Moon-net December 2021

moon-net@mailman.pe1itr.com

107 participants
129 discussions

by Max Mucci, N5NHJ (I8NHJ)

Hi All, Moving forward to the next project. I have 2 each of brand new M2 432-12EME, used few times for EME contacts from my backyard and than stored in the attic. The elements can't be unmounted, therefore shipping can be a bit problematic. The perfect deal is a local pick-up (north Texas) Asking $170 each, plus shipping. 73 de Max, N5NHJ (I8NHJ) one of EL2PP, 1A0KM, JT1Y, E30GA, T77V, TT8MM, T32R, K5K, XR0X, S05X, 4O3T, BS7H, K4M, PJ7E, PJ7DX, 6Y1V, C6ANA, VP5/I8NHJ, ZF2NH, KP4/N5NHJ and...

1 year, 5 months

MKU PA 23CM - 250W

by Paul Andrews

Moonmen, I am preparing to use this Khune 250w amp. The amp has an "ON" pin. Is this really on "on" switch or bias supply? If this is really an "on" switch, I could leave +50v supply applied with RF drive applied and toggle the output with +12v applied to the "on" pin and no device damage. If this is bias, I will damage the amp if +50v is applied with RF drive and no bias. The 1 page user manual is silent on this question. Does anyone have experience with this? 73 - Paul - W2HRO

1 year, 5 months

HH-12 encoder linearity

by Ermanno Ferriero

Hello friends. I am using HH-12 absolute encoders for azimuth detection. I have 2 HH-12 available and I have made some measurements to check linearity from zero to 360 degrees. I found a deviation of + 6 degrees max. Who uses the same encoder did you find these deviations or are my HH-12 not appearing to be perfectly linear? Thank 73 Ermanno / ik7ezn [image: image.png]

1 year, 5 months

Re: [Moon-Net] HH-12 encoder linearity

by Ermanno Ferriero

Hi, thank you all for the considerations and as always moon-net is an inexhaustible source of advice. In particular, the indications of Roger, Keith and Wolfgang make me think that it could be a problem of imperfect verticality of the mechanism that supports the disc. Excluding encoder problems since everyone agrees on quality and compliance with specifications (that's what I wanted to know). i will investigate with a laser level the perpendicularity of the mechanics system to the various degrees of azimuth. Thanks again everyone 73 Ermanno / ik7ezn Il giorno mer 22 dic 2021 alle ore 16:06 Keith Naylor < keith.naylor(a)micronet-uk.com> ha scritto: > Ermanno, > > You appear to describe a systematic error. There are 3 possible outcomes > here. > > 1. The decoder you are using has a missing bit.....or there is an error > in the external decoding electronics > > 2. The azimuth bearing relative to your mount is not really horizontal > wrt earth. That is an ultra common problem > > with sat systems I see every day. As azimuth changes then elevation will > change also. Howerver, a delta of 6 deg does seem quite large.... > > 3. Depending on how good the mount is the same effect as (2) can occur > as inertia changes with elevation. This has the > > effect of distorting the dish and sightline, being a mirror like action > that could be some 3 deg mechnical so you measure 6 deg electrically when > > looking at sun or moon etc. > > ....... > > To get to the bottom of the problem I think you need to fix a laser (gas > HeNe or similar <1mr low divergence) on the mount and establish what > > the beam is doing at some distance away as azimuth angle changes. > > ........ > > Both (2) and (3) can of course be solved in software if you can measure > real angles at the dish mount. > > FWIW, given the chip thats used in the HH-12 and comparing the actual > chip manufacturers specification its probable you might see +/-0.5 deg > > linearity over the temperature range specified, in practice this should > be somewhat smaller over say -10C to +40C. > > Hope my explanation is clear. > > 73' > > Keith G4FUF > > > >

1 year, 5 months

HH-12

by Georg Hylinski

Ciao Ermanno > Hello friends. I am using HH-12 absolute encoders for azimuth detection. I > have 2 HH-12 available and I have made some measurements > to check linearity from zero to 360 degrees. I found a deviation of + 6 > degrees max. Who uses the same encoder > did you find these deviations or are my HH-12 not appearing to be perfectly linear? > Thank > 73 Ermanno / ik7ezn Sorry to hear you are having that big of a deviation with your encoder. I would like to help you troubleshoot First of all: When operating properly the encoder should be better than 0,6 degrees over the full 360 arc. Are you using the encoder in a text fixture on the workbench? Or is it installed in your antenna rotor? Have you tried to swap it for a another HH-12 (should you have one at hand) just to check if it is the encoder or a mechanical or the software causing the problem? Should the encoder be faulty I would like to have it sent back to me, so I can check for a reason it got damaged. I can send you a new one in return. Here are some tips that might help: Check the clutch connecting the encoder to the antenna rotor axis. Sometimes these can slip and cause faulty readings. I had that happen once when a connecting rubber hose (used as a clutch) got weak over the years and caused slipping. Make sure there are no strong magnetic fields (Motors or permanent magnets) close to the encoder. They may cause the encoder to fail. Hope this will help zero in on the cause of your issues and we can fix them fast. Greetings es 73, Georg, df1sr www.df1sr.de -- Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft. https://www.avast.com/antivirus

