CQ-DATV issue 49
Author: Trevor Brown; Ian Pawson
Date: 2017-06-28T23:00:00+00:00
Description: DATV magazine from dotMOBI
Publisher: dotMOBI publications

Table of Contents

Production Team

Production Team

Contributing Authors

Editorial

TV Amateur

Sample Contents

DATV News

Broken DX record!

Amateur Television Quarterly

Micro corner

The Node MCU module and its BASIC programming

DCC 2017 Flyer
An FM TV transmitter using the HB 100
DKARS advert

Write for the CQ-DATV Magazine

CQ-DATV NEEDS YOU!
Guidelines
Writing
Images
Intellectual property
Language
Payment

DATV-Express Project - May update report

DATV Express advert

Information

About this eBook
External links
Legal Niceties (the small print)
Copyright
Notice to Contributors

Coming up

CQ-DATV 49 Credits

Production Team

- Terry Mowles - VK5TM
- Ian Pawson - G8IQU
- Trevor Brown - G8CJS

Contributing Authors

- John Hudson - G3RFL
- Ken Konechy - W6HHC
- Mike Stevens - G7GTN

Please note: articles in this magazine are provided with absolutely no warranty whatsoever; neither the contributors nor CQ-DATV accept any responsibility or liability for loss or damage resulting from readers choosing to apply this content to theirs or others computers and equipment.

Editorial

Yes it is nostalgia time. Some of you may be old enough to remember the transmitters utilizing gunn diodes (a semiconductor electronic component, with negative resistance of the 70’s. These transmitters were in large part spin off’s from the Soflan motion detectors with horn aerials and the gunn diode in a complete package, these motion detectors seemed to be at every rally stall, but alas dried up some years ago. If you modulated the power rail with a video signal they made excellent low power 10GHz TV transmitters.

The receivers were a little more complex in that you required a way of mixing the signal down to an IF frequency often around 50 to 100 MHz and then an FM IF strip and detector to recover the signal. But fortunately these units were soon followed on the same stalls by FM TV receivers for Satellite TV using KU band LNB’s that could in some cases, be converted to 10GHz with a change of Puck. This did not work for all LNB’s as some had rather selective filters in the front end.

The Marconi blue capped LNB marked the start of this technology in the UK. Now a new motion detector is here, the HB100, and they are moving around on EBay for just a few UK Pounds and outperform the old gunn diode technology is both power and stability, alas they don’t come complete with antenna, but John G3RFL is on the case.

In the last issue he used one as part of a frequency counter and in this issue has pressed one into service as an FM-TV transmitter. It would seem others are on the same wavelength so as to speak, with dish feeds and horns and even a lamp shade aerial to really get some DX capability out of these inexpensive units.

Talking dish feeds does anyone remember the penny feed which was a way of illuminating a dish from a WG 16 wave-guide, well that UK coin long since passed into obsolescence and due to the poor design of the Euro, we are reliably informed it is not a direct replacement due to a lack of foresight at the European Central Bank.

While on the memorabilia trail, our Facebook site CQ-DATV has had one or two outpourings on the old 1980’s TV handbook written by our very own Trevor assisted John Wood (http://cq-datv.mobi/handbook.php), like all books the circuits date and chips become obsolete, but interesting to see the technology of the times which does have a habit of spawning new ideas. The TV handbook was part of a series of several, books from TV compendium and Micro and TV projects, which only existed in print format, but never the less they do exist and if you would like to see more of the same we could investigate getting the rest of the series scanned and available for electronic download.

Staying with the RF side of things Ken W6HCC has updated his TV DX contact list and presented it in this issues. Nice to see that ATV is still alive and populating our airways and the path lengths that can be achieved. Ken has also sent in his DATV express May edition report, so plenty to read up on.

Just so our magazine is balanced as we know you don’t all engage in RF transmissions due to low QTH’s and 20 degree gardens we have our usual Micro Corner and this time its Mike G7GTN’s turn to add to our growing internet repeater using the Node MCU module and its BASIC programming.

Trevor kicked it off with control via I^2C of the Transmitter on-off controls, cross point switching and a rotatable receive aerial and this time Mike has added audio idents, well you did not expect Morse code did you, this is the 21st century and you can only push nostalgia so far, so its speech idents.

