Posts by PA1EW

BG0AUB Hello Zhaofeng, the use of a conductive support, diameter < 0.1 wavelenght, INSIDE a helix is perfectly OK!. SWR may change a little bit, but will be good. The helix construction shown by G4SDG on the 1st picture in the other thread "DIY Helix for 2.4 GHz uplink . Can I use 5mm copper tubing?" is a very good example how to do it, in my opinion. See also the examples and explanation from G8AWB in the same thread.

You can use 10mm x 10mm square aluminum support tube which is light and strong.

Use only a few (nylon/teflon) vertical supports, exactly as seen in that picture and do not use any other support fixing the helix wires. This is to avoid degradation of the beam pattern.

I have written a "How-To-Construct a helix" document with a lot of practical information, that I can provide to you (and any other interested)!.

You probably know that this type of helix has less gain than a small offset dish with a small helix- or patch feed. My 1.0m wide offset dish with dualband helix/LNB-feed is putting out a very nice signal to QO-100 , but smaller dishes working equally good.

73 s Ed PA1EW

Hi Zhaofeng,

Many thanks for the first QSO with you !. The IS0GRB websdr usually is working OK, so I assume that you might have local internet connection problems?.

Nice helix that you are using now. But, perhaps there is some negative effect from the reflector not in the correct position (not 90 degrees angle) due to the weight of the long antenna. Please see the picture with a better solution how to construct the antenna/reflector mounting. See you soon back on QO-100

73 s Ed PA1EW JO20UT

df2et Hi Florian, sorry to hear about your problem with the MKU.

Question: are all frontpanel LED's OFF or do these light up - except for the RF power?.

In case of the 2nd situation: Once I was testing a new H2010 Ultraflex 10 coax cable with inferior N-connectors that resulted in a SWR-shutdown of my MKU2424A. If this is the case with your setup, you could try other cables/antenna or use a suitable dummyload to see if the up-converter works properly.

Another hint is perhaps measuring the bias-current with the converter just powered 13.5VDC - no PTT - no RF drive = 135mA, with PTT - no RF drive = abt 900mA

Also, checking for presence of a correct PTT signal could be wise.

Good luck !!

73 Ed PA1EW

This is my version (shown before in other subject). This PP cover will last for some time and also has a good drain...

The same solution working great as well with a dual-band feed helix-LNB.

73 Ed

Hi Guntram,

You also may optimise the feed position by observing the obtained TP- noise floor. Just maximise it, this is well visible during adjustment.

73 Ed

Hi Stef, just a thought: the dielectric lens seems not fully inserted. Try to make it fit and push it further in. Good luck!

73 Ed 9A/PA1EW/P

So, finally found my lost Jetson space antenna on planet Earth...😁

73, Ed. 9A/PA1EW/P

The portable setup working nicely abroad as well 😁. Made several good contacts as S57/PA1EW/P from Bled Slovenia JN76bi.

The Dishpointer Pro app proving to be very usefull in the “forrest” campsite.

73 Ed

The last picture did not fit in anymore(?). So, I'll show it here again.

I have added also pictures of the latest status with improved mic-input to the FT817ND (lefthand side input via ethernet cable). This is much more convenient...

73 Ed PA1EW/P

Tnx Heiner!. I am very happy with the setup. As expected the Kuhne MKU upconverter is perfect for this purpose and the Helix-dualfeed does also a good job. There is a RF-splitter in the box that will be used to connect to a SDRplay RSP2, but not used here to keep the setup simple as can be seen.

Hope to work you and many others during my upcoming vacation when I will take the portable station along.

73 Ed

First field test at a demonstration last Friday at our VERON Maastricht Radio Club with the portable QO-100 full-duplex setup was very succesful.

Initially tuned the 70cm RX to 435,800MHz (EB-frequency 10489,800MHz) and the beacon could soon be received with a clear and strong signal.

Clear view to the sat with 20W from the MKU2424A into the 60cm offset dish producing respectable Up/Downlink signals. Even just on battery-power!.

Fellow HAMs were surprised about the very good quality, like a local repeater hi,hi.

