Showing posts with label uhf. Show all posts
Showing posts with label uhf. Show all posts

18 Dec 2020

How do they do it?

 

On Amazon Prime I noticed this UHF (446MHz?) transceiver for £11.95.  Included are a charger and earpiece /mic. 

Another supplier has a pair for just £16.99 a pair.

When I worked at Pye Telecom we would struggle to make the charger for this price! Things have changed a lot in the last 20 years. It must be sheer hell being a UK PMR manufacturer these days. I am sure there are even cheaper ones if you look.

Assuming they ship across the world and make a profit, just how do they do it?

11 Oct 2019

UK VHF/UHF-only beginners licence?

Southgate News has a piece on a possible "beginners licence" to encourage VHF/UHF activity. This would be non-technical and with restrictions on power and bands. Certainly a casual look at our VHF and UHF bands would suggest these are not well used and maybe we should be encouraging use of these bands. Back in the 1980s, these bands were busy.

See http://southgatearc.org/news/2019/october/new-uk-entry-level-licence-proposed.htm

11 Jun 2018

Even more simple VHF and up licence?

On Southgate News there is a report about the RSGB's thoughts on activity levels on VHF and UHF bands. Apparently activity levels have dropped badly in the UK and there is talk of an even simpler exam and licence to encourage activity. There is no doubt that the hobby is facing a future crisis as people get older, less active, and die.

Like many things, we seem to try "dumbing down" as the answer. The basic issue is radio is not the magic it was to many in the 1950s and 1960s. These days you only have to look at the magazines for sale in newsagents to see this. Sadly, there are far more gaming, PC and railway magazines with, if you are lucky, just a couple of radio magazines.

Certainly, many on 2m have switched to FT8. A casual tune across the bands would suggest low levels of activity. Some would argue much less wide bands would do.

See http://southgatearc.org/news/2018/june/could-a-new-entry-level-licence-boost-vhf-uhf-activity.htm#.Wx42tPZFzIU

8 Dec 2017

New VHF/UHF log periodic

If you have plenty of money, you may want to consider the new log-periodic from InnovAntennas at just under £200. Personally, I think this is expensive, although others may disagree. Each to their own. I know they have to recover development and manufacturing costs, but just under £200 for some aluminium?

See http://www.innovantennas.com/antennas-a-accesories/on-line-shop/view/productdetails/virtuemart_product_id/469/virtuemart_category_id/75.html

See also https://en.wikipedia.org/wiki/Aluminium

6 Nov 2017

Low cost Chinese handhelds

I ordered a pair of Chinese UHF portables for just over £13 a pair. One arrived. I have still to chase the company for the second unit. It seems they had got the order wording wrong.

Sorry, but I ordered a pair and that is what I expect to get - in the end.

Gearbest - remember the name. We'll see how they do in the end.

7 Oct 2017

Low cost miniature UHF handhelds

Slowly, but surely, the Chinese are conquering the world by stealth.

You can buy 2 very low cost miniature UHF transceivers from China for £22.82 with free airmail shipping to the UK. Two! These give you 400-470MHz coverage and a Band 2 FM receiver! How do they do it and make money? How can any western or Japanese supplier hope to compete? There are even lower cost transceivers if these are too expensive!

See https://www.gearbest.com/walkie-talkies/pp_775273.html?currency=GBP&vip=2674264&gclid=EAIaIQobChMIyKyzvdne1gIVa6btCh37pwkvEAEYASAEEgK2VPD_BwE

8 Feb 2017

VHF/UHF DX Handbook

Southgate News brings news of a free digital download of this famous book from the 1990s.

See http://www.trpub.net/assets/applets/VHF-UHF_DX_Book.pdf

6 Jun 2016

VHF/UHF tropo forecasting

Usually I go on 2m and 70cm (mainly the Tuesday evening UKAC sessions) and work what I can with my QRP.  Some users use prediction maps, to get some idea of the likely tropo ranges. I came across one today and there is Hepburns available at http://www.dxinfocentre.com/tropo_eur.html . No doubt keen users have their own favorite.

A reminder that tomorrow evening is the June 2m leg of the RSGB's UKAC contest. This is usually well supported. With the fine, settled, weather there are likely to be quite a few portable stations out and about on good hilltop sites. Even with 5W QRP and an omni antenna I can usually work about 200km in flat conditions, further with a lift, from home.

30 Apr 2014

VHF/UHF beacons PI7CIS Holland

Although I can copy the VHF beacon PI7CIS (144.416MHz) almost 100% of the time on my small 3el VHF beam (callsign clear but S-meter does not move on FT817) I have still to copy the co-sited UHF beacon with the same callsign.  On UHF (432.416MHz) I have the same low loss coax (Westflex) and a co-located 5el beam on the very same beam heading. I know this beacon is not GPS locked, so it may drift, but I am surprised not to have yet detected it at all, even allowing for the additional losses in the feeder (maybe a few dB?).

