WRVS497

I purchased the AURSINC NanoVNA-H and the Surecom SW-102 from Amazon. Originally I just had only the NanoVNA but like Sshannon mentioned it doesn't provide power (watt) or impedance matching information. I intend to make my own antennas as well as ensure my radios will last me in the field using the proper gear. At around $125 for both tools you cant go wrong with them in your tool box. Even if you hardly use one over the other, it wont break the bank just to have it when you do need it, or when another radio friend might benefit from that information. The $500 MFJ's or the RigExperts is a different story. Only consider those if you are making antennas to sell or get involved in competition where it makes sense to be as close to perfect as possible.

Good thing I asked and I really appreciate the feedback! At $160 for the MFJ product and the amount of effort it would take to figure out axorlov's suggestion i think ill just make another antenna for the SDR side and separate the two. Back to the drawing board and thanks again.

I'm designing a cheap GMRS base station setup using a Baofeng GMRS-9R, a laptop with an SDR and SDR#, a Y-cable, and an antenna tuned for GMRS frequencies. I have these things already and figured I would play around with this while saving up for a real 50W base station radio. (Probably the Wouxun KG1000G) My question is, would an inline DC blocker (normally used to block dc voltage from a bias-t) block the TX voltage from an HT and protect the SDR in this design? Or, is the TX voltage AC and the DC blocker would be rendered ineffective or damage both it and the SDR? The DC blockers I have are cheapos from Amazon https://www.amazon.com/dp/B07P1KPQCX?ref=nb_sb_ss_w_as-reorder-t1_k7_1_10&amp=&crid=3R9W9HMRI3RAW&sprefix=dc%2Bblocker&th=1 I have not found anything equivalent for AC blockers either so my assumption is a DC blocker would be the way to do this. I know that duplexers accomplish this but they are frequency based and my intent is to transmit and receive on the HT and receive on the SDR to watch the GMRS spectrum for potential traffic as well as signal strength analysis. Would the SDR just be overloaded from the transmission regardless?

The Laird BB4503 and NMO mount upgrade definitely made a difference. Much less popping static now while in motion and the only interference I notice is the common multipath and/or obstruction dropouts which you cant do anything about. In addition the antenna is shorter with no external spring so it doesn't move and has a much lower profile on the roof. Thanks for all the responses, especially @gortex2 for the Laird suggestion. I like the quality of these antennas so they will likely be my go to.

Alternator noise is on the low end of consideration. I have an aftermarket audio system in this truck that I installed myself with multiple amplifiers, a DSP, signal RCAs, speaker wire, and power cables all custom. There is zero engine whine on the signal RCA's or from the speakers so I'm fairly certain this is not an issue. My amplifiers are much stronger than the radio so if alternator noise was an issue it would be blasting at me. That doesnt mean that my equipment isnt filtering out, just saying I would certainly hear it there first. In addition to that my coax for this rig is separated from the power cable(s) by more than a foot for the majority of its travel through the vehicle. The one place where they meet each other I ensured the traversal is perpendicular so I'm not convinced that would be the issue. Not saying its impossible just dont think thats it. I'm pretty sure its the antenna design and coupled with the spring based on earlier replies. Having said that, I went ahead and pulled the trigger last night on that Laird BB4503 and the GBR8Pi that @gortex2 linked me to. I couldn't wait. We shall see what happens.

Wow that DIY filter. who would have thought you could use a regular old link like that. Guess it really is all about the turns. Thanks again ya'll. Looking at those Lairds I think I'm definitely going to consider those over the midland series. Much appreciated!

Much appreciated! let me figure out what I got going on. I don't have any meters yet so it would be interesting to see the SWR, etc. I have gobs of electrical gear and tools as I do all my own mobile sound system work but when it comes to radios I'm totally green. If I don't catch you on the airwaves ill DM you.

Also, has anyone used or have any information about how well the CompacTenna LMR works for GMRS? https://www.dxengineering.com/parts/can-lmr-i I've had this one on the wish list at DX for a while but the $200 price tag is a bit much right now. Apparently these things are money as long as they are in the right spot on the vehicle.

Thanks all for the information! Based on this I'm going to start with the wiring and ensure everything is grounded properly and minimized voltage drop occurs. I hate using cigarette lighter for power anyway, other than charging phones. The coil spring does makes sense. This antenna has a short spring at the bottom so there is potential there for sure. @marcspaz Hey I've spoken to you before. I'm on the Warrenton and Bull Run repeaters frequently so if I catch up to you one day we can test it out. I'm typically on ~0630 to ~0730 in the mornings and 1600 to 1800 evenings depending on when we get on the road after work. I also considered all the random stuff in between me and the repeater but when stationary there is rarely any consistent static. In motion its every caller, stationary its only the ones that are far from the repeater and having trouble reaching it. @WRQC527 can you link me to the noise filter you are using? @gortex2 Can you link me to some of those LMR antennas as well? Thanks again

I'm definitely considering an NMO setup. Looking into the MXTA26 antenna with the MXTA27 hood lip mount. I've heard good things about Trams but also heard good things about the Nagoya. What is it about the NMO mount that could potentially solve my issue?

Curious if anyone has had this same phenomenon and/or a solution. I have a Nagoya UT-72G mag mount on the roof of my Tacoma with a Midland MTX275 micro mobile. The Midland is powered off the dash cigarette lighter plug using the stock cable and plug. When parked, my transmit and receive is quiet and other mobiles on the channel/repeater copy loud and clear. As soon as I get going however, any time a transmission comes in I hear consistent popping and static on RX and when I TX, other mobiles say that it sounds a bit staticy and/or "picket fencing". Again this disappears when I stop at a light, etc. I have not yet tried ferrite chokes on the power line however I did try one on the antenna cable near the connection to the radio without any change. I do plan on rewiring the power situation with a 12v relay, some 10ga power cable (OFC) and a fused power block as well as grounding the negative cable close to where the radio is mounted. I plan on having additional radios later hence the choice of cable size. Before I go down the rabbit hole of moving the antenna, replacing the antenna with something more "expensive", or throwing chokes everywhere, has anyone experienced this with their rigs or the UT-72G specifically? Could this be a flaw with the antenna itself or is there additional grounding necessary to counter wind static? If its wind static what is the best way to bleed static off the antenna from a roof mounted position? I assumed the grounding side of the coax would take care of this but maybe I need to ground the connector to the truck frame? Throwing out ideas here. Thanks in advance for your help and knowledge.

I was wondering the same. The ODroid N2+ is a great alternative for these type of things. Would love to be able to install the relevant software and install myself.

Also new here. Wondering if there are any folks who commute on Rt 29 an/or 66 that use the Warrenton repeater that want to share traffic info. I didn't see any relevant clubs.