[Moon-Net] Some reference wanted
DW Harms (Dick)
qtc at kpnmail.nl
Mon Sep 30 09:19:35 CEST 2019
Wellcome amongst the crowd of smaller 23 cm stations! Your result is not too bad at all, but are those figures from JT65c or WSJT-X. They differ...
Any way there is certainly room for some advices.
1. Check the illumination of your dish. You can simply do that by measuring sunnoise and move a 40x40 mm alu plate along the edge of the dish. If you see variations in noiselevel, you are overilluminating. If not, you could be underilluminating...
2. For best illumination I suggest a septum feed such as VE4MA, RA3AQ or OK1DFC.
The advantage is that you have seperated TX and RX entries. The LNA should be mounted AS SHORT AS POSSIBLE on the feed, with a good relay in between to increase isolation. The 20-25 dB of the septum is not enough to protect against your QRO hi!
3. Unlike on 2m, a noise figure of below 0,3 dB is strongly needed. 33 dB gain is nice to overcome cable losses (see 4...) but the NF is more important.
4. Get rid of the Ecoflex 15 cable soon as posdible! I have never seen worse cable losses than on this type of cable. Recently I measured 7(!) dB loss on 23 cm, in my 5 m long TX cable... no wonder my own echoes were weaker than normal hi! So, use 10mm Cellflex (like I do now) or better.
5. Trees are nice, but for EME on 23 they are our enemies. Wet leaves attennuate in particular on the RX side, to my surpise not much on TX!
Any way, clear all leaves in the path between your dish and the moon!
I love autumn/winter hi!
6. Last advice is to download EME-CALC, made by VK3UM and still being maintained by his friends (thanks guys!!).
With this software you can check what sunnoise you can expect given the parameters of your station.
Looking forward to our first 23cm QSO Franz. With 100W in a 2 meter dish it should be easy. I worked smaller stations!
73, Dick PA2DW
RIG: K3, TR1296H, all GPSDO locked, 2.4 m dish, 500W at feed, OK1DFC feed with choke, LNA G4DDK
>> Op 30 sep. 2019 om 08:30 heeft Franz (OE3FVU _ PE0WGA) via Moon-net <moon-net at mailman.pe1itr.com> het volgende geschreven:
> Hi All,
> I have been working on my mini 23cm EME station for a while, which resulted last week in the first EME reception and yesterday in my very first EME contact with HB9Q.
> Actually, although I have been active as a Ham since 1975, it was the first 23cm QSO under one of my own calls ever. So: DXCC 1, Grid 1, INI 1. J TX is just 100 Watts in the shack, so
> probably not more as some 40 or 50 Watts at the feed. But before optimizing TX, I want to optimize RX first.
> I have a 2m (US TVRO) Dish and a loop feed with an Ukrainian 33 dB LNA, followed by some 30m ECOflex15, to my IC9700 and WSJTx. I have seen a number of stations.
> What I would like to know what signals I could expect i.e. what other people with a similar, but optimized setup have as signals.
> Following signals I have seen this weekend:
> LZ1DX best -15, I called Ned both sat and sun, but he doesn’t hear me
> DL3EBJ best -20, I called Sunday, but also no joy.
> JA6AHB Best -21, I called Saturday, but alas
> SM6CKU Best -17 on Wednesday, RX only
> SM4CCG Best -24
> HB9Q Best -4, 1st QSO received -14 from Dan
> IK5VLS Best -23
> As I have no idea what I should expect on WSJTx signal strengths with an optimized 2m setup, any info is welcome! I know that my feed is far from optimal, but is that the only flaw?
> Unfortunately, I was not able to spend much time as I had Dutch visitors over the weekend. (Poor planning, hi)
> Thanks in advance for any information!
> Best 73
> Franz - OE3FVU
> (also PE3FVU, ex-PE0WGA, ex-PA0WGA)
> 2m DX Station: 143 DXCC, 48 US States, 38 Zones, 800+ Grids
> 2m DXCC #121 and working on 2m WAS and WAZ
> 144MHz DX stations meet at www.on4kst.com
> Moon-Net posting and subscription instructions are at http://www.nlsa.com/nets/moon-net-help.html
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