First QRP setup. What do you recommend?

Discussion in 'QRP Corner' started by K7NNR, Apr 15, 2021.

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  1. KD9SMG

    KD9SMG Ham Member QRZ Page

    I have an 817ND and plan on that being my only rig (plus an HT) for a while as I figure things out :) My challenge is antenna as well, since I really need either a vertical or an end fed random length (since I don't know what band I'll spend most time using). Assuming I build my own, seem to be no consistent agreement on 9:1 or 49:1 unun. I'm open to votes :)
     
  2. N8TGQ

    N8TGQ Ham Member QRZ Page

    I started with this:

    https://qrpguys.com/end-fed-half-wave-sota-antenna-tuner

    A 123' wire will give you 80, 40, 20, 15 and 10 meters.
    A 66' wire will give you all those bands except 80.
     
  3. K1CWB

    K1CWB Ham Member QRZ Page

    A 49:1 is typically used for end fed half wave antennas. If you cut your wire for a half wavelength (give or take) on the lowest band you want to use you'll get many other higher bands (multiples of the lowest band) to use as well without a tuner. With some of the other bands however, you may need a tuner. It's a great choice if you don't have or don't want to buy a tuner. I'm actually going to build one myself soon just to have another go to antenna for experimenting.

    A 9:1 is typically used for random-ish wire antennas. You generally need a tuner for most bands but if you experiment with different wire lengths for your element and counterpoise you may find you'll be able to bypass the tuner on several bands as well. I say random-ish because there are several lengths that work better than others and some you may want to stay away from but overall you can find something pretty random and make it usable with a decent tuner. This article linked below may be helpful for you if you go this route.
    https://www.hamuniverse.com/randomwireantennalengths.html

    I personally use a 9:1 and have for over a year now and it's been great for experimenting with different wire lengths and different configurations. I've made my share of contacts (maybe even more than my share) both stateside and DX with only a Yaesu FT-818 as my main rig. I will say though along with end fed antennas it doesn't hurt to build yourself a half wave dipole for your favorite band as they are a good bang for the buck performance wise. If you decide to build a 9:1 here's a link below I used to base my build on.
    https://www.hamuniverse.com/randomwireantennalengths.html

    As far as my vote goes I won't be too helpful as I would build both. They are not too difficult to build and you can never have too many antennas at your disposal or as back ups. Whatever you choose be patient as you're using lower power and propagation changes often. Most of all have fun. I've had a lot of fun using QRP power with my end fed antenna for over a year now and it's been a great learning experience.
     
    G0CIQ, WD4ELG and W4ZNG like this.
  4. K1CWB

    K1CWB Ham Member QRZ Page

    W4ZNG likes this.
  5. W4ZNG

    W4ZNG XML Subscriber QRZ Page

    I'm glad you mentioned this and discussed the rationale behind these ratios. I did some playing around with random wires and a 9:1 unun last year.* The bottom line was that, in comparison with a low 40/80 NVIS dipole, for a 75' random wire the noise levels were up 12-18 dB and the output signals were down 3-6 dB. It did tune up easily though, and everything worked after a fashion.

    I should've repeated this test with the Par 10-20-40 end-fed. However, I've since moved and that antenna farm is now history. I suspect though that the performance would be better, much closer to the dipole than to the random wire. Next time I go camping I'll do the testing.

    Something that's really been working for me is this mutant W3EDP: https://thewakesileave.wordpress.co...dp-a-special-design-for-a-balcony-down-south/ I modified the design slightly, substituting 450 ohm window line for the 300 ohm TV leads in the original, mostly because it's tougher and easier to work with. At only 21' it's trivial to hang vertically, and though I don't have any specific numbers, the performance is pretty good. The crazy thing about this is that it tunes down to 80m (it shouldn't, but hey there it is) and I've made a number of QRP contacts there too.

    -----
    *Feb 2020, blogged here: http://coyoteswamp.blogspot.com/2020/02/quasi-random-wire-results.html When I went to look it up, I could have sworn that it was two or three years ago. Feb 2020 somehow seems so long ago.
     
    K1CWB likes this.
  6. N2DTS

    N2DTS Ham Member QRZ Page

    The KX2 is a great radio, but not for the price really.
    That is just the way it has to be unless it was made in China.

    The Xiegu G90 IS made in China and is half the price and twice the power, and the antenna tuner is great (and included).
    Its an sdr and it works very well.
    Backpacking up a mountain, the KX2 rocks!
    Park bench or in the car, the G90 is great.
    Laptop radio in the den, the KX2 is great.
    The 20 watts of the G90 can help poor antenna's to work better....
     
  7. KD9SMG

    KD9SMG Ham Member QRZ Page

    Thanks all for your replies and sharing your experience. One more question —I’m also looking at a 2m/70cm vertical. If I Mount it on aluminum flagpole and run the coax down along the pole is that a problem?
     
  8. WN1MB

    WN1MB XML Subscriber QRZ Page

    Skip the unun and limiting your match range. Instead, just use a hunk of wire, a counterpoise, and a very simple L-network tuner.
     
    VK3YE, WD4ELG and W5ESE like this.
  9. KE8OKM

    KE8OKM Ham Member QRZ Page

    I would suspect the Aluminum pole will create swr issue depending on how you mount it. Others more qualified than I will answer that one.

    I have a Diamond x30a 2/70 on a cheap 4m long windsurfing mast 20% CF I also have a N9TAX Rollup Jpole hanging about the same height as the x30a from a tree branch. The difference in signal tx/rx is imperceptible the price difference is not. The N9TAX is VERY easy to hang and move about in order to find a good location to access your favorite repeaters.

    Erik
    KE8OKM
     
  10. N1RBD

    N1RBD XML Subscriber QRZ Page

    Agreed. When I went ultralight CW (MTR3b) my SOTA kit went from about 6-7lbs to 29oz.
     
    G0CIQ, US7IGN, KE8OKM and 1 other person like this.

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