AmateurRadio.com

On my first outing with the Intek H-520 Plus handheld transceiver a week ago I found that the batteries died as soon as I pressed the PTT. It turns out that this is a very common problem with this transceiver. M3XEM has even made a video about it which he has posted on YouTube.

After trying some different NiMH cells, freshly charged, my H-520 seemed to be happy using my longer whip antennas, though it still wouldn’t work with the supplied mini-whip. But after only a little use of the batteries it began cutting out again when using a 2ft centre-loaded whip. The only antenna it would still accept was the 4ft whip with counterpoise. I felt that something wasn’t right, so I decided to investigate.

I measured the battery voltage and current. The batteries were not freshly charged but had been used on Sunday to make numerous calls though no contacts. With the radio turned on and receiving the current drain is 90mA and the battery voltage was 7.71V. This is substantially above the 7.2V nominal voltage which suggests that there should be plenty of life still left in the batteries. This was confirmed by the battery state indicator.

I then transmitted into a dummy load. On the 1W setting (with slightly under 1W output) the current drawn was 750mA. On the 4W setting (with about 3.5W measured output) the current drawn was 1.3A. The voltage across the batteries whilst full power was being transmitted dropped to 6.75V, significantly less than the 7.2V nominal voltage. The current consumption is not excessive in comparison to an FT-817 which is specified to draw up to 2.0A at 5W output. One factor contributing to the voltage drop is the use of separate AA cells. Most handheld radios use battery packs in which the cells are welded together to minimize resistive losses.

The radio still worked fine at 6.75V, but this was transmitting into a dummy load. On most of my 10m antennas – and as observed by M3XEM – the battery voltage would fall away after a couple of seconds and the radio would cut out and restart. I tried to measure the voltage across the batteries when using the two short whips and it fell right away to 3 or 4 volts! This explained why the radio cut out and restarted. It must be drawing a lot of current to cause such a large drop, but I was unable to measure exactly how much as the radio’s voltage sensor cut the power to the TX too quickly for my meter to catch the reading.

My conclusion is that when presented with a load that is something other than 50 ohms, the PA of the H-520 draws an increased current. This effect is significant enough that the radio cuts out even on the 1W setting using the mini-whip antenna. This current draw may be more than rechargeable AA cells are designed to sustain, quickly pulling the voltage below the “low voltage” sensor level.

The transceiver isn’t really “eating the batteries” as some users have claimed, as the cells quickly recover their original voltage when the load is removed. The problem is purely and simply poor design which causes the PA to behave in this way and draw too much current when presented with a mismatch. As can be seen from the schematic (which is included in the manual) there is no SWR protection to back off the power.

It is very unlikely for a whip antenna on a hand held radio to present a perfect match, so the H-520’s performance in this respect is lamentable. As I noted in an earlier post, the supplied whip antenna was found to give its best match at 28.5MHz. It would present a high SWR on the UK and EU CB frequencies that most buyers of this radio would use and I doubt if any buyer of this particular radio would have found it possible to use the highest power setting with this antenna.

Another glorious day and Olga and I took a picnic lunch up to Watch Hill. We go there not because it is a SOTA summit but because it is near home, a nice walk, not a steep climb (so Olga is happy to come with me) and one of the easiest operating sites for me to reach when I want to get away from all the electronic QRN I’m plagued with at home. Unfortunately there isn’t a picnic table up there and I haven’t yet found a way to support the MP-1 antenna on a bare hilltop. Using a right-angled PL-259 adapter and a 259 to 3/8 adapter on the back of the FT-817 only works if you have a level surface to put the radio on and no breeze. So despite taking them with me I wasn’t able to get any use out of them. No doubt a photo tripod would do the job but that is too much ironmongery for me.

I did also take the Intek H-520 Plus and a couple of BNC mounted whip antennas but although there clearly was propagation on 10m I didn’t manage to work anything. I did hear something puzzling though. After one call on 29.600 I heard what I’m sure was a native English speaking voice announced something on the lines that this was the EA????? repeater. Unfortunately I’m getting increasingly slow witted these days so I don’t remember the exact announcement nor the full call and I didn’t hear it again. 29.600 is supposed to be the 10m FM calling frequency and not a repeater output so what could it possibly have been?

Back home later in the afternoon and VHFDX.net showed that there was a big Sporadic-E opening on 6m and even 2m in Eastern Europe. I decided to try 10m which seems to be the neglected band and managed to make several contacts including a new country for me, OD5NH in Beirut, Lebanon.