1 year, 5 months

Re: [Moon-Net] Find Delta Phi

by Leslie L

Joe, Great tip on doing the "save all", and not trying to do it in real time, as I foolishly have in the past. 73 Les W2LPL

1 year, 5 months

Check log

by ben＠sm6cku.se

I was on for three hours Saturday evening in the contest and worked 25 stations on 23cm, but I didn't participate in the contest. Still QRP around 50 watts at the feed. On CW I worked DL1AT#, G4CCH, UA5Y#, DG5CST, SK0CT# and SP9VFD#. Digital QSO's with PA3FXB, OK1KKD, OK1USW, DL1SUZ, DK1KW, DF3RU, SV8KOU#, DL7UDA, IK2DDR, IQ2DB, PA0TBR#, SP3YDE#, SM3KPX, OK2DL, OM4XA, IK5VLS, FG8OJ, IK7EZN, GM0PJD and UA4HL#. Wish you all Merry Christmas and Happy New Year 73 de Ben SM6CKU

1 year, 5 months

Final section of ARRL contest 2021

by Peter Blair

My plan was to concentrate on 432. First pass, 432, PA gave a problem so QRP, I2FHW, G4RGK, PA5Y, WA6PY, Second pass, added 9 more on 23cm, Third pass 432, PA fixed, DL7APV,SM2CEW, PA3DZL, UA5Y, S51LN, DF3RU, NC1I, YL2GD. 12 CW QSOs with 8 random including WA6PY with his single yagi. Thanks to all for nice QSOs in variable conditions. 73 Peter G3LTF

1 year, 5 months

Find Delta Phi

by Joe Taylor

Hi all, Several people have asked me recently about the "Find Delta Phi" function on the Setup menu in MAP65. It's described briefly on page 16 of the MAP65 Users Guide: https://www.physics.princeton.edu/pulsar/K1JT/MAP65_Users_Guide.pdf Here is some expansion of the user instructions, bringing them up-to-date for MAP65 3.0. 1. "Find Delta Phi" works with JT65 signals and uses numerical relative amplitudes returned by the Deep Search algorithm. Be sure to check "Aggressive Deep Search" and "No Q65" on the Decode menu. 2. A good procedure is to check "Save all" on the Save menu at a time when there is plenty of activity -- at least several EME signals of reasonable strength, at least a few dB above your decoding threshold. Record these signals for 20 minutes or so. You should be looking for at least one case, and preferably several, that have comparable signal strengths in the X and Y channels of your dual-polarization system. If your xpol system is in the "+" configuration, this means signals being received at polarization angles around 45 or 135 deg. 3. Remember that Deep Search decodes messages in which the first word is either MyCall or CQ, and the second word is a callsign in your CALL3.TXT file. "Find Delta Phi" is programmed to step through values of Dphi = 0, 30, 60, ... 360 deg, attempting a Deep Search decode at each value. A plot of DS vs Dphi should be one full cycle of a sine wave. You want the Dphi corresponding to the sine wave's maximum. The numbers under TxPol (mislabeled for this purpose) are the trial Dphi values. 4. Attached files show several examples of determining Dphi for my xPol system as it was configured some 15 years ago, using the *.tf2 files that were used during the original development of MAP65. FindDeltaPhi.png is a screen shot of the MAP65 main window after running "Find Delta Phi" on a signal received from IK3MAC on November 11, 2006. File delta_phi.txt shows these results and three other examples from files recorded a few minutes before or after this one. Note that to get Deep Search decodes from these files it was necessary to temporarily set MyCall to the first callsign in each message. 5. File FindDeltaPhi.pdf shows a simple plot of the noisy sinusoids corresponding to each of the test signals. The estimated values of Dphi cluster around -50 deg. You could "eyeball" these solutions with reasonable accuracy from the DS-vs-Dphi numbers, or from the plots. Note that 310 deg is equivalent to -50 deg. 6. A trivial bug in MAP65 3.0 (as distributed with recent Windows versions of WSJT-X) prevents the line "Best-fit Dphi = xxx deg" from being displayed. You can use MAP65 v2.7, which is fully equivalent for this purpose, or you can "eyeball" the fit to the sine wave's maximum. Dphi accuracy within 20 deg or so is "good enough". 7. Finally: Attached file DPhi9.png is a screen shot saved a few days ago by Mauritz, SM2BYC, on the MAP65 testers' Discord channel. An eyeball fit in the way I described shows maximum DS at Dphi (under the TxPol label) of about 105 deg. To be sure of this value, Mauritz, I recommend entering Dphi = 105 on the "Setup | Options | Station" tab and making several additional tests, thereby iterating your calibration procedure. -- 73, Joe, K1JT

1 year, 5 months

BLF189XRA burn

by iw4ard＠aririmini.it

Hi guy, someone can tell me where I can find a BLF189XRA in Europe at an acceptable price. Thank you so much for info. Vy 73 de Gianni, IW4ARD

1 year, 5 months

← Newer
1
2
3
4
5
6
7
...
13
Older →

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

Moon-net December 2021