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Author Topic: SAT Antennas - available & WISH  (Read 921 times)
N6JSX
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Posts: 217




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« on: July 03, 2007, 05:51:15 AM »

The availablity of commercial sources of SAT antennas is dwindling.

M2 - sells full range of OSCAR antennas.

KLM - was acquired by M2 but M2 didn't continue the KLM product lines and barely supports KLM products.

Hy-Gain - appears to have been bought by MFJ - still selling OSCAR antennas. (Hope the old Hy-Gain quality continues with new MFJ ownership.)

Cushcraft - no longer sells SAT antennas - the 2m A14820T could be used for 2m CP but requires a special CP harness that Cushcraft does not sell.

Arrow - has a hand-held 2m/430 but not CP.  

KMA - is a source for VHF/UHF log periodic but not CP.

Comet - is a source for VHF-UHF log periodic but not CP.

No company builds a cross-yagi Log-Periodic that could be a full coverage SAT antennna 100-1300MHz. Yes, Log's have less overall gain but it still has directional ERP and the cost/setup would be greatly reduced with a three (2m/430/1200) in one antenna. However, for SAT Ops a very good external filter would be required to OP TX on one band at-the-same-time RX on another band on the same single feed Log.

I've not found any source that offers an after-market mast-mounted cross-yagi "add-on" to allow the user  vertical, horizontal, left twist circular, or right twist circular polarization operations.

Mast-mounted (200W TX-passing) RX-low-noise-amps are expensive with very few commerical sources.  
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WD9EWK
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Posts: 249


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« Reply #1 on: July 03, 2007, 10:20:03 AM »

Hi!

I agree with the general theme of your message, and it could be extended to the radio manufacturers.  Yaesu discontinued the FT-847, and - for the moment - has nothing to replace its satellite capabilities.  Kenwood has its TS-2000, and Icom has its IC-910H, for satellite-ready transceivers.  Other rigs from Yaesu (FT-817, FT-857, FT-897) and Icom (IC-706 series, IC-7000) *could* be pressed into satellite service for 2m and 70cm, but none of those are full-duplex and would most likely need something else to hear the downlinks while transmitting to do it right.  Until something like P3E or AMSAT-NA's Eagle are launched, all these manufacturers might be waiting to see if there is any demand in the ham marketplace for satellite-capable radios and antennas like those you mentioned.  

Quoting from near the end of your posting...

"No company builds a cross-yagi Log-Periodic that could be a full coverage SAT antennna 100-1300MHz. Yes, Log's have less overall gain but it still has directional ERP and the cost/setup would be greatly reduced with a three (2m/430/1200) in one antenna. However, for SAT Ops a very good external filter would be required to OP TX on one band at-the-same-time RX on another band on the same single feed Log."

Huh?

I use an Elk Antennas 2M/440L5 5-element 2m/70cm log periodic for satellite work, and I have heard the same comment about the need for a filter or something to be able to transmit and receive simultaneously with a log periodic.  You might need a good duplexer if your radio has separate antenna connectors for each band (not like the one built into most IC-W32A HTs, where 2m TX desenses the 70cm receiver when the RX is in the 430-440 MHz range).  Otherwise a radio with a single feedpoint should be fine with its own built-in duplexer when using a single-feedpoint antenna like a log periodic.  

My (FM) satellite Field Day station this year was an Icom IC-2720H mobile radio with the Elk Antennas 2M/440L5 antenna.  A bit smaller and lighter than the Arrow Antennas handheld 2m/70cm Yagi, a single feedpoint on the antenna that goes to the single antenna connector on the radio, and worked fine.  I worked passes at 5W as WD9EWK (1B-AZ) and at 15W as W7ON (1C-AZ) during the weekend, since the IC-2720H can work full-duplex easily unlike my IC-W32A HT with its known duplexer issues.  I have worked passes when transmitting at 50W on 2m and have had no issues hearing the 70cm downlinks on the FM satellites with this IC-2720H/log periodic combination, but I prefer to use lower power levels... I hold the antenna most of the time.  :-)

73!



Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
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Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
KB9CRY
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Posts: 4283


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« Reply #2 on: July 03, 2007, 10:53:53 AM »

I wouldn't say the supply is dwindling, it's more like it's been static for many years.  And yes some of the components are expensive.

Welcome to the world of satellite operations.  It's always been like this; there just isn't a huge demand.  There were a few other entries (2.4 Ghz downlink dishes and BBQ grills) available when AO-40 was operational but they've all dried up when that blew up.

