Monday, July 4, 2011

FT-450 SDR Interface to Softrock Ensemble II

EDIT (9/2/2011): Here is a copy of the SDR Presentation I did for my local ham club and used this FT-450+Softrock setup as a live demo. 


I have been playing with a Softrock SDR Ensemble II HF Receiver for a while and then I read about a european ham, who modded his FT-450 to work with his SDR (a Mercury SDR, not a Softrock), so I thought I might follow in his footsteps and do some experimenting as well.


The first thing I tried as duplicating the IF-tap that he had performed, it was fairly simple to do, just connecting a stereo cable up to a couple of pads on the RF board on the bottom of the radio and you can extract the I/Q signals from the built in quadrature detector(SDR) built inside the radio itself.


Here are the points on the board.









While it did 'work', it was quite disappointing to see only a few khz of bandwidth on the the display after having been spoiled using my Softrock to see 192khz wide bandwidth that usually covers most of an entire band in real time.


You can see the parts of the band that do escape the 10hkz roofing filter on the FT-450 IF in the SDR software here, you end up with a little signal on each side of the center point:





That was pretty sad looking compared to my Softrock in 192khz, look at the whole band goodness.   So, after that experiment, I moved on to trying to perform the "RF Tap", where you tap into the RF front end of the FT-450 to provide an RF out just after the passband filters, the preamp, and attenuator, and the transmit/receive switching inside the radio.  

This lets you share the same antenna with your SDR Receiver and your FT-450 continuously, and use the SDR as a sort of panadapter for your rig that has independent receivers.

This mod is also pretty easy, it involves bringing an antenna connection from inside the FT-450 to the outside to feed into the FT-450.  

When you pull the bottom board out of the FT-450, you will see that there is quite a bit of room inside there for cooling fins and airflow, and this makes it pretty easy to put in the ultra thin coax run to a jack on the back.

You can see all the room in there in this photo:


The connection points for the coax are on the bottom board that normally covers that space, so its a simple matter of soldering the coax leads to the correct points on that board, running the coax in the corner and under the board into this big space, and to the back of the radio.

Here is where you can see the points to connect the coax leads:

The coax is connected to the leg(that you can't see) on that inductor to the top left next to the finger.  

I made a little strip of copper to solder to the metal shield box that I could lay the coax into, let it provide some stability and strain relief for the cable, and solder the coax shield to as well.  The center conductor of the coax is soldered to the top left pin on the inductor.

Here is a photo(sorry, its a little fuzzy) of what it looked like after the coax was soldered to the board.



I then ran that coax down in the crack between the case and the board, to the open area underneath where I put in a SMA Connector into one of the cooling slots on the back.  The slots are nearly big enough and barely needed any drilling to make the SMA connector go through.    BTW, I put my board into a computer static bag, sealed as best I could, and then used a powerful shop vac to make sure that any stray metal pieces were not going to be loose inside the radio after using the drill on the aluminum rear panel.

Here is the SMA connector:





The Softrock radios, have a pretty strong signal that they leak back down the antenna and that would NOT be a good idea to leak signal into the beginning of the receiver IF Stage in the FT-450.   So, I used a buffer amp to put between the FT-450 and the softrock to eliminate that possibility.  A buffer amp creates a one-way only RF connection and does not allow any signal to leak back up to the FT-450.  It also provides a little bit of pre-amplification as well.  I choose to use one of the popular Clifton Laboratories Z10000 buffer amps, that is used by many people interfacing Softrocks with various types of radios.

This photo shows my finished setup, FT-450 SMA-BNC -> connected to the Buffer Amp -> connected to the Softrock.



With this setup, I can now get the full 192khz bandwidth use out of my Softrock, use is as an independent receiver, while sharing the single antenna, getting automatic T/R switching, and still take advantage of the front end preamp(IPO), attenuator, and extra bandpass filtering inside the FT-450 front end.  

This is much better than when I was using the Softrock before, I had to either disconnect the FT-450, or use another no so good antenna for receive only.  Being able to have both radios connected to my 80M OCF full-time has made the Softrock receiver a very important part of my radio setup and working right alongside my FT-450.






There just is no comparison between the 10khz output of the FT-450 internal IF, vs using the full 192khz of the Softrock.

Its quite a setup that complements my FT-450 for just only the $74 for the Softrock Ensemble II HF Reciever, and the $25 Z10000 buffer amp.  


