Here’s another test of the UV-3R in simplex, again with somewhat surprising results. This time, we tested comms between the UV-3R in the field, and my Yaesu FT-897D as the base station. The UV-3R again relied solely on its stock antenna. The FT-897D relied on a quarter-wave vertical with drooping ground-plane, mounted in the attic (because, despite my service as a member of its board of directors, I am unable to convince my benighted HOA that Radio is Good, which means you can’t have exterior antennas).
The antenna (which I made yesterday, and a full posting on that will be coming soon) showed an SWR of 1.3 at 446 MHz. It sits on a PVC mount I made, and is about 30 feet above ground level. Here it is, cunningly hidden in our attic, stealthily emitting its RF emanations, where no one can see:
I set the Yaesu to show two Watts on the power meter (so it would be putting out the same power as the UV-3R), left my XYL (who is KG4QFG) and our ten-year-old son at the base station, got on my bicycle, and proceeded to nearly kill myself (as ham radio is disgustingly good at turning middle-aged men like me into useless fatasses who can barely pedal to the end of the street before wheezing and gasping like a semi tractor-trailer coming to rest after a thousand-mile run). Full list of settings for both radios were: 446.000 MHz, simplex; 2.0 W rf out; 71.9 Hz CTCSS, Rx and Tx.
My son and I exchanged signal reports at a number of locations, with me trying to get far enough away (before collapsing into a puddle of Extra class embarrassment) to lose his signal. What we got surprised us, and is marked on the map after the link below…
This sat-photo is turned 90 degrees, so that east is up, and north is to the left. The arcs are drawn at one mile, two miles, and three miles from the base:
The red dot at the lower right is the base location (you can see a distance scale nearby). The green dots indicate locations where our tests read S9 or above on both signal meters. The yellow dots indicate signals less than S9. All locations were 100% readable. The yellow dots seem odd because they are within the one-to-two mile distance, whereas the readings from distances beyond two miles were all S9 or better. The local terrain is probably the reason, as that stretch of road dips down a fair bit. East of that stretch, there’s a lot less in the way of houses, trees, and whatnot. Still, these results kind of amazed us. You can see our best DX set out with the orange line on the right-hand side. We had full signal, both ways, at 3.5 miles with our setup. Note that that path is through a rather large building (Verizon’s Virginia headquarters) that is much taller than our house.
We’d have tried longer distances, but I was afraid I’d die if I had to return over anything greater (though my son did a great job of sustaining the old man, by deciding to advise that I fasten my seat-belt before each trip to the next stop, and predicting the amount of turbulence and interesting sites to be experienced on each leg of the voyage; he’s not that interested in radio, but he has a great imagination).
As tests go, this one is a bit odd, as it both tells us something remarkable, and also tells us very little. That is, we were surprised by the long distances we got, but we also would have liked to know where the signal began to drop off. The problem with that was that I hadn’t expected to be able to get two miles away, much less over three, so the map I took with me wasn’t big enough. Also, there’s that fatass factor, which kind of limits how far you can go…
The antenna was a couple of hours’ worth of work, made from some ordinary UHF connectors, RG-58, some PVC I got at Home Depot, and two coat hangers. Making it was easy. Tuning it was easy, too, but that also yielded a rather big surprise.
My next post will be about the antenna itself. (And, yes, I know it is almost heresy to build a single-band antenna for 70cm when the world is so thoroughly supplied with designs and products for dual-band antennas that work on 2m and 70cm, but I wanted something optimized for the one frequency I wanted to use, and something that would be easy to make. I got what I wanted, so two meters can just wait for another day.)
More soon!
73,
WA4LDA
Sounds like a fun time. Just wondering why not do the tests on 2 meters as it travels better on groundwave. Of course then you’d have to ride a lot further! I have a ham friend in a similar situation, with all his antennas in the attic, including wire loops for HF. He gets out as well as my dipole out in the trees. As long as you don’t have aluminum siding, all is well. 73
Hi, Matthew! Thanks for stopping by.
The boring technical reason for not testing 2m is that–as I understand it–groundwave is a phenomenon limited to about 100m and longer in wavelength, and that the factors affecting which of 2m or 70cm does better for you are subjects of some empassioned (and often quite colorful) debate. Thus, we have the slightly less boring anecdotal reason: the UV-3R sucks on 2m.
Have a look at my prior post on this topic. After doing a lot of useless reading about it, we decided to just take our UV-3R and VX-5R into the streets and find out which band worked better for us, with the radios and antennas we had. As you’ll see from our results, 2m was close to useless, while 70cm outperformed all of our expectations. I’m sure that there are nine and sixty explanations for this, and that every one of them is right. However, we have what we have, and it sucks on 2m (and works great on 70cm).
