Search found 1487 matches

by daveB
09 Apr 2020 17:02
Forum: Antennas
Topic: Another Small FM aerial
Replies: 1
Views: 41

Another Small FM aerial

This one is at the modelling stage - but I'm hoping to build it in the next few days. It isn't as good as the 5 ele compact, but will cost next to nothing as it will be made from recycled Triax FM3s. them I bought around the time they were discontinued and the pair cost me £5.98 + p&p. It is a twin ...
by daveB
09 Apr 2020 09:43
Forum: DX Alerts (FM)
Topic: Tuesday (7th) Tropo?
Replies: 2
Views: 152

Re: Tuesday (7th) Tropo?

Thursday 9th April the Langnberg transmitter site is coming through quite well on most frequencies - but not quite at rDS level. More local stuff from Belgium has been coming through at RDS level overnight and this morning and there are a few Dutch stations present. It's not a strong lift - but bett...
by daveB
08 Apr 2020 13:18
Forum: VHF Band 2, OIRT & DAB
Topic: Console v3 / RDS Spy / FDM-S2 / Damn Windows 10!
Replies: 7
Views: 108

Re: Console v3 / RDS Spy / FDM-S2 / Damn Windows 10!

Where is File Analyser? I admit to not using SDR Console very often - I've only got the Jan 7, 2020 build (was it that long ago?) - but on that version: One the top menu bar click on View then on the menu bar that appears below the furthest rignt option "More Options" has the Data File Analyser in ...
by daveB
08 Apr 2020 10:49
Forum: VHF Band 2, OIRT & DAB
Topic: MS technique questions
Replies: 10
Views: 132

Re: MS technique questions

How can I revisite that wide span without consuming a whole day, going up and down to each empty fx and staying there for the whole recording time? What SDR hardware do you use? You can use SDR# software with the FilePlayer plug-in from rtl-sdr.ru to play back I/Q files from a number of SDR program...
by daveB
08 Apr 2020 00:13
Forum: VHF Band 2, OIRT & DAB
Topic: MS technique questions
Replies: 10
Views: 132

Re: MS technique questions

Recording 6, 8, or even 10 MHz is best as some meteors will produce a reflection on many frequencies. This is one snapshot from the Perseids in August 2015. It shows a strong burst lasting about 90 seconds with short bursts before and after. The range covered is 87.5 - 94.5 PerseidsMeteorShower-2015...
by daveB
04 Apr 2020 16:01
Forum: Antennas
Topic: Hourglass antenna
Replies: 2
Views: 109

Re: Hourglass antenna

Hi Paul, I've tried modelling this in 4nec2. I can't manage to match your dimensions, I end up with a resonant frequency closer to 100 MHz for 2 mm diameter wire (which is roughly 4mm electrical cable). But then I'm not modelling any form of support and ground conditions willl affect it. I did a sca...
by daveB
03 Apr 2020 16:12
Forum: Receivers
Topic: Murata ceramic filters available on ebay
Replies: 2
Views: 56

Re: Murata ceramic filters available on ebay

HI Franco

Here's the link to the shop:https://www.ebay.co.uk/str/Microphonics ... 7675.l2563
They don't have any 80 kHz or 53 kHz filters

David
by daveB
03 Apr 2020 11:37
Forum: Receivers
Topic: Murata ceramic filters available on ebay
Replies: 2
Views: 56

Murata ceramic filters available on ebay

I didn't think I would be buying filters for an analogue tuner again, but having decided to bring a Sony ST-311 back into service I found I needed to. Currently 180 kHz, 150 KHz, and 110 kHz filters with a centre frequency of 10.70 MHz are available. A pack of 5 x 110 kHz is £9.83. The seller also h...
by daveB
03 Apr 2020 11:10
Forum: VHF Band 2, OIRT & DAB
Topic: Getting Ready for the 2020 ES Season
Replies: 0
Views: 43

Getting Ready for the 2020 ES Season

It's getting to that time of year. For me the first Es reception is near the end of April but the earliest has been on the 10th. It's a good question as to what this season is going to be like as it we appear to be right at the bottom of the cycle. Will sunspot numbers start to climb or not, and is ...
by daveB
31 Mar 2020 00:12
Forum: Antennas
Topic: My new FM aerial
Replies: 12
Views: 329

Re: My new FM aerial

I didn't realise you had to either have a balun or the ferrite chokes All beam aerials with an unbalanced feed will benefit from a balun. I used two of the fat clip on chokes in close proximity to the feed point. The Triax folded dipole has a built-in balun. You could always coil up a few turns of ...
by daveB
30 Mar 2020 13:37
Forum: Antennas
Topic: My new FM aerial
Replies: 12
Views: 329

