Trying to get answers on Full duplex HT for satellite

Discussion in 'Satellite and Space Communications' started by KE7GVK, Jun 25, 2015.

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  1. KE8AKW

    KE8AKW Ham Member QRZ Page

    I would probally go with a FT-8900 Or 8800, they put out 50W and are full duplex and are small. As for HT that kenwood will work. You should really try to invest in full duplex with SO-50, So you know your hitting the satellite, and know when to stop transmitting so your not causing interference. As for the antenna, I would say Arrow Antenna, Theres also this thing called a Alaskain arrow antenna, Same antenna just one more element on 2M and three more elements on 440, Its slightly bigger, but it will give you a better kick. I have not heard anything about the Alaskian but would buy one over my arrow antenna I have, if thats what the specs claim.
     
  2. N8HM

    N8HM Premium Subscriber QRZ Page

    It's also a beast. I'd like to try one myself, though.
     
  3. N1EN

    N1EN Premium Subscriber QRZ Page

    I have one. While it can be used hand-held...it's big and unwieldy. It really needs to be on a tripod.
     
    AL4Y likes this.
  4. WD9EWK

    WD9EWK Ham Member QRZ Page

    Yes, mobiles can transmit at up to 50W, but let's not encourage that. Unfortunately, that is a problem on many SO-50 passes - stations running way too much power.

    A mobile radio will require a larger battery to power in the field, compared to HTs. I have a couple of 12V jumpstart batteries for my radios. When I am in the field working SO-50, I like the full-duplex IC-2820H as my radio. It can transmit at up to 50W on 2m, but I try to keep the power down to one of the lower levels (5 or 15W). Higher power drains the battery faster, and I don't want to hold my antenna while transmitting at 50W.

    73!
     
  5. KE7GVK

    KE7GVK Ham Member QRZ Page

    I ended up going back on what I said in my initial post and bought an IC-W32A from someone on ebay, also ordered an Arrow antenna with the duplexer....I still can't believe how much the price was jacked up for the duplexer....but I'm feeling lazy and was willing to pony it up so it would be what I wanted straight from the box. I appreciate all your opinions and help, and I'm sure I'll be posting more as I run into questions for working birds.

    Thanks again!

    73
     
  6. WD9EWK

    WD9EWK Ham Member QRZ Page

    Good luck!

    Keep in mind that the duplexer that comes from Arrow Antennas is rated for no more than 10W - basically, to work with an HT. It is rather fragile, and doesn't handle a lot of hard bumping around very well. This happened with my Arrow, and was the reason I went to a different duplexer when using an HT with my Arrow.

    An antenna that is not "similar" to an Arrow, but is used by many satellite operators, is the Elk Antennas 2m/70cm log periodic:

    https://elkantennas.com/product/dual-band-2m440l5-log-periodic-antenna/

    Unlike the dual-band Yagis like the Arrow, a log periodic antenna has a single feedpoint. This is perfect for use with HTs and other radios that also have a single antenna port, since no duplexer is required. When using two radios, you would use a duplexer with an Elk - and the duplexer also acts like a bandpass filter. I have used Elks for my satellite operating since 2009, after using an Arrow for a few years.

    You'll read and hear lots of opinions on which of these commercially-made antennas is best for satellite work. In general, either version of the Arrow (normal, or Alaskan) or the Elk would be good antenna choices when working satellites. The homebrew equivalents are also popular.

    Good luck, and 73!
     
    VK3AS likes this.
  7. K6LCS

    K6LCS XML Subscriber QRZ Page

    >> ... I still can't believe how much the price was jacked up for the duplexer ...

    Never thought the price for the Arrow was outrageous ... (grin)

    But please know you can get in to the world of high gain for about twenty bucks: Build yourself
    a tape measure beam or other easy-to-build sat antenna project. Heck, I worked the ISS voice
    last year with 2W and a tape measure beam ... and regularly work SO-50 with one, too. Plans
    for several DIY projects on the ANTENNAS page at ...

    http://www.work-sat.com

    There's even an article there describing how a Scout troop used scrap material - and barbed wire! -
    to successfully work the ISS!
     
  8. N4UFO

    N4UFO Ham Member QRZ Page

    A good choice for sure, but don't get frustrated if you still can't hear yourself coming back over SO-50. I have one... second one after trying to find one that doesn't have desense problems on UHF and I finally just accepted it. Some sources say if it has a 5 digit serial number it will be okay, but that is not necessarily true as I found out. It's more like if it will respond to a certain out of band receive mod... I think if it will open up to 800 Mhz then it's got the old style receiver front end without the desense.

    That said, I have used it with an Arrow on SO-50 and had good success. I have a 'Y' splitter cable that goes to a set of headphones and to a digital recorder through an 'attenuator cable' I got from Radio Shack on closeout. I hold the HT in one hand with the cable and digital recorder clipped to the back and the Arrow in the other, using my fingers to adjust the frequency knob on the HT to adjust for doppler. (The W32A is a better choice over the W31A because the W31A requires button pushes to adjust frequency!) While I don't hear myself coming back through the bird, I do hear an uptick in white noise and I usually only need to have their side of the conversation to get all the relevant QSO data to log.

    P4180028.JPG P4180007.JPG

    When the new FM birds get launched, there should not be a problem with hearing your downlink... there shouldn't be any desense to worry about. I think you'll be much happier with the W32A than using two small HTs. I got a couple of Baofeng HTs to try and work full duplex and had nothing but problems. I had either desense or RFI no matter which way I hooked it up. Not to mention dealing with two HTs was one handful too many. :D

    Good luck and enjoy the birds!!!

    73, Kevin N4UFO
     
  9. KE8AKW

    KE8AKW Ham Member QRZ Page

    Yes thats what I mean, you probably don't want to run 25W out of a arrow anyways (friedchicken). If you want some nice radio and power, of course you need a battery.
     
  10. N4UFO

    N4UFO Ham Member QRZ Page

    Just to be clear... the Arrow diplexer is limited to 10 watts. More than that will likely damage it.

    As for the new birds and UHF, just a reminder to all that you don't want to run much UHF transmit and be pointing a handheld antenna anywhere near people. You can fry the retinas of eyeballs! I once had to carry a 4 watt UHF HT on a job. I had to hold it away from my head to talk on because if I held it close like most people do, I would develop a headache. When I took my GROL exam they go into great detail about this and how not to hold it in front of your face looking at the rubber duck. It doesn't take a lot of RF in close proximity to do damage to eyes.

    There will be temptation with the greater path loss on UHF to use more TX power with the upcoming birds... But with the gain from 7 elements on UHF, if you were running 25 watts and accidentally pointed it at someone in a crowd around you watching... You could harm someone!!! (That's an ERP of 250-300 watts or MORE! Even a 5 watt HT would be around 50 watts.) Be VERY, very careful!

    73, Kevin N4UFO
     
    VK3AS likes this.

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