September 2014 - AMSAT-BB - mailman.amsat.org

test equipment for an amsat ground station
by Samudra Haque 13 Sep '14

13 Sep '14

Cross posted to Tacos / Amrad and also Amsat-BB as it may interest homebrewers. I made a ugly bug (well, The PCB was very nice when I started, and really convoluted when I finished .. ) frequency marker box (from junk parts). I will donate this to K3GWU amateur radio club and research station for general use. I used (what I had) 3.68 MHz, 40 MHz, 50 MHz, 60MHz sealed crystal oscillator. I used a voltage regulator and bypass caps to feed power into the units via individual switches, so I can turn on any combination manually of the oscillators, or all or some at the same time. I then combined the inputs into a common point and from that point used a 10 pF capacitor to get an output to an SMA bulkhead connector through a brass box. Of course, I then needed a 3.3V regulated output for a microprocessor so I put in an additional 3.3V LDO as well inside the bus and all components are happy now. I even put an LED just to satisfy my curiosity and then sealed all in a box. I do see on a simple analog scope all wave forms and my frequency counter shows the fundamental frequencies produced. A spectrum analyzer (thank you K0BRA) shows different products of the frequencies.Obviously the frequencies I saw were just whatever the crystal oscillators I had on hand, so they can be replaced, or added to. In this line, what improvements could I do to make it an useful general purpose box for testing in the radio shack, and for AMSAT birds, is there anything of interest that might be useful to qualify a station ? One could use a microprocessor to switch in circuits, that much I can do, but which type can be used to generate accurate frequency standards ? If only a clock pulse generator (square wave) source was available, what type of circuit would allow multiple frequencies be slaved to a crystal standard ? Any old schematics reference would be appreciated. I even saw how easy it is to use a audio transformer to modulate the power leads and transmit QRP AM on the 0.5m length RF cable. I can now use this to verify operation of the RF splitters and combiners. 73 de N3RDX @ K3GWU if you are in Foggy Bottom area of DC and have an interest in ham radio, I'm at GWU.

1 0

Re: [amsat-bb] Hand helds for FM birds
by Bill ACITO, W1PA 13 Sep '14

13 Sep '14

I love my Yaesu FT-530's (yes, I have a couple) for handheld; they don't de-sense. Bill W1PA

4 3

Will you be my first...
by Steve May 13 Sep '14

13 Sep '14

...contact on AO-73? I think I have my station working, so I am going to try to work the pass around 3:27 UTC tonight. If anyone is on that would be great This will be my first attempt on anything other than SO-50, so it could be a little rocky. Steve, W5IEM

4 6

Antenna suggestions
by Keith McDonnell 13 Sep '14

13 Sep '14

I am about to upgrade my antenna system which now is only a pair of Eggbeaters. I would like to get a 2 meter C.P. and a 70 cm C.p. Yagi. I alread have a g5400b az/el rotor. I have looked into the Hygain oscar link system, M2's offerings as well as Gulf Alpha antennas. If anyone has any experience with these, or others, i would appreciate your comments. You may email me directly. Thank you and good health to all. 73, keith Kg2ix(a)optonline.net

7 6

Re: [amsat-bb] Hand helds for FM birds
by Rick Tejera 13 Sep '14

13 Sep '14

If you can find the D72A's predecessor, the TH-D7A, on the used market, that will do fine as well. Got my VUCC Sat using one.. Rick Tejera Saguaro Astronomy Club www.saguaroastro.org Thunderbird Amateur radio Club (K7TEJ) www.w7tbc.org -----Original Message----- From: amsat-bb-bounces(a)amsat.org [mailto:[email protected]] On Behalf Of Paul Stoetzer Sent: Friday, September 12, 2014 06:50 To: Rolf Krogstad Cc: amsat-bb(a)amsat.org Subject: Re: [amsat-bb] Hand helds for FM birds Yeah, I screwed up the model number! On Fri, Sep 12, 2014 at 9:48 AM, Rolf Krogstad <rolf.krogstad(a)gmail.com> wrote: > Is that the same as the Kenwood TH-72A? > http://www.aesham.com/multi-band/kenwood-th-d72a/ > > Rolf NR0T > Amsat #38889 > Amsat-UK e-Member > > > On Fri, Sep 12, 2014 at 7:18 AM, Paul Stoetzer <n8hm(a)arrl.net> wrote: > >> The only current production model that works for Mode J full duplex >> is the Kenwood TH-D7A2. There are few other full duplex handhelds on >> the market, but they all suffer from desense on 70cm when transmitting on 2m. >> >> The other handhelds may be adequate for the Mode B FM transponders on >> EO-80 >> and the Fox-1 series, but they will not work for full duplex on SO-50. >> >> 73, >> >> Paul, N8HM >> >> On Fri, Sep 12, 2014 at 8:12 AM, Rich/wa4bue >> <richard.siff(a)verizon.net> >> wrote: >> >> > I lost some information once published on the BB. >> > >> > What FM hand helds work duplex 70 cm and 2 meter for OSCARS? >> > >> > Does anyone have a preference??? >> > >> > Rich W4BUE >> > _______________________________________________ >> > Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum >> > available to all interested persons worldwide without requiring membership. >> Opinions >> > expressed >> > are solely those of the author, and do not reflect the official >> > views of AMSAT-NA. >> > Not an AMSAT-NA member? Join now to support the amateur satellite >> program! >> > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb >> > >> _______________________________________________ >> Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available >> to all interested persons worldwide without requiring membership. >> Opinions expressed >> are solely those of the author, and do not reflect the official views >> of AMSAT-NA. >> Not an AMSAT-NA member? Join now to support the amateur satellite program! >> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb >> > > _______________________________________________ Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