73 Ed PA1EW/P

i2NDT Hello Claudio. The (very old) box is made out of a lightweight "plastic" and was available many years ago at a local electronics shop. I am not sure if this still can be found.It was unused by me for a long time, but now I finally found a good use for it...!.

It measures 22 x 22 x 31cm.

73 Ed

DL5CN Hi Andreas, tnx for showing. Some nice ideas here with counter weight for the dish and a sunscreen for the laptop. The add-on table to the tripod leg is great .

73 Ed

Work-in-progress on the plastic "Portable Box". Fitting of the 144MHz driver (Yaesu FT817ND) and 435MHz IF-receiver (Kenwood TM-455E) on a metal sub-frame.
Some smaller parts, like Bias-T, splitter and attenuator, will be placed inside as well.

73 Ed

DD0KP Hello Heiner, Looks like a great solution!. Though, I am curious about possible extra attenuation to the 2.4GHz patch radiator from the PVC material?. I recall reading some negative reports about PVC for this use.

When possible, please tell us what you measure without- and with this PVC cap.

Thanks!.

73 Ed

DL5RDI Hi Johannes, thanks for testing and sharing this useful info !.

Do you refer to the Leo Bodnar Dual-GPSDO or the mini-GPSDO with single output?.

73 Ed

A75GR Hmmm..., I was already wondering about heating up with transparant covers and so it seems to be a real challenge with these temperatures

Good luck with the protective cover as you describe.

Anyway, it is an impressive construction that will give good signals over QO-100!.

73, Ed PA1EW

df2et Hi Florian, well done!. The new installed reference input connector looks really good.

I did not open-up my modified converter yet, but thanks to your clear pictures I can see how the two side halves are separated. So, only unscrewing the 2 lower frontpanel + 2 backpanel screws will make the sides to separate, I guess?.

Anyway, I am very happy with the modification as the standard stability, without external reference, seems sufficient for most work. Hope that Kuhne will provide soon some information about this extra feature. I will probably make use of it later.

73 Ed PA1EW

I want to present my design for a single-dish portable station as described below and partly shown in the pictures. For me it should meet the following requirements:

·       Easily detachable construction (transport by car)

·       Single offset dish 60cm, dual band feed

·       Stable tripod mounting

·       Comfortable adjustment of dish heading

·       Compact “radio-box” to carry two full-duplex transceivers + SDR

·       12V operation (battery) possibility

A new adapter bracket (picture 1) was constructed to mount the Triax 64 dish in a stable way to the tripod pan-tilt head. The dish's own (elevation)adjustment is fixed and not used. Another bracket (left side in picture 4) is added to carry the plastic box with Mini-GPSDO 27,841846MHz + 30MHz low-pass filter + battery pack 5V.

As my modified Octagon LNB was readily available to be combined with the 5,25 turns LHCP Helix, I choose this for the moment above the patch-feed to be used as dual feed. The Helix/LNB mounting has been improved from the quick-and-dirty tape-construction to the detachable- and adjustable Helix-reflector mounting as shown in picture 2 & 3.

The construction allows also for LNB skew-adjustment rotation at any time. Releasing the two wingnuts (pictures 2 & 3) on the sides will then allow for LNB –focus adjustment, the Helix reflector is moved too. The Helix reflector is held in place also by the front-section of the Octagon LNB.

Last item to be finished is a compact housing for the FT817 (144MHz TX driver) and a TM-455E (435MHz RX). The modified MKU2424A (=B) up-converter will be placed on top. A compact 13.8VDC/22A SMPS supplies the power when 230VAC is available, when not, a 12V gel-battery could be used. Hook-up for SDRplay RSP2 is also foreseen. Hope to work you soon via QO-100 with this portable station!.

I am curious who has similar- or totally different portable constructions, please let us know and show.

73 Ed PA1EW/P

om0aao Hi Viliam, when looking at the middle photo with the assembled patch, I can add two more things that possibly affect performance:

• grounding contact of the N-connector body. It seems to be on "stand-offs" and would be better when attached over a large contact-area
• the black isolating/support (material?) in between the radiator and reflector may cause degradation. Small Teflon bushings would be better perhaps.

73 Ed