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Author Topic: Arrow-II 146/437-10WBP : test data  (Read 5140 times)
N6JSX
Member

Posts: 216




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« on: October 28, 2012, 06:19:09 AM »

I received a proper 'as designed' 2m driver, months ago but the hot summer kept
me from analyzing. {The gamma wire measured 7.5" the spec calls for 8.0"}
Data file can be found in:

http://groups.yahoo.com/group/HAM-SATs/files/Antenna%20-%20Commercial/Arrow%20II\

The proper dimension (per manual/spec) works better and provides an overall
improvement to both 2m & 70cm VSWR. When looking at each antenna as a
mono-bander all looks very good.

It is only when using the duplexer do issues show up. I consistently see the
duplexer lowest VSWR on 70cm near the very top of the band - far from the SAT
usage freq. It appears the duplexer is tuned/component selected taking the
duplexer to the high end of the 70cm band.

Arrow may need to give the duplexer design some attention especially since Fox-1
(and future SATs) will have TX  up-link on 70cm !!!

However, "as is" the ARROW is still very usable as the SAT freq's are still below 1.5:1 VSWR on 70cm.
  Grin

N6JSX/8
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N6JSX
Member

Posts: 216




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« Reply #1 on: October 28, 2012, 07:37:44 AM »

http://groups.yahoo.com/group/HAM-SATs/files/Antenna%20-%20Commercial/Arrow%20II/
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N8HM
Member

Posts: 81




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« Reply #2 on: November 01, 2012, 01:01:56 PM »

I can get into VO-52 and AO-7 on their 70cm uplinks fine with the Arrow and 5 watts, so I don't think it's a big problem.
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WD9EWK
Member

Posts: 233


WWW

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« Reply #3 on: November 01, 2012, 02:35:07 PM »

I can get into VO-52 and AO-7 on their 70cm uplinks fine with the Arrow and 5 watts, so I don't think it's a big problem.

Have you tried FO-29 with that setup?  I did in the past, and had desense when I had the Arrow as my antenna with two FT-817s connected to each of the Arrow's feedpoints.  Even at 5 watts. The FO-29 desense went away when I went to the Elk, and then used a Comet diplexer to feed the single feedline from the antenna to the two radios.  VO-52 and AO-7, along with Fox-1 when it is launched, all use 70cm uplink frequencies which gets you away from desense due to the 3rd harmonic of the 2m uplink transmitter for the current FM bird(s) and FO-29. 

N6JSX mentioned the duplexer design for the Arrow.  It is not very durable, and - of course - only rated for no more than 10W due to the size of its components.  You can improve things with some other duplexer, but most of those will be larger than the one from Arrow Antennas.  Before I switched to the Elk, I replaced the small Arrow duplexer with others (once I used a Diamond duplexer, then an MFJ that looked just like a Diamond duplexer, then one from Comet). 

Good luck, and 73!
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Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
N8HM
Member

Posts: 81




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« Reply #4 on: November 02, 2012, 04:02:28 PM »

Just got an MFJ duplexer last week. The S meter no longer activates on the TH-F6A receiving on 435 MHz when transmitting with the FT-817 on 145 MHz, so that's encouraging, but I haven't had an opportunity to try it on a pass of FO-29 or SO-50 yet.

Still getting used to tuning for Doppler. I've heard myself on the AO-7 downlink and made one QSO on VO-52. I keep getting which way to tune screwed up in my head!
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K6LCS
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Posts: 1499


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« Reply #5 on: November 02, 2012, 06:46:17 PM »

>> ... The proper dimension (per manual/spec) works better and provides an overall
improvement to both 2m & 70cm VSWR. When looking at each antenna as a
mono-bander all looks very good ...

I am amused at how folks feel compelled to "improve" what already works excellently out of the box - er, I mean, "bag."

(grin)

If you purchase an Arrow satellite antenna, please know that it works splendidly - with NO modifications. There are thousands in the field, with that many pleased owners. I couldn't ask for better performance from my eight-year-old Arrow - the one I have used in front of scores of audiences the past few years.

And so it goes ...

Clint K6LCS
909-241-7666
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Clint Bradford, K6LCS
http://www.k6lcs.com
N6JSX
Member

Posts: 216




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« Reply #6 on: November 03, 2012, 07:05:43 AM »

K6LCS: Once again you are incapable of connecting the dots in seek that 'thrill up your leg' in berating me in SAT blogs Grin....

I bought this antenna from HRO VA on Sept 15th , 2010, for $139.95. Due to the performance observed the following year (when I had free time) I conducted tests as the ARROW was not performing as expected, my data confirmed a problem. Upon investigation found the problem to be a workmanship issue - the 2m gamma wire is one inch too short.  Embarrassed

I contacted ARROW asking how I may fix/replace this short wire as the BNC appears to be press fit into the element. ARROW sent me a new replacement 2m driver element with the proper length gamma wire, 8".  Cool

The results of my retest are as I stated - good. Now if you want to go one step further - how many NEW ARROWs were sold with an out of spec 2m driver element?  Huh

I still say the duplexer 70cm side needs attention especially with the FOX SATs going to 70cm 'uplink', we will want all the HT power into the antenna not compromised in a 'slightly' detuned duplexer.  I'm more than willing to conduct a retest when ARROW sends me an improved duplexer. 
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K6LCS
Member

Posts: 1499


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« Reply #7 on: November 04, 2012, 09:13:35 AM »

>> ... berating me in SAT blogs ...

