Simple VHF receiver by Charles Kitchen

Charles Kitchen N1TEV is a well known designer in the USA and across the world. 

This is a circuit for a VHF receiver that can be adjusted to decode SSB, CW and NBFM in addition to AM.

See https://www.arrl.org/files/file/Technology/tis/info/pdf/9712039.pdf .

New challenge needed

HF bands present no real challenge. Recent microwatt tests on 10m WSPR have been fun, but I need a new challenge. 

My 2.5W 8m FT8 signal has been received in most of the places I had hoped for, and this is not likely to change until there are a few new countries on the band. At the moment I am inclined to ask for a new 8m permit from April 2024 - April 2025 even though I have to pay to do research, which I find utterly stupid!

Later today, I may QSY to a VHF band FT8 as this is "different" and not something I have tried for a while.

VHF NFD

In all, I had 2 short periods on 2m VHF NFD.  8 stations were worked.  More could have been worked had I stayed on longer, but I was exhausted. In the end I was just giving away points.

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

DX VHF FM QSO

The IARU VHF/UHF Region 1 Newsletter has details of the FM 2m QSO between ZS3 and ZD7,

See https://www.iaru-r1.org/index.php/vhfuhsshf

Tropo forecasts

Although I rarely use this myself, there is a useful program to predict tropo openings on 2m.

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

VHF AM

It is a number of years since I last used VHF AM. At one time nearly all VHF activity was AM. These days most activity is FM with DX being mainly SSB, with FT8 coming up fast. Ex private mobile radio (PMR) AM kit is often very inexpensive.

See https://sites.google.com/site/g3xbmqrp3/vuhf/2am

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

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

Bands 30-88MHz

The lower VHF bands are becoming less popular for professional users as antennas on handhelds are long and there is Es interference from time-to-time. This is great news for amateurs as lower VHF ex mobile radio gear is often cheaply available and the chances of amateur 6m and 4m allocations around the world get better. I certainly hope we get a small 8m (40MHz) allocation (mainly for Es work) and we see 6m and 4m allocations worldwide.

VHF NFD

Yet again, I almost forgot this! I was prompted by a Facebook post by the Cambridge Club. I have just been on (5W and a 2m omni antenna) to give away a few points. Because of my poor voice I was not on long but my best DX was G4RFR/P (250km) in IO80ST on 2m. I worked G3PYE/P (local) on 70cm with my 2m halo. The contest runs until 1400z today.

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.

VHF conditions up?

We normally hold an East Cambridgeshire net at 1900z Mondays on 144.575MHz FM. If the channel is busy we move down 25kHz or further.  This evening it was busy so we moved down to 144.550MHz FM. G4CPE (Luton) was a "smooth noise" signal with me working G3KKD.  Next week we will be back on 144.575MHz FM all being well.

2m VHF beacons

So far, I have not tried listening to the 2m Cornish, N.Ireland and Scottish beacons with the big-wheel horizontal omni antenna. I must give these a try. I expect I shall only hear them via MS or lifts and possibly aircraft reflections. On my 3el 2m beam the N.Ireland beacon was right on the edge. Normally I can copy the Kent beacon as well as beacons in Holland and Belgium.

GB3NGI (N.Ireland) 144.482MHz Ballymena
GB3MCB (Cornwall) 144.469MHz St Austell
GB3ANG (Scotland)  144.453MHz Angus

See http://www.microwavers.org/maps/2m.htm .

UPDATE 1517z: A casual listen on each frequency (probably not for long enough) and none was detected. I shall try again and listen for each for longer. I remember the GB3RMK Scottish beacon on 6m could always be copied by MS pings for a few seconds every 10-15 minutes. I was using a wire dipole at the time.

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?

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.

VHF beacons

With Andrew G6ALB's superb and kind help, my manually turned, Moonraker supplied, dual band 2m/70cm antenna is up and working, no thanks to the rubbish patch lead from Moonraker which had 2 dodgy crimped connectors! The N connector at the mast end has had to be replaced and at the shack end the SMA crimp is intermittent. Andrew is going to replace this with a PL259 plug shortly.

With the patch  lead working (by wiggling!) I can copy the following VHF beacons at any time: GB3VHF  Kent (144.430MHz), GB3NGI N.Ireland (144.482MHz) and PI7CIS Holland  (144.415MHz). There may be others too but I have yet to have a good look. The Cornish beacon seems too far to copy, at least so far. I have yet to check 70cm beacons. On the halo PI7CIS on VHF was just nudging the noise floor, so the 2m beam is certainly helping.

The manual antenna rotation method (out of the guest bedroom window) seems to work fine: I can reach the pole OK and can peak beacons by listening on the shack loudspeaker.

When the shack end PL259 is added, the Westflex cable should no longer be intermittent. The Moonraker crimped connectors will then have all been replaced. Says a lot for Moonraker's quality control doesn't it?  Don't think they can ever check crimped patch coaxes, which I assume they buy-in. A simple sampled ratio pull test is called for. If any fail reject the batch.

Now looking forward to Tuesday evening UKAC sessions to try the beam in contests on 2m and 70cm.

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.

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.