Showing posts with label fm. Show all posts
Showing posts with label fm. Show all posts

29 Aug 2021

FM broadcasts in Switzerland

John EI7GL's blog gives us the news that Switzerland is to go QRT on Band II FM in 2024, so people will have to use DAB. As time progresses, this will become more commonplace. 

I am not sure what DAB coverage is in the UK compared with Band II FM.

27 Aug 2018

East Cambridgeshire 2m FM Net

Surprisingly, considering it was a Bank Holiday, there was a good turn-out this evening for the East Cambridgeshire FM net on 144.575MHz. After the net closed G3TFX/A joined us. The net meets Mondays at 1900z.

Later still, I had a G QSO on 50MHz FT8.

12 Jul 2018

Transatlantic FM DX

Southgate News reports that Newfoundland Band II FM signals were copied in Northern Ireland.

See http://southgatearc.org/news/2018/july/88-mhz-trans-atlantic-signals-heard-in-ireland.htm#.W0Zy8fZFzIU

10 Nov 2017

Real or Fake?

Supposedly this guy worked 2m transatlantic in 1982 on FM. I find it hard to believe this was genuine. It seems amazing that this was not well publicised at the time. Make up your minds.

22 Apr 2017

HB100 10GHz frequency agility

Steve G1KQH sent me this link:

http://ik1zyw.blogspot.co.uk/2017/04/hb100-10-ghz-module-frequency-agility.html

You may recall that the HB100 is a very low cost Doppler radar module that can form the heart of a wideband FM 10GHz transceiver.

13 Feb 2017

East Cambs 2m FM Net

This is on 144.575MHz FM (yes 144) at 2000z Mondays, vertical, and is open to anyone. Regulars are G4NUA (Cambridge) and G3KKD (Quy). The chat covers anything and we usually finish about 2030z. This started life as an AM net.

If there is QRM we usually QSY downwards in 25kHz steps to find a clear channel. When there is a lift we can sometimes hear stations in the Midlands.

7 Nov 2016

QRT - all bands

After listening a bit after 2000z on 10m JT65 and taking part in the East Cambs net on 144.575MHz FM, I decided to go QRT on all bands. I shall be back on 10m JT65 tomorrow, hoping for better results than today.

11 Apr 2016

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.

16 Mar 2015

Local 2m FM net

Most Mondays, a group of us in Cambridge and East Cambridgeshire meet for a net on 144.575MHz FM. We started as an AM net on 144.55MHz but had to QSY as one net member had no AM.

Although my voice is still very poor, I try to come on most Mondays but I prefer to listen more than talk. The net is open and we welcome newcomers. Some Mondays there is no-one around, but that is the exception. Usually there are about 3-5 of us on. Note 144.575MHz FM, not 145.575MHz. 8pm local time Mondays.

UPDATE 2035z:  Only 2 of us this evening G3KKD and G3XBM.

2 Feb 2015

70cm AM test with low cost modules

This evening I listened for G6ALB on 70cm. Andrew is 3km from me. We both have V2000 vertical co-linear antennas. He was using a very low cost SAW locked TX module, which produced as much FM as AM when modulated with an electret mic. The biggest problem was Andrew's low power and low level of modulation.  He needs more mic gain, more TX power (10dB more?) and some pre-emphasis on the audio. TX power today was very low milliwatts. From 433.925MHz up to at least 433.990MHz a lot of squeaks and whistles could be heard, presumably from more local ISM devices. I was receiving G6ALB using an FT817 at about RS41 on FM and weaker on AM. This very initial test produced results that were expected. To use a super-regen module on RX (the intention is a very simple AM voice transceiver) will require G6ALB to be considerably stronger than on these first tests.

11 Nov 2014

How do they ever make a profit?

On the internet you can buy a dual-band handheld with antenna, battery, chargers(2), earpiece and belt clip for just £25.29. At this price I find it unbelievable they can make a profit. I think it is even cheaper if you buy a batch of 3.
 .
See http://www.banggood.com/LBaofeng-UV-5RA-Yellow-Dual-Band-Transceiver-Radio-Wakie-Talkie-p-947385.html  .

Shipping is just 29p. shipped to the UK by registered air parcel. It is available in a variety of case colours.

19 May 2014

East Cambs 2m Net

Every Monday evening at 8pm UK time there is a net on 144.575MHz (note 144.575MHz , NOT 145.575MHz) FM in East Cambridgeshire. The net started some years ago as an AM net on 144.55MHz but one joiner had no AM, so we went over to FM, vertically polarised.  Usually there are 3-4 people on the net and others are very welcome. Discussions are wide ranging and cover all sorts of amateur radio subjects.  Usually one person has a query and the others try to answer the question. Occasionally we do on-air experiments too. We always finish by 9pm latest and quite often earlier if we run out of topics.

