Larsen 2/70 Mobile Antenna Kicks Butt

A few months ago I had a Larsen 2/70 mobile antenna installed on my truck, (well I had someone put the NMO mount in, and I did the hard part of screwing the antenna on, lol). No, but seriously, my truck has some serious side curtain airbags that I didn’t want to mess with. The professional installer even had issues routing the coax through the headliner & down to my radio because of the airbag setup. The bags, and canisters & lines used to inflate the bags took up almost all of the space under the headliner, not to mention the crummy 4″ speakers that Toyota puts up in the headliner (they’re disconnected, but still remain). So the technician had to route the coax towards the front of the truck & bring it down  one of the front quarter panel beams, which worked out fine because the NMO mount I bought came with 17 feet of RG58A/U coax. I bought the cheap browning one on Amazon, I think I paid around $14 for it, still priced accordingly online:

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This mount had pretty good reviews, and upon arrival, it seemed of decent quality, gave a slight tug on the ends to make sure a crummy crimp job wasn’t done (as I’ve had on MPD digital cables’ from Amazon in the past!). It took the technician a good hour to do this, and these guys were experienced police/ems/fire radio installers, they said it was one of the more difficult installs they had done because of the airbags. But alas, they did an outstanding job,  so if your ever looking for a good install, give RZ communications a call (they’re located in East Austin).

After installed I placed the Diamond NR770HNMO antenna I already had been using on a previous Diamond mag mount. I wasn’t planning one using the Diamond long though because when I took it off of the mag mount, I noticed that there was quite a bit of moisture underneath where the center contact made connection with the antenna, this was no bueno, I could try an o-ring, maybe some dielectric grease? Well, after using the antenna for a few days, I started to notice quite a bit of flex in the antenna. I just wasn’t comfortable with how the Diamond made contact with the sheet metal, the base was so narrow, and the sheet metal used on most vehicles isn’t exactly super thick, so there was a slight wobble due to this. With the Larsen this was completely eliminated due to the wide base.

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I used the Diamond for a few weeks, but we started having some really hard rains in Texas over the past several months and moisture just kept getting in there, and I would occasionally have to tighten it just ever so slightly, maybe from the little branches it smacks occasionally? It’s also chrome plated, blah, I hate chrome. So 1980’s, lol. I like matte black, stays clean, hides dirt, hides scratches, I just knew I had to replace this thing with a Larsen. I’d seen so many good reviews on Larsen’s, I just bit the bullet and spent $50 on the 2/70 version, sometimes you can find them cheaper at hamfests or online elsewhere. I’m so glad I replaced it too, because not only did I ‘feel’ like I had a slight increase in performance, but the antenna was so much more stable up on top of the truck! Check out the difference in width of the bases:

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I really like how the Larsen almost cinches down on top of this little black seal that fits perfectly under the base and forms a nice tight seal. I haven’t had any water seep in, you should still occasionally check underneath to clean the contacts, and remove any debris/moisture that might sneak in there. Being exposed to the elements constantly is harsh on these little guys. The Larsen is just a tad lower profile too, which decreases flex. The antenna element is also more flexible, the only downside is it bends back a bit when your doing 65+mph, the Diamond is more rigid in that regards. If the element ever gets bent, you can just bend it back very carefully.

There are all kinds of mobile antennas on the market today, but after using the ones that I’ve used, and viewing others hams setups, I like the Larsen. Hands down, wins every time. The only case where I would use the Diamond over the Larsen, would be if I was using a lip mount, as I occasionally do when I go on a long trip, or to a hamfest and have as many radios hooked up as possible!

