Posts Tagged ‘10m’
Nothing but whispers
In the last few days several people have posted in their blogs or in forums that conditions on 10m have been great. Either I have been listening at the wrong times or this QTH is as bad on the higher HF bands as it is on VHF. When I have tuned across the 10m band I have found only one or two signals strong enough to be heard above the S4 noise level I now have on this band and none loud enough to work.
It’s probably my QTH. Last year when Olga was away in Ukraine I operated from the car with my QRP K2 and an MP-1 antenna on a mag mount and from just a few miles away but overlooking the coast I worked DX on 15 and 17m that I had never heard from home. Unfortunately going mobile is no longer an option as I am not allowed to drive due to my illness.
Something must be working right though. Most of the day I have been running WSPR on 10m with 5 watts to the dipole and my signal was spotted on 5 continents. It’s good, but it isn’t the same as having an actual conversation. You can see why my interest these days is turning more towards things like EchoLink.
10m DX
Ten metres has been open this afternoon. I was alerted to this when someone on the Transmission1 radio forum mentioned that 27MHz was full of Russian taxis. I had a listen and sure enough their FM transmissions were clearly audible well up into the lower end of the amateur 10m band. This is one of the penalties of having CB radios that are easily modifiable for use outside their allowed band, I guess. And there’s no chance of anything being done about it in Russia, the land where the Kalashnikov and the bribe determine the rules.
I switched to SSB and quickly worked A61AM. One of the things I love about 10m is the number of times you hear a DX station, give your call and they come right back. I was not even running full power – 80w is normally all I use. True there were a couple of pileups apparently of pirates using calls that consisted of just two letters 🙂 but I avoided those. By the way, why is it that DX stations so rarely give their own call? Sometimes you have to listen for five minutes to hear it again and verify that you logged it correctly.
Propagation was obviously good into Russia but I also worked Mike, SV5BYR on Rhodes, Barney ZS6TQ, Burhan TA1BX and Norman 5B4AIF. It’s really great to hear 10m opening up, that’s for sure!
Sign of things to come?
I finally got caught up with things so I could find time to experience the HF band conditions everyone has been talking about. I put the K3 on 10m WSPR while I was doing my computer jobs. I missed some chances of being heard because the WSPR rig control doesn’t switch the K3 into DATA mode and in SSB mode only the microphone is live not the line input. My apologies if the sound of typing affected anyone’s WSPR reception! After spotting the error and correcting it I was received by five VK stations, which is quite pleasing for 20 watts to an attic dipole!
When I was finished with the computer I had a listen around the 10m band. There wasn’t as much happening as the WSPR results would suggest so I tried 12m, where some PSK31 was heard. After making one contact there (ER1RY, Moldova) I went back to 10m and saw some faint traces. I worked several Russians and heard but didn’t work three South African stations. I was also spotted from Madagascar by someone on the PSK Reporter site. That would have been a nice contact! I checked the SSB end from time to time but only heard a handful of signals too weak to work.
Ten metres is one of my favourite bands so it is great to see some signs of life. But I fear that improved propagation is going to bring problems for digital mode enthusiasts. As Paul, PC4T complains in his latest blog post, when you get good propagation people operate wherever they can within the band plan so the weak signal modes get trampled over by the wide, loud modes.
Unfortunately there is no “gentleman’s agreement” that says PSK has exclusive use of 14.070 – 14.072 or that only JT65A can be used from 14.076 to 14.078. Here in Europe, even the band plan separating CW, digital and voice modes is only a gentleman’s agreement. The frequencies mentioned above, like the QRP frequencies and others, are just “watering holes” that benefit people who operate those modes but can be ignored by others with no fear of any official penalty.
There has been an explosion in the use of digital modes over the last few years as more hams connect their computers to their radios and discover sound card software. The effect of this has mainly been that you could often find PSK31 activity when nothing else could be heard. Poor conditions have prevented the bands from getting too overcrowded.
