Al, K2UYH, will be working on the 432 and above EME Newsletter this weekend. Send your news, especially about the amazing 3cm CW contest activity and any technical items to him at alkatz(a)tcnj.edu
Previous NL can be found at http://www.nitehawk.com/rasmit/em70cm.html
73 Peter G3LTF
WA6PY was QRV in the 3cm EU-Dubus EME Contest and QSO'd:
9A5AA DL7YC ES5PC HB9BHU HB9Q HB9SV JA4BLC OK1CA OK1DFC OK1KIR OZ1LPR PA0BAT
PA3DZL SP6JLW VE4MA.
I was struggling with fining Moon to the west due to the sudden shift of EL
readout by 4 deg and close proximity to the Sun. I am using MAB-25 absolute
encoders. I had this problem before. I will have to find out what's wrong.
Finally when I was able to find the Moon I heard and QSO'd JA4BLC.
Next day I heard very strong signals from G3WDG calling someone. When I
tried to call Charlie TWT PSU started to trip off. It was 102 deg F = 39C
outside and in my shack was 45C. I had little more than 1 hour of the EU
window left. Due to extensive heat I decided to go QRT instead of debug the
When I started to operate contest, sequencer in my transverter didn't switch
to TX. I found faulty SMD 1206 resistor and another cold soldering on the
sequencer board. This problem took good 30 minutes. My 10 GHz transverter
was built 1995 and it is for many years mounted outside on the dish. The
only modification I made many years ago was to replace Xtal oscillator chain
with PLL driven by TCXO and DRO based VCO. I think I have to get it on my
bench now and carefully check for potential problems before ARRL EME MW
VY 73 Paul WA6PY
A while back Mike W9IP gave me a link to download a update that allowed me
to be able to update my keps online, but my computer crashed and lost it. I
will back it up this time. Does anyone have the link ? I checked on the
update page and didn't see it.
Thanks and 73
Anyone wanting a DCI pass band filter for 2m or 70cms?
There are a couple on a UK radio for sale website priced at 140 pounds each.
Just 'google' the following - G3CWI Online Fleamarket and then put 'DCI' into the 'enter keyword' box.
I've nothing to do with seller but I know that they are in demand.
We arrived yesterday in JP89. But the campsite was crowded so we havn't got
electrical power, the Internet was on and off, it was rai ning dogs and
cats and it was very windy. So there was no activity possible.
Sorry for those who waited for it.
Today we arrived in JP88. Conditions are ok here. Tomorrow morning I´ll set
up the antenna, if weater permits.Moonrise here will be abt. 10:00 UTC.
Keep the fingers crossed.
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Bob, sounds like someone in your neighborhood has put up a wireless weather station like a Davis Vantage Vue or other unit.
Sent from my Verizon Wireless 4G LTE Droid
On Jun 27, 2017 4:59 PM, Bob Atkins <ka1gt(a)hotmail.com> wrote:
> I'm just putting my 432 eme antennas back up, having installed motorized drives for Alt, Az and polarization. The antenna (2 x 29el yagia) has been down for about 6 months. While testing the Rx I found a couple of problems.
> (1) First is I'm getting a 140ms burst of noise every 18.75 seconds. Analyzing it, it's a short burst of digital data (coded as brief 5-10 cycle bursts of 30kHz modulation). It's spreading all across the band and originates at 433.95 MHz, so I assume it's a bad ISM transmitter somewhere in the area. It appears to be real and not due to preamp or receiver issue, since it's still there with no preamap and a 3dB line loss. The fact that it's as regular as a Pulsar suggests it's some sort of automatic telemetry device(?) rather than a garage or car door opener. I see quite a few ISM signals pop up in the 433.9 region, but only this one is regular and spreads out all over the 432-435 region.
> My question is how resilient digital modes (JT65) are to this type of QRM. The pulses are quite easily audible (maybe 5-10dB out of the noise)? Noise blanker has no effect since they are relatively long (140ms). It's annoying but if it's not going to significantly degrade performance, I can live with it. I will try to locate the course of course, but previous attempts at finding the source of QRM haven't usually been successful.
> (2) The other odd thing is that, based on sun noise, the beam pattern of the two yagis (horizontal stacked) seems to be about 5 degres off boresight in the horizontal plane. I'd never noticed this before, but I'd never had the ability to remotely sweep the array across the sun and take measurements. The antennas are physically aligned well, have identical (within a few mm) length feed lines of the same coax from the same spool and the power splitter is symmetrical to within a couple of mm. I wouldn't expect 100% perfect boresight alignment, but 5 degrees just seems like a lot when the beamwitdh of the whole thing is around 15 degrees.
> Any thoughts? I'll try switching around feed lines etc. to see what effect that has, but is there something I may be missing. I'm no antenna expert.
Like Peter and Sam, I made a special effort to get my station working on 10G RX for the DUBUS weekend. It is a Channel Master/Andrews 2.4M offset dish with a F1OPA preamp. This gives 1.1dB moon noise and 14.1dB sun noise. Heard on CW OK1KIR, OZ1LPR, HB9Q, IK2RTI, SP6JLW, PA0BAT, DL7YC, and DB6NT. Detected WA3LBI & G3WDG on JT4 but had finger trouble with WSJTx so couldn't decode them.
Already I have resolved a mechanical problem with the dishes autotrak and I am aiming to get a 15W PA installed at the feed.
I designed the mabmpu board which supports hh-12, mab25, ets25, mab28 absolute encoders and makes them appear as US digital a2 encoders on the SEI bus using the PIC firmware and hardware interface. Each mabmpu board supports one encoder. The sei bus supports up to 15 encoders on the SEI bus. However, the various controllers have limits based upon their design. Oe5jfl, f1ehn, and drztrack support 2 encoders, Raztrak supports up to 15 encoders. Mabmpu board has been verified with the forementioned controllers.
Mabmpu boards are $45/each usd plus shipping (not including the encoder).
Sent from Samsung tablet
Ed and others interested:
I've bought several different encoders at:
Not the cheapest, but very solid and well made. I've had no trouble in
nearly 30 years. Sales people are knowledgeable and good to talk to.
Shipment easy and reasonable.
Any "box" that reads 5 v quadrature signals and can set the number of
quad crossings per revolution in some terms will work. I get encoders
with an index signal because I use relative encoders. But if you have a
stop or home, index not needed, and your counters can be reset on boot.
Absolute encoders = $, although there are some new magnetic types with 2
deg accuracy or a little better.
Mind the rf, good grounding, metal enclosures, etc etc. Elevation best
done with a simple weight on the shaft and a completely sealed box. USD
also has drivers available for long cables as well as counter output
chips. My counters are read at 100 feet from the antenna.
Good non-hunting tracking.
Dr. Don Latham
PO Box 404, Frenchtown, MT, 59834