Re: My new FM aerial

Hi Chris, That rather changes the goalposts - and the performance. With the 3rd director the modelling shows a very poor f/b ratio at 88 MHz rising throughout the band to over 21 dB at 108 MHz for your current set up. The f/b ratio reached about 13 dB at around 93 MHz. But it is slightly better than...
by daveB
29 Mar 2020 14:31
Forum: Antennas
Topic: My new FM aerial
Replies: 12
Views: 329

Re: My new FM aerial

I have done a bit more optimisation, which has made a significant difference to the performance. For a small trade off in gain I've got 11.8 dB f/b at 88 MHz, peaking at 24.2 dB at 98 MHz and dropping to 20dB f/b at the top end. SWR is 1.5:1 at the band ends down to 1.2:1 in the middle. Gain is 5.2-...
by daveB
28 Mar 2020 21:13
Forum: Antennas
Topic: My new FM aerial
Replies: 12
Views: 329

Re: My new FM aerial

Thanks for the dimensions Chris. I plugged all the numbers into 4NEC2 antenna modeller and go some answers. Like the Triax FM5 the f/b ratio at the low end of the band is quite poor - round 8 dB a 88 MHz, 11.5 db at 90 MHz, the 14.6 dB at 92 MHz it peaks at over 25 dB at 98 MHz and drops back to 16 ...
by daveB
21 Mar 2020 11:16
Forum: Antennas
Topic: AirSpy Loop Antenna
Replies: 0
Views: 56

AirSpy Loop Antenna

I know lots of people are interested in a shielded magnetic loop antenna, judging by the huge number of views for my other posts. So this may interest you - and I have no other connection with AirSpy other than buying an AirSpy mini. I got a product e-mail from them on 20th March https://airspy.com/...
by daveB
18 Mar 2020 09:57
Forum: Medium Wave & Long Wave
Topic: Short Break
Replies: 11
Views: 258

Re: Short Break

I know I am cagey about giving out the location Absolutely right - so make sure you don't put an accurate lat/long in FMList if you create a separate location for logging. Otherwise you can zoom right in on GoogleMaps. That subtle nasal/throat feeling that something is about to develop . That's how...
by daveB
16 Mar 2020 12:20
Forum: Medium Wave & Long Wave
Topic: Short Break
Replies: 11
Views: 258

Re: Short Break

Scrub that. Cancelled. Self-isolating.
Hope it is just a cold/flu but best to follow the guidance. I've stayed home for the last few days with a what appears to be a cold - no fever/no persistent cough.
by daveB
13 Mar 2020 22:40
Forum: Medium Wave & Long Wave
Topic: Evening Asia reception on Loop Antenna
Replies: 1
Views: 86

Evening Asia reception on Loop Antenna

A brief listen of recordings on 13/03/2020 between 19:55 and 21:02 yielded, clear identification of CRI 1521 at 19:55 to 20:01, Radio Free Asia on 1557 and HLAZ on 1566, plus Asian pips on 972 and 1143. Between 2050 and 2058 Taiwan on 1557 and HLAZ on 1566 were peaking quite strongly and very weak p...
by daveB
12 Mar 2020 23:32
Forum: Antennas
Topic: Wideband shielded loop antenna project
Replies: 7
Views: 2586

Re: Wideband shielded loop antenna project

Hi Simon, It is the pre-amplifier characteristics. I would expect the Wellbrook and similar loops are designed to avoid pick up of strong VHF signals - to avoid messing up the inter-modulation figures. At VHF it acts more like a full wave loop and with the LNA board from ebay if has a surprisingly g...
by daveB
11 Mar 2020 12:15
Forum: Antennas
Topic: My new FM aerial
Replies: 12
Views: 329

Re: My new FM aerial

Hi Peter,
An interesting aerial - if you could supply the dimensions I'd like to model the antenna characteristics to see how it performs - it ought to give a better F/B ratio than a standard 4 ele array.
by daveB
10 Mar 2020 12:20
Forum: Antennas
Topic: Wideband shielded loop antenna project
Replies: 7
Views: 2586

Re: W/band shielded loop antenna project - latest

The home built balanced loop amplifier has died with no obvious problem - it first started operating intermittently. Testing gave no obvious answer, so to save time I replaced it with the original e-bay circuit board yesterday when there was a clear spell and no wind. So now I've been able to carry ...

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