Indications are this 75W, coastally located (Scheveningen) beacon, is operational, unless anyone knows better? The antenna is reported to be a dipole aiming 90/270 degrees which would be poor in my direction.

Anyone know the PI7CIS UHF beacon's current status please?

27 Apr 2014

3 el/5el beam

VHF/UHF beam with V2000, 2m halo and HF Par antenna behind
The dual band 2m/70cm beam is erected and is working now the useless Moonraker crimped coax connectors at both ends of the low loss Westflex coax have been replaced by decent soldered connectors. Andrew G6ALB also restrung my Par 10/20/40m end fed back up so I am now operational as follows:

630m Earth-electrode 15m baseline

40m Par end-fed
20m Par end-fed
10m Par end-fed

The Par also matches on 60m and 30m via the auto-ATU.

6m V2000 vertical
2m 3el horizontal and halo
2m V2000 vertical
70cm 5 el horizontal
70cm V2000 vertical

This means I am decently equipped for the bands I am mainly interested in. The dual band yagi is small and cannot easily be seen from the front of the house. The most I run is 5W pep, although I use 2W mostly and just 5mW ERP on 472kHz. 2W is more than enough to be copied all around the planet on 40m, 20m and 10m.

22 Apr 2014

2m/70cm antenna

Today I unpacked my 3/5el beam for 2/70cm, the wall brackets and the coax leads. I am missing a small SMA female to SMA female connector  (just ordered from eBay) to join the 20m long Westflex coax to the small patch lead to the FT817.

As far as I can tell, I have everything I now need, when the SMA connector comes. I shall have to wait until Andrew G6ALB can come over to help with the wall brackets. At the moment my health is still too poor (too giddy/clumsy)  to do the erection on my own, sadly.

14 Apr 2014

Aborted 481THz NLOS test

I am beginning to think that ALL tests outside the house should stop until I am a lot better (stroke). The best description is I feel, all the time when on my feet, as if I have drunk 8 pints of beer and am very drunk and clumsy.

This evening, my wife drove me out to an NLOS test site where I managed to drop the RX head hard on the ground. The head immediately stopped working even before I started hunting for my signal! I could hear no hiss at all. There was no sign of the very visible moon noise in the RX.

The test would have been marginal anyway, especially with a bright full moon, but to be unable to carry out the test at all was a great shame.  It is just that everything is SO hard for me at present and setting up optical kit is stretching the limits of my current abilities. Feeling clumsy nearly all the time is tiring too.

Even getting my VHF/UHF beam up at home will require help. Andrew G6ALB has kindly offered to erect it for me. This should be an easy task for me - normally it would be - but not at present. At least, when erected, VHF and UHF activity should be straightforward at home in UKAC sessions on Tuesday evenings. Sitting down my balance is fine. I just hope this soon improves. Walking is getting better but balance/giddiness are still big issues.

11 Aug 2013

Rotatable mast bonus

Regular readers may remember that I was asking about rotators some months back. Well, I have just realised that the place where I intend to fix my 2 inch diameter mast at the new QTH is such that I can rotate it by hand by opening a window about 10 feet from my new operating position. This means, if I so choose, I can erect a small beam for 2m and 70cm, or a combined 2/70cm beam and turn it 360 degrees very quickly using the trusty "Armstrong" method. So, initially I'll erect the V2000 vertical but may well add some small (not too sharp) beams for VHF/UHF contest and tropo work. Turning a beam by hand is quicker than a rotator and allows signals to be peaked by ear.

Anyone have any recommendations for a combined 2m/70cm horizontally polarised beam with around 3-6 elements, ideally fed with a single 50 ohm coax? I have seen combined 2m/70cm HB9CV antennas but think there are other options too.

19 Apr 2013

VHF/UHF take-off at new QTH

This evening I went up to our new, well being newly renovated, bungalow on top of our local "hill" immediately next to the Burwell windmill.

Currently the roof is being re-tiled and there was scaffolding everywhere, so I took the opportunity to climb up a ladder to the roof level to judge the VHF/UHF take-off.

Well, the good news is that even at just above the gutter level there is an excellent virtually unbroken (clear of houses) take-off from the north west all the way around to the south. With an antenna a few metres above the roof apex height, it should have a pretty good take-off in most directions.  It just begs me to get some better gear for the 2m, 70cm and possibly 23cm and 3cm bands. We'll see.

I was also checking out optical communications possibilities. At lower heights, the horizon view is obstructed, but I should be able to arrange my optical beacon for cloud-bounce and clear air forward scatter, non line-of-sight, tests with the beacon firing up at around 20 degrees up from horizontal in many directions out towards Cambridge and beyond.

18 Apr 2012

Low cost rotator

In my search for a low cost rotator for small and lightweight VHF/UHF yagis I see that Conrad Electronics UK sells an "external TV rotator" for £52.99, plus postage from Germany with a free 2 year warranty.

3 core cable, 70 secs 360 deg rotation, 45kg load, 300Nm bending moment, 21.6Nm torque.  See eBay item 180832166179.

Does anyone have any experience of this rotator?