View Full Version : Troubleshooting Assistance Requested
KB3MBM
03-31-2011, 12:55 PM
Good morning, everyone!
I'm getting back into the hobby and recently reconnected my Yaesu 2m rig in my Jeep. I've noticed, however, that my Rx and Tx are not up to par to other HAMs in the area. Unless the conditions are perfect both geographically and meteorologically, I have trouble receiving and "hitting" the local repeaters that I hear and see other HAMs operating on.
I'm going to do a little troubleshooting this weekend to see if there's a loose connection, a fouled connector on the antenna, or something else that could be giving me this problem.
I am using an Yaesu FT-7800R with a Diamond NR770HBNMO antenna mounted on a Diamond adjustable mount clipped on to the tub of the Jeep.
Any and all assistance is appreciated. Thank you!
Respectfully Submitted,
Rich C.
KB3MBM
First thought:
Check your antenna grounding scheme...
KD0CAC
03-31-2011, 02:40 PM
Rich , not that I'm an expert but seeing that this post got to page 2 with no answers , I take a swing .
Grounding the chassis of radio , then is the antenna mount getting a good ground ?
Lots of missing or ambiguous info , comparing to other hams , how far from repeater are you and those that you are comparing to ?
Any sign of high SWR on meter ?
When checking out this weekend what kind of test gear do you have to check with ?
Do you have a watt meter to see if the radio is putting out full power .
Not sure of what antenna mount you have or how its mounted , tub of Jeep , if mounted on outside , it may not have enough ground plane .
KB3MBM
03-31-2011, 02:58 PM
Grounding is one of the first things that came to my mind.
As far as testing equipment goes, I do not own or otherwise have access to anything at the moment. When I set up my radio the first time I had the assistance of some more knowledgable and better equipped HAMs.
When I lived in the Philadelphia area, I would use the local Phil-Mont repeater (147.300). When I moved to Virginia a few years ago, I removed the radio from the Jeep because: 1) the apartment had rules about CBs and other transmitters; and, 2) Auto break-ins and theft were high in my area. (Burke, VA, near Fairfax, VA.)
I've been looking into purchasing some testing equipment -- a good DMM, an SWR meter, a watt meter, etc. -- but I have to get approval from the CFO before I go doing that. ;)
K9STH
03-31-2011, 03:16 PM
For a "decent", but definitely low priced DMM, take a look at those sold by Harbor Freight. Occasionally, they go as low as $1.99 on sale. Of course, they are not a "Fluke". But, for general use they do a pretty good job. The "Item number" (HF "stock number") on the ones that I have is 98025.
These are not "auto ranging", you have to turn a switch for various ranges, but for the price they are very handy to have around. I have acquired a number of these (when they are on sale at $1.99 or $2.99) and have them in all my tool boxes, in the automobile, in "junque drawers", and all sorts of places. If I happen to damage one (haven't done so yet, but that is always a possibility), the cost is so low that I am basically out nothing if that happens.
The brand name is Cen-Tech and most of them are in a red plastic housing. They are on sale right now at $4.99. However, at various times over the year, they drop to $2.99 and even $1.99. Here is the URL for the DMM:
http://www.harborfreight.com/7-function-multimeter-98025.html
If you have a local Harbor Freight that is where to get them (no shipping).
Glen, K9STH
KB3MBM
03-31-2011, 04:14 PM
I never thought to look there (Harbor Freight). I am tempted to go to the local Radio Shack and pick one up, but previous experience has me questioning that line of thought.
I'm going to see if my wife will let me go down to Woodbridge and check out the local HRO store. These tools are going to be necessary, regardless. I aim to upgrade to a General Class (at least) this summer, and I'm sure I'll need the tools for a home base as well as any upgrades to the mobile set up.
Thanks for all the hints and suggestions!
K0RGR
03-31-2011, 06:06 PM
Sears sells excellent DMM's.
There's a cheap SWR bridge out there that should work well for you. The Vanco SWR-1 works up through 2 meters, and can be had for around $29.
The fact that weather affects the setup probably means that something is not connected securely. I believe I have the same antenna, and had some of the same issues with a trunk lip mount on the hood of my pickup. I was careful to remove the paint under the mounting screws for the lip mount, but ultimately, I put several pieces of copper foil tape under one end of the mount. The strips of tape are about 2 feet long, and radiate out under the hood. This insures that there is at least some kind of counterpoise attached.
