Posts Tagged ‘4m’
Four Metre Band and OFCOM rubbish decisions?
There was an announcement on the RSGB and OFCOM sites advising some UK full licence holders that 70.5 to 71.5MHz is being made available for one year by special permission for further digital experiments, a bit like 146-147MHz here in the UK.
Sorry, but has OFCOM gone stark raving mad???
I can see no good justification for this 1MHz of spectrum. 2m was already under-used and the 146-147MHz allocation is probably being used by a tiny handful of people from time to time only. DATV tests could quite as easily happen at 70cms.
I can think of far better parts of the spectrum OFCOM could have allocated e.g 100kHz around 40MHz (for Es propagation experiments), 73kHz, below 8.3kHz and a contiguous 5MHz allocation. Oh no, these require a brain to be engaged by OFCOM people.
Maybe this is an April fool’s wind-up, although I suspect it is true.
Surely if OFCOM wants to further real experimentation in radio science there are better ways of going about it? Yet again, I am totally unimpressed. Between OFCOM and the RSGB, I think this is, yet again, a stupid stupid decision. So we now have 2MHz of extra spectrum for 12 months that a very few might use. Big deal. OFCOM, engage brains, think radio science. If you want to help grow future engineers that we so badly need, these allocations will not help at all. Think again!
See http://www.rsgb.org/ .
See http://www.70mhz.org/ .
Look, No IP
A couple of years ago we changed our broadband Internet service provider. The new provider did not support a static IP address. I have a QNAP network attached storage device which is primarily used for backup. However, it’s actually a Linux box that runs the LAMP (Linux, Apache, MySQL and PHP) software which I occasionally use as a web server for experimentation. I sometimes need it to be accessible from the internet. So I opened a free account with DynDNS in order to access the server using a host name.
Some time last year after I came out of hospital I started to receive emails from DynDNS informing me that my account was being disabled due to abuse and inviting me to open a paid account. As far as I could tell, the only “abuse” was that my script to inform DynDNS of my current IP address was running more than the number of times DynDNS permitted. I had no idea why it should start misbehaving like that and cynically thought it was just a ploy to convert free users to paid subscriptions. I was in no frame of mind to deal with the problem, nor to dig into my wallet, so I simply closed the account and had done with it. This would have had the effect of breaking some APRS-related functions on my site but I had other things of greater concern to think about.
A few days ago I decided to look into why the CDGVHF ANSRVR group was not sending any messages. ANSRVR is an APRS tool used to send APRS messages to groups of interested people. CDGVHF stands for Cumbria Dumfries and Galloway VHF group and it is intended to disseminate alerts about VHF and UHF openings in the Cumbria, Dumfries and Galloway area (grid square IO84.) It’s essentially a filter that acts on emails sent out by DX Sherlock and converts them to APRS messages addressed to ANSRVR. I could, of course, just have the emails sent to my smartphone. But it’s more fun to make use of ham radio!
I looked for an alternative free service to DynDNS and decided to try No-IP Free. As far as I can tell, No-IP won’t accuse you of abuse for updating your IP address too frequently, in fact its client software appears to do this every few minutes which seems like plenty. It does have a requirement that you confirm your account is being used once a month, which could be a bit annoying, but I’ll see what happens at the next update.
In the meantime, CDGVHF is now sending out propagation alerts again. To receive alerts of VHF and UHF openings in the IO84 area just send an APRS message to ANSRVR with the text CQ CDGVHF. You’ll need to repeat this from time to time as the server unsubscribes you from the group after 8 hours of no activity, unless you are using KJ4ERJ’s APRSISCE software which can maintain your subscription for you.
Twins from Taiwan
One of my plans for this year had been to try other bands when out activating on the fells. I was going to try 4 metres. Many SOTA activators use 4m FM already and the introduction of new hand-held 4m radios from Wouxun seemed likely to cause a surge of interest in the band. Moreover, 70MHz offered the prospect of chance long distance Sporadic-E contacts during the summer months which has always been one of my main interests.
