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1296 transverter options?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by K3RW, Aug 18, 2017.

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  1. K3RW

    K3RW Premium Subscriber QRZ Page

    One problem I have is understanding what 'else' is needed for a transverter setup. Most likely I'll be using a ICOM-7100 or 706MKIIG. I could use 2m or 10m for the IF on either rig.

    So I buy the transverter, but I'm quickly learning there are other parts potentially needed as well. Are there block diagrams out there that show what these parts are?
     
  2. W0AAT

    W0AAT XML Subscriber QRZ Page

    Transverter, driving rig, antenna will get you on the air low power(and 2 watts on 1296 can do a lot during good band conditions). Oh and some form of keying cable to match your radios, TX out pin... it is when you add amplifiers and preamps where you need relays to switch and protect things, and a sequencer to make sure those relays switch when thy are supposed to.

    Some radios have a bad spike on TX, you may want to research and make sure yours is not one of them. If it is then an outboard attenuator with a bypass relay for receive is needed, or a sequencer to hold the ALC low but that is not a guarantee to eliminate spikes.
     
    AF6LJ and K3RW like this.
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    If your rig is set up for transverters (many are, but many aren't) and the transverter has internal T/R switching to a common antenna port (many do, some don't), you don't need anything else at all -- well, maybe a way to measure output power and SWR at 1.2 GHz, as most "standard" hamshack meters can't do that.

    If your rig is not set up by design for use with transverters, then "overdriving" one with excessive power from your HF rig can be a pretty big issue and may require the use of an external power attenuator to get the HF output power down into the range of what the transverter can accept. Many transverters can accept drive levels from just a few milliwatts up to maybe a watt or so; DEMI made some that would accept up to 20W drive (internal attenuator). "It depends."

    If the transverter does not have an internal T/R switch (and some don't), you'd need a coaxial relay with good performance at 1.2 GHz to do the switching (that is easily controlled by the transceiver), and such a relay can cost $100-$150; however they can also be found "used/surplus" for lower prices than that. If the transverter needs switching at the baseband (HF) frequency, a cheaper relay can be used there as it will only be operating at 10m or 2m and not at 1.2 GHz.

    Output power/SWR measurement can be taken care of with a surplus Bird Thruline or similar and the appropriate element(s). Most "ham radio" type meters won't work at 1.2 GHz, although a couple of specialty models might.

    It's not complicated.
     
  4. KM3F

    KM3F Ham Member QRZ Page

    Why is there a problem understanding?
    Transverter is transmit conversion/ receive conversion to and from the IF being used.
    The two functions have to be switched between, usually in the Transverter unit.
    You need a RF drive cable to the Transverter for T/R.
    You need a cable for PTT between the radio and the Transverter so it switches with the radio and to the amplifier if one is used.
    An antenna and power supply for the transverter.
    That's all,
    Good luck.
     
  5. K3RW

    K3RW Premium Subscriber QRZ Page

    I often see transverters with a 2m IF and others with a 10m IF. Is there any benefit to one over the other (sensitivity, etc.)?

    The 7100 and 706MKIIG have 2m all mode, as well as 10m. The 7200 and 7600 only have 10m. The 7600 has 'transverter mode'. Not sure which of these is the 'best-suited', but if I had to take one mobile it would probably be the 706.
     
  6. K3RW

    K3RW Premium Subscriber QRZ Page

    To me it is confusing because there are transverters that can switch and others that cannot (just learned that), so additional parts may (or may not) be needed. And there are sequencers, relays, and all sorts of this and thats that may or may not come into play. Having never used one, it is some of the most foreign and confusing stuff I've ever tried to read, and it is hard to budget when I can't compare A to B.

    I thought I could just buy a transverter and a couple of cables, since I wasn't thinking of running an amp, but it quickly gets complicated on what the additional parts (if needed) are necessary. After getting sticker shock on some of them, but finding others cheap (but needing lots of additional hardware), its quite an undertaking.

    If ICOM would just make a(nother) 1.2ghz all-mode, do 50w, and keep it around $450...
     
  7. N2SLO

    N2SLO XML Subscriber QRZ Page

    If ICOM would just make a(nother) 1.2ghz all-mode, do 50w, and keep it around $450...[/QUOTE]

    Good luck with that- however, if you have an IC-9100, for another $600 you can get the 1.2G module that is rated
    for 10 watts. This band is expensive- then add as mentioned a Directive Systems loop yagi and then an external amp and you are
    over $2K. An investment for sure, but its one and done. I did it- we have plenty of activity in the NY, NJ, CT and New England area
    to justify the cost. For some areas little or no activity so probably not worth it. .... Good luck
     
  8. KM3F

    KM3F Ham Member QRZ Page

    I use DEMI transverters on 2m, 1.25m and 70 cm all driving amplifiers.
    There are no sequencers involved because I do not use mast mounted Pre-amps.
    Some of the parameters that need attention for serious work is a frequency counter for the highest frequency, to have good readout accuracy, calibration of the transverters, and being sure the driving radio is calibrated to at least WWV on the highest frequency you can receive WWV at, and attention to cooling the Transverters so drift in minimized.
    You would find that contest stations often have a huge amount of drift and are off frequency especially if trying to find another station by frequency.
    At 1296 it is even worse.
    On Kenwood radios from the TS 2000, TS 480, TS590 and TS990 all have the ability to see the operating frequency in real time display on any band set up on as designed into the radios by menu and direct display key in.
    You need the calibration and see the actual frequency to work repeaters in split mode using PL tone just like any other FM radio.
    When all is calibrated you dial the VFO to wherever you want to go and check the counter once after warm up for each band and make fine calibration corrections as needed.
    Might sound complicated but its not once you get into it.
    Now I have an SDR receiver to look at both Rx and TX signals with.
    The problem is today with plug and play the user looses or never attains the knowledge behind what the radios do inside the box. Only difference with Transverters is some of it is done outside the box and need set and calibration and some leads to make it all work the same way.
    This is Ham radio so you need attention to these things to run a good station.
    Good luck.
     
    K3RW likes this.
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    No real advantage to one baseband frequency over another; all the "sensitivity" occurs in the transverter's front end, not in the HF rig. Using 2m as a baseband results in a somewhat lower frequency local oscillator in the transverter, which could make for slightly less drift and slightly better frequency accuracy over time. I "adjust" my 1.2 GHz xvtr L.O. from time to time to keep it on frequency, so I'm always within a couple hundred Hz. Those who don't can be off a few kHz (!) on 1.2 GHz, but ops are pretty used to this and tune around a bit to find each other.

    If the 7600 is designed for use with transverters (I don't have one and haven't checked this), it is probably your best choice in that if may already provide the very low HF drive levels for use with most transverters and may even be set up to change the digital display to indicate the band you're using with the transverter, e.g., set it to 1296 MHz and the display could read 1296.xxxx instead of 28.xxxx. That's not much of a big deal, but it's kinda cool.
     
    K3RW likes this.
  10. WA9SVD

    WA9SVD Ham Member QRZ Page

    The CONFUSION is for which band is under consideration! His post starts by talking 1296 MHz, but then says he is considering a transverter for 1.25 M, or 222 MHz. The two are NOT interchangeable.
     

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