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KX1 not impressed

Knowing my limitations, I want to reduce the weight of my gear so I can tackle longer hikes. I had an opportunity to buy a KX1 and figured this would fill my need.

Before I even took it out, I was underwhelmed by the output power. So I went out and bought some 16850 batteries and made a pack that puts out 11.5 +/- volts and then did some tests (results of which I already chucked).

The radio performs as it is supposed to, although I wish it would be closer to 4 watts on all bands instead of just on 1. In addition to the lower power than hoped, it will not push power through coax and anything longer than lead, loses half the transmit power. By way of comparison, my 817ND put 5 watts through any coax of any length on any band.

I fabricated a random wire antenna as described in the KX1 (or tuner literature) and tried testing that. I was able to make contacts on 40M and 20M, but with low RST and no contacts on 30M. I tried (for grins) hooking it up to my Buddipole and no contacts at all, RBN didn’t even pick me up, likely due to 50 feet of coax.

Now I am carrying my usual 40 pounds of gear AND 2.5 more so I can keep testing this out. I would hate to do a 12 hour round trip hike to get skunked on the contacts.

Any help you KX1 users can pass along would be greatly appreciated as I would really love to make a 15 pound pack (10 of it being water).

73,

Mike

Not to your KX1 question but what do you have in that pack? My pack for a days multiactivations is around 12Kg so around 26lbs with an FT857D. I carry stuff in case I get overnighted, a bit of a first aid kit, some basic tools, plus sat phone and PLB.

Compton
VK2HRX

I wrote it up here, but my pack is 7 pounds, 10 pounds of water, 6 pounds of random misc stuff and all my radio stuff is 17. I know I can shave that down quite a bit, but in most cases I do not mind carrying the pack.

Hi Mike

You say your KX1 won’t push power through coax. That sounds like the coax or the load at the other end (the antenna) is faulty. So, back to basic fault finding… Does it output the right power into a dummy load? If not, the Tx has a fault, but if the power is OK into a dummy load, it does point to a coax or antenna problem.

Hope this helps

73 Andrew VK1DA/VK2UH
in Exeter this morning

The KX1 admittedly does not produce a lot of power but I would consider the consistently poor propogation conditions of late when evaluating performance. I used a KX1 for 2+ years on 75 activations and something near 650+ contacts with the majority using a loop antenna (terrible efficiency). I only failed to make the required 4 contacts on 1 activation during an especially strong solar event. I always tried to give the little rig the best opportunity to get out - watch the contest schedules and be sure you’re not drowned out by that traffic - watch the NOAA geomagnetic forecast and current Planetary K Index, and watch TamithaSkov on YouTube, if she says the conditions will be poor don’t even try.

I always ran on at least 12.5 volts to get max power on TX. When conditions began to decline in the winter of 2015 I switched to a link dipole - my contacts and signal reports increased so I’d say use max voltage and a high efficiency antenna to get the most out of the KX1 - somewhat obvious suggestions but maybe helpful - 73 Rick WB0USI

Dr OM Mike,
I activate some years with the KX1 and made from DL, ON, HB0, OE, EI, G and EA8 QSO’s with whole Europe, W and VE. The QSO with VE1WT was from DM/RP-443 next to a telecom tower and between trees. That day earlier I lost the cable from my battery pack, so with only the internal batteries the KX1 puts 1.5 W into my antenna. My advise is not to use any coax since the KX1 is designed for a wire antenna. With a W3EDP antenna system, the internal tuner tunes all four bands.
With 14 V from my battery pack, the power output is around 3 W with a SWR between 1.0 and 2.0.
73 de geert pa7zee

I just sold my kx1, it maxed out at 2.5 watts for 12 volts. If you are getting more than that on all bands you are already beating my power output. Just bear in mind the real difference between 2 and 4 watts though, 3dB. That’s probably not enough to be noticed at the other end.
It’s odd that your kx1 will not transmit power through the coax without it losing half of it’s initial power. Either the coax is bad or the kx1 is not matched at the output which is unlikely because presumably you measured it at about 3-4 watts into a dummy load at the output already, it’s a puzzle.
How do you know it loses half of the power through coax by the way?