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I’ve found that the Diamond seats better on the lip mounts, the Larsen hangs over a bit on the edges, so I’m not sure if that would affect the ‘seal’ on the bottom, although I have seen hams use them on the K400 lip mount, there are also other lip mounts available that have a wider base that fit the Larsen more appropriately, so there are certainly plenty of flavors to suite anyones taste 🙂

I like having options. It seems we have plenty to pick from still with amateur radio, which is a good thing. Larsen hit the nail on the head with this product, maybe that’s why the design hasn’t changed in ages? After 3 months of being on my truck, the antenna has shown absolutely no signs of wear, tear, bends in the antenna, etc. The Diamond was also just a tad bit taller than the Larsen, I think Larsen puts one more coil in the center. I will miss the ability to fold the antenna over, but the times I’ve needed to park in the garage, I just pull out a crescent wrench & remove the whip. Takes just as much time as it does for me to get out & fold the Diamond over 🙂

Not to mention when I met up with a large portion of our local club, I’d say about 75% of the hams had one of these on their vehicle! Some were almost 20 years old! The plastic had faded a bit, some guys had even replaced their whips after some pretty nasty run ins with branches, but the base had remained. A little bit of black matte paint, and you could fix that right up!

Just a short little write up to hopefully help someone decide on their next mobile antenna 🙂

73

K5ACL

WLN KD-C1 UHF Handheld Transceiver Review

So, the Baofeng UV-5R5 that I bought a little less than a year ago has started to show some signs of wear. The antenna connection point has become loose, and the battery isn’t lasting very long anymore (has the original battery). These are problems that have always been inherent in the potatofengs, but alas, I’ve had no reports of bad audio, i’ve made many a contacts on them, and even though I consider them disposable, they hold up surprisingly well.  So I kept it, and even bought the Baofeng’s ruggedized version, the GT3TP, which has an additional power setting of 8 watts (not that this matters much, some claim they’ve been able to hit repeaters they haven’t before or they can make farther simplex contacts). I think they’re neat little radios at an affordable price. Eventually when one gets the bug anyways, and most do, you’ll end up upgrading in the end 🙂 Trust me…

I found out about a little radio being sold on Amazon for $13.99 as of this writing. Price is slowly creeping up though, I think the secret is no longer a secret! It’s a WLN KD-C1 handheld, which only does UHF, and has a fixed antenna. High power is 2 watts! This could be a great option for crossbanding which is always convenient when your trying to stay engaged around the house or property, but yet stay connected to your local repeater of choice, or even to monitor simplex during tropospheric ducting events!

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I was interested in this particular radio, well due to the price of course, but also due to the fixed antenna. This would be a great option to just throw in your pocket without having to worry about a huge antenna jabbing me in the armpit. Also works great for riding on the motorcycle! Slips right into your pocket or clips to your belt. The charging cable is a USB to Micro USB cable, so it should charge on a USB port too. I had to download the software from the following website: KD-C1 Software (.rar file) which my antivirus identified as harmful, but was not. Once the software was up and running, I programmed 3 crossbanding channels into channels 1-3, 2 UHF repeaters on channels 4-5, & I programmed the UHF nat. simplex channel on the rest of the 11 channels (16 channels in total). If you leave an empty memory slot blank, you’ll get a loud audible alarm when you change to that channel, I wanted to avoid that.

It’s just a tad bigger in receiver size compared to the Baofeng, but still fits easily in the palm of your hand, and actually weighs much less than the Baofeng. It looks like there’s a drop in charger for this radio, but it just came with a little wall wart adapter. Audio is plenty loud on the little speaker, & it takes the same headsets & programming cable that the Baofeng uses.

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Overall, I’ve been able to crossband to my house from about 2 miles away, even with the fixed antenna. I like the fact that there are no buttons or moving parts besides the selector knob. For the price, it was a no brainer, one can never have too many cheap electronics that accomplish the same job as the big boys!

I made a review video & a programming video, to help get anyone started:

So far my record for crossbanding on high power, has been about 3.5 miles away from my house, that’s with some moderate hills in between. I’ve since ordered another since the price was right 🙂

My first homebrew OCF, eat your heart out Buckmaster

About a month ago, I decided to hop up on my roof, and do the ole’ switcheroo changing the orientation of my Buckmaster OCF to see if I could possibly make contacts in areas of the world I hadn’t yet before. Being in an inverted V position, this was fairly simple, so I disconnected the balun and swapped positions of the legs. Everything was tied off nicely, legs were still the same height above the ground that they were before I made the switch. Everything should be fine right? Wrong…. SWR was just over 3 to 1 on 40m, the same on 10m, and of course it was expected on 6m, as this version of Buckmaster already had a 3 to 1 SWR on 6m (as advertised). But 20m was perfectly flat! 1 to 1. How could this be? My first thought was that ‘Well it must be interacting differently now because it’s in a different spot.’ So back up the ladder I went…. that’s what I’m known by now.. K5ACL ‘Always Climbing Ladders’ LOL!