It may have escaped your attention that this is CQ-DATV issue 49 and the next edition CQ-DATV will mark 50 issues (half way to our centenary issue). With more than a quarter of a million total downloads, we feel we are supporting the ATV community worldwide! But it might not have escaped your attention that this demand is being fed by some very familiar faces and we would like to see some CQ-DATV contributions from other readers, even if it is just a photograph of your shack or something you built that did not perform and we could help with. Let’s see if we can celebrate our half century with a bumper issue. As usual all copy to editor@cq-datv.mobi. Please sit back and enjoy CQ-DATV 49.

CQ-DATV Production team

This magazine was created using :

TV Amateur

Sample Contents

TV Amateur is a German Language ATV Magazine It is published 4 times a year and if you would like to subscribe go to http://agaf-ev.org/

DATV News

Broken DX record!

Hams in England have broken the 200kM distance record using 146 MHz RB-DATV.

Known Digital-ATV DX Records
updated 2017-06-01 by Ken W6HHC
24 GHz
124 KM | JA6DME & JA6EES | 2011‐11‐12
Locations Mont Ten‐Zan and Mont Ge‐Zan
10 GHz
450 KM | HB9JBC & F4CXQ | 2005‐06‐21
Locations JN40CT (Sardinia) and JN12OH (Spain)
93 KM | G8GKQ & G8GTZ | 2016-07-05

H.264 video - DVB-S protocol at 333 KSymb/s FEC=7/8. G8GKQ used RPI and DigiThin at 250 mW. G8GTZ used PIPO and DATV-Express at 3W.

Locations IO80WP (Povington Hill near Lulworth) and IO91GI (Walbury Hill)
32 KM | G8GKQ & G8GTZ | 2016-06-23

H.264 video - DVB-S protocol at 333 KSymb/s FEC=7/8. G8GKQ used RPI and DigiThin at 200 mW. G8GTZ used PIPO and DATV-Express at 5W.

Locations IO91JA (Lane End) and IO91JH (Hannington)
5.7 GHz
341 KM | JL1BLF & JH1GED | 2011‐08‐06
Locations Mont Chokai‐san and Mont Kashimayari‐gatake)
2.4 GHz
~ 1000 KM | OR4ISS to IØKPT (one-way) | 2014-03-08
~ 1000 KM | OR4ISS to IK1SLD (one-way) | 2014-03-08

Initial DVB-S protocol live video transmissions from HamTV in orbit aboard ISS SR = 1.34 MSymb/sec and 2.0 MSymb/s using SR-Systems exciter & MPEG2

Locations Orbit to Matera, Italy and also Orbit to Casale Monferrato, Italy
252 KM | JA6SPI & JA5MFY | 2009‐11-03
Locations ??
1.2 GHz
440 KM | G4KLB to G1LPS | 2010‐10‐11
Locations IO90BR and IO94EQ
(tropospheric ducting ‐ one‐way DATV)
419 KM | G4KLB & MØDTS | 2010‐10‐11
Locations Bournemouth, England and Yarm, England
(tropospheric ducting)
379 KM | VK3RTV(RPTR) & VK7EM | 2011‐02‐23
Locations Mount Dandenong, Victoria and Penguin, Tasmania
(operators VK3BFG, VK3DQ , VK3WWW and VK3TRX)
252 KM | JA5GYU & JA6JNR | 2009‐11-03
(1 Watt)
70 CM
696 KM | F1FY to G8GTZ | 2013‐09‐24
(DVB‐S 2MS/sec FEC=1/2 ‐ ‐ one way reception)
696 KM | G8GTZ to F1FY | 2013‐09‐25
(DVB‐S 2MS/sec FEC=1/2 ‐ ‐ one way reception reported by FM)
Locations IO91KH (near Basingstoke) and JN16VB (near Roanne, France)
600 KM | DBØTAN (repeater) to F9ZG | 2014-11-28

DVB-S - one-way DATV - Tropospheric ducting (signal 25 dB S/N over ca) Locations Wasserkuppe (Hesse state, Germany) to IN99KC (Normandy, France)