But with better propagation people are going to be fighting for space. PSK is going to need to spread beyond its usual 2kHz on the most popular bands, as will JT65A. The “modes du jour” most of which offer no significant benefit over those that already exist will cause confusion by operating on top of one another. And the outmoded, inefficient RTTY, for which no technical justification for its continued use exists, will stomp over everything running the legal limit just as it always has, only this time more people are going to have their contacts spoiled and get angry about it.
It’s going to be a fun few years!
An FM/AM/SSB handheld for 10 and 12m
I love handheld radios. The “holy grail” for me is to make long distance contacts using a handheld radio with attached antenna. Ten metres is probably the best band to achieve this. Six metres might give stronger signals when conditions are right but it is open too rarely. Lower frequencies are open more often but a practical hand-held antenna is too short and inefficient for voice contacts using low power to be possible. You can put up a ground mounted vertical or hang a dipole in the trees but then it isn’t portable.
Last year I got an Intek H-520 which I used on 10m FM but although I did make some nice contacts with it I was disappointed with the radio itself. It was very power-hungry for 6 NiMH AA cells to the extent that the radio would shut down when used on maximum power unless the batteries had just been charged up. There is another problem with 10m FM in general which is that there are not all that many channels. There is a lot of QRM when the band is open, you are competing with people running a lot more than 4W to a whip antenna and in the FM mode “capture effect” means the strongest signal wipes out all others. So when I saw that a multimode handheld including SSB and covering both the 10m and 12m amateur bands was available, I decided that this was the toy for the forthcoming summer months. SSB offers the chance for some exciting handheld contacts.
The Albrecht AE2990AFS is a multimode multi-standard CB handheld radio that is readily configurable for amateur band use. There are instructions on the web and even a YouTube video on how to do the modification but the supplier included a printed copy in the box. Briefly, you pull out the rubber PTT cover which reveals five contacts next to the PTT switch. Using a soldering iron and solder wick you remove a bridge between two contacts (preferably without touching the hot solder wick on the case and melting it like I did!) then you short out two other contacts while turning the radio on. You can then choose various channel options including three for hams: Code 0 (10m + 12m switching between them using the CH9 button), Code 1 (10m band only with home frequencies 29.300 and 29.600 selected using CH9) and Code 2 (12m band only.) I chose Code 0 to get the benefit of two amateur bands.
No batteries are supplied and no charger either. The lack of a charger is a bit annoying as the charger socket is a fairly small barrel type that isn’t easily obtainable (even after you’ve guessed the dimensions.) The battery pack takes 9 NiMH AA cells and has contacts on the bottom. A drop-in charger is available as an optional extra. I will probably make one as I did for the old TH-205E. But first I have to establish what the charging voltage is. The box the radio came in suggests the charger/DC socket on the side of the battery pack takes 12V. You can certainly run the radio off that, but when it is switched off it draws no current. It looks as if you would have to crank the voltage up to about 18V to charge 2400mAH NiMH cells at 240mA, which would probably have dire consequences if you switched the radio on with the charger connected. But with the lack of propagation on 10 and 12 metres I probably have a few weeks to figure it out.
The antenna supplied is about 8 inches long. I checked it using my antenna analyzer and was pleased to find that it was resonant on 28.5MHz with quite a sharp SWR curve. However such a small antenna is probably little better than useless for making contacts over more than a few miles. I have a 45in telescopic 10m antenna and that is what I plan to use with this radio.
The Albrecht AE2990AFS is ready for the new European harmonized CB frequency allocation (which the UK wants to opt out of) so the output is rated at 4W on FM and 4W PEP on SSB. The actual power measured on 10m FM from this radio was only 2.13W. This is similar to what I found with the Intek H-520. With the Intek I was able to get inside, find the power adjuster and tweak it up to 4W. That’s when I discovered why it had been set lower in the factory – the current draw at 4W is just too high for many AA rechargeables to sustain. Most CB users would never know their radio was giving less power than claimed because they have nothing to measure it with, so they would never complain. If it cut out whenever they press the PTT then they would. We hams complain that our radios are expensive but they are built to a higher standard than CB radios. You get what you pay for.
