AmateurRadio.com

Following my maiden high altitude balloon launch last month of MADHEN Eggsplorer-1 at the World Egg Throwing Championships I have agreed to attempt another launch at this years National Hamfest which takes place on the 25th-26th of September at the Newark Showground.


Once again I will be assisted by the members of South Kesteven ARS and hopefully this time it won't end up splashing down and being lost at sea.

I intend to have a SSDV system running on a Raspberry Pi using the usual UKHAS RTTY protocol and possibly this time a LoRA transmitter which allows faster transmission and higher resolution, however this requires ground stations to use a LoRA receiver, this are straightforward to build. I have done some experiments with the code base developed by Dave Akerman but didn't implement them in the Eggsplorer-1

As to any special payload? Well following the yokes about "Ham n Eggs" following the sending of an egg in the stratosphere, who knows....?


Anyone interested in joining South Kesteven ARS and being involved then contact me via the club website at www.skars.co.uk or our facebook page

One is a Tait T535 2-Channel Mobile PMR which can be converted to amateur 2m operation relatively easily. Details are available on the internet including David Pye's website. I intend to use this unit to set up a permanent APRS internet gateway/digipeater.

While walking around with the Tait I attracted the attention of another seller who had some PYE MX294 units for sale. One was already converted to work on the 25kHz spaced simplex and repeater channels with CTCSS. The other was only partly converted and they came with a box full of spare boards and mounting plates and an original microphone and speaker. I wasn't really looking for any more units but seemed a bargain for £20.

The PYE MX294 was indeed converted and seemed to work fine on the simplex channels, and while it was receiving and transmitting on the repeater channels it wasn't transmitting the CTCSS sub-tone. With some sage information from Ian MW0IAN on twitter it was a simple issue to solve, using the oscilloscope I confirmed the tone was being generated it was the pot controlling the level that was set too low.




The Tait is proving a little more involved. It has a diode matrix board to set the Tx/Rx frequencies which has been set incorrectly. It also had a CTCSS board that was hard-wired in rather than socketed which I have now removed. The information of which diodes to link/unlink is freely available, however I decided to create a small windows utility to simplify the calculation. This is available for download from my website, it is supplied as is and with no warranty.


There are a number of modifications to add multi-channel to this radio by the use of eproms, but I am considering devising an Arduino solution to allow setting of frequencies and possibly selection of CTCSS.

The shack has gained a couple of 'new' radios, one of them look familiar?


It is the Trio/Kenwood TR9500 that I repaired last month for a fellow club member. Having no transmit audio I'd replaced a faulty transistor in the microphone pre-amp. Subsequently it's owner reported it was still misbehaving and locking up in transmit mode.

I'd offered to give it another look but the owner decided to cut his losses and wanted shot of it. He had just purchased a nice new radio at the National Hamfest and was also selling a 2m Trio/Kenwood TR9000 multi-mode set to make some room.

I liked the look of these pretty sisters and got both of them for a very reasonable price, the TR9500 costing just £10 in lieu of the previous repair work. I collected them at the weekend and got around to checking them out last night.


The TR9000 is a lovely compact rig, the case has the odd scuff but the front is in good condition and has cleaned up nicely. I just need to attend to the microphone plug as it wearing the ubiquitous piece of brightly coloured insulating tape. It is fully functional and I made a few contacts on it during last nights 144MHz UKAC. It is nice sounding and seems to have a good sensitive receiver.

The troublesome TR9500 has been back on the bench and connected to a dummy load and my X-50 dual-band collinear and I cannot find anything wrong. The ALC 'issue' I suspected was a red-herring, the audio does cuts out and the S-meter goes to S9 but only when the RF gain knob is turned to minimum not maximum as I'd thought, the same thing happens on the TR9000.

It is entirely possible the fault reported by its previous owner is intermittent (a bad joint, sticky relay etc) It is also a possibility that RF was leaking back in the rig causing it to lock up. I plan to use it in anger maybe during next weeks 432MHz UKAC especially if the receiver proves as sensitive as that in the TR9000. 

As I mentioned the National Hamfest took place recently and since it is local to me I decided to go along on both days. The Friday was by far the busier day with lots of sellers in the outdoor flea-market with a genuine 'buzz' which seemed lacking on the Saturday, there were a lot less sellers outdoors.

The main hall left me a bit underwhelmed, the layout seemed a bit messy and some areas were cramped while others seemed to have acres of spare room. It was also very hot in the main hall especially on the busy Friday, however it was still an enjoyable couple of days and met up with some fellow tweeters and operators. 

My purchases were modest and as well as the usual connectors and cabling I picked up a nice as-new 7A regulated linear power supply, a foot switch, a replacement satellite Quad-LNB, a very sorry looking 70cm linear amplifier and picked up one of those lovely Czech morse-keys for when I brave doing the code!

I also picked up this little 2.4GHz B/W video monitor for a whopping £1 and it works a treat. I have a number of 2.4GHz wireless security cameras (purchased back in 2009) intended for a PC-based PVR CCTV system but the whole PC system proved unreliable so they are sitting idle. This little monitor can receive on the four standand channels and as a bonus runs off 13.8V so ideal for sticking in the car and driving around the local housing estate eavesdropping on other similar cameras - I am joking of course!


The very sorry looking 70cm linear amplifier is a Tokyo Hy-Power HL-60U. I found it hiding away in a box of junk on one stall and after a bit of haggling got it for a fiver! From its appearance I really didn't expect it work, especially since the warranty seal had been broken. I wasn't too bothered about the power amplifier I was far more interested if the built in GaAsFET pre-amplifier still worked.


Getting it on the bench I opened the case, expecting to find it plundered and butchered and was pleasantly surprised to find the insides looked almost pristine. I think the main PA transistor may have been replaced, but while it looks a bit messy the flux resin around its joints looks the same as other areas of the PCB so not sure. It looks slightly different internally to some another photographs I found on line and I have searched the web for a manual and schematic with no joy. Tokyo Hy-Power went bankrupt last year and the website and precious data downloads have all but disappeared.


As it looked intact with nothing missing I connected up the dummy load, power meter and fed the input from one of my Baofeng handhelds. It powered up and was giving 15W out for a measured 3W in with no distortion on the audio, so far so good. However after connecting up the FT-857D and slowly increasing the input power is became apparent that 15W seemed to be about the limit of its output, not the 60W as promised.

Removing the dummy load and putting it on the X-50 antenna I had a listen around for weak stations to checked the operation of receive pre-amp and it worked! Should prove useful for the 70cm contests.

Friedrichshafen “Ham Radio” 2014 Attendance Tops Last Year’s Numbers, Show Emphasizes Youth.

“Attendance at Germany’s annual international “Ham Radio” exhibition on June 27-29 — the Continent’s biggest Amateur Radio event — was 17,100 this year, up from 15,300 visitors last year. This year’s Ham Radio teamed with the Maker World create-it-yourself exhibition at the Messe exhibition center in Friedrichshafen. The gathering attracted some 200 exhibitors from 34 countries plus 300 flea marketers. Ham Radio 2014 placed an emphasis on youth-oriented themes and activities and also honored one of 2013’s major DXpedtions. DARC chose “Creative Amateur Radio — Build It Yourself” as the theme for this year’s show.”

- via ARRL news

Filed under: Ham Radio Tagged: arrl, convention, europe, hamfest