I decided not to get one of the new Wouxun radios, however. Whilst the new 4m/2m dual bander looked tempting, I didn’t need another hand-held with 2m capability and any dual band antenna would be an undesirable compromise. The single band 4m Wouxun was almost the same price as the dual bander, so was not a good deal. Instead, I had a look to see if I could find something like a low band version of the Motorola GP300. I couldn’t, but eBay turned up a professional radio called the H112PLUS made by Cybercom Electronic Corporation Limited in Taiwan, available in VHF low band, high band and UHF versions for just over £50 shipped. A particular attraction was that the radio claimed to conform to IP54 weatherproofing specifications – useful when operating from rainy fell-tops.
Unlike stuff from Hong Kong or China, the “expedited shipping” method used to send the radio attracted the attention of UK Customs so delivery was delayed by over a week and I had to pay an additional £25 tax and ParcelForce collection fee to receive it.
On opening the box I was extremely impressed with the very high quality of the product. This was one of the most beautifully made hand-held radios I had seen. As far as build quality is concerned this is the opposite end of the spectrum from the little Baofeng. However the little Chinese radio is miles ahead when it comes to usability and performance. The H112PLUS is about the same size and weight as the Kenwood TH-D72 so it is one of the chunkier hand-helds. Programming software, cable and a desk charger are included in the price.
So to the shortcomings. The knob on the top is a rotary control marked Vol/Ch but in fact it only controls the volume in discrete steps. Most of the time when you turn it, nothing happens. It is as if the CPU in the radio is asleep and doesn’t notice you operating the controls for a while. The buttons on the front panel, which are used to change channel and access menu functions, are also a bit laggy in operation. If you try to hurry the radio, the firmware locks up and you have to pull the battery pack. The programming software is also a bit flaky and locks the radio after writing to it, requiring another battery pull.
By the time I received the low band radio I was awaiting an appointment for a scan for my as yet undiagnosed brain tumour and was a bit anxious. I was wondering if I would ever make a 4m contact and so, rather stupidly but with the aim of having something to look forward to I ordered a second, high band version to use on 2m. This arrived after I was out of hospital and attracted a £30 tax and collection fee despite being exactly the same price.
The high band version suffers exactly the same shortcomings as the low band one but as it covers the 2m band I was able to try it out. The main problem I noticed is that it has probably the worst receive audio of any hand-held I have used. There is a compression option which appears to clip the audio and make it sound like those police radios but even with this off the audio is still quite distorted and the actual volume from the speaker is not all that loud. The little UV-3R is much louder and sounds much better!
The programming software allows you to set power level (high/low power) frequency and CTCSS/DCS tone so you can access repeaters. There is no 1750Hz tone burst, of course, and no option I can find for setting the squelch threshold. There are scrambler options that are no use on the ham bands. I then discovered a bug. If you program separate transmit and receive frequencies (as for a repeater) and then save the results as a file, when you load the saved file the frequency splits are lost. The developer has acknowledged the bug and has promised a new version of the programming software.
The output power is about 5W on the low band radio and 6W from the high band one. The battery pack is NiMH and rated at 1500mAh. Someone has told me it is identical to one made by Kenwood. Battery endurance, even on standby, is not great.
When ordering the low band model you are given the option of specifying one of two frequencies for the helical antenna. I chose 69MHz. On the antenna analyzer the best SWR coincided exactly with 70.45MHz, which was rather nice. However the ERP from the helical is about 5dB down on a telescopic whip. The high band radio comes with a short helical that is resonant on 150MHz, but you can pop the cap off and add a few turns to the spring to get it down to 145MHz. The antenna socket is TNC so you need an adapter to use most other ham radio antennas. The speaker/mic two pin jack uses the Icom/Maxon standard.
The radios do work. I even had a 4m contact with a Scottish contest station during VHF field day. Given my health situation I have not had the opportunity to test these radios out in the field with good external antennas to see how they stand up to the high levels of signals encountered on hilltops. However, I attempted to reproduce the test I carried out in the Handheld receiver blocking shootout and the 2m H112PLUS was as bad as the poorest receiver I tested. The received repeater signal cut out when a signal at the bottom of the 2m band was keyed up, when most other radios under the same conditions showed little or no desensing.
Overall I think the H112PLUS is a radio that is of more interest to collectors than someone wanting a real hand-held workhorse. It is well made and the waterproof specification is an attraction but the poor receive audio and flaky software and firmware are a big disappointment and I have doubts about the receiver’s ability to handle high levels of out of band signals without desensing.