Looking for LNB

HB9SKA Hi Thomas. I think the Octagon OTLSO has been discontinued. I bought one about two years ago and I can confirm it has PLL technology and a 27MHz Xtal. I have also tried the 'Octagon Quad LNB Green' which has a 25MHz Xtal. I see that a two output version is being advertised cheap on Ebay https://www.ebay.co.uk/itm/Oct…136100:g:gAMAAOSw6lpch~rp

I have found that the PLL Octagons need 15 minutes or so to warm up and then the drift is acceptable for SSB. However, I have modified mine to accept an external reference to keep it really on frequency. I hope this helps you. 73 Russ.

Hallo...

difficult to get the old (working models).... they are out of market
i you have luck you get one ?

made some tests on newer models.... mostly NEGATIVE... some wobbling!

OLD MODELS WORKING GOOD AND TESTET ALSO WITH TCXO INSIDE:

OCTAGON OSLO CHARGE1208/1301 RDA3650M TCXO 26MHz (TXC-7N) LO:9388,9

OCTAGON OTSLO CHARGE 1208/1301/1306 RDA3565ES TCXO 27MHZ (D75F) LO:9750 (THE BEST ONE)

all newer MODELS looking not so good...

maybe some progess in future...???

73 de Michael dg0opk

Is there a solution to modify an OCTAGON OTSLO CHARGE 1208/1301/1306 RDA3565ES 27Mhz WITHOUT unsoldering the quartz crystal ?

e.g. Stabilizing with 10Mhz GPSDO

I Have one but not so certain unsoldering the crystal

Quote from dl4sdr

Is there a solution to modify an OCTAGON OTSLO CHARGE 1208/1301/1306 RDA3565ES 27Mhz WITHOUT unsoldering the quartz crystal ?

yes, just like with any PLL LNB - use a programmable GPSDO to generate the reference frequency and feed it onto one of the crystal pads via a ~100pF capacitor. if you feed in the original reference frequency, you have gained a crystal filter for your reference. if you feed a modified ref to get the passband to somewhere in 70cm for example, it will still work without modifications.

The HD-line HD-BP2 is a great product and easy to modify.

Still available a.o.here:

https://www.amazon.co.uk/dp/B004Y62XYC/?tag=wwwpabrorg04-21

Succes!

I ordered one and will give it a try

Vy73 DB8TF

@ DH5DAX and others here:

...and feed it onto one of the crystal pads via a ~100pF capacitor.

I am a little bit unsure because in Article cq-dl 1-2019 there is written:

and feed it onto one of the crystal pads via a ~100nF

Is the difference critical if i use a GPSDO e.G. Leo Bodnar ?

HB9SKA Hi Thomas. I can only speak about the Octagon Quad LNB Green which I have. Before modification, It drifted quite a bit for the first 15 minutes or so and then became manageable - only slight re-tuning required then. I suspect that the dual output version (for which I sent the link) will be the same as it also has a 25MHz Xtal. None of them are going to be rock stable on their own but these are acceptable. 73 Russ.

Quote from G4SAQ

HB9SKA Hi Thomas. I can only speak about the Octagon Quad LNB Green which I have. Before modification, It drifted quite a bit for the first 15 minutes or so and then became manageable - only slight re-tuning required then. I suspect that the dual output version (for which I sent the link) will be the same as it also has a 25MHz Xtal. None of them are going to be rock stable on their own but these are acceptable. 73 Russ.

Thay will be rock stable by definition surely, but the rock itself is the issue by the time it is multipiled by 390. Hence the replacement with an external LO. That is almost essential for narrow modes but there are other solutions - e.g. correction based on the beacon. Wideband is a different matter. You may be better off not locking if it increases the phase noise.

Mike

In addition tho what G0MJW states: these LNB's disciplined with crystals and/or TCXO's are inadequate for narrow band purposes by definition.

My explanation concerning the above is like an old vinyl record turned grey (and based on common knowledge on the microwaves bands for decades ...) :

while (1) {

For narrow band usage you have to 'know your frequency' within (preferably) +/- 10 Hz, which is a precision of 1E-9 @10 GHz. 1E-9 = 1 ppb = 0.001 ppm. A single crystal or TCXO can't achieve this precision/stability.

}

Quote from Laaglander

Still available a.o.here:

https://www.amazon.co.uk/dp/B004Y62XYC/?tag=wwwpabrorg04-21

UK shipping only

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UK shipping only

Quote from DN1HRZ

UK shipping only

On Amazon DE you get it delivered from france.

https://www.amazon.de/HD-LINE-…refinements=p_4%3AHD-LINE

I found the Avengers today in the Netherlands on a hamfest for 7€, they are identical to the songle octagons with 27MC. I will check if i can find his details, he was a French guy.

Jerry

Quote from dl4sdr

@ DH5DAX and others here:

...and feed it onto one of the crystal pads via a ~100pF capacitor.

I am a little bit unsure because in Article cq-dl 1-2019 there is written:

and feed it onto one of the crystal pads via a ~100nF

Is the difference critical if i use a GPSDO e.G. Leo Bodnar ?

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The cap is only to block off eventual DC on the input, so it isn't necessary at all if you feel lucky - but if you then by mistake swap the two ports, you end up feeding DC to your crystal which it probably won't like too much. The value isn't critical at all, as long as it passes your desired reference frequency.

Hallo...

JUST A NOTE ABOUT !!!

because of the QO-100 activity now I found more and more of "resellers" with some dubios work and thats why it is needed to put a warning on my homepage... !!!

MAYBE IT IS NOT A GOOD STYLE .. NOT TO GIVE THE SOURCE OF THERE INFORMATIONS AND DESIGNS and maybe they should put some serious measurement results if they have REALLY verified there work...???

http://www.dg0opk.darc.de/Octagon_LNB_mod_March2017.html

I have DONE.... and the references to G0MRF and ZS6BTE are written inside the article and all is OPEN for PRIVATE USE (HAMRADIO) and not for COMMERCIAL PURPOSES!

THANKS de Michael dg0opk

Hello,

if it helps to find an LNB, I'm using a Megasat Diavolo Twin, which is still available from: https://www.reichelt.de/lnb-tw…volo-twin-p74259.html?r=1

73 de Achim