Meanwhile I modified several Diavolo Twin LNBs for an external LO input.
I found out that there are at least 3 very different versions of this LNB in the market.
After I wrote a report of my modifications V1 several month ago, I wrote a second one called V2 in which I also show the V3.
You can find them at : https://elektronik-muenster.de/viewforum.php?f=17
German language only, sorry.
But there are many photos, so everyone should understand it.
The 2 Diavolo Twin LNBs I modified was bought at Reichelt Elektronik Germany for about 12,- Eur.
Where did you buy yours ?
You can check which pin to use with a simple functiongenerator and a scope :
(no need to put it in the dish)
First of all : Make it an antistatic workplace !
All semiconductors in LNBs are very sensitive !
After removing the crystal,
power up the LNB just by giving around 12 V to one of the F-Connectors.
Take a functiongenerator an set it at the crystalfrequency and an output of about 1 Vss sinewave.
Now connect the functiongenerator via a capacitor of about 1nF to one of the ex x-tal pads.
Now check with a scope the unused pad : There should be a signal, similar to the one you supplied.
If not, exchange the pads and check again.
Ich danke Dir für das Projekt. Da ich keine externen Taktgeber habe, werde ich wohl auf eine interne TCXO-Lösung setzen (müssen).
Hallo Marco !
Einen Vorschlag für einen externen TCXO von mir findest Du unter :
Der von mir schon genannte Diavolo Twin + dem indoor TCXO läuft super gut und stabil.
Der Conner Winfield TCXO ist an sich ja schon sehr stabil und wenn man den auch noch ins Shack verlagert ist der fast so gut wie GPS stabil.
Und das Signal ist sehr jitterarm. Daraus resultiren sehr saubere und "unverschmierte" CW uns SSB Signale. Wesentlich besser als alles was aus den meissten digital stabilisierten Oszillatoren rauskommt. (bis auf wenige Ausnahmen)
Ich habe hier einen QO100 Dauerempfänger auf der CW-Bake laufen.
Der ist innerhalb 2 Wochen nur um einzelne Hz gewandert.
Ich empfehle den Diavolo Twin.
Gibt's aktuell z.B. bei Reichelt für 10,95 Eur.
Sehr stabil arbeitende PLL, sehr guter Signal-Rauschabstand, einfach umzubauen.
Umbaubericht von mir unter :
Hi Frank !
About the different TCXOs you should read my article :
Up to now I did not see any TCXO with a frequency at 25.8 MHz.
And variable control-range of VCTCXOs is several PPM only. (so some Hz)
You can never tune a 25,0 MHz VCTCXO to 25,8 MHz.
Hello Frank !
At the moment not many news.
As I already wrote, I made a new version with Conner Winfield TCXOs and they work excellent.
Meanwhile the TCXO-Board with the golden DIL-case-TCXOs from china came in and I did a quick test. The result was not that nice. This TCXO seems to deliver much jitter. (as other hams also described) I found out that "ghost signals" appear in the receiving window. They appear every 200 kHz.
I assume that inside this TCXOs actually a PLL is running with a loopfreqency of 512 Hz.
That really sounds intersting !
Hello Sat Fans !
Meanwhile I updeated my Postings about my "simple indoor TCXO for LNBs"
The shematics and layout files for version 1.1 are availabe now.
You can find them at :
(sorry, german language, you can use deepl.com to translate)
I changed from FOX TCXOs to Conner Winfield TCXOs.
The FOX TCXOs are digitally compensate in 1 Hz steps, which leaded to 390 Hz jumps in the received signals.
Not comfortable at CW or SSB.
The well known Conner Winfield TCXOs are analog compensated and very stable.
In my tests the frquency of my indoor LO moved less than 100 Hz in a period of several days.
If it's a standard PLL LNB this schould work.
All new ones are using one of two common PLL / Mixer IC-Familys.
I modified several LNBs for that.
For Dual LNBs you can find Info about that at :
Taitien VCTCXO in field tested : Works fine ! No Jumps anymore !
I ordered some Conner-Winfield TCXOs and will test them with my constuction.
On success I will do a PCB redesign with them.
Many thanks for your replys and suggestions.
Surely the hotair station is the best solution, but I wrote my report for the everage Radio-Amateur, who usually does not have those.
I often try low-level methodes to help people with poor toolchoice.
At an other Diavolo I tried the 2 solder iron methode as I described in one of my reports which works excellent.
Well, some people need to make faults which others did before
Thanks for the suggestion of variable output, I will put that in my redisign which must happen anyhow with the other TCXO.
I will have a look at the OH2AUE mod, maybe I can implement that too.
Meanwhile I modified my 25 MHz indoor LO with a VCTCXO from Taitien.
It's the TXEAADSRNF 25.0
Actually I planned to use that with my next project, a GPSDO directly for 25 MHz with only one PLL (no 10MHz between), because ist's voltage controllable.
It's a pitty that the new oscillator has a bit weaker output and a bit lower DC level.
So I had to add a C and two Rs to get the BS170 working fine.
Well, I will let you know the fieldtest result after daylight.
If you want to have infos about modifications of Diavolo Twin and Octagon LNBs, you can find it here :
I wrote some reports how I modified them and how to build a simple indoor TCXO.
Everything written is in german language only. Sorry.