I used a common hig impedance buffer to get an “RF second receiver” output (not an “IF out”) from my new Yaesu Rig.
In this way I am able to connect and use an external SDR.
I used a “PAT70” from Dave G4HUP (SK) that I had laying around from some time…
I got all the connection points taking inspiration from the same zone my FT991 has its elad panadapter installed, and from the FTDX101 native RF out I found looking to its tech supplement (search the net…).
This is the result :
This is the board fixed with some kapton tape:
This is the rear fan I disassembled to add 4 little nuts in order to create some space to let the thin coax to pass through (I didn’t want to drill holes into the chassys):
This is a closeup of the connections for power supply +8v taken from “RX8 line” and ground (black)
and finally the details also for the RF signal point:
DISCLAIMER: Even if at the moment my testing gave no problem , I take no responsability if you damage your radio trying to replicate my experiment.
FINAL NOTE (for all the courious Hams):
In order to understand what could have been the convenient place to take the RF signal from, I took inspiration from the tech supplement manual of the big brother FTDX101.
This rig has a native panadapter, so I tried to compare that schematics with the one of the FTDX10. Somehow similar connections….
Thank you for the above information. I also just got a FTDX10. and would like to hook up a sdrplay for a second receiver inorder to work Dx on split mode and hear both freq. One question is the Yellow wire in your photo connected to area circled in RED marked RF and the other end goes to solder joint next to the black wire on the pat70m board??? Looks like this will work much better than using the mfj 1708bsdr along with the sdrplay. (the mfj product will
loose at least 3db . Thanks again Tom N2UD
Yes it is the “RF in” to the PAT board and goes near the black wire.
Anyway, 3db of signal lost are half of an “S” point…. so not a big deal in receive path, probably…
Not true, the MFJ only has a relay to ground the output RF going to the external sdr, those relays and coaxial lines inside the box will not have more than 1 db loss.
From the current manufacturer’s website, I get the sense that these PAT boards should be chosen to match the rig’s IF. They don’t list a board for the FTDX10, though they sell the PAT70 which you used. What am I misunderstanding about IF (1st & 2nd) and PAT board selection? Can more than one specific version work work in any given radio? Would you have used the PAT70 if you didn’t already have it on hand? Can you suggest the most appropriate one from their offerings if other than PAT70? Thanks.
https://www.sdr-kits.net/index.php?route=product/category&path=66_73_84
These PAT boards differs by Low Pass Filter as mentionend in the manufacturer’s web site, to match your needs.
My article clearly states that I am getting RF as SECOND RECEIVER, not IF … (it means full RF spectrum).
For example, if anyone would have choose the PAT70 to use it as second receiver for a RIG that is all band (so also VHF, UHF, and whatever…) it will not work because the LPF cuts everithing above 70Mhz.
If you choose to get the 1st IF, it will work because all frequencies are shifted there….
Thanks Andrea, just completed the mod to my FTdx10, works great.
Thank you for you information.
DE Bruce VK2RT
The input to the PAT Buffer is 100K to ground in parallel with the gat of an FET. While I don’t have an FTCS-10 schematic, I’d expect the “tap point” to be 50 ohm impedance. If so, the loss would be much less than 3dB.
Here is a link of the technical supplement i found in internet:
http://www.radiomanual.info/schemi/YAESU_HF/FTDX-10_serv_2021.pdf
This could answer your comment maybe…
Hi Andrea.
Is there any reason why you didn’t use an SMA socket on the rear casing for this install, other than warranty?
Thanks.
Hi, the main reason is that I wanted something reversible, that once eventually removed would have rolled back the “stock” condition 🙂
Cheers.
Thank you. And thank you for taking the time to present this information along with the chance to ask questions.
Curious about the add-in for SDR Console on the right on the main image. Does that allow control of the radio from SDR Console?
Thanks in advance.
Ed N
Hi, It’s not a plugin; it is for TRANSMIT purposes (as written in the picture, top right) if you have a TX capable SDR.
To control the radio in SDR console it is an embedded feature you could activate configuring it from the menues; if I remember correct, it uses Omnirig…
Ciao
Thanks for sharing your project.
I wonder, why you take the signal after attenuation and preamps (after the SCP AMP) and not the RX signal before RL3001. So the SDR would be independent from the radio settings?
73 de HB9HDG Daniel
Hi,
it was a choice… I wanted to take advantage of ftdx10 filtering capabilities…
But I guess you could do it also your suggested way.
I didn’t investigate in recent times, so I forgot the details I analyzed at the beginning.
Hi ANDREA,
I complete done the modification. It works perfectly!
73,s de SY1DNN
Andrea, how do you protect the SDR from overload or RF when transmitting? I have something similar for the older FT-950, and @ 100 watts, the SDR shuts down. I presume, too much RF.
The point where I take the signal is on the same RX path of the radio, hence It has the same level of protection…
So we could rephrase your question: “Yaesu, how do you protect the radio RX from the TX path ?” 🙂
Any regrets?
And, did I read correctly that tapping the location that you did transfers the radio’s filtering and signal processing to the sdr?
Fighting qrm and hoping to use sdr play as my main interface.
Thanks in advance!
No regrets, of course 🙂
The tap points are taking RF signal AFTER radio’s filtering (but can be taken in other points before that filters, see schematics); as mentioned some comment above this.
A.
Confirm this works just brilliantly.
I think this is a novel approach so your using a far better way instead of those sloppy MFJ boxes plus the carp out of China but I wonder if anyone looked at some way to get an IF out like in the 101D. Q3040 is the post amp on the output of the mixer which might give you a true second RX output giving you the advantages of the band pass filtering plus the mixer of the Ten when operating on the same band would give you a better in band second RX besides just a pan display.
The current signal pickup is the equivalent of the original FTdx101 rig.
The big brother FTdx101 has both “RX OUT” and “IF OUT” on the rear panel.
I based my work looking to both schematics diagrams (BTW, publicly available in Internet).
To be more specific the difference between original ft101d RF OUT and “mine” ftdx10 is that the 1st one is taken BEFORE the “SCP AMP” block, and the second one AFTER it.
coming back to the IF OUT suggestion, thanks; that could be a starting point I will investigate and eventually I will share the results in a new updated article 🙂