Phasing Two VHF / UHF Antennas (
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- Опубліковано 26 сер 2024
- Dick, WA6MDI, has a Icom 9700 with the single Cushcraft A270-10s. He would like to add a secound phasing harness but would like to keep the single feed line. Watch to learn more about phasing harness and what is possible for him to do.
#9700 #weaksignal
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I live in the UK and my 9700 comes with 3 bands without extra module as mentioned at 3:33: 2M/70cm/23cm. 👍
Thank you for sharing all you do.
Thanks again Dave for the video 👍.
There's a diagram on the internet that shows a twelfth wave matching network for driving two antennae with one coax. I believe this is for "mono band" use only, But I wonder if it can be"trimmed" for acceptable harmonic bands?
And yes, commercially made diplexers and triplexeres are available. I have one for 2m/70cm added to my IC 9100.
Keep up the good work and we'll keep learning 👍
Un-un, seems like a good solution! I'd probably nanoVNA before I transmitted the first time, but I think it would work!!!
LOL, Dave, that was 7.5 minutes to say you didn't have an answer. 😄 I think his solution is to remove the duplexer and feed each antenna independently, and then have a phasing harness for each band going between the two A270-10s. As in using 1/4 wave 75ohm leads to match the 50ohm feed, as described in the ARRL antenna book. I've looked at that for pairing two Arrow antennas, but it gets to be too much cabling.
Doesn’t the IC9700 have two separate connections ? One for 70 cm and one for 2m ? In addition to the 1.2GHz. I’m asking because the poor guy will have to use a diplexer to allow both to be fed via one coax.
This one was very interesting. All Techs can use 2 meters but this antenna of course is beyond what a newbie would need. Thanks for the little mention. KF0GPX
Quarter wave ( or odd multiples of) transformers made with coax are normaly used to split or combine two signals. Made with 75 ohm coax or 2 75 ohm lines to produce 35 ohms. Can that be made to work on both bands is the question. My first guess is to combine each band first and then connect one of the existing harnesses. I suggest reading up on VHF and UHF antennas and operation and talk with some OM's that into it first. It is a lot of time and effort but, contacts 600 1000 miles are not uncommon. There a number of VHF clubs in 6 land.
how about parallel folded dipoles? they should be like 300 ohm each, so stacking 6 of them should give around 50 Ohms without a balun?
I would like to hear the resolution to this operators delima, although a complex situation, it sounds very interesting!.
What about spacing? I didn't hear anything about spacing for a dual band antenna. I've never heard of stacking dual band antennas before. This makes no sense to me whatsoever.