Moon-net June 2018

moon-net@mailman.pe1itr.com

170 participants
154 discussions

5760 Septum Feed Coupling Probe question

by H Dee

Interesting discussion about feedhorn probe diameter. On the same note, can anyone tell me what the purpose of the 3.5mm Dia. x 2mm long bead/ferrule on the probes for the 6cm version of the septum feed is ? I suspect it has an effect on the impedance but why does no other version in the suite require this ? How critical is the size of the bead and location down the length of the probe ? Reference Page 68: http://www.ok1dfc.com/eme/technic/septum/SM6FHZ_sept.pdf 73, Hugh VA3TO/ NA3TO

4 years, 11 months

something better than JT65 and FT8?

by Lyle Dysinger N4QH

we all know jt65 digs out the weak signals in the noise than the ear cannot hear. but what about getting rid of the noise so that we can audibly hear the those weak signals. adobe soundbooth CS5 and 6 does just that. why aren't we using such an application? seems to me more experimentation with this could lead to no more heated up finals, and more personalized QSO's.

4 years, 11 months

Cables + scope probes

by Stephen Hanselman

I have a gaylord (4x4x4 foot box) full of Scientific Atlanta Control cables. If any one needs some let me know off line what the part numbers are and I’ll look to see if I have them. Pricing is $1.00 per foot plus actual shipping. Really the shipping costs may be a limiting factor. I also have a cabinet full of Tektronix scope probes, i’, not sure but I’m betting just about every part number probe they made. These are $10.00 each plus shipping. Again let me know off line. 73's Stephen Hanselman, KC4SW Datagate Systems, LLC 3107 North Deer Run Road #24 Carson City, Nevada, 89701 (775) 882-5117 office (775) 720-6020 mobile s.hanselman(a)datagatesystems.com www.datagatesystems.com a Service Disabled, Veteran Owned Small Business DISCLAIMER: This e-mail and any attachments are intended only for use by the addressee(s) named herein and may contain legally privileged and/or proprietary information. If you are not the intended recipient, any dissemination, distribution or copying of this e-mail and any attachments is strictly prohibited. If you have received this e-mail in error, please immediately notify me and permanently delete the original and all copies and printouts of this e-mail and any attachments. Sent from my iPad

4 years, 11 months

homemade dish drawing and details

by Chris, PA2CHR

Hello all, I am planning to build a dish for use on 70cm. and 23cm. Maybe later also 13cm. It will be made from aluminium with mesh of about 6mm. F/D = 0.4 When looking at available space, weight, gain and mechanical construction my idea is to build a 3.70 mtr. one. This is my first step in dish building .... and I am looking for some "tips and tricks" if possible. Is there anyone who build a dish with this diameter: 3.7 ( 3.6 - 4.00) mtr? I have to decide: the tube diameter 15 or 20mm. square aluminium/ feed support/ etc. A detailed drawing of a homemade one would be beautiful, hi J I also have to decide yet what feed I will use. Thanks for reply ! With kind regards / 73's Chris PA2CHR WW - loc: JO32DB (75HA) Chris Ploeger, Mokkinkdijk 1, 7255 LM HENGELO-Gld. The Netherlands. T: +31 (0)575 - 463113 I: <http://www.pa2chr.nl/> www.pa2chr.nl / E: <mailto:post@pa2chr.nl> post(a)pa2chr.nl (HB9/PA2CHR - F/PA2CHR - EA6/PA2CHR - T98CHR - LX/PA2CHR - J45M -ZA/PA2CHR 3A/PA2CHR - 4U1ITU - LA/PA2CHR - 4O3A - 9A/PA2CHR - T7/PA2CHR - T70A - IC8/PA2CHR C37MS (2011) - HB0/PA2CHR - 4O/PA2CHR - Z38/PA2CHR - ZS/PA2CHR - Z21EME - IK0/PA2CHR HV0A - TK/PA2CHR - E44CM - IK8/PA2CHR - 3DA0MB - TD9CHR - E7/PA2CHR)

