Month: September 2015

Practical Wireless 70 MHz contest

The popular shortwave and ham magazine Practical Wireless runs a 70 MHz contest once a year. The contest attracts a number of entries from all around the country, including one keen team who climb Helvelyn in the Lake District (M0BKQ/P). The entry from M0TAZ/P didn’t include a 900m accent to the top of a mountain, we operated from the JO01 Kelvedon Hatch Secret Nuclear Bunker near Ongar Essex. The location is over 100m ASL and affords nice views over the Essex countryside.

The Setup21159214803_346a15ad19_k

Power Honda 2KW gas powered generator

Transceiver Icom 7100

Mast Racal 12m PU12

Antenna M0UKD homebrew 4E

Linear amp M0UKD 160w homebrew

 

The activity started at 1PM and finished at 5, activity levels were moderate with the first 2 Hrs being the most active. Many portable stations operate 10w or less so the amplifier and 160w did mean we sometime had to listen very hard to get a calling stations details. Sometimes people assume that because they can hear you loud and clear their signal must also be good.

21764052605_373d546013_kThe weather was sunnyScreen Shot 2015-09-28 at 11.10.34, and this must have helped encourage people to operate portable outdoors.

We managed to work 47 stations our best DX being Scotland GM4JR at 454 km and was pleased to work into Wales GC0VPR/P, GW0EIY/P and GW4EVX/P and also the Netherlands PA4VHF.

 

The QSO map pins indicates the location and number of stations worked.

Many thanks to John M0UKD for the use of his beam and 70 MHz amplifier, both worked flawlessly and George M1GEO, Dave M0YOL and Chris G8OCV for assistance with the mast and words of encouragement.

Thanks to everyone who called, and hope to work you again soon 73 Dave M0TAZ

 

Further pictures are available online.

National Hamfest 2015

Its been a while since I ventured out to an amateur radio rally, having been to a few at Pickets Lock Enfield and  Canvey over the years, today saw a trip to the National Hamfest at Newark Showground.

21732946465_acbf088b53_k The highlight for me was the launch of Pinky, a high altitude balloon The SSDV payload callsign PINKY transmitted on 434.575MHz USB RTTY 300 baud 880Hz shift ASCII-8 no parity 2 stop bits. The data stream could be tracked either by direct reception of via the internet. Pinky climbed to around 25KM above the earth before retuning. The payload was recovered by the chase car, some 15 miles South near Grantham. You can read the full report on Andrews blog M0NRD with pictures on how the team put together this successful HAB launch.

 

It was really nice to meet up with some of the exhibitors, and I spent quite some time chatting to the Linear Amp team about their new 1KW solid state amplifier, and their range of 300w solid state VHF and UHF amplifiers.

21111906023_c7cbf2c259_kRoger Banks the MD for Linear Amp UK and Chris Bartram (Design Engineer) demonstrated the new 1KW HF amp and also spoke about the design behind the 100% duty cycle VHF amplifiers.

I also spotted some items that I could afford, less than the £2,000 amplifier… I purchased a drive on mast clamp that would hold a roach pole, and also some mast guy rings that would be helpful in the field. 21110230994_6585798bb3_k

Other exhibitors included Icom, Kenwood and the big suppliers W&S and Martin Lynch. I was looking for the new Icom 7300, but this wasn’t available for display. The outdoor area was  quite poor, with just a few stalls and despite a very large area and unbroken sunshine not many people had decided to private sell.

 

It was nice to see the Camb Hams putting on a special event callsign and working a few in Flossie for the weekend.  Flossie (left with the pump up mast) I understand has reached the end of her life, and is soon to go to the big scrapyard in the sky so this could be one of the last few outings.

21707624136_32e67af03b_z        21112672903_6b5ac59202_z

A rally wouldn’t be complete without a burger and some chips, here you can see George M1GEO and his dad Chris G8OCV (right) eating some of the delightful cuisine.

21707664096_800a57a94c_zOne last thought, I noticed the new super gainer DX 21546093659_6059c9cb49_k

penetrator antenna called the CHAV1…

Works from 3.5 MHz to 440 MHz …

 

 

 

 

 

A joke, well at £149 I would think so…

 

73 Dave M0TAZ

Second 70 MHz contest

21389340019_c7a44b34a8_k

We had some great September weather today for the RSGB 2nd 70MHz contest. We setup a station at the Kelvedon Hatch ‘Secret Nuclear Bunker’ as seen above, using John M0UKD 70MHz amplifier and his 4 element DK7ZB 12.5Ω Yagi. The mast was my 12m Racal PU12 a push up 12m mast, and the location was around 100m ASL. The radio was the Icom 7100, as this provides all mode 70 MHz coverage.

                                        QSO map

QSO Map - 2nd 70MHz RSGB Contest

Conditions seemed quite flat, we didn’t manage to work into Scotland or Ireland but our best DX (as many others) was PA4VHF at 449km. Other highlights were GJ3YHU in Jersey and M1CJN/P in the North York Moors.

A very enjoyable day of operating and testing the new amplifier. Next week, it’s the Practical Wireless 70MHz contest, so lets hope for the same weather and some band openings perhaps? Maybe I’m asking too much

The Claimed Scores are available. Thanks to John M0UKD, George M1GEO, Dave M0YOL and Chris G8OCV for help & company!