I don't remember ever seeing you in any blog anywhere. Whatever.

I am not sorry to report on my first-hand experiences and observations over the years with Arrow antennas. You seem to have received one with a problematic part - which you ID'd and Arrow immediately fixed/replaced for you. That only re-confirms my experience with Arrow: that they are responsive and care about their products.

And for those who are considering purchasing an Arrow satellite antenna, I would recommend that they set it up and perform no modifications to it, and get to know its performance right out of the packaging. There are no widespread problems with the units. And I daresay the vast majority of owners will be delighted with its 2M/440 performance.

Clint Bradford K6LCS
909-241-7666

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Clint Bradford, K6LCS
http://www.k6lcs.com
N8HM
Member

Posts: 81




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« Reply #8 on: November 05, 2012, 11:04:37 AM »

I can get into VO-52 and AO-7 on their 70cm uplinks fine with the Arrow and 5 watts, so I don't think it's a big problem.

Have you tried FO-29 with that setup?  I did in the past, and had desense when I had the Arrow as my antenna with two FT-817s connected to each of the Arrow's feedpoints.  Even at 5 watts. The FO-29 desense went away when I went to the Elk, and then used a Comet diplexer to feed the single feedline from the antenna to the two radios.  VO-52 and AO-7, along with Fox-1 when it is launched, all use 70cm uplink frequencies which gets you away from desense due to the 3rd harmonic of the 2m uplink transmitter for the current FM bird(s) and FO-29. 

N6JSX mentioned the duplexer design for the Arrow.  It is not very durable, and - of course - only rated for no more than 10W due to the size of its components.  You can improve things with some other duplexer, but most of those will be larger than the one from Arrow Antennas.  Before I switched to the Elk, I replaced the small Arrow duplexer with others (once I used a Diamond duplexer, then an MFJ that looked just like a Diamond duplexer, then one from Comet). 

Good luck, and 73!


Desense problem is solved. I've got the Arrow duplexer in line and then I split the signals out again using an MFJ duplexer. That provides enough isolation to eliminate the desense. Of course, I'm not sure how bad the insertion loss is. I heard SO-50 down to about 10 degrees of elevation today. Of course, I'm in an urban area, so the buildings are always a problem.
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WD9EWK
Member

Posts: 233


WWW

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« Reply #9 on: November 05, 2012, 02:20:54 PM »

Desense problem is solved. I've got the Arrow duplexer in line and then I split the signals out again using an MFJ duplexer. That provides enough isolation to eliminate the desense. Of course, I'm not sure how bad the insertion loss is. I heard SO-50 down to about 10 degrees of elevation today. Of course, I'm in an urban area, so the buildings are always a problem.

That's one way to deal with the desense.  It's unfortunate that you have to employ a second duplexer, but many use a duplexer on the 70cm feedline like you did to deal with desense from a 2m transmitter - no matter what the antenna or antennas happen to be. 

Good luck, and maybe we will hook up soon on a satellite pass - in FM, or SSB.  73!
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Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
N6JSX
Member

Posts: 216




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« Reply #10 on: March 29, 2013, 06:49:33 AM »

FYI,  I sent my findings (at the time I started this topic) with concerns to ARROW, addressing the Duplexer issue - to date no response. No answer as to how many ARROW's were sold with a too short 2m gamma match.

As a technical challenge I'm now looking at how to improve/build my own Duplexer using tunable trimmer capacitors with a secondary desire to increase the power from 10W max to >45W and still retaining a small size.

Some have solved this Duplexer concern in buying Diamond/Comet HAM 2m/70cm Duplexer but the size, weight, and cost are significant. And they do not come with the BNC option (only SO-239/PL-259 or N).

With the new U1 FM SATs using 70cm as the uplink, and FOX1 going to orbit this year, I want my Duplexer optimized for SAT uplink freq to couple maximum power up with minimal internal heating/waste. But we really need the Duplexer to be capable of passing 100W.   

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KQ6EA
Member

Posts: 609


WWW

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« Reply #11 on: March 29, 2013, 04:39:06 PM »

Yes, the Arrow works "AS-IS".

Yes, it can be improved.

Yes, Clint is an Arrow Booster all the way.

Yes, this is REALLY getting old.....
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KO4MA
Member

Posts: 119




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« Reply #12 on: March 29, 2013, 06:10:07 PM »

But we really need the Duplexer to be capable of passing 100W.   



No, we really don't. You won't need anywhere near that power for Fox. I worked AO-40 with 25 watts and an Arrow on the uplink at 60,000 km, and SO-35 on Mode B FM with 5 watts and a dualband whip.
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W4HIJ
Member

Posts: 367




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« Reply #13 on: April 05, 2013, 09:14:39 PM »

But we really need the Duplexer to be capable of passing 100W.   



No, we really don't. You won't need anywhere near that power for Fox. I worked AO-40 with 25 watts and an Arrow on the uplink at 60,000 km, and SO-35 on Mode B FM with 5 watts and a dualband whip.
Not trying to get too far OT here but what is the projected power/antenna combo for Fox? Anyone know yet?  Will directional antennas be a necessity on TX or might an omni do?
Michael, W4HIJ
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