KB3MBM
03-31-2011, 07:24 PM
I was actually thinking of running a psuedo-counterpoise by having a copper wire radiate out from the mount.
I have one of the Diamond adjustable lip mounts at the back door of the Jeep, near the hinge points. I'm going to see if there's anywhere else I could mount it.
K9STH
03-31-2011, 08:15 PM
Radio Shack shows the only DMM that they sell to be "out of stock". The price on it is $19.99.
Glen, K9STH
K0RGR
03-31-2011, 10:16 PM
I was actually thinking of running a psuedo-counterpoise by having a copper wire radiate out from the mount.
I have one of the Diamond adjustable lip mounts at the back door of the Jeep, near the hinge points. I'm going to see if there's anywhere else I could mount it.
I find that the hood, on the side opposite the broadcast antenna, works well for me. Be careful of proximity to the car's electronics, though.
KB3MBM
04-01-2011, 01:43 AM
@ K9STH: I'm wary of Radio Shack, but maybe this one will be different. I'm in a rural area, so they may actually be an electronics store instead of a front for cheap RC toys and cell phones like the one at the Fair Oaks Mall near Fairfax, VA.
@K0RGR: I don't think I can mount it to the hood the way the metal is folded over. I may have to keep the antenna where it is.
KB3MBM
04-05-2011, 01:29 PM
Radio Shack was a bit of a disappointment this past weekend. I think I may take a little road trip with the dog down to HRO in Woodbridge, VA on Friday.
K0RGR
04-05-2011, 07:46 PM
@ K9STH: I'm wary of Radio Shack, but maybe this one will be different. I'm in a rural area, so they may actually be an electronics store instead of a front for cheap RC toys and cell phones like the one at the Fair Oaks Mall near Fairfax, VA.
@K0RGR: I don't think I can mount it to the hood the way the metal is folded over. I may have to keep the antenna where it is.
You may be right - I seem to remember somebody else running into that on a Jeep. Which Jeep is it - there are too many anymore to know what 'Jeep' means. If it's a CJ-style Jeep (Wrangler) with an external spare tire, you may be able to use the tire mount. I had an SUV years ago like that. I simply took a piece of 1/4" thick aluminum plate, and drilled it to fit under two of the mounting holes for the spare tire. Then, I removed the two lug nuts that were holding the tire, and used them to hold the aluminum plate in place. The plate was long enough to extend clear of the top of the tire, where I bolted a piece of aluminum angle bracket, which is where I installed the antenna. It was more than strong enough to support a big HF antenna, or a really big VHF antenna. Since the strap rested on the tire, it had a shock absorber, too for when you hit a tree. I've also seen people have little mounting plates built, and bolt or weld them onto the rear of the Jeep.
AG6JU
04-06-2011, 04:12 AM
one time I had a HAM friend , who had similar problem, receive fine, but does not transmit well. it turned out, that he was using small gage wire to connect his radio to cigarette lighter plug, when radio is in transmit mode, the input voltage to radio was dropped to 9 V and output power was only 5 watts stead of 50 watts. after we replaced with heavier gage wire like AWG 12 connect directly to battery, and measured 50 watts output.
K6CPO
04-07-2011, 02:18 AM
I never thought to look there (Harbor Freight). I am tempted to go to the local Radio Shack and pick one up, but previous experience has me questioning that line of thought.
I don't know about today, but Radio Shack once sold quality products. I have an old, beat up Micronta analog multimeter I bought at Radio Shack over 30 years ago. It still works perfectly, although the dial is almost completly worn off and the handle is broken in four places (and wired back together.) I've thought about buying one of the newfangled digital meters, but just can't justify the expense...
N3GWT
04-07-2011, 03:48 AM
:)HI Rich , I have a NR770 on the trunk of my car which i switch With a bigger NR790 Diamond if I need gain and more range ,the 770 is more a local antenna I use it here in Atlanta area and get simplex range from south east side to north west area Kennasaw above Atlanta but signal fades depending on position and the bigger high gain antenna gives better coverage you might have to get a good gain antenna from HRO, an antenna with a fold over section will solve clearance problems in parking garages etc. On your problem check the connectors under the Nmo mount the small pin and the post on the mount are subject to dirt and corrosion so if they are not clean they can create a increase in resistance at the connection.
KB3MBM
04-07-2011, 04:26 PM
@ K0RGR: Yes, I've got the "Army" style Jeep