14 comments:

Bart said...

WS4E;
Do you have any follow-up comments on this setup?
I currently use an FT450D as well, with a "Ham-it-Up" converter / 850T2 SDR for pan-adapter use. I had it setup with an MFJ T/R switch for automatic recieve/TRX switching, which did not last very long as the MFJ unit is not well built. I assume RF has messed it up as it is not in a grounded box. So, I went to a manual antennna switch in the meantime.
SO - seatching for a better solution, I looked at a few articles on IF out for the FT450D (not much out there) and came across your very interesting RF stage idea - Great!
So - after a couple years, how is it holding up? Do you recommend it still, would you have any lessons learned or mods to the original to make?
I am not sure if the buffer amop woujld still be required with my SDR system, but it shouldn't hurt either - and insurance is always a good thing.
Thanks again for this blog post - it seems a unique entry for FT450D panadapter use.
73v de AA7VA

WS4E said...

Bart.

Here is a quick update. Since I got a Funcube Dongle Pro+ a while back, and I also have a RTLSDR, both of which can tune up into >50mhz, this summer I finally got around to trying the 68mhz IF-tap that allows you to follow the tuning of the radio as documented here: http://www.mods.dk/view.php?ArticleKey=2559ffdb7b42e45b64ad69bddd4881f8&i=1-yaesu-FT-450-Adding-an-IF-tap-to-FT-450-D-

And honestly I was not impressed at all. The signal width is very small, only about 30khz because you are tapping after some filters. And the signal quality going to the SDR was actually quite poor and noisy, I guess because you are after quite a bit of amplification as well.


By far the best setup to me still is using a Softrock Ensemble connected to the RF tap I documented in that blog post and using it as an independent HF receiver. The signal quality that way is excellent and you can pretty much have as wide a signal on the SDR as your SDR can handle. An RTLSDR+Upconverter will of course provide nearly the same capability, just at a slightly less receiver quality, so I would suggest you give it a try.

Myself, I still use this on a regular basis of being able to use the Softrock and the ft-450 side by side sharing the same antenna. It works great.

And I would say that yes, the buffer amp is probably going to be required for most any of these applications, because I am pretty sure nearly all these SDR's leak oscillator signals back up the antenna port and that could get back into the FT-450 receiver and affect its performance.


You do remind me that I need to do a blog post about my experiments with the Funcube and an RTLSDL and the IF Tap.


Hope that helps.

-Don
WS4E

Bart said...

Than k you sir -
I will work on that - need to check to see if my warranty is up yet on the FT450D first ;)

Bart said...

As a side note, try the newest version of SDR# - the noise reduction system is by far the best, but doubt it could be linked to provide Yaesu VFO changes like PowerSDR, HDSDR or the like do, not work with DXLabs logging -
But for just listening, it is incredible!!!

Bart said...

Don,

Two more questions on specific amp build if I may -
First, is your Clifton Labs buffer amp the base version? I assume so, but if it has any k2 or K3 parts, I need to know that before I order the kit.
And then second, what gain resister or number do you use for the R7 for the FT450D? Would you change it for better performance? Reference for question is http://www.cliftonlaboratories.com/Documents/Z10000B-U%20v1r02%20Manual.pdf page 7

And a question on the signal path - Would you add a High Pass filter to it to keep Am broadcast interference out? The figures on gain start about 5 Mhz according to the graphs in this PDF, so I don't know if it is required or not. How does the 160 Meter receive do? I cannot use it doe to AM broadcast interference with my NooElec NESDR Mini 2+ that has a 0.5PPM TCXO fed from their Ham-It-Up converter. This chain would be fed by the buffer amp, so I don't know know what gain to use. True, the Soft Rock has band pass filtering and more bits in its decode (8 bit vs 12 or 14?) so I will likely go to the newer V-111 Softrock soon, but I have the SDR in hand and use it through an antenna switch currently as mentioned in my first post. Reference on the dongle is here - http://www.nooelec.com/store/sdr/sdr-receivers/nesdr-mini-2-plus.html plus I put it into their aluminum case for grounding and shielding.
Also, do you think there might be room inside the 450 to put the buffer/amp board, or is external box the only way to go. I haven't opened the radio yet, so I am not sure if there may be room for the board.

