K2: What do you have in your portable/travel kit?
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Summer is around the corner (finally here, up at the arctic circle). Those of you organized enough to have the K2 ready to be taken on the road or on the trail on a short notice, what do you have in that travel kit, aside from the K2 itself?
CW-key, mike, headphones, log book, pre-cut antenna wire, telescoping pole,...? 73 - Kristinn, TF3KX |
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A good book to read because of the lack of contacts possible for common G-stations who are never "DX" to anyone? Not an issue for TF3KX.
Seriously, a wire dipole antenna and some means of attaching it to supports. Open wire and coax feeder. A balun (I have the auto ATU). DC lead and PSU. Key, Microphone. notebook. I do not have a lightweight telescoping pole but it would be useful. Mobile phone. Duck Tape. Mike
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K2 and K3: What do you have in your portable/travel kit?
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..and a small power supply.
Just bought the MFJ-4125P which at 1.3 kg or 2.9 pounds is light and small. Comes with Anderson Power Poles at the front. Switchable 115-230 V Drawbacks are a noisy fan (with medium duty use a series resistor to the fan cuts noise) and MFJ so far has not supplied an updated schematic and is slow in responding to this matter. 73 Len SM7BIC _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2: What do you have in your portable/travel kit?
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In reply to this post by TF3KX
A type of antenna that I keep packed for use at short notice is a halfwave
centre fed dipole for use as a vertical, where part of the coax feeder forms the bottom half of the dipole. With this arrangement the coax feeder comes away from the bottom of the antenna not from the centre, radials are not essential and matching is easy. The complete antenna and feeder could be made using a single length of coax. Although it is a single band antenna there might be a modification, which I have not yet tried, to get it to work well on two perhaps three bands. I have used this scheme to feed Half Squares and other types of phased vertical arrays. If of any interest to you please let me know and I will send you a diagram. 73, Geoff GM4ESD Kristinn, TF3KX, wrote on Friday, May 09, 2008 3:07 AM > Summer is around the corner (finally here, up at the arctic circle). > Those > of you organized enough to have the K2 ready to be taken on the road or on > the trail on a short notice, what do you have in that travel kit, aside > from > the K2 itself? > > CW-key, mike, headphones, log book, pre-cut antenna wire, telescoping > pole,...? _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2: What do you have in your portable/travel kit?
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In reply to this post by TF3KX
Summer means beach time here in the Carolinas. I take my K1, lightweight 20m dipole (K1 ATU tunes to all 4 bands), Palm Mini-Paddle, 5.0ah gel cell, earphones, bungee cords and a couple of telescoping lure retriver poles: http://www.basspro.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10151&catalogId=10001&langId=-1&partNumber=37104&hvarTarget=search&cmCat=SearchResults
Oh, sunglasses, sunblock, hat and swimsuit.... 73 de Ken - N4OI / K1
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Re: K2: What do you have in your portable/travel kit?
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In reply to this post by Geoffrey Mackenzie-Kennedy
Geoffrey Mackenzie-Kennedy wrote:
> A type of antenna that I keep packed for use at short notice is a > halfwave centre fed dipole for use as a vertical, where part of the coax > feeder forms the bottom half of the dipole. How do you terminate the radiating part of the coax? I've tried antennas based on this principle both on HF and 2m. On HF, I tried the "no counterpoise antenna" by M3KXZ with very disappointing results. On VHF, I've had good results with the coax antenna by LA1IC described (in Norwegian!) at http://la2t.org/teknikk/vertikal2m.html. Choking off the radiating part of the coax is challenging, because we're trying to choke a voltage node. I was told that the coil which terminates the radiating part of the coax on the 2m antenna is chosen to resonate as a parallell trap at 2m with its stray capcitance. On the HF antenna, I just wrapped the feeder around a large toroid 10-15 times, and that did not work well. My 2m antenna needs are modest, so take this with a grain of salt. 73 LA4RT Jon _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: K2: What do you have in your portable/travel kit?
