VK Logger Ham Radio Forum Archive

Looks great Scott! And thanks for sharing the pictorial steps of your build....it certainly helped!
I decided to purchase a "ready built" LNA from MiniKits as my eyes aren't much cop these days with SMD....and anyway, Mark has all the test eqpt to ensure the LNA is doing what it's supposed to!

Have made up a meter scale to replace the std 50uA one, using a neat program called MeterBasic.
Although MeterBasic is the no-frills free version, it still allowed me to make the scale non-linear despite indications that it wasn't an option.
The full-blown version is called Meter, but to access all its functions you have to purchase a "key" which costs around US$35.

This is my interpretation of Iain VK5ZD's transverter controller.

The HP 6 pole relay was a lucky find on Ebay. My initial impression was that they were a nice cheap option for anyone else considering a project like this. Sadly for the seller but lucky for me, he misjudged the market and I got mine for well under $50. Now, if you can find them in working order for under $150 you are doing well.

The micro is a PICAXE 40x2 running modified VK5ZD code. Panels were made using Galva software, printed on A4 and held in place with contact film.
An interesting project and I learned (remembered) a lot during the construction and software debugging.

Thanks to Iain for sharing his excellent idea.

Now on the air is a compact 1 - 2w 40m SSB transceiver.

NE602 x 2, LM386 x 1, BC548 x 2, 2N2222 x 1, BD139 x 2

The happy coincidence of a 16 MHz VXO and 8.867 MHz ladder crystal filter allows frequency agility with off-the-shelf crystals.

Two parallel crystals allow a wide tuning coverage for a VXO - from approx 7.050 to 7.130 MHz. 3 x IN4004 diodes are used as varactors in this VXO.
An inbuilt L-match antenna coupler for end-fed wires is provided but hasn't been connected yet.

Not a new project but one from 20 years ago that, despite the dust, was found to still work when the right crystal was put in.

https://www.youtube.com/watch?v=fkzrJqK-ChQ

Parts of it were on the workbench....
Some work left to do, but it's up....

The dish had one panel of mesh missing, so until a replacement is found, 1mm Al sheet instead.......

Phil VK4CDI

great to see the progress Phil it will make a big difference ! well done!
cheers mark VK2AMS

Won't work properly Phil with the panel at 6:00, work out your operating schedule for the day and position the alloy panel at the correct operating time for the QSO .....in UTC of course...... You find an enhancement of 8-10dB by doing so.....

Graham VK8GS

Bought 2 of these BWD Model 509A CRO's yesterday at the RedFest. One had an issue with intensity fixed with a pot from the junk box. Other didn't work at all and fault was traced back to a faulty transistor replaced with an equivalent and now works. OK they are only 10MHz bandwidth but still usable. Total cost $15 plus two parts out of the junk box

Adrian

Just testing our new 2m Beacon PLL board from 3XDK, nice job,. Not long and the horrible off freq. chirp that is on air now will be clean and sparkly on freq.!!

Here's my take on a thunderbolt GPS-DO LCD monitor. Case was recycled from a defunct HP sweep generator. Power supply, 6 way splitter and microcontroller fit with lots and lots of room to spare.

My newly-constructed 2.4/3.4 GHz dual-band ring feed. Return loss on both bands is better than 18dB. Sun noise comparisons between a prototype dual-band ring feed and a pair of VK2AES/VK3ES-type cavity-backed dipole feeds on a 1.2m dish indicated that the ring feeds are at least as good. The "radome" is the lid from a Bunning's paint spray can. It has no measureable detrimental effect on the feed's performance.

For those wishing to replicate this feed, here are its key dimensions:

Reflector disc: 64mm dia. (to fit into the plastic lid)
2.4GHz ring: 39mm dia., spaced 15mm above reflector plane
3.4GHz ring: 28mm dia., spaced 12mm above reflector plane

The mounting bracket is fabricated from brass sheet. For the reflector disc I used a piece of 1/16" single-sided, fibreglass pcb. The penetration for the feed line is a 1/4" brass hex-head bolt drilled to take UT-141. Its head is filed down to minimise any detrimental effects on the feed's behaviour.

Each ring's circumference needs to be adjusted for best match at the desired frequency. It is important to keep the two rings as parallel as possible to the reflector plane, and also as concentric and circular as possible.

Now we only need to take one 1.2m dish for these bands into the field instead of two, which is a big plus in the logistics. A remotely-operated RF/IF coax relay system switches the feed to either of two transverters mounted behind the dish.