BTW - as an update to my last post, I am now using HDSDR because it links with DXLabs Commander through Com0Com virtual serial cable software so I now have point and click on the band display graphic for frequency control over the Yaesu - Very nice!!!

Thank you sir - 73

Olly said...

Bart - how did you get on? I am planning the same thing with my FT450D

Bart said...

Olly -
Clifton Labs is not now in business, he stated health reasons for its closure. So I did some searching and came up with this site:
http://g4hup.com/PAT.htm
Dave is very easy to work with, and he ships from a Texas shipper, so no long lag time. I am waiting on the arrival of my unit, and will report when it is installed.
The install seems esy enough, and with his connector kit there is no need to drill the back of the FT450D (or so it says, I hope so). The install is easier with an internal to the radio methogd that looks nice, here is a short exercise in install in our radios
http://g4hup.com/FT450%20Installation.pdf
Also, the Soft Rock stuff is all out of stock, and I hope it goes back into production so I will continue to use my NooElec 'Ham it up' converter and dongle.
Maybe Don will add to this conversation?

WS4E said...

Yes, the softrock is currently not offered, although he says he might make an order of more kits available sometime this year.

Personally, I would recommend this as a worthy replacement, http://www.omnia-sdr.com/. It is based on the Peaberry SDR which was a follow on effort to the Softrock design.

I think that would be a worthy choice for a high quality, good cost SDR to use in this same application.

I have 5 other HF radios, and I STILL USE this setup and really find it amazing to use. Outside of spending thousands$$ on a Flex 6000, I don't see anything else being better.

Olly said...

Thanks Bart - Yes I am quote happy with the Ham it Up converter - it is just a pain to use two antennas or a manual switch as I am sure you are aware! I am in the UK so anything from the US is going to take a while but your suggestion does look good, especially all being contained in the rig!

What would be the advantage of moving to softrock or similar?

Bart said...

Olly -
Note that the PAT comes from G4HUP - he is in your neck of the woods! It is just nice that for those of us in the old colonies have a local mail source. So you should get faster service than me.

http://g4hup.com/PAT.htm is his website

The advantage of a SoftRock or other is that they may not need the Ham-it-Up converter and that they have some filtering that keeps the out of band stuff lower. I get a lot of noise from the computer or power supply (switching) or such that puts regular fast spikes in the pan display on 80 meters and lower. I also get ghost images from local AM radio stations that should be filtered out. I have moved around the radios, P.S as far as I could, antenna, power, computer and their connection cables to minimize those blips, they are a bit smaller now but they are still there. Grounded aluminum cases are already in use, so perhaps more snap on chokes are called for?

Anyway, other SDR options are primarily for the filtering and higher bit length for selectivity improvements. And yes, that does cost more.
I did get the T/R switch back from MFJ with a new relay switch so it may go to use the pan adapter model on the old HW101 - can't do rig control, but I can see what signals are around the band!

Maybe I can get some pics and put them on a blog somewhere, I'll let you know.
Thanks again to Don for posting this, it got me started. Maybe I can help someone else - after all, that is the point of being a good "Elmer"!

73
Bart AA7VA

Olly said...

Thanks Bart

Keep me informed of how you go and I will do the same!

73 to you!

Olly

Olly said...

I got this working. It works well for all bands that the FT450D can tune to. You have to tune the radio to the band you are interested in seeing but then you can get the whole scope of the band.

It was a fiddly solder job inside the rig. Tiny little connections which I did struggle with but all seems well!

Bart said...

Still haven't recieved mine yet - anxiously wating!
I did upload a vid to YouTube that shows what I have right now and how it works - I guess I may make a vid to show how to install it when i get it.
Hey Don - I mentioned you and this website in it, hope it is ok. I didn't think to ask prior to uploading - sorry if it offends in any way, but you have helped me and I appreciate that.
Here is the link to the short clip - it is my first one, so there are mistakes -

https://www.youtube.com/watch?v=WWNJUjrVLSk&feature=youtu.be

WS4E said...

Good video Bart. I also really like the way that device from G4HUP looks. I have considered installing my buffer amp inside the radio, it just a single little pcb inside the case so it would not be that hard to do. I just was not sure I was going to keep this at the time I first did the mod. I guess since its been a few years now I should have installed it internal.

Looking forward to seeing how it looks in your radio.

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