Once again, WSPR is revealing the existence of consistent propagation paths every day on 10m between Iceland (TF), the Faroes (OY) and northern Norway (LA/LB) and the UK and north-west Europe when there is no Sporadic-E and no other propagation except over very short distances between closely located stations. This has occurred even during periods of zero sunspots.

I’m guessing that because we have only in the last few weeks had a large number of WSPR monitors on 10m because of the Sporadic-E season, no-one has previously observed it. But I’m surprised at the lack of comment about it. Perhaps this is a phenomena known to everyone but me, in which case I’d welcome some enlightenment.

QRZ.com has just announced that it will be making available an online logbook. It will also be offering an awards program and will be organizing a contest to recognize the first person to make confirmed contacts with 100 other QRZ users.

I like QRZ.com and think this is a great idea. I don’t know whether they will be providing an API for logging programs to post entries to the log in real time but if they do then I want my program KComm to support it so I have volunteered my services as a tester.

From John Harper AE5X’s blog I have discovered that Ten Tec will be re-branding the Chinese HB-1A QRP CW transceiver. The Ten Tec versions aren’t exactly the same – they will be selling two versions, one covering 40 and 30 metres and one covering 30 and 20 metres whereas the original covers 40, 30 and 20. This may have something to do with meeting FCC spurious emissions specifications.

As it happens, my HB-1A is on eBay at this very moment. Not that there is anything wrong with it, just that it doesn’t do anything that my FT-817 can’t do and I’ve spent quite a lot on new radios recently so it seems right to dispose of some of the ones that aren’t being used.

But its performance wasn’t exactly spectacular. It’s a bit sad to see the company that made and discontinued the Argonaut 516 HF QRP rig and matching 526 6’n’2 metre rig offering such a basic radio as its only QRP product.

I’d love a Ten Tec 516 / 526 pair, so if anyone has one in mint condition that they’d like to sell or trade for an Elecraft K3/100 drop me an email.

Computers and radio really don’t mix. I was trying to connect the FT-817 to the shack computer. I plugged the USB cables into the back of the PC, then as I lifted the cables vertical to feed them behind the shelf unit I heard the noise level on 2 metres come up quite clearly. I could probably reduce the noise using clip-on ferrites but any more noise than I already have is unwelcome. I think I might give up the computer altogether and go back to paper logging!

I also proved today that it isn’t possible to work satellites with indoor antennas. Yesterday I tried receiving AO-51 with the 3/4 wave vertical I made, but I got a readable signal for only a few seconds. Today I tried the 6 element Yagi I made a few weeks ago which received signals off the Moon when used outdoors. Pointing it at the satellite from inside the shack I again heard only a few seconds of signal from the satellite. I think there is just too much attenuation at 70cm to use indoor antennas, so satellite operation is out of the question.

I could probably combine the 6-element 70cm and the Moxon 2m antenna to make a portable hand held antenna for satellite use. But whilst it would be an interesting challenge to make a satellite contact using the FT-817 and a hand held antenna out of doors I had really hoped to be able to do it from inside the shack.

I received a response from the web host support desk about the problem that is causing the WebProp update scripts to fail to access the WWV solar data. The reply was:

There is nothing we can do to fix this it’s a configuration error on their end with their dns. This is occurring because of invalid dnssec configurations at noaa.gov. We will not bypass the dnssec configurations implemented within .gov. The only way to have this corrected is by the dns administrators at noaa.gov signing their zones.

20-May-2010 15:26:00.099 validating @0x827fff000: swpc.noaa.gov SOA: got insecure response; parent indicates it should be secure
20-May-2010 15:26:00.116 validating @0x80284f000: swpc.noaa.gov SOA: got insecure response; parent indicates it should be secure
20-May-2010 15:26:00.159 validating @0xadb055000: swpc.noaa.gov SOA: got insecure response; parent indicates it should be secure
20-May-2010 15:26:00.204 validating @0xad9af8000: www.swpc.noaa.gov A: bad cache hit (www.swpc.noaa.gov/DS)

This is way over my head, but I think they are saying this is due to a problem at NOAA’s end not mine.

I will give it a couple more days, but if the problem doesn’t go away then I will have to remove WebProp. I know this will be a pain for those who have included it in their websites but there is nothing I can do about it.