I figured switch the orientation of the antenna back to the exact spot it was at before, and so I did, and back into the shack to check & make sure everything is ‘hopefully’ back to where it was before (or at least close?). But the issue still existed! My SWR was the same on those bands! Contacted Buckmaster and they said that if the SWR was perfect on one band, but not the others, then most likely it’s due to its surroundings. But that still doesn’t explain why it was working fine right before I switched it. Did I screw something up in the balun? I’m pretty gentle on my equipment, it wasn’t like I was swinging the balun around my head smashing it on the concrete or anything. But I had no way to check the balun! Buckmaster purposely seals these baluns with this epoxy resin container thing that is practically impossible to get into, and for good reason I suppose, but as hams, this is never a good option, because we need to be able to open things up and check out our equipment, especially antennas! I get that it has this fancy thick pvc coated wire that would last 10-20 years, but honestly that’s of no use to me when the regular ole’ household copper wire I use works just the same.

So, I thought I’d try another project, get a proper 4:1 balun from Balun Designs, and run your own wire. In doing so, I thought I’d try to squeeze out some more bands with the one I was creating by bending the legs of the OCF. I got the 4:1 balun that has the dual core stacked toroids, which is ‘supposed’ to minimize interaction of OCF’s with nearby surroundings. Skeptical of buying yet another balun, I’d heard good things about the Buckmaster antennas, but after what happened, I wasn’t sure paying another $90 for a balun was the right thing to do. Alas, I strung it up in place where the Buckmaster was, and used longer wire this time, it ended up being about 46′ on the short side, and 91′ on the other. The balun designs balun worked absolutely perfect in this application and where I have it strapped to the pole (a bit sturdier than the Buckmaster design too). Back into the shack I went to check my initial prune job on the wires. I hooked up the RigExpert AA-30 to my feedline, and to my surprise, the results were totally acceptable, just as they were! Don’t go changing anything! SWR was a tad high on 80, but I’m afraid to make any other adjustments in fear of screwing up the numbers on the other bands. That’s the only downside to making an OCF, what you see is pretty much what you get. You can play around with the location of the feed point and length of legs to find the optimum location/lengths, but with these numbers, I’m satisfied.

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6 meters works too, the SWR is about 1.4 to 1 around 50.200 which is even better than the Buckmaster on 6m, this length of wire must work better. (The buckmaster had 45′ & 23′ legs). I can even use this on 30m with the tuner, the SWR registered around 4 to 1.

From what I’ve read, the height at which your apex sits also determines what type of balun you should be running. Granted the Buckmaster uses a 6:1 voltage balun, this one is a 4:1 which from what I understand is the appropriate balun for the height I have it at (about 25-30′ up). The 6:1 balun would work better if the apex were closer to 50-60 feet to bring the impedance down to the appropriate level.

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I’m really happy with the performance of this 4:1 balun from Balun Designs. Time will tell how it holds up to the elements. Now to figure out what went wrong with the Buckmaster. I’m going to need to test it at a different QTH to see if the problem is replicated, if so, I know that most likely there is something wrong inside the balun. Maybe I can get a refund or a replacement since it’s still under warranty. The OCF is an understated antenna in my opinion, the magic is in the mathematical relationship to the other bands, and in the appropriate balun. My original plan was to possibly put up a fan dipole with resonant 1/2 wave lengths of wire, but that would mean I would have to string up at least 14 different wires just to work the same number of bands that I can work with these two wires!

Now time to work some contacts!

 

73

K5ACL

N5OAK Logos

Jeff, K1NSS, was kind enough to make these logos for our amateur radio club just in time for field day! I had many decals made so folks could slap’em on their vehicles or wherever, to hopefully promote the hobby & the club!

 

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He’s such a great artist, I recommend him to anyone looking for logos/art/qsl cards! You can check his site out at Dashtoons.