28 Apr 2014

Super simple FM TX - try on 2m?

See http://makezine.com/projects/super-simple-fm-transmitter/ .

This is a super simple TX for Band II FM using readily available parts.  With a smaller coil (1 turn less) and C4 smaller (and made tunable) I think it could be used experimentally on 2m FM, but stability is likely to be poor, so really only of use for short range and short durations.  From here, I'd expect this to be detectable at least 3km away (next village) even if the power is at uW or low mW levels. A few uW go a LONG way if connected to a reasonable antenna like my V2000 or 3el beam. There is no harmonic filtering either: a small low pass filter is advisable really.

With lower modulation levels (adjust) it should be fine with NBFM. The 2N3904 is a ubiquitous transistor available for just a few pence from many sources. The other parts are just pence.
Image at http://makezineblog.files.wordpress.com/2013/10/kogawa_simplest_transmitter.png?w=620&h=354

My thanks to Southgate Amateur Radio News for finding this before me.

7 May 2012

Monday nights at 8pm on 144.575MHz FM

Every Monday evening a number of East Cambridgeshire locals get together on 144.575MHz FM for an hour between 8-9pm clock time. The usual stations on the net are G6ALB, G3KKD, G4NUA, M3YPZ and G3XBM.

Originally this started as a regular session between G6ALB and G3XBM on 144.55MHz AM. We managed to engage in some sort of QRP related experiment most weeks. We've worked each other on all bands from 1.8-432MHz with extreme QRP and had 1-way contacts on 8.97kHz, 136kHz and 500kHz QRP too. We are 3km apart, which is an ideal distance to try all sorts of things from listening to each other on crystal sets to trying to see how weak a signal can be copied on each band: you may be surprised how little signal can be copied at this range: it is no wonder we suffer from so much interference on HF these days as nanowatts go a long way.

These days the net conversations cover all manner of subjects but, sadly, Andrew G6ALB and I don't get to do experiments so often: this is a drawback of a larger net. At some point I think Andrew and I will find another spot to do experiments on another evening whilst letting the Monday net continue as it is. It is fun to simply chat.

Let me share a pearl from this evening:  Alex M3YPZ, who has a truly fascinating background going back to working on radar in WW2 and research in Cambridge University, mentioned he had a book on how to improve his memory.  He lent it to someone   ....but could not remember who.  The joys of getting a bit older!

If you are the area feel free to call in to the net.

14 Apr 2012

QRP FM pedestrian portable

Today I got back from a week in north Devon where my wife and I had a holiday cottage. The weather was pretty good for the time of the year allowing us to get up onto the hugher parts of Exmoor on several occasions. With my trusty VX2 handportable I managed to work plenty of stations through various repeaters in South Wales but my best DX was a simplex QSO on 145.525MHz with G4TRA in Gloucestershire at 101km. Despite just using the VX2 and a quarter wave whip he gave me a report of 59+20dB when I held the rig horizontal. To quote Steve, "you sound like you are in the next garden". Following this contact I worked MW0ZAP simplex. Time (and batteries) prevented me trying for more QSOs but I'd forgotten how well FM simplex works when you are on top of a moorland hill with a 360 degree takeoff.

13 Feb 2010

10m FM

This afternoon I called CQ on 29.6MHz FM but no-one came back to my call. Going back 20 years or so there was a lot of activity on 10m FM with many people in the UK using converted FM CB rigs. With 4W and a vertical half wave I could work out to about 30-40kms without problems. Sadly, activity is very low here now except when there is sporadic-E about. 10FM was a good way of checking DX as often quite distant repeaters would pop up out of the noise, especially ones on the east coast of the USA. 

30 Dec 2008

70cms good conditions tonight

Just worked GW0LJW in Gwent and G3VEH/M via a 70cms repeater in Somerset tonight when running 5W (actually about 1.5W into the antenna after the coax run) into the vertical colinear. Conditions are definitely up in that direction as the distance is about 250kms.

19 Dec 2008

29MHz FM

Just after 7pm tonight (Friday) I hope to do some tests with G4NUA in Cambridge around 29.6MHz FM. We will both be HORIZONTALLY polarised (Homebase-10 wire halos) running around 10W FM. If there are others in the mid-Anglia area who would like to join us then please do call in.

At one time there was a lot of activity on 29MHz FM but there is much less these days or is it just around here?

1930hrs update: successfully heard G4NUA at RS56 but he could only just detect my FM carrier (no modulation) his end. Surprised that we were unable to work each other at this distance with a pair of horizontal halos. On 2m he was 59++ and on 70cms 56. Ted was using the FT8900 4 band 50/35W FM rig covering 10m, 6m, 2m and 70cms - nice radio.