4 years, 11 months

Re: [Moon-Net] Question about coupling probe of OK1DFC septum feed

by steve＠k5dog.com

Bob, I don't remember where I saw it, but someone tested probe diameter VS isolation between the TX and RX. Perhaps someone with a better memory has a link to this document. I don't know if that is extremely important unless you are seeing LNA damage. I have always used a piece of the outer shield of UT-141 with no harmful effects. Steve, k5dog > -------- Original Message -------- > Subject: [Moon-Net] Question about coupling probe of OK1DFC septum feed > From: Bob Atkins <ka1gt(a)hotmail.com> > Date: Thu, June 28, 2018 2:11 pm > To: "moon-net(a)mailman.pe1itr.com" <moon-net(a)mailman.pe1itr.com> > > > Most of the construction articles for the OK1DFC septum feed seem to use coupling probes with a 6mm diameter. Typically something like 40 - 43mm x 6.3mm (1/4"). Is there a technical reason why the diameter of the probe is so large. The resonance is determined by the distance from the rear wall of the closed waveguide, the length of the probe and the setting of the tuning capacitor. Presumably the diameter will have a small effect on the tuning, but only a small effect and the tuning capacitor compensates for that. So why 6mm rather than 2mm or 3mm? My thought is that the probe diameter really doesn't matter much and 2mm, 3mm, 4mm, 5mm and 6mm would all perform similarly once tuned to frequency. You probably wouldn't want to go too thin, especially on the TX port where it may be handling significant power I guess. > > example: > [cid:f316b04a-dc0f-452e-b52f-6628ef60381c] > > My reason for asking is that I'm tuning up the feed for best return loss. I'm currently using a 1.5mm coupling probe because I had 1.5mm silver plated copper wire available. Return loss is good (-40dB). Am I missing something by not using a 6mm coupling probe? I don't think I am, but wanted to get other opinions since I may be missing something. > > Bob, KA1GT

4 years, 11 months

Question about coupling probe of OK1DFC septum feed

by Bob Atkins

Most of the construction articles for the OK1DFC septum feed seem to use coupling probes with a 6mm diameter. Typically something like 40 - 43mm x 6.3mm (1/4"). Is there a technical reason why the diameter of the probe is so large. The resonance is determined by the distance from the rear wall of the closed waveguide, the length of the probe and the setting of the tuning capacitor. Presumably the diameter will have a small effect on the tuning, but only a small effect and the tuning capacitor compensates for that. So why 6mm rather than 2mm or 3mm? My thought is that the probe diameter really doesn't matter much and 2mm, 3mm, 4mm, 5mm and 6mm would all perform similarly once tuned to frequency. You probably wouldn't want to go too thin, especially on the TX port where it may be handling significant power I guess. example: [cid:f316b04a-dc0f-452e-b52f-6628ef60381c] My reason for asking is that I'm tuning up the feed for best return loss. I'm currently using a 1.5mm coupling probe because I had 1.5mm silver plated copper wire available. Return loss is good (-40dB). Am I missing something by not using a 6mm coupling probe? I don't think I am, but wanted to get other opinions since I may be missing something. Bob, KA1GT