Also, a quarter-wave antenna at 2m has to be over nineteen inches long, and it’s really hard to get a straight piece of wire nineteen inches long out of a coat hanger…
My HF antenna is a set of four metal Slinky toys, connected in two pairs, strung across the attic, fed by ladder-line, tuned with one of those (in)famous MFJ VersaTuners.
Does it work?
Well, it radiates, I know that. I have worked Italy with it from here in Virginia (and that was at the utter valley of the sunspot cycle). It seems to radiate off the sides on 20 meters, off the ends on 40 meters, and off the planet on 15 meters. I’ve had pretty good results on 30 meters, but my code abbreviations are a little rusty, so maybe the other guys were all telling me to boost my power instead of sending me love and kisses. All in all, I’d trade my attic Slinky contraption for your outdoor dipole in one of Grace Hopper’s nanoseconds, but that’s partly because I have a bad attitude about being told what to do by my HOA.
Where’s your QTH? Maybe you can tell me how my Slinky is doing in your neck of the woods.
HI!
My son (KF5PMF) and I (K0APK) did a similar “test” of my UV-3R about a month or two ago. The differences is he had a FT-857 in his car working into a 2 meter, quarter wave vertical, and I was using the UV-3R from my back yard. We don’t have documented results like you, but from my memory the results were the about the same as yours but for 2 meters. As I recall, the UV3R to UV3R “tests” were disappointing after a mile or so, however when working a good receiver like a local repeater or the FT-857, then the results were significantly better. This tells me that range will be limited by both Transmit power AND the UV-3R receiver sensitivity! We did a few tests between his apartment and my house (about a mile) on 70 cm, and the same pattern showed up. He doesn’t have a mobile antenna for 70 cm yet…. I am keenly interested in the 70 cm performance as the only Echolink-capable repeater in my area is on that band.
Kelley (my son) also started off with a Coax-Fed Slinky antenna due to living in an apartment. Kelley says he will loan me his Slinky so we can have a “Slinky to Slinky” QSO. It has become something of a joke around here…. Kelley was interrogated by the Wal-Mart personnel on just “WHY” he need all those Slinky toys before they would sell them! . We had some marginal success with it on 40 meters when mounted outside, but nothing when inside his apartment. That is why he is willing to “loan” it…
Cheers and Tnx for your report(s)! I enjoyed reading them.
Don Spoon
-K0APK-
Hi Don,
Interesting that your 2m performance was similar to our 70cm performance. I suppose that the problem with testing different radios is that, unless you have some kind of baseline for one of them, you don’t know which radio you’re testing. We had awful 2m results in our VX-5R/UV-3R test, but there’s just as much reason to think that was the VX-5R’s fault as the Baofeng’s.
Just sitting here on the second floor of my house, I can get a 70cm repeater in Frederick, MD, to beep back at me with the UV-3R. Haven’t tried a QSO through it yet, but it’s fully 35 miles away (of course, it’s also up almost 1,800 ft above sea level, and I have a fairly unobstructed path to it).
That’s pretty funny about Wal-Mart. Sounds like someone was up late the night before, watching Flash Gordon serials or something (lot of coils in those). Sad fact is, after being immensely excited by an online article stating that the two-Slinky model resonates at 7MHz (and that the four-Slinky version resonates at half that), I have also read that they generally perform about the same as plain old doublets of the same overall length, matched with a tuner to your rig. The curious fact of their resonance is probably just a coincidence, rather than any reason to believe they are particularly great radiators.
When I talk to some hams about it, they seem to think that the “trick” is in the fact that the coil winds up a lot more wire into a smaller space, end-to-end, than the same wire stretched out straight, as though the full half-wave is just being wound up into less space. However, the numbers don’t come out, and that resonance phenomenon is probably driven by the induction of that big coil more than anything else.
These little UV-3Rs are certainly remarkable, eh? The wife and I used to carry FRS radios with us, for use in shopping centers and the like. We had a pair of Cherokee FR-460s, back when FRS was young. They were fabulous! But, we eventually broke one and found out then that they were gone from the market. The other FRS units we’ve tried (even those by Motorola!) have all been unmitigated junk, losing their settings, ignoring their own CTCSS tones, refusing to hold a charge, and so on. (All this while their original “talk for up to one mile!” distance claims have been inflated to preposterous numbers on their packages.)
So, we bought a pair of VX-5Rs. However, those are just too durned heavy for casual use. We thought about that little Alinco you see here and there, but that was too costly. But then we saw the UV-3R on eBay! Almost the same size as the old Cherokee unit, dual-band, broadcast FM, NOAA Wx, software programmable, and cheap!
So far, we’ve been very impressed and the XYL seems willing to take it with her on trips when we might split up. Might also get our son more interested in radio, so it’s a win-win-win all around.
Drop by again soon (will have my post up on the 1/4-wave 70cm antenna with a couple of days; that might interest you).
Cheers!