With its 9 cell battery pack the Albrecht doesn’t need to draw so much current as the Intek for the same power. While it was on the bench power supply I measured the current draw on FM “high power” (2W) as 800mA. On the low power position which is meant to be 1W but was actually 0.51W the draw was 500mA. Unlike the Intek there is a “warranty is void if you remove this” sticker over the two halves of the case so I can’t delve inside undetected. As I have heard of people who bought similar radios under other brand names which broke and had to be returned under warranty I don’t want to void it, so I’ll have to live with 2W output, at least until next year.
On SSB the modulation out of the box was almost nonexistent. This is dependent on the mic gain setting, which can be adjusted from the front panel. After increasing it the SSB modulation was much improved and although I don’t have a peak reading meter the average level gave me to believe I was getting 4W PEP.
The audio on SSB sounded clean but if you increase the mic gain in order to get reasonable talk power there is noticeable frequency modulation on the signal. I am guessing that the battery voltage sags a bit on speech peaks and this pulls the local oscillator. I had read about this issue in some forums discussing the other incarnations of this radio and someone stated that in the Albrecht versions this problem had been fixed. It appears this may not be the case. I doubt that the fault would make the audio unreadable but I would expect to receive comments about it.
I recorded a number of audio samples at different mic gain settings for comparison. You can hear the FM increase on voice peaks as the mic gain increases.
- Albrecht AE2990AFS SSB audio – mic gain 7
- Albrecht AE2990AFS SSB audio – mic gain 8
- Albrecht AE2990AFS SSB audio – mic gain 9
- Albrecht AE2990AFS SSB audio – mic gain 10
- FT-817 audio (for comparison)
When configured for ham band use the radio displays frequency as you would expect. The display has an attractive blue backlight. Tuning is by up/down buttons at the side. There is an annoying beep at every button press, but this can easily be silenced. The standard tuning step is 10kHz which is a bit large for convenient band scanning. You can change the step size for fast or slow tuning – the steps are 100kHz, 10kHz and 500Hz. The 500Hz step size is still a bit large for satisfactory SSB tuning. There is a clarifier control but it works on receive only. So some people you call will complain you are off frequency.
There are five memory channels which store frequency and mode, so you can switch quickly between FM and SSB calling frequencies for example. You can select a shift or offset of up to 990kHz for repeater use. There is also a CTCSS tone for repeater access, but the manual implies it is a fixed 88.5Hz tone which (apparently) is used by 10m repeaters in the USA. This is straight from the manual – I can’t vouch for it.
With the lack of any propagation on 10 or 12 metres I obviously haven’t had a chance make any contacts with the radio or evaluate the receiver sensitivity. The RF gain and squelch sensitivity can also be adjusted from the front panel in the same way as the mic gain. There is even a roger beep!
So there you have it. The below-specification power and FM-y SSB audio are fairly major faults, all things considered. But the Albrecht AE2990AFS is the only true handheld SSB-capable radio for any amateur band currently available. If that’s what you want, it’s your only option.
Simple Sideband Transceiver for 10m
Roger G3XBM has started a new project: a simple sideband transceiver for the 10m band. Roger’s projects are always interesting so this page will be one to keep an eye on. If it can be made small enough to fit into a hand held case this could make a great portable radio capable of DX contacts during the sporadic-E conditions during the summer.
Regular readers will know that last year I worked the Czech Republic using a hand-held Intek H-520 FM transceiver with a telescopic whip. The Intek, despite being a nice looking radio, is actually a horrible piece of kit with a PA that sucks the power out of the rig’s batteries, especially if the antenna presents anything other than a perfect SWR. And the trouble with 10m FM in the summer is that too many people are trying to use too few frequencies so there is terrible QRM and the “capture effect” means that only the strongest station is heard.
A little double-sideband rig, even with only a couple of watts output, ought to work much better. I shall be following Roger’s project with interest and intend to make this my next radio project too.