73,

Ian mm0gyx

Hi Mike,

I gave a look into your gear evaluation, and I think there is way to make it lighter.

Radio gear:
it is extrange your are getting that low power. Is your Kx1 properly aligned?

  • I would recommend to move from AA cells into Lipo. You get rid of the AA container box. The weight/power balance is in favor ot Lipo, I would say.
  • To be able to ensure a succesful activation and keep the weigh low, I would go for a MTR radio. It covers 40-30-20 m bands and power is increased to full 5w. Weigh and current drain is so low with it! And the cost if affordable. (I’m not linked to LNR in any way…)
    http://www.lnrprecision.com/store/#!/Mountain-Topper/p/45010523
  • Coax, not necessary for Kx1.For 817 use RG-58 or RG-174 better. Optimize a short run of it instead a long one.
  • Antenna: a tuned antenna will make the use of tuners redundant. An end fed with proper feeder?
  • Antenna wire: a lighter one, you don’t need big section of wire for QRP.
  • 817 container: if you go with your 817 forget about the waterproof box: instead make your rucksack watertight with a rain cover and light zip plastic bags for the 817… I operate mine without taking it our the rucksack.:
    Release of my '817 Comm-pack'

Pack:
I see you have almost everything there!!
But you could do some changes:

  • Rucksack:move to a lighter and robust one with technical fabric, instead of cotton (that is what I believe you have).
  • Seat: move to a piece of sleeping pad cut out of a regular foam one. Weights nothing instead of the leather you have.
  • Water bottles: move to a cheap & regular plastic bottles and forget about alu or stiff plastic and the military canteen.
  • Compass: change it into a lighter one withour all that metal
  • Logbook: carry a few number of sheets instead and something to stick them to: a small clipboard (A5 size…), You are not going to use a whole notebook in an activation trek.

Well, a lot to think, if you want to make some changes,IMHO…

73 de Ignacio

2 Likes

I’ve had excellent results on over 100 activations with a KX1 and internal ATU. Never really measured the power out but I suspect 3-4 watts on all bands. Perhaps you should consider posting on the Elecraft reflector to get some assistance on troubleshooting.

73, Barry N1EU

Mike,

Not sure what is going on with your KX1, but I do know that I could not hear you yesterday on any band on your first two peaks. On the third summit (Lemmon) I did not hear u at first then magically you were good copy on 40M. I’m not sure what happened there, or if it was just conditions.

You most likely have already done this, but I would ck the antenna and coax at home and see if u can duplicate what u were seeing in the field.

73

Pete
WA7JTM

Thanks for the responses, it is much appreciated. I will try to address everything in order.

VK1DA

The coax I used for my test is good; I check all my coax out on my analyzer before using it. I tested it on a 3 foot piece and a 50 foot piece into a dummy load. The power was significantly lower at the end of the 50 foot piece. The random length wire antenna only has a 6 inch piece of 174, so loss in coax, if using my desired configuration, will not be an issue. I only tested the 50 foot piece because I thought I might try using my buddistick (I did, with poor/no results) with the KX1 and just tried it for giggles.

By way of comparison, my 817ND puts out 5W on all bands through all lengths of coax, so it appears to be an issue with the KX1.

I bought the unit used and hoped that it would work ok out of the box so I could get some of the more difficult summits sooner, but I think it is going to the bench first.

WB0USI

I did give some consideration to propagation etc, I think the issue for me is I have refined my 817 setup and just wanted that same refinement out of gate with this. So I am lowering my expectations a bit and going forward from here.

I will also use those references for future propagation stuff.

PA7ZEE

I am going to research that W3EDP antenna, The only coax I use is a 6 inch piece to connect to the radio.

MM0GYX

Only on 1 band did I get above 3 W, the rest were below more or less.

