Posts by S57RW


    I've ordered from DX Patrol the version with down converter since for portable operation prefer to have the rx on the rig not needing to carry the laptop around. Generally it works fine. If the unit is inside in the shack the frequency stability is fine. If operated outside there is some drift due temperature changes, but still not a big problem for SSB or CW operation. In any case a big improvement over the previous LNB with an 8ppm reference.

    When used with a FT-817 as RX even with its gain set to minimum have to use a 20dB attenuator to get better S/N ratio.

    Have still to test digital modes like KG-STV where stability is a must. I suspect for this a GPSDO as external reference will be necessary.

    Dirk tnx for the information that the bias is not short circuit protected. Usually is difficult to make a short when screwing the F connectors but you never know. Better have the unit switched off when screwing cables on it or LNB.

    Best 73's Andrej - S57RW

    Don't forget thermal methods. How much a load heats up with RF compared against a second identical load fed with DC.


    Agree with you to consider differente between DC and RF. In the article the author recommends max 0,5W but for very short time. Anyhow not clever pushing the limits. If you burn the resistors it is a real hassle to desolder the box for replacing not speking about burning an expensive rf final after… For this reason got some attenuators I use when applying more than abt. 1/4 W.

    73's Andrej - s57rw


    For power measurements I'm using a rf probe published years ago on the following article:

    The article is in Slovene language but it is not complicated to make so can be understood from the schematic and building scheme. Mine is working up to 6cm band. The author states it should work on 10GHz as well but don't have any source on 3cm to try it. One thing to know is that seems the disk capacitor has a resonance on 13cm and for this reason the probe is showing abt. 20% less. On other bands is quite accurate. It was the case also with mine so after build is good to check it against a known source. After you know the % of error on 13cm than thats not a problem for measurements. The max power is limited by the dummy load resistors and is abt. 0.5W. For very short measurement mine survived up to 1W... For more it is good to have some attenuators at hand.

    One warning if somebody decide to build it. Don't buy the BAT62-03W diode on eBay from Chine. They are fake at last from the seller I got it. 1st got the diodes from China and could measure power up to abt. 440 MHz corrcetly. On 23cm was showing only abt. 30% of the true power and almost nothing on 13cm. After bought from and got it working as expected.

    73's Andrej - s57rw


    As was mentioned under this topic don't understand why there should be any tolerance limit. With beacon level signal strength you have a great readable signal so why need to go over. Such signals can be even understood just with a LNB without the dish. Don't think anybody has problems of a huge local QRM on 10 GHz being unable to copy signals at beacon level...

    Concerning pirates, idiots and psychos don't think additional chat rooms would help. Will even make it worse. They are not doing that to test their technical abilities but to make troubles. What they enjoy is people speaking about them and knowing they are really making troubles. If we don't speak about too much most of them will lose interest.

    What I enjoy the most working QO-100 is making CW QSOs using just the upconverter giving out abt. 80mW into a 85cm dish and still getting a quite solid readable signal back. I find that fascinating that so low power can travel 36.000 km and still usable. Hope will complete soon a more stable LNB so can try digital modes and make tests what is the lower limit the signal can be decoded back. Know other have tried but like to do myself and have fun.

    Best regards,

    Andrej - s57rw

    My last QSO trough FO-29 was abt. mid June when was still perfectly working. After had some construction work in the house so was out from any ham activity. So unfortunately don't have a telemetry record from the last days. Also by working LEO's usually just used the CW telemetry beacon to find the SAT and than tuned to find somebody calling or to call CQ.

    However tnx for the post it is an usefull request if maybe somebody has a record of last days.

    Best 73's

    Andrej Jerman

    Not a new news but apparently the FO-29 LEO SAT went SK somewhere between 9th and 10th July after 23 years of great operation. Nobody heard from since than. I'm sorry for that since it was a great bird. Made my 1st LEO SAT QSO with linear transponder over this bird and many more later.

    Wasn't active on LEOs since abt. 2 months and tried the FO-29 few days ago without checking the SAT's status prior. Of corse heard just silence.

    Best 73's!

    Andrej - S57RW

    Was reading in the morning the docs published on the CEPT website from Ancara conference and I think IARU-R1 and DARC (as heard they were the most involved, but probably also others not to discriminate somebody) done a great job. The IARU view on the topic was written very professionally and the German regulator in their view used most of the facts from the IARU document. Probably apart the document there were many activities made by IARU. Finger crossed enough members will oppose to the French proposal. If understood well if we get 7 opposing the 2m band is safe for now.

    Just wanted to point out how important is to be a member of your national amateur radio union. By being you also support IARU and we can do something against such interests. Unfortunately I'm afraid in the future there will be more and more interest by commercial users for RF spectrum and our bands especially VHF and above are the most interesting being easy to take away if needed by commercial users. So far didn't happen here but in US they lost part of the 220 MHz band due interests from the USPS.

    Having our sociaieties we have some chance avoiding above from happen. It is like throwing bricks when you don't agree with something. If you throw them alone maybe you broke a window or two before the police arrest you. If an organization throws bricks is like "all their members" are throwing. Having many people trowing bricks is a different story and we have some power.

    I'm also interested what will come out for the 23cm story. In the agenda is mentioned there is no intention to take us the band away but I'm afraid about power limits, etc… There is an IARU response on that topic too.

    For quite the same reason have decided to become also an AMSAT-DL member. Since I like satellites it is how can give some small support to this activity. Probably without AMSAT organizations around we wouldn't have a single bird in space.

    Best 73's!

    Andrej - S57RW

    For LEO SATs I'm using a LPF on the 2m side with 2x FT817 and the arrow antenna. Simple to make. Got the schematic from the PA1IVO website:…able_satellite_setup.html

    Works great both in mode J and B with no noticable desense on RX part. 1st time when tried to work LEOs without the LPF had interferences in both modes when using the arrow and couldn't hear my transmission back at all.

    Never measured the response of the filter but PA1IVO claims should have -50dB on 70cm. Seems that for FT817 and 5W it provides enough attenuation. Probably by using more power and a pre-amp on RX this one wouldn't cut enough and the one Peter posted would be more suitable.

    73 de S57RW