70 MHz from Bedsford Park

An afternoon in the sun looked like an ideal opportunity to work some station on 70 MHz. Bedsford park is the highest point around at the dizzy height of 100m ASL. I decided to take the 12m roach pole and Icom 7100 and the slim jim.

The portable trolly, battery and antenna.

21357384560_a979147db4_k

After setting up the radio, powered by a 90Ah leisure battery my first visitor was the local parks patrol. They have recently been kitted out with a look alike “emergency” response vehicle, complete with blue lights and checkerboard markings. We had the usual chat that started along the lines of “Have you asked permission” … (oh this isnt going so well.) I didn’t quite work out why I need to ask permission to sit in the park with a fishing pole and Icom radio, it seemed like the local dog walkers with their poop machines or the kids throwing sticks into the conker tree was just fine but thats another story. He was quite amicable once I told him I was a licensed amateur radio operator, either that or he was just confused by the term.

 

Sitting on the park bench

21357600008_0e239187d3_kAnyhow, after the passing of the parks police enforcement team. I got down to some operating, calling CQ on 70.450. It was great to hear so much activity, and I quickly worked 12 stations.

I managed to work.

M1COI – Henry- Belvedere

G3XFE – Chris – Eastbourne / Tunbridge wells

G8YNC – Peter – Alexandra Palace

G3VSJ – David – Hoddesdon

G4UAQ – Ian – Maidstone

The Slim Jim up 12m on the roach pole.

M0KSJ – Kevin – Chislehurst 21519234286_b96ad94059_k

G3VPS – Peter – East Grinstead

G3RQZ – Peter – J6 M25 Godstone

G8NDL – Ken – Swanley

G8KQA – Roger – East Sussex

G7CRQ – Adam Wallington.

 

 

 

 

 

A very enjoyable afternoon, thanks to everyone I worked 73 M0TAZ

 

DMR radio TYT MD-380 First impressions.

After reading a review on the @essexham website I decided to take a look at the world of DMR and the MD-380 seemed like a good place to start. The radio is available from ebay for around £100 including programing lead, software and delivery ! If you want to purchase from the UK, with support then I would suggest you look towards Taylor Made RF for around £149.

So the basics, the radio is 1w or 5w, 280g weight and is supplied with a 2,000mA battery. You can program the radio with up to 1,000 channels and will operate between 400 and 480 MHz. VHF versions are available, but most DMR repeaters are UHF at this time.

tytera2

If you decide to go down the self service route you will need to register your call sign and obtain a “unique” number. This number will need to be programmed in once you receive your radio, so the addition of a USB programing cable is very helpful.

Once you receive your DMR radio its likely to be unprogrammed and you will need to source a codeplug. These are available from various websites, and due to the number of repeaters coming online they can quickly go out of date.

UPDATE Jan 2016

The structure of the DMR network has changed substantially since I first wrote this article, and many of the codeplugs have become outdated. New codeplugs that reflect the FEB 16 structure can be found at GB7JG and GB7CL website.

The following links have been retained as they may provide updates in the future, at the time of writing the codeplugs are outdated codeplug central .  GB7DD website also contains a great deal of information on DMR including codeplugs.

You may also want to download the programing software and then review the latest firmware versions available for your radio.

You will also need to have a basic understanding of “talk groups” and you will find some information on the protocol to follow.

New to Feb 2016 was the reworking of UK talkgroups. The structure has changed, and all radios will require reprogramming. The new structure is explained in this PDF available from GB7DD website

updated_dmr_talkgroups

 

Its not possible to have all of these active at the same time, and the diagram here explains why. DMR uses two timeslots, so thats one frequency time divided into 2 and you can use 1/2 of that repeaters capacity by using one of the talkgroups.

Activity and repeaters

You can review who is on DMR and the activity levels in near real time and see the signal level and BER that you accessed the repeater. A complete list of DMR repeaters and associated coverage maps can be seen on the UK repeaters website.

First impressions

Excellent value for money, solid construction and easy to read display. Audio reports are good, speaker volume and resolved audio quality are very good. The programing software and USB cable are essential, I had no issues with running these under Windows 10.

Hope to work you on DMR soon 73 Dave M0TAZ

Wire + Tree + Catapult = HF portable

Today I decided to put a wire in a tree and see if anyone could hear me. While portable for a couple of days I thought it would be fun to use one of the very tall trees at the back of the van here. I used a fishing weight and a catapult to fire a wire about 20m up into the tree, the wire then goes from the shack here up into the tree and then back down in a slope. I left the rest of the wire on the reel so who knows what that does to the antenna. It seems to tune well on 80 and 160 with my small portable manual ATU.

Station Icom 7100 and portable  ATU MFJ 901B,

21419034381_c59014d14a_k

Running just 20w into the end fed wire I was able to work M0UKD John, G7UVW Dave and M6RKE Ryan. We decided to use Hellscriber as its a fun “digital” mode, and quite easy to copy even under poor conditions. Its interesting how you can visualise the QSB and multipath on the screen.

Here is a screen shot decoding John M0UKD.

21429132421_f173cd3b0a_k

© 2015 Dave, M0TAZ