Million Questions but I will start with one - 2 meter

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KE8EYM, Jan 11, 2019 at 4:37 PM.

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  1. KE8EYM

    KE8EYM Ham Member QRZ Page

    I am a pretty inexperienced noob with only a handful of contacts under my belt. I have a small 2 meter HT with 5 watts that I am working with. I have built a couple antennas and on a good day I can hit the repeater that is about 22 miles away but not reliably. I would like to bump things up a bit so I can make more contacts. I have been looking at radios with different outputs. My question is with 2 meter is it worth spending the extra money for something like a 100 watt radio over a 50 watt or a 25 watt.
     
  2. ND5Y

    ND5Y Ham Member QRZ Page

    Antennas, and where they are located, are way more important than power.
     
    KC8VWM, N2SUB and N0TZU like this.
  3. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Indeed.

    If this is for "mobile" work, use a very good mobile NMO mount whip on the roof of the vehicle and then 25 or 50W should work just about anything.

    If this is for "home station" work, a very good outdoor antenna, elevated well above the roof and fed with low-loss coax should allow you to work almost anything even with the 5 Watts, although 25-50W can certainly help at times.

    You didn't say what kind of antennas you have built or how they're installed, but even a simple 1/4-wave ground plane on a mast above the roof (maybe 20-30' above ground) should work quite well; a commercially-built 2-3 element vertical colinear omni antenna up 40 or 50' above ground will work much better. "Height makes might" on VHF.
     
    N0TZU likes this.
  4. KE8EYM

    KE8EYM Ham Member QRZ Page

    Thanks for the replies!

    Thats kind of what I was thinking. Just wondering the advantage if any to getting the radio with more power. Right now I use the same radio for both mobile (I have a mag mount which is not the greatest. I am looking to up grade that antenna but I am not on the road that often.

    I built a J pole that was around 20 feet on my roof which worked ok. I also built a 3 element yagi and that is what gets me to the repeater in town occasionally. It is mounted at about the same height. I like working on the antennas so trying to fine tune them is fun. I do need more height.

    What should I be looking for when it comes to coax?
     
  5. AG6QR

    AG6QR Subscriber QRZ Page

    If your signal is on the edge of readability, a doubling or halving of power can provide a noticeable difference, but usually not a dramatic difference.

    Going from 5 watts to 50 watts is a tenfold change in power, and that can be dramatic for a signal that was marginal.

    But as others have said, the antenna is key. And on VHF, height can transform a mediocre antenna into a super one.
     
  6. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    The problem with handheld units (HT is a registered trademark of Motorola) is that most of them have receivers that badly overload when connected to a decent antenna. A goodly portion of this overloading is NOT from amateur radio signals but is from commercial two-way FM stations operating on nearby frequencies.

    A such, a better antenna will usually improve transmitter performance but also degrades receiver performance because of the overloading of the receiver.

    Glen, K9STH
     
    AI3V likes this.
  7. AI3V

    AI3V Ham Member QRZ Page

    A DB is a DB whether you get it by power, antenna height or antenna gain.

    Of course your Rx will improve by the same DB for #2 and #3 above :)

    The question you want to ask is "is it cheaper to increase tx power 10 DB, or get a 10 DB better antenna.

    This being 'murica and all, I say get both. :)

    P.S. nobody serious about vhf weak signal work runs qrp.

    Rege
     
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  8. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Depends how long the cable needs to be!

    My attitude about VHF is "the coax should always be at least 100 feet long and run vertically.":)

    For very short runs, on 2m even RG8X isn't bad; for more than 50 feet, I'd step up to at least RG-213/U or better still something like LMR400. My own 2m antenna cable needs to be 170 feet long (atop a tower at the opposite end of the house from the station), so I'm using 1/2" hardline for most of that, but switch to RG-214/U to go around the rotator and up to the antenna, and transition to a very short length of RG8X (about four feet) inside the shack to make it flexible enough to not pull wattmeters off the shelf and stuff. The transitions are just UHF connectors, but on 432 MHz I go to type N -- and on 902, 1296 MHz or any higher frequency, absolutely type N only.
     
  9. VE3CGA

    VE3CGA XML Subscriber QRZ Page

    I used to run a FT60R into a mobile 30W brick amp. In the car a 5/8 antenna with this gave excellent coverage and occasionally I could get into systems across the lakes. At the house I built a 4 element quad, vertically polarized with 50' of rg8x and up about 30'.
    Worked very well here, Sarnia, Kitchener, St Thomas, Woodstock, Exeter, St Marys. Occasionally getting into NY, Penn, Ohio and Detroit.
    I also had a beacon on 2M. It was a HTX202 (5W) feeding RG8 into a slim jim up 55' off the side of my tower. I could hear it in my mobile as far as Kitchener and clearly about 15miles west of London and in Exeter. Not so good to the south due to the tower being in the way.
    Height as mentioned is desireable with a decent antenna either collinear or directional antenna and a typical mobile rig (25 - 50W)
    Look up coax loss calculators online and you can decide what type of coax you should use.
    Your terrain also can make a difference, good if your on a hill , bad if you are in a gully.
    Finally it depends on how active repeaters and simplex are in your area, and how long folks will be using that in the future. We are repeater heavy here and a couple years ago there was lots of useage, then I started hearing more stations south of our border (even a sstv net) than locally.
    Its pretty dead here and for my area, wouldnt put much effort for 2M fm . In fact I hear more on the satellites than on our repeaters.

    If you are getting a lot of usage on 2M fm then look for a used mobile rig (and 12v supply) with a decent antenna up at least 25'
    Incidently I worked a satellite (AO91) with just my FT60r while visiting my son in BC, you might want to try that, lots of guys doing it with small handheld beams and dual band handhelds.
     
  10. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    This is a serious problem with cheap handhelds (aka Baofeng, et al) but I've found it's still a problem even with most amateur radio 2m FM mobile rigs. Nowadays. Wasn't always like that.

    The best 2m "amateur" mobile rig I've ever tested for this was a 1977-vintage Kenwood TR-7400. It had zero out-of-band coverage (covered 144 to 148 MHz only, nothing outside that) and had multiple helical resonators (RF and mixer) to keep the front end very tightly filtered. I could hear a 1uV 2m signal when a 1kW 155 MHz pager transmitted literally 100 feet away on the same hilltop. "Today's" mobile ham rigs cannot do that.

    Some commercial stuff (Motorola) can. Some older ham gear can, if it has no out-of-band tuning capability. But it seems "nowadays," the trick is they cover all over the place and have zero front end filtering. You get what you get.
     
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