MFJ 18xxT series

Discussion in 'QRP Corner' started by KC3JIN, May 31, 2019.

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  1. N3PM

    N3PM Ham Member QRZ Page

    https://www.ebay.com/itm/25-JSC-JRF...IsAAOSwNbFasqwD:sc:USPSFirstClass!18328!US!-1

    This is what I have seen used for multi-band dipoles. Ages ago.
    I figured if it worked for a dipole, why not radials/c'poises?
    The computer cable should work as well. The wires on my ATAS 25 kit are segmented and coupled with powerpole style connectors.
    The big thing I found with portable antenna set-ups is to log all your successful configurations for future ops.
    Mike N3PM
     
    KC3JIN likes this.
  2. KC3JIN

    KC3JIN Ham Member QRZ Page

    Agreed, if it works try to write down how it worked. Ask my XYL, I'm a great cook but not consistently :)
     
  3. KG5BJV

    KG5BJV Ham Member QRZ Page

    I have the 1899t and always used it on a mag mount on my a/c unit outside on my Yaesu ft817nd 2o meters through 2 meters always got a good ground this way made plenty of local and world wide contacts just using 5 watts. Don’t use it now the center pin broke off on my radio was lucky to get it out too top heavy!!
     
    KC3JIN likes this.
  4. KU3X

    KU3X Ham Member QRZ Page

    I found the MFJ 1899T to be a great little antenna. If you use the chart that I provided on the following web page, you'll have an easy time to set up.

    http://www.ku3x.net/portable-qrp/mfj-1899t-whip

    Yes, it is kind of heavy to put on a little QRP radio like the KX2. The mono band version are less of a load. I also have the 20 meter MFJ mono band telescopic whip and I use one ground counterpoise wire with it. Again, the length of the wire is the same as the one I use with the 1899T and it provides a perfect match. No trimming was needed on the mono band whip. I just extended it all of the way, attached the counterpoise and when I checked the SWR with the meter on the KX2, without the tuner in line, it dipped down to 1.2 to 1 in the center of the band.

    Barry, KU3X
     
  5. K8JD

    K8JD Ham Member QRZ Page

    I checked the specs on the MFJ1899 and it is only 52 inches extended, kind of a little antenna for anything below 10 M ! Teamed with a QRP rig it will not get very exciting results !@ Even worse if y0ou don't want to deploy some tuned length radials for the bands ou expect to use.
     
  6. KM6KJI

    KM6KJI Ham Member QRZ Page

    I'm having fun with the MFJ-1820T directly mounted on my FT-818ND. My priority for QRP portable is operating anywhere quickly, minimizing the setting-up time. The MFJ-18xxT series work very well for that purpose I think, although they are of course much more compromised antennas compared to a full size vertical or dipole antenna.

    [​IMG]

    I used to own the MFJ-1899T a while back and it worked fine, but now I prefer the mono band ones because:
    1. my QRP operation is mostly on 20m during day time
    2. efficiency of the 1899T on 40m and 80m is not very good, while the loading coil is longer/heavier due to those bands
    3. the shorter/lighter base part (loading coil) of the mono band version makes it more comfortable to use with the FT-817/818ND specially when the antenna is mounted on the BNC connector on the radio
    4. tuning the mono band version is much easier, you get the minimum swr on the lowest portion of the band just by fully extending the telescopic element, given that the counterpoise wire is cut for the band. For the 1899T, you will need to remember (or refer to the chart for) the right length for both the telescopic element and the counterpoise wire per each band
    5. operating multi bands from 80m thru 6m in one QRP session or expedition is just a dream TBH, or it is nice to have just in case but not really practical
    For the same reason as the #2 above, I would not even think of buying the MFJ-1880T. I may buy 1840T but I will not expect too much out of it. What about 17/15/12/10/6m? I will wait until the band condition and/or the activity on those high bands get better.

    73,
    Yoon
     
    KC3JIN, KE0EYJ and KU3X like this.
  7. KC3JIN

    KC3JIN Ham Member QRZ Page

    Thank you Yoon! I feel the same way - I don't feel like such a small antenna could perform so well on low bands. And I also prize speed and portability.

    But I realize, on the other hand, that though the 1899t is 4x the price of a monobander, it does tune to more than 4 bands... That makes me want to ask another question.

    Ugh! Who would've ever thought it'd be easier to just buy everything in the catalog.................
     
  8. KM6KJI

    KM6KJI Ham Member QRZ Page

    I understand, the multiband option is always attractive. If there had been a high band only version (20m-6m) in the same size as the monobander, I would have bought one already.
     
    KC3JIN likes this.
  9. KA0USE

    KA0USE Ham Member QRZ Page

    https://www.amazon.com/superantenna

    scroll down to see radial (counterpoise) sets.

    being a po-boy, i made my own with a ring terminal holding 4 wires.
     
  10. KC7JNJ

    KC7JNJ Ham Member QRZ Page

    jackite still makes a 31 ft pole. I have their 28 footer. (they dont make a 28 any more} I find it simple to use. I drive a wooden stake in the ground that is cut to go up in the pole. Slip the pole over the stake, it stands up with no fuss. I can run my wire right up it or run the wire as a slooper. 31ft over 20ft makes a big difference. I know that is not the question you asked but I think it will work better then what you are asking about.
     

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