired output frequencies I had in mind. After all, one has to eliminate the obvious before tackling the complicated..... [I used 0x11 plus 0x00 for one frequency, and 0x11 plus 0x39 for the other.]

Surprise, surprise, the thing actually worked - accurately on 11.000 GHz (but under PIC control, not the default!) and interestingly 'close to the mark' on 11.390 GHz. The 'close to the mark' character got me interested to the point of trying to see what might be 'going wrong' about the place and I tracked it to a dud MMIC in the buffering-amplifying circuitry after the VCO. Replacing that MMIC with an identical one recovered from the boards taken from another Elcom unit did two good things - getting the 11390 MHz signal to be on exactly the right frequency as well as lifting what was low final output power up to a 'normal' level (around +13 dBm).

Another interesting point about this success with the LCDFS-1101-B is that the output frequency jumps between the two frequencies written into the PIC controlling code simply by 'hot switching' the PIC frequency selector switch (G4FRE design feature). On all the '1201 models that I have, changing frequency requires powering it down and then up again, but this one handles 'hot switching' with ease.

I trust that these comments will further the possibilities for other users of Model '1101 Elcom synths to get them up and running!

Very best wishes,

--Doug Friend, VK4OE.