1 0

REMINDER -- SPECIAL EVENT -- ROSELAND RADIO -- SATURDAY, SEPTEMBER 13th
by Robert Kovacs 12 Sep '14

12 Sep '14

In celebration of its 69th anniversary, the Roseland (NJ) Radio Club (K2GQ), will be operating as special event station K2R from Eagle Rock Reservation, West Orange, New Jersey (grid FN20), from 10:00 a.m. to 2:00 p.m. EDT. We're hoping to work the SO-50 pass at 12 Noon EDT (1405 Z). The Club's other activities will be Two Meter simplex (146.55) and QRP HF on 20 m. Hope to hear from you all then! 73, Roseland Radio Club -- K2GQ Bob Kovacs KC2WYH AMSAT Member 38504 .

1 0

Hand helds for FM birds
by Kevin M 12 Sep '14

12 Sep '14

At this point a pair of $40 Baofengs would be the best, most economical solution for full duplex. 73, Drew KO4MA --------------------- I second that suggestion. I went through two IC-W32As trying to find one that would not desense on SO-50... no luck. (information out there about the serial numbers is not correct!) With batteries and accessories, it cost me MUCH more than $80 and is now sitting in a 'go bag' for taking mobile. Other advantages of two Baofengs: - You don't need a diplexer on the antenna... uses two separate coaxial feedlines - May be lighter... I have a UV-3R+ and a UV-5R and together they are quite a bit lighter than my IC-W32a - You don't need a headset or a speaker mic with a headphone jack. You can plug an earphone or cheap headphones into one and hold the other HT to talk into; it's not much bigger, if at all (depending on model), than a mobile hand mic. - Sure, you can plug headphones into a duplex HT and hold it to talk into, but it is likely heavier and difficult to use the push-to-talk AND adjust receive frequency with one hand on the SAME unit. The trick with using two HTs is holding the antenna with one hand and the TX HT in the other, WHILE occasionally tweaking the frequency on the RX HT. AC0RA has operated "two HT" mode many times and his suggestion is to clip the RX HT on your person (belt, maybe shirt pocket) and then hold the TX HT in a way that you can free two fingers to adjust the RX HT. It works. No different than holding a speaker mic so that you can adjust receive when using a duplex HT. If you are using a tripod mounted the antenna, then no worries! One hand for TX HT and the other to adjust the RX. I recommend the UV-3R+ over the regular UV-3R as the plugs and accessories are the same as later models and easier to find. (The UV-3R uses an 'annoying' 4 conductor phone plug. Makes it difficult to rig up a 'Y' cable to split to a digital recorder.) The UV-3R+ is two watts whereas the UV-5R is four watts. Otherwise they are similar radios. Frankly I would recommend a pair of UV-3R+... the smaller size is more advantage than the two watts. If someone is hogging the uplink, three dB isn't going to matter THAT much. As always, your mileage may vary... =^) 73 es GL! Kevin n4UFO

1 0

FO-29 and being a good transponder op
by Andrew Glasbrenner 12 Sep '14

12 Sep '14

Lots of activity has been happening on FO-29 in the evenings lately. The pass times are favorable, and there are rovers out and about. This evening, there were at least three mobile, portable, or omni antenna stations all piled up in the very center of the passband calling CQ on top of each other. None were hearing the others it seems, or willing to move. It was an ugly, embarrassing mess, completely unnecessary. Folks, FO-29 has a passband that is 100 kHz wide. There is no reason to all pile up in the dead center and QRM each other. Spread out a little bit, ESPECIALLY if your operational plan is to call CQ with omni antennas or half-duplex and tune around for replies. You'll make more contacts and have less QRM in the long run. The long standing convention on linear transponder satellites has been lower third CW, middle mixed CW and SSB, and upper third SSB. Let's try to use this resource in a more responsible and cooperative manner. 73, Drew KO4MA

4 5

Two out of three ain't bad
by Rick Tejera 12 Sep '14

12 Sep '14

Thanks to all who offered advice & hints. It was the missing dash. I appreciate the answers and learned a few things I didn't know about what is, for me at least,. A little used feature. Next on to Cat control. But for now, bed time Rick Tejera Saguaro Astronomy Club www.saguaroastro.org Thunderbird Amateur radio Club (K7TEJ) www.w7tbc.org

1 0

Office Closed
by Martha 11 Sep '14

11 Sep '14

The AMSAT Office will be closed on Friday, September 12th. We will reopen on Monday morning at 10:00 AM -- 73- Martha

1 0