4 years, 11 months

Re: [Moon-Net] homemade dish drawing and details

by Ton PA0TBR

Hello Grant, Skip, Skip: Your pictures did not come through, can you email it direct to me ( pa0tbr(a)mubo.nl) please? Thank you for showing that tool. Yes, that is properly made, nice and strong. The 2nd picture looks like a roller bender which is what I tried to make, but out of wood. I was also shown this: https://www.hbm-machines.com/producten/plaatbewerking/plaatwalsen/hbm-60-mm… Unfortunately I started with my tool before I saw these tools. Oh well, I don't mind the woodwork. 73, Ton pa0tbr On 28 June 2018 at 00:19, <moon-net-request(a)mailman.pe1itr.com> wrote: > Send Moon-net mailing list submissions to > moon-net(a)mailman.pe1itr.com > > To subscribe or unsubscribe via the World Wide Web, visit > http://mailman.pe1itr.com/mailman/listinfo/moon-net > or, via email, send a message with subject or body 'help' to > moon-net-request(a)mailman.pe1itr.com > > You can reach the person managing the list at > moon-net-owner(a)mailman.pe1itr.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Moon-net digest..." > > > Today's Topics: > > 1. Re: homemade dish drawing and details (Grant Furnald) > 2. Re: homemade dish drawing and details (Grant Furnald) > 3. Re: homemade dish drawing and details (Skip Macaulay) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 27 Jun 2018 15:27:04 -0600 > From: Grant Furnald <ve6ta(a)xplornet.com> > To: "Moon-Net is an e-mail reflector intended for discussion and > announcements concerning amateur radio moonbounce communications. " > <moon-net(a)mailman.pe1itr.com> > Subject: Re: [Moon-Net] homemade dish drawing and details > Message-ID: <201806272127.w5RLR5eJ007795(a)r300b.itr-datanet.com> > Content-Type: text/plain; charset="utf-8" > > https://www.princessauto.com/en/detail/16-ton-hydraulic- > pipe-bender/A-p8708018e > > Hi ton: > > I used this bender to make my 5.5 meter dish out of 2?x1? aluminum tubes. > > My fellow ham VE6BGT also used it to make his 7.5 meter dish but changed > the round rollers out to square shouldered rollers which worked much better > than the original. > > I used a formula to bend the tubes every few inches and then tested them > in a jig. > > 73 > > Grant > VE6TA > > > Sent from Mail for Windows 10 > > From: Ton PA0TBR via Moon-net > Sent: Wednesday, June 27, 2018 2:34 PM > To: moon-net(a)mailman.pe1itr.com > Cc: Ton PA0TBR > Subject: Re: [Moon-Net] homemade dish drawing and details > > I am also very interested in the plans for a dish.? > > I am building a tool to bend aluminium ribs (20*20 mm) but was surprised > by the forces involved while bending. So now I am busy with a 2nd mod to > improve the tool. I wonder how others do form the ribs to the correct shape. > > 73, > Ton PA0TBR > > > >

4 years, 11 months

Re: [Moon-Net] homemade dish drawing and details

by Ton PA0TBR

I am also very interested in the plans for a dish. I am building a tool to bend aluminium ribs (20*20 mm) but was surprised by the forces involved while bending. So now I am busy with a 2nd mod to improve the tool. I wonder how others do form the ribs to the correct shape. 73, Ton PA0TBR

4 years, 11 months

Earlybird registration MASVHF Conf

by Rick R

Seeking additional speakers and papers for the Mid-Atlantic States VHF Conference for the weekend of Sept 28-30, 2018 at the Holiday Inn Bensalem-Philadelphia. Please send your topic or paper to rick1ds(a)hotmail.com To register for the conference, visit www.packratvhf.com<https://nam03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.packra…> click the link for speaker info, conference registration, payment and hotel registration information http://www.packratvhf.com/conf/2018_vhf_registration.php<https://nam03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.packra…> TNX--HP to C U all there. Rick, K1DS

4 years, 11 months

Balun for 2M antenna (EME)

by Fred Juch

Hello, maybe someone can set me straight. I have a Hy-Gain VB-214fm antenna and I will eventually put 4 on 2M EME. I do not want to discuss the choice of antenna here, it is already in house. I am reworking the feed system to make it more rugged as the default is a split open coax on the feed system. I am changing the feed system to one described here: http://www.radioaficion.com/HamNews/articles/1481-14-element-2-meter-yagi-pr oject.html And again here: http://realoldiesradio.com/?p=475 The ½ wave balun is described as 77 cm of RG213 (velocity factor .66) as in the text. As I am using parts on hand I will use LMR-400 with BNC connectors (also in hand) for the balun. I used this calculator: http://wxtofly.net/wavecalc.htm to calculate the 1/2 wave length at 144.1 MHz with velocity factor of .84 (Should be .85 but that is not in the tool) to 87.4cm. First question - am I correct here? Length etc. Second Question - is this from the finished BNC center pin on one side to the finished center pin on the other side? Third - can I ignore the internal connections of about 2 cm inside the box connecting the Balun to the elements? See picture, mine will be similar except the feed and balun are on the same side of the box. There is also a vertical rise of about 1 cm to go from the bottom of the box to the top of the radiating element. Am I over thinking this? Other Details this antenna has a hairpin matching system so the input impedance is 200 ohms. This ½ wave coax provides a 4-1 balun. I have about 800 Watts on 2M at the base of the tower. After I get this going, I will work on the phasing harness for the 4 antennas. Thank You in advance for your answers. You can reply direct if you desire. Fred Juch, N5JXO fjuch(a)austin.rr.com

4 years, 11 months

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Moon-net June 2018