EA2BD

I am experimenting with the 16850 batteries. 3 of those give me approx. 11.5 volts and they are slightly larger than a AA battery. I have to use them more to see about longevity etc, but I think that will be a good fit for the KX1. They don’t give max power to the unit but I think what I am getting is a good compromise.

I did look into the MTR and that might be the way I end up going if this radio does not work out.

As for my 817 setup: for the hikes I do with it (8 miles round trip) I have no issues with the size/weight; that is why I have not scaled it down. I factor in an exercise component and don’t really mind it the way it is. In the event I decide this is the radio for the longer trips, I will definitely scale the stuff you mentioned (and other stuff) down.

As for the pack, everything you mentioned I have thought about, with one exception: the seat. I carry that leather because several of the summits I have done are super steep with rocky, moving ground. The second use for that leather is to save my pants/butt when I have to slide down rocky slides etc. It works really well for that and so I keep it in the pack.

WA7JTM

Technically I did 4 summits that day, even though, to us it was one Friday night and 3 on Saturday. I used the KX1 on Friday, made only 4 contacts (thank goodness) and on Saturday, I ditched it on my first summit after making only 2 contacts (local) and half hour or more of trying other bands. I then switched to my 817 setup and I was back in business.

I am going to put the KX1 on the bench today and test it out completely and then get to building a better antenna system. I would really like to make a “long range” setup without having to take my other one apart.

73,

MIke
N1IDN

Hi Mike,
Clearly some issues with the antenna system (what I refer to as implementation losses!), when those are resolved, think about a 12.8-volt LiPo external battery. As you may know, power out is quite sensitive to voltage; more may make the difference during the less than brilliant band conditions we’ve been experiencing lately. Drop over to the plant when in town, and we’ll have a look at your setup.
Best,

Ken, K6HPX

You don’t need coax to connect the W3EDP antenna. Use a BNC male to two dual banana female jack connector.

73 de geert pa7zee

Nice! I have a few of those and didn’t think to use them.

Thanks for that.

Mike

I’ve been more impressed with my KX1 than I ever was with the 817 I had many, many years ago !!
I get 4 watts out of it with a Buddipole 4S1P A123 battery, I also use a KX3 Voltage Regulator that Gary, N8WTT makes and sells. It maintains a constant 13.9 volts to the KX1 from the A123 battey. (www.n8wtt.com)
I don’t activate here in Florida, just chase, but I do lots of portable ops from beaches, parks etc. My antenna is a simple EFHW wire strung up a 32’ Jackite pole with 20’ of coax.
With this setup I made a contact with a SOTA activator in WA from FL, he was running 10 watts from his KX3 into the same type antenna !!
Of course, band conditions play a big part also !!

Hope this helps…

72/73 de Ed
N7EDK
All Elecraft, all the time ! (K1, KX1,KX2, KX3)

Comparing the KX1 to an 817 isn’t exactly apples to oranges so lowering your expectations a bit is a good idea :wink: Do you know if this radio was factory built or a kit? I built my KX1 and the torroids are critical to operation and power output. Just for reference the output displayed on my KX1 was 2.5W on 40, 4.0W on 30 and 3.5W on 20. If your radio was a kit you may want to go over the unit to be sure everything is built as designed paying attention to the winding and orientation of the torroids. There also was a power mod that was standard on later models - check the Elecraft KX1 pages. Good luck, I hope you get it working - it’s a fun little radio with a great receiver!

Crossing my fingers for you, 73 Rick WB0USI

I did the power mod on mine Rick, and carefully moved the winding’s on the torroids for spacing and it made a big difference !!
My output display would read 3.8 to 4 watts on 20m.
It is a really fun and simple little radio with a great receiver !!
I’ll never sell it, but my new KX2 is a KX1 on steroids…hi hi !!

72/73 de Ed
N7EDK

KX2 looks like a lot of fun at about the same size as the KX1! I upgraded from the KX1 to KX3 recently and it looks like the KX2 is basically a KX3 after Honey I Shrunk the Kids :wink: I’m still finding things the KX3 will do - my poor little KX1 hasn’t seen much action since!

Have fun - 73 Rick WB0USI