1.25m transverter on FM repeaters

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by K3RW, Jan 27, 2018.

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  1. K3RW

    K3RW Premium Subscriber QRZ Page

    I'm looking at getting a 1.25m transverter so I can try 222 SSB. We have a few 1.25m FM repeaters here, but the 222 net is SSB.

    But just curious, since the transverter claims it will do any mode I throw at it, and it will cover up through the FM repeater portion, how do I setup (or can I) the tone squelch, etc.?

    For the transverter to cover 222 to the end of the band (they don't cover 220-221.9), one needs to have a rig that can tx at 26 MHz through 10m, or one that does 10m through 32 MHz. I'll test my rigs to see if the MARS mod on them cover one or the other. Not sure if CB interference will be an issue. I'll probably get whichever MARS mod would work with it.

    Anyways, to get on a FM repeater, would I put my rig on FM mode for 10m, and use the same tone squelch on 10m FM that is listed for 224Mhz? Or does the transverter try to mix this tone and I can't do it?

    Just curious. Its alright if I can't do repeaters. Went 4 months of daily scanning on them, calling infrequently, and only heard repeater IDs anyway.
  2. K7JEM

    K7JEM Ham Member QRZ Page

    Yes, you need to set up your 10M rig to TX the right PL tone, and you need to set the TX and RX to the proper offset, IOW the 10M rig will have to TX 1.6MHz lower than the RX, since that is the offset used on 220.
    K3RW likes this.
  3. K3RW

    K3RW Premium Subscriber QRZ Page

    Ah, thanks so much. I forgot about the offset difference.

    I think on one rig I can make the offset to just about anything so maybe that will make it less complicated.

  4. K6CLS

    K6CLS Ham Member QRZ Page

    Well best wishes for your FM repeater adventure. I'm sure you will get it working pronto.

    Any plans for 220 SSB? Maybe there's a net nearby or something. Do you have a good horizontal yagi?
    K3RW likes this.
  5. K3RW

    K3RW Premium Subscriber QRZ Page

    Thanks so much.

    Yep, the plan is to get on 222 SSB during the weekly net here in the Portland area. Its probably a small group since it is SSB and not FM. NCS is maybe 8 miles away and I can hit the same NCS on 432 SSB with just a mobile whip. I hope in the next VHF contest I can actually throw a 1.25m station on SSB and monitor FM simplex as well.

    I don't have a yagi for VHF/UHF+ yet, but will build my own ground plane--that should be easy with my analzyer that goes up to 230MHz. If I get brave I might try a collinear build. Some of the nets here are vertical or horizontally-polarized, but most are both. The VHF/UHF ones here seem to do both. I'd prefer to pickup a cheapo 1.25m HO antenna if I can find one. I've got the M2 HO stacks for 6/2/432 and they work well. I have a eFactor stack and it works very well too. At least I can tell where to swing the 'eventual' beam, and the HO stacks do much, much better than a vertical, and work great mobile.

    If there is a problem at all, its that I shouldn't expect more than about 4-5w out on the transverter. The maker claims it can go more like 7-8w but I've seen tests of them online and the signal gets really ugly above 5w. For contests and nets I've had no issues running the different rigs on 2 and 432, but I wasn't running 4w either, ha, more like 30-50w.
  6. K6CLS

    K6CLS Ham Member QRZ Page

    Hey that's great! I like 220 band, a lot quieter and perhaps better propagation than 2m. Explore, enjoy, maybe some day we'll get tropo. I can dream can't I?!?
  7. W0AAT

    W0AAT XML Subscriber QRZ Page

    Been there done that! I was using a Uniden 2510 that I modded to cover 26 to 30mhz. Worked well and made several FM simplex contacts
  8. KM3F

    KM3F Ham Member QRZ Page

    As you probably see, the FM Rx (from the repeaters) is on the upper end of the band in the 224 - 225 range.
    All offsets are negative or minus. This will keep your transmit from going out of band unless you make a mistake and your radio will TX out of band above 29.7.
    That means your receive tuning will go above 29.7 based on a DEMI Transverter spec.
    You won't transmit there because the negative 'off set' will take your TX lower in the band to the repeater input frequency so no worry about going out of band for just receive.
    Not every repeater has their PL tone tuned on even though they list one.
    You program FM the same as on 2m or 70cm.except for split difference and off sets.
    I put together an all mode 222 rig with a SS amplifier and matching power supply that came out of a multiple 220 system that was tried in the upper northwest then removed for lack of business success.
    Power out is up to 190 watts all modes and under variable power control.
    My Kenwood has a menu option to make the radio readout direct on the 222 band but you must calibrate it for accuracy with a frequency counter to be sure what frequency your on when moving the VFO and programming the repeater frequencies..
    If you set repeaters to radio memory, they should hold each time you go to the memory number. This is based on Transverter frequency stability.
    Here in my area I have accessed at least 20 repeaters with activity on only a few.
    Wonderful band if it would be used more.
    Equipment and antennas are a bit scarce but keep looking.
    I run a stacked pair of 8 element beams because the initial cost of the beams is low.
    Also there maybe some activity on SSB during VFH contest times.
    Good luck.
    Last edited: Jan 28, 2018
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I've done this for years with 135cm transverters.

    No, the transverter will not alter the CTCSS tone in any way: Use the tone you need, programmed on 10 meters, and it will come out fine on 222 MHz.

    However, you'll need to use "split" operation on the 10m rig, and dial in the two VFOs to accommodate the correct "split" operation.

    I still have my VE3CRU-special MMT220 (modified MMT144 from Microwave Modules, converted to 135cm operation by Hans, VE3CRU) from about 1977 or so.:p
  10. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    222 MHz experiences tropo propagation much like 144 MHz does.

    A "bonus" is that when a tropo duct forms, it often works better on 222 than on 144 -- and often doesn't work on 50 MHz at all. I've seen these ducts operate where "the higher you go in frequency, the better they work," and 10.3 GHz can produce stronger signals than 222 MHz does. So, that's the "higher frequency" bonus.

    Unfortunately, sporadic-E on 222 is very rare. In 45 years on the band, I've only worked Es exactly once on 222 MHz and that was in June 1987. Worked W5LUA in TX from FM27 in VA -- definitely Es, as 144 MHz had it also, and six meters was wild all weekend -- it just never closed. That weekend was a contest, and we had 204 "different" grids worked using low power on 50/144/220/432 MHz. Amazing condx, I've never seen them repeat.
    K3RW likes this.

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