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Hello Jon,
My apology for a slow response, waging war with the grass all day! To terminate the radiating part of the coax I use a high impedance trap whose inductance is a length of the incoming feeder wound as a solenoid, with the turns spaced slightly. To determine the capacitance required to resonate the coil formed by the outer of the coiled coax I use an air variable capacitor, then replace it with a length of open ended RG-213 as the capacitor. The important thing to note here is that the capacitor made using coax must not be connected as an open ended stub, which could upset the trap. I would also suggest that relying on stray capacitance to resonate a trap is a questionable approach. During my first attempt I used a large quantity of cores over the coax which did not work well because the choking impedance was too low, in fact I blew some! With this method of feed it also becomes a relatively simple task to feed a top loaded T antennas from ground level without the use of a high impedance matching network, placing the current maximum at the top. For multiband use I had considered using Close Coupled Resonators in a fixed installation, but not for something to be rolled up. Thank you for the link to LA1IC's antenna, much appreciated. 73, Geoff GM4ESD Jon K Hellan LA4RT wrote on Friday, May 09, 2008 1:28 PM > How do you terminate the radiating part of the coax? I've tried antennas > based on this principle both on HF and 2m. On HF, I tried the "no > counterpoise antenna" by M3KXZ with very disappointing results. On VHF, > I've had good results with the coax antenna by LA1IC described (in > Norwegian!) at http://la2t.org/teknikk/vertikal2m.html. > > Choking off the radiating part of the coax is challenging, because we're > trying to choke a voltage node. I was told that the coil which > terminates the radiating part of the coax on the 2m antenna is chosen to > resonate as a parallell trap at 2m with its stray capcitance. On the HF > antenna, I just wrapped the feeder around a large toroid 10-15 times, > and that did not work well. > > My 2m antenna needs are modest, so take this with a grain of salt. > > 73 > LA4RT Jon _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
coaxial dipole (was: What do you have in your portable/travel kit?)
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To make a coaxial dipole strip the external insulation from the end of
your coax to a length about 10% longer than 1/4 wave. This leaves just shield (braid), center dielectric, and center conductor. push back a bit of the braid so it increases in diameter. Fold it back over itself and carefully stretch it backward until it covers the remaining external insulation leaving just the center conductor and center dielectric exposed. The folded-back braid should now form a cylinder over the coax. Trim this braid until it is 1/4 wave long. Trim the center conductor until it is also 1/4 wave long. You now have a dipole that is end-fed. The folded-back braid functions as both radiator and 1/4-wave stub to cancel the currents on the shield of the coax. For 2M I put this whole thing in a piece of PVC pipe and shoot in some foam insulation to keep things in place. It works just peachy. Caveat: you may find that turning the braid inside-out to make the outer element to be a real challenge. You can cheat by cutting the braid off, compressing it so it slips over the outside of the coax, and then reattaching it to the shield of the coax with solder. To be honest, that is what I usually do. ;-) Brian Lloyd Granite Bay Montessori School 9330 Sierra College Bl brian AT gbmontessori DOT com Roseville, CA 95661 +1.916.367.2131 (voice) +1.791.912.8170 (fax) PGP key ID: 12095C52A32A1B6C PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: coaxial dipole (was: What do you have in your portable/travel kit?)
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And if you accomplish the very accurate building instructions from Brian, twice, and feed it as a dipole, but with a half wave wire fed in the middle, and add a quarter wave wire on each end, but make the joining very sturdy, you now have a very good, but low profile gain antenna on ?? what band were we building this for? I have mine on 20. It is fed with open wire and works just fine on 80 thru 20. More details or if you want I will build one for you for cost. --... ...--Dale - WC7S in Wy> From: [hidden email]> To: [hidden email]> Date: Fri, 9 May 2008 14:53:55 -0700> CC: [hidden email]> Subject: [Elecraft] coaxial dipole (was: What do you have in your portable/travel kit?)> > To make a coaxial dipole strip the external insulation from the end of > your coax to a length about 10% longer than 1/4 wave. This leaves just > shield (braid), center dielectric, and center conductor.> > push back a bit of the braid so it increases in diameter. Fold it back > over itself and carefully stretch it backward until it covers the > remaining external insulation leaving just the center conductor and > center dielectric exposed. The folded-back braid should now form a > cylinder over the coax. Trim this braid until it is 1/4 wave long. > Trim the center conductor until it is also 1/4 wave long.> > You now have a dipole that is end-fed. The folded-back braid functions > as both radiator and 1/4-wave stub to cancel the currents on the > shield of the coax. For 2M I put this whole thing in a piece of PVC > pipe and shoot in some foam insulation to keep things in place. It > works just peachy.> > Caveat: you may find that turning the braid inside-out to make the > outer element to be a real challenge. You can cheat by cutting the > braid off, compressing it so it slips over the outside of the coax, > and then reattaching it to the shield of the coax with solder. To be > honest, that is what I usually do. ;-)> > Brian Lloyd> Granite Bay Montessori School 9330 Sierra College Bl> brian AT gbmontessori DOT com Roseville, CA 95661> +1.916.367.2131 (voice) +1.791.912.8170 (fax)> > PGP key ID: 12095C52A32A1B6C> PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C> > > > > _______________________________________________> Elecraft mailing list> Post to: [hidden email]> You must be a subscriber to post to the list.> Subscriber Info (Addr. Change, sub, unsub etc.):> http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm> Elecraft web page: http://www.elecraft.com _________________________________________________________________ Windows Live SkyDrive lets you share files with faraway friends. http://www.windowslive.com/skydrive/overview.html?ocid=TXT_TAGLM_WL_Refresh_skydrive_052008_______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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