Langstone build thread - join in the fun!

[radiogareth]

Times must be hard in China too, https://www.ebay.co.uk/itm/113707397566 just offered £15 each for 4 of these and it was accepted - free P&P.
Power handling here (but please check for yourself) https://www.teledynedefenseelectronics. ... quency.pdf
Gareth

[radiogareth]

Wow, that's service!! Ordered yesterday, delivered this morning from GREECE!!

And now to the puzzling......control wires ....its got a common terminal (POW +COMM), with 6 others -2 - -7, but it's a 7 pole switch (common central BNC and 7 outlets)......

As supplied, out of the box, its was showing continuity between J1 and IN.....supplying DC (28V) to each successive pin did as I expected - connected IN to the chosen output - you can hear the click as the relay pulls in. So -2 links IN to J2, 3 links IN to J3 etc.....

But how do you select the original J1 - seems its the default position, no voltage at all and that is the default/rest position. Handy that as if I don't power my 'remote select' switch it can still feed my down the garden default antenna.

Its now 36 years old, I wonder how many of its 1,000,000 operations it has left?

Gareth

[G7JTT]

Been looking for a broadband PA of a few watts if possible and came across this device AE618. It's spec'd 50MHz to 1000MHz at around 40dbm and of course eBay has them on a board and heatsink for around £30+

https://www.ebay.com/itm/183884983946

Any thoughts on the suitability for a low power PA for portable hill topping ? It goes without saying filters for each band will be required.

All the best John

[radiogareth]

Looks handy, but what bands are you planning to operate when you get up the hill? 70cms would seem to be a good fit for beam size, 2m at a push perhaps?
This is perfect for 70cms as full drive possible with Lime or Pluto. https://www.ebay.co.uk/itm/433MHZ-335-4 ... 2749.l2649
Mods as per the article in a recnt CQ-TV, plus an output filter easily added https://www.ebay.co.uk/itm/433MHZ-Low-P ... 2749.l2649
Gareth

[g0mjw]

Why a braodband PA John? There are only 4 bands. The RA modules from Mitsubishi give 1-10W (depending on model) of DATV and are available for 6/4m, 2m and 70cm. The lower power ones are not too expensive. There are also other fairly cheap PAs available for each band as modules, kits or designs. https://www.minikits.com.au/electronic- ... amplifiers

I have built up band by band power amplifier / pre-amp combos. By the time you have messed about with switching in and out TX and RX filters for each band it's easier just to have it all in one. They can share a heatsink and case if needed.

Mike

[DL5BCA]

Hi at all,

got my raspi toys today. I still had a modified Pluto - in an aluminum housing ...
First attempts made ... Worked on 70cm over the local repeater.

73 Thomas DL5BCA

[G7JTT]

Just looking at one box solutions, but your probably right by the time I add switching and filters might be better off with the modules all on one heatsink and just DC switch individual PA's. As to aerials the low band 50/70 thinking wire delta loop's made foldable and 2/70/23 Yagi all on one boom with removable elements. There are plenty of design's for 2/70 with one feed point and was thinking have the 23cm at 90' to the other elements so you'd just rotate the beam. The whole idea is to try a bit of DATV SOTA, using low SR and low power but relying on height to get any distance

All best John

[radiogareth]

John, I've been using a 12 element ZL special that I designed around sections 7-9 (discarded the #10th) of a 10m fishing pole. Its lightweight, quick to assemble, has got serious gain and mounts at 6m AGL. Or a bit less, a 6 element yagi that uses sections 6&7 on a 7m pole. It works too.
All the parts for the ZL are 3-D printed and use 2.3 alloy welding rod as the elements.
Message me if its of any interest.

Gareth

[G7JTT]

Thanks Gareth already have some high gain yagi's for operation from the car, what I'm thinking is something lightweight not such high gain and must pack down to a small size to fit in a rucksack. This will be more a fun setup than a serious contest type setup as I'm hoping to leave it in the car (and possibly works van ) so that it's ready to use as and when. At the moment I travel all around the New Forest (for work) and there are some great high spots that would be fun to try. Mind you I'm still waiting for an adaptor to arrive to finish it so can't do anything with it yet anyway's.

All the best John

[radiogareth]

Finally, after all sorts of distractions, i'm back on finishing the packaging of my Portsdown/Langstone. I've been looking at the long pin socket on the back of the RPI since I started wondering how to deal with multiple connections to various pins now and in the future without shorting something out. I think this solves it, in part, by providing separation and multiplication. Each piece of veroboard only connects to one row of pins, after careful filing and relieving of the copper where its near the second row. The two lone pins are for the screen power. The rest may well be soldered and loomed.
A picture speaks a thousand words....
Gareth G4XAT

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