DX-Patrol Up-Converter - Output Power

  • Hallo !

    I have a query about DX-Patrol Upconverter, incase any operator here has the answer..! ;)

    I need to understand, on the product info / handbook it states that output power is 200mW @23dBm, is this a fixed value - can this be controlled or reduced...? do you control output power by reducing the input IF power...?

    Vielen Dank !

    RH - G0TKZ

  • do you control output power by reducing the input IF power...?

    Yes. Many people use way too much input power. This is immediately visible as spurs on the transponder, so an attenuator 3-20dB or 10-40m lossy coax depending on how low an output you can set your transmitter help a lot. 200mW output equals 23dBm. You will need a big dish or an amp.

    73, Martin

  • Absolutely right. Unfortunately the manaul does not refer to what this pot does, thus many owners never touch it.

    Correct me if i'm wrong: I think it sets the level of input power that is passed to the 4 resistors next to it. These convert excess input into heat. So while it may be true that 6 Watts is the absolute maximum, it is not necessary to waste power. It will only heat up the converter. The manual says the VOX circuit will trigger from about 100mW, so i believe anything between 200mW (to safely trigger VOX) and 1W of drive should be more than enough.

    The output is 200mW max. , so you need a big dish (>150cm dia. for a decent signal) or an amp.

    The DX-Patrol amp's drive is rated 70-80mW for full output, so you will not get around fumbling with that pot.

    73, Martin

    Edit: i believe anything between 100mW and 200mW of drive should be just fine.

  • yes, the input power is dumped into the resistors ( and 6watts is a lot to dissipate), after this 50ohm/6Watts dummy a portion of the power is taken by the pot meter to drive the up convertor. I havent checked the min. drive needed when you bypass the vox ptt and make a hardwired ptt . But given the type of mixer, the MCL ADE-35 is rated at 50mW, ADE-35+.pdf (minicircuits.com), a lower drive below 50mW is definitely possible if you bypass the input ATT resistors.

  • Well, there's the rub:

    There is no wired ptt.

    It's appreciated the manufacturer intented to make it easy to use, but this in turn creates a problem by not providing wired ptt.

    The AMP HAS wired ptt and VOX, but the upconverter has no ptt in or out.

    You need 100mW to trigger VOX. I'm pretty sure, with 100mW INput the Output on 13cm is more than 100mW. The amp max. drive is 80mW.

    Thus , if you use it according to the manual, your options are:

    Clean, but stuttering signal. The upconverter stutters because input level is low.

    Clean but stuttering signal, because upconverter AND amp stutter, same as above.

    Distorted signal without stutter, because you provide enough input power.

    No signal at all, because you can not trigger VOX from a too low input level.

    There may be a small power range where all is ok. But again, it is not clarified in the manual. Oh, i know , you must insert an attenuator between upconverter and amp. This is not stated in the manual, either. Just put everything together, you will be fine. NOT!

    Look at the transponder. If I'd place bets which signals are coming from this brand, i'd win more often than loose.

    Yes, i know, there are dirty signals coming from other brands, too. Some users care, some do not, others just don't know because nobody tells them so.

    73, Martin