528 KM | G3PYB & F5AGO | 2013‐09‐24
(DVB‐S 2MS/sec)
Locations near W YORKSHIRE and JN06DP (near Poitiers, France)
501 KM | W4HTB & WB8LGA | 2014‐07‐26
(DVB-T QPSK FEC=1/2 2 MHz Bandwidth) - Tropospheric ducting
Locations Bowling Green, KY and Marengo, OH
235 KM | G8GTZ & F9ZG | 2016‐06-12
H.264 video - DVB-S protocol at 125 KSymb/s using DATV-Express w/ 19-ele yagi
Locations JO00HU (Fairlight near Hastings) and IN99KC (near Cherbourg)
121 KM | KH6HTV to KØRZ | 2011‐11-21
(video resolution HDTV 1080i ‐ protocol ITU‐T/J.83B QAM‐64 ‐ one‐way DATV)
Locations Cheyenne, Wyoming and Boulder, Colorado
144 MHz
294 KM | G0MJW/A & G8LES | 2016-12-29

tropo-ducting - H.264 video - DVB-S protocol at 125 KSymb/s with DATV-Express and 9-ele yagi at GØMJW. G8LES also used DATV-Express with 10-ele X-yagi.
Both produced 25W ERP. - on 146.5 MHz - UK temporary band allocation

Locations IO83RO (Winter Hill) and IO91LC (Four Marks)
281 KM | G8GTZ & G0MJW/A | 2016-12-29

tropo-ducting - H.264 video - DVB-S protocol at 125 KSymb/s with DATV-Express and 9-ele yagi at G8GTZ. GØMJW also used DATV-Express with 9-ele yagi. Both produced 25W ERP. - on 146.5 MHz - UK temporary band allocation

Locations IO91KF (near Basingstoke) and IO83RO (Winter Hill)
237 KM | F3YX to F9ZG | 2011-11-09
DVB-S protocol at 1000 KSymb/s using modified SR-Sys MiniMOD (one-way) on 145.0 MHz experimental license 5-Minute max
Locations JN18AP (near Limours, France) to IN99KC (near Cherbourg, France)
195 KM | GW8VPG & G8GTZ | 2016‐12-11

DVB-S/H.264-video protocol at 333 KS/s - GW8VPG using DATV-Express w/ 9-ele
G8GTZ also used DATV-Express w/ 9-ele yagi on 146.5 MHz - UK temporary band allocation

Locations IO81LS (Blorenge Mountain in South Wales) and IO90JO (Isle of Wight)
50 KM | MØDTS & G1LPS | 2015‐02-21
H.264 video - protocol DVB-S at 333 KSymb/s using experimental DATV-Express on 146.5 MHz - UK temporary band allocation
Locations North York Moors, England and Spennymoor (County Durham), Eng
50 MHz
64 KM | G8ADM to G8LES | 2015‐02-10
DVB-S protocol at 1.133 MSymb/Sec with FEC=3/4 (one-way) on 51.2 MHz using 200W avg Pwr Out and BW approx 1.5 MHz
Locations North of Harrow (IO91TO) to North of Alton in Hampshire
See more details at www.von-info.ch/hb9afo/records/recordse.htm

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Amateur Television Quarterly

USA $27.00 year, Canada / Mexico $27.00 year DX $37.00 year (US $) Cyber: $15 year.

Published by ATV Quarterly Visa, M/C, AMEX PayPal via Cheques or Money Orders to Internet: www.atvquarterly.com P.O.Box 1594 Crestline CA 92325 email: wa6svt@atvquarterly.com tel (909) 498-6887

By Mike G7GTN

The Node MCU module and its BASIC programming

Due to a lack of 'elbow grease', this article is held over to the next issue.

In CQ-DATV 48 (http://cq-datv.mobi/48.php) we looked at the HB100 10GHz exciter, that is used as an inexpensive door radar to detect people and open the door. For this issue I thought we would have a look at pressing one into use at a 10GHz FM TV transmitter.

The HB 100 radar unit

The way to FM modulate these units it modulate the power rail supplying the oscillator rather like we used to do for Gunn Diodes. This modulator design was originally developed for such a purpose. The video is first passed through a CCIR 405 pre-emphasis network that reduces the low frequencies so that the higher frequencies deliver more modulation and hence more power into the FM side bands, to combat chroma noise, a well documented FM TV problem. CCIR 405 de emphasis is part of all FM TV receivers, so if we get the pre emphasis cure correct, then the de-emphasis cure will present a flat video response, with a reduced chroma noise level than flat response modulation would deliver through an FM modulated transmitter -receiver chain.

FM CCIR 405 pre and de-emphasis

HB 100 Video Modulator

Audio is applied to a simple CA3140 op amp which has a stage gain of 10, set by R3 - R4 to 10k - 1k and then used to modulate Q1 (BC108) sound sub-carrier oscillator by driving two 1n4001 diodes which are behaving as variable capacitors. The oscillator is set to 6MHZ by C5 C6 and L1. The video and audio sub-carrier are then combined to modulate a BC547 which provides the necessary current gain required to drive the HB 100 which draws about 30mA from a 5 volt supply, R24 provides fine tuning of the HB100 frequency, by adjusting the voltage that is video and audio modulated..