Just the way it is.
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W7AIT
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Posts: 489




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« Reply #3 on: July 03, 2007, 01:56:39 PM »

N6JSX-

I built my "HOT ROD ARROW" entirely from purchased parts, the entire system!  Take a look at Jan/Feb 2007 AMSAT Journal.

1.  I’d looked into possibly making that and selling it commercially to hams.  It would take ** several hundred thousands ** of my own dollars to get into it as a “start up”.  I won’t go into details of why and how it cost that much, but it does, even if  only ONE each production unit is ever sold.  I’ve seen the case where a end insulator Jig, NRE (non recurring engineering costs), and fabrication for the Jig costs $20,000 just to make one tool for production!  If you want more information on why it costs ** several hundred thousands ** to start up, the details, see me later.

2.  I then did a “market survey”.

THERE IS NO MARKET!

Out of 600,000 US hams (+ foreign hams), only 3,000 hams are into satellites.  Of those 3,000, only 5, yes FIVE are actively looking to purchase any equipment.

Response to my article served as the market survey.   Out of 3,000 hams, only 5, yes FIVE people went on to build my antenna.  Yes they liked it, yes it worked.  So that proved there IS NO MARKET sufficient to sustain spending several hundred thousands of my dollars to make a product for that.

The “Big Boys”  Yaesu, Kenwood etc, do the same market research and came up with similar results.  They do it with rigs, antennas etc.  If they can’t get a Return on Investment (ROI), they don’t do it, or get out of the market.  Think Kenwood and them paring back the entire amateur line – they  did that to maintain profitability; sell only those products that continue to make money and don’t get into anything new that doesn’t make money.

One of the “Back Pack Antenna” manufacturers (I can’t mention the name) also does marketing surveys and found similar for their back pack idea, except thousands or tens thousands of hams responded and it was worthwhile for  them to spend the start up money and get a return on investment.  That company is successful today.  They will not get into satellite antennas because there is no market and they would lose money doing that.

So you will just have to homebrew satellite antennas, build rigs, scrounge parts and modify existing commercial gear to get and maintain a satellite station.  

It’s a niche market, a very small one at that.

Now if I changed my model of doing business to ** custom built to order **,  a “Time and Materials + Profit”, I could make money.  Government contractors do it all the time making  small lot quantities of highly specialized equipment, antennas, tanks, boats, radar’s, radio’s, etc, using the Cost Plus model (Cost Plus Contracts),  and they make a profit, because the customer pays the full COSTS (parts, labor, overhead) plus the fixed PROFIT.  So the Military contractor stays in business.  He always makes a PROFIT.  I could model my business the same way.  I chose not to for reasons.

Keep scrounging parts, homebrew, and modify, that’s the sprit of ham radio anyway.  Satellite stations aren’t plug and play turn key stations, not by a long shot.

Ok I hope this helps.
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AA2BN
Member

Posts: 3




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« Reply #4 on: July 06, 2007, 06:08:53 PM »

You didn't mention Gulf Alpha Antennas

http://www.gulfalphaantennas.com/

I have the 2m 5x5 CP Yagi and the 435 MHz 8x8 CP Yagi. Both perform well and the materials are of very good quality. The assembly and tuning instructions could use some refinement, but if you understand how Yagis are constructed you'll do fine.

I had an original set of Hy-Gain Cp Yagis, and after 20+ years mounted outside the phasing harnesses succumbed to UV. When I called MFJ to enquire about replacement I found they were very expensive (more than the cost of the new GA antennas). However, I was really put off when the gentleman from MFJ said it would be at least 6 weeks delivery since they had none in stock and "we have to learn to make them". I thanked him for his time and hung up.

73,

John AA2BN
AMSAT# 22683
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AB2KT
Member

Posts: 62




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« Reply #5 on: July 07, 2007, 05:48:40 PM »

The S-band BBQ-grille dishes are still very easy to come by, for use with WiFi systems. There are lots of them for sale inexpensively on ebay, as "mesh WiFi" antennas.

I recently bought one brand-new, together with a feed rated up to 100W and mounting hardware, for a little under $30 plus shipping. What it doesn't have, of course, is an S-band->2m downconverter, but that's not an issue in my application, which is portable and uses a short feedline directly to a preamp and a USRP and computer running GnuRadio.

Ditto on both the Elk and Gulf Alpha antennas, BTW.

73
Frank
AB2KT
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