Hi Gents, this evening i just received the VB1020 kit and the full software key.
Firetank:
Congratulations on you new DSA815-TG. I'm sure you will enjoy it very much. Although I want to to caution you that Rigol has been having problems with their 'expensive' VB1020 VSWR Bridge for the last couple of years. And as a result they have lowered the specifications a couple of time since it was initially released for production. I included a plot of one I tested for a friend in 2013, but please note that they have since reduced the Return Loss Specification to 20dB typical and 15dB minimum. So if you measure your new unit I expect that it could possibly be worse than my test results were.
I have included some links for Return Loss Bridges that are available. You can also use a Mini-Circuits Directional Coupler (although what you get will be what you will have). You may be happier using a Return Loss Loss Bridge (that can be adjusted and tweaked at least a little A/R), and there are several available at reasonable cost ($70 to $150 is reasonable). And then you may want something even better(?). All of the units I referenced I think are probably at least as good as the VB1020 (yes, I believe even the cheapest). I would recommend returning your VB1020 for full refund, and by the way you have the VSWR Key, so that will remain on your DSA. Tell them that the performance is way too low for your use of a RLB, and you will get your full refund. The VB10220 is a nice clean package, but it doesn't work very well for its intended purpose.
What should a RLB have for a minimum Return Loss (with the UUT port terminated with an excellent 50 ohm termination)? Ideally 30dB minimum for general hobbyist measurements, 35dB is preferred, and 45dB minimum for laboratory type measurements. The amount of error, either to the worst, or 'incorrectly' to the better, can be very significant even with a Return Loss Spec. of 30dB. You may want to to do a little research about RLB's to understand and appreciate this.
Not recommended, but very inexpensive:
http://www.ebay.com/itm/100M-1000MHz-RF-Reflection-Bridge-VSWR-SWR-Bridge-Antenna-Analyzer-Module/171589343360?_trksid=p2047675.c100009.m1982&_trkparms=aid%3D777000%26algo%3DABA.MBE%26ao%3D1%26asc%3D20131227121020%26meid%3Da0eb29102f10459ba35638440de62a60%26pid%3D100009%26prg%3D20131227121020%26rk%3D1%26rkt%3D4%26Again not recommended, but still inexpensive:
http://www.ebay.com/itm/3MHz-1200MHz-RF-Reflection-Bridge-Directional-VSWR-SWR-Bridge-Antenna-Analyzer-/171521995972?pt=LH_DefaultDomain_0&hash=item27ef81f4c4Is 500MHz enough for you(?):
http://www.ebay.com/itm/NEW-1-500-MHZ-reflection-bridge-standing-wave-bridge-rf-bridge-/111510492079?pt=LH_DefaultDomain_0&hash=item19f68b13afThis may be a good option:
http://www.ebay.com/itm/NEW-1-1000MHz-1GHz-reflection-VSWR-bridge-bridge-bridge-RF-SWR-bridge-/131329059012?pt=LH_DefaultDomain_0&hash=item1e93d268c4This is probably a Best choice:
http://www.amtronix.com/rlb.htm Note that it needs a reference '50 Ohm Termination', and one to check its Return Loss* capability (* you will need this with any RLB you buy, or make).
Edit by Ted572: Added the following information. 1/10/2015: Added Mini-Circuits ZFDC-20-4 Return Loss Data.
Explore all of the available RLB options: Search eBay, Google, etc yourself. Do you want to buy or make yourself, and most important what capability suites your primary interest?
Recommended 50 Ohm Termination: Mini Circuits (MCL) model KARN-50-18+, N male connector, 2 Watts, DC to 18GHz, $14 each (brand new).
http://www.minicircuits.com/pdfs/KARN-50-18+.pdf This is an excellent 50 Ohm Termination. You can spend up to ten times more money from other sources, but I don't think you will get any better quality than what this unit has. If you are going to build your own RLB, then I suggest getting at least two (2). One for the reference termination, and one to use for checking (calibration) for your available Return Loss. You can see a KARN-50-18+ on the back side of my RLB (50 Ohm REF).