Chas
VK3PY

.......And my new VE4MA feed for 5.76GHz, jointly constructed with David VK3QM:

Chas
VK3PY

They look good Chas!

CU in the contest

Peter VK3QI

Chas,

re our discussions about isolation between loops etc.

I note that on the RF Hamdesign dualband, dual feed system, has the two feeds are on diametrically opposite sides of the centre of the circle.

And in their 3/5/10 triband unit the 3 loops are mounted 3, 10, 5.

Maybe that is their secret to reducing the coupling effect?

I can see another 5/10 unit on your drawing board!

Cheers

Peter VK3QI

Actually, Peter, my initial dual band 2.4/3.4 feed was a cobbled up replica of the RF Ham Design unit with diametrically opposed feed points. In the photo below you can see the hole in the reflector where the second feed line entered (to which was attached the outer, 2.4GHz loop). The interaction between the two loops was hideous. I then attached both loops to the same feed line as shown in the photo, and it just all worked fine.

I don't know what effect the miss-shaped loop has on the 2.4GHz radiation pattern, but if there is any effect, it must be very subtle indeed as it does not measureably detract from the dish performance (as compared to the mono-band VK2AES feed). If anybody constructs one of these feeds, I'd be keen to learn of their experiences.

As for 5.7 & 10GHz, we use separate 600mm dishes for each band. A new dual-dish tripod mount has been constructed for deployment in the next field day. Pictures of that secret weapon will be posted after the event. The VE4MA feed shown in my earlier posting is destined for that system. Incidentally, the VE4MA dish on a 600mm, 0.4 f/d dish outperformed the commercially-made waveguide feed in its original dish (a "Tsunami" 5.7GHz link dish, also 600mm diameter - see picture below) that we've been using by 3dB on sun noise measurements.

73,
Chas
VK3PY

I have only recently regained my license, after a 10yr hiatus. There are so many more areas to explore now, more than I remember anyway.
I have just completed a GPSDO, based on a Trimble Thunderbolt, with a M1DST monitor and using a distribution amp I obtained cheaply off of fleabay.
Work commitments have me away from home at least 7 days out of every 14, so time to actually work on projects can be limited.
Other projects on the go (and cluttering up the work area) include:

Fitting an Xref-Ft to my FT897 Transceiver,
70cm DVB-T TX,
23cm FM ATV Tx/Rx,
23cm Transverter,
23cm 150w PA,
23cm EME setup,
9cm Transverter,
9cm PA's,
9cm EME setup,
3cm YIG oscillator,
3cm Tx/Rx & PA,
3cm EME setup.

I also have a DATV-Express card and BATC DTX1 to setup in boxes.

Nothing like knowing what you will be doing for a while

73
Andrew
VK4YMB

Nothing if not ambitious, Andrew!

I like your GPSDO. Very neat.

Best of luck with all that.

Andrew,

The GPS unit looks great! 8 outlets. Wow!

Only suggestion I would make, would be to use BNC connectors instead of SMA.

SMA sockets have a tendency to develop poor connections after multiple connections and disconnections of fly leads to the other equipment. BNC on the other hand, is far more reliable. Also note that the majority of HP, Gigatronics, Techtronix etc. equipment tends to standardise on BNC for 10MHz inputs.

Cheers

Peter VK3QI

VK4YMB wrote:
Fitting an Xref-Ft to my FT897 Transceiver,
70cm DVB-T TX,
23cm FM ATV Tx/Rx,
23cm Transverter,
23cm 150w PA,
23cm EME setup,
9cm Transverter,
9cm PA's,
9cm EME setup,
3cm YIG oscillator,
3cm Tx/Rx & PA,
3cm EME setup.

Andrew - Welcome back into the hobby. I did something similar after returning to the hobby and in a short amount of time managed to get all bands upto 10GHz - so it can be done if you focus. I now know what you want 1484MHz for

73,
Wayne ZL2BKC

Thanks for the comments and suggestions.

Peter - That's a good tip about sma, bnc connectors and equipment. The distribution boards I am reusing have F type outputs and the sma adapters I have used were what I have on hand. At the moment I only have two items to connect to the unit and they both have sma inputs. No doubt I will need to use different adapters as I progress.

Wayne - I plan to double the 1484Mhz and use it in my 3.4GHz transverter.

73,
Andrew VK4YMB