Test Signal having passed through CCIR 405 pre and de-emphasis

Having now tamed the HB100, got it on frequency and managed to video modulate it, the next stage has to be getting interfacing it to a suitable aerial. Research took me to http://f6hcc.free.fr/10ghz.htm and Jean’s work, where he placed the unit at the focus of 60 centimetres offset dish. The HB100 module “illuminates” the full surface of the parabola and the gain is high (about 30 dB). Having done much work with dishes, it is important to illuminate the full surface of the dish and not over illuminate where power is wasted.

RF Polar diagrams for the bare HM100 unfortunately not a perfect cone but for a small shallow dish requiring 120° might get a reasonable illumination.

Jean F6HCC’s solution might also need a little weather proofing

PA1SDB’s centre fed IKEA Lampshade

But there were other solutions on the net and this elegant solution by Peter PA1SDB uses an IKEA lamp shade which just happens to be a parabola.

The HB100 was placed with the two transmitting antennas in the dish of a dish. because the antennae are on the edge of the HB100 print. The maximum radiation, the focus point, was found by measuring the field strength at a distance of 8M with a 1N23C diode detector.

The other problem is that the dish also focus the sun light and heat onto the centre and mounting sensitive electronic equipment there and also equipment, like the HB 100 that can change frequency with heat can be a problem. You might have guessed it's June and we have had a couple of warm days in the UK with a forecast of more to come and I am in a reflective mood over a cold beer in the garden.

So to try and bring something new to the party, I opted for a horn antenna. This was cut out of a simple piece of 22 SWG aluminium purchased from PlumbBase.

Template and cut out horn

Once I cut out the shape in my carefully calculated template, it was a simple fold into the horn, my geometry seemed to work and the basic horn took shape.

It then needs the edges sealing together, never the simplest of operations for small units. I have soldered them together in the past, yes you can solder to aluminium. You need to clean the joint well, immerse the job in an oil bath, scrape the surfaces again and then solder them while still immersed in the oil bath. You need a powerful soldering iron, that delivers heat, as the oil bath has a cooling effect. For this task I was clearly going to have to come up with a different solution.

Johns prototype HB100 Horn

I went for gaffer tape for the strength and lined the inner joints with silver window alarm tape, something I might revisit later.

The last problem was interfacing the horn, I did consider connecting a semi rigid coax to the HB100 and then using the other end to fashion a wave guide probe for adding to the horn, but for the time being I mounted the HB100 inside the HORN on two bolts I did not cut the horn out just drilled two holes so I could run some gain measurements which were a little disappointing in that I initially measured a gain of 10dB and this had side lobes, but 20dB down.

So perhaps the dish solution might be the way to go as it delivered a 20dB improvement over my simple horn. Watch this space!

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DATV-Express Project - May update report

By Ken W6HHC

The DATV-Express project team has officially slowed down to “back-burner” mode.

Art WA8RMC reported increased attendance (maybe 150 hams) for the ATV forum sessions at the recent “Dayton Ham-vention” at the new location in Zena Ohio (right next door to Wright Patterson Air Base). Art reports good inventory on the DATV-Express boards.

Ken W6HHC continues to test-and-learn the terrific DVB-S DATV exciter Portsdown Project that is based around RPi-3 and the RpiDATV software of Evariste F5OEO (modified by BATC Portsdown team). Ken’s test set-up is using the (optional) DATV-Express board as the modulator (instead of the normal Portsdown modulator board). Ken has succeeded in transmitting video:

- MPEG-2 encoding with Pi-CAM

- H.264 encoding with Pi-CAM

- H.264 encoding with NTSC camera via EasyCAP video capture

- Test patterns via JPEG file

Block Diagram of Portsdown/RPi-3/DATV-Express using either Pi-CAM or EasyCAP or even JPEG file as video source<

Charles continues to take a break from the DATV-Express efforts and is involved with with the team working on the USA Phase 4B geosync satellite project that will use DVB-S2X protocol primarily for data transmission of voice, JPEGs, and TCP-IP. Charles mentioned that there is no announced launch date for the Phase 4B satellite, yet.

Future DATV-Express Project Reports are expected to be quite short for the rest of 2017.

“Project speed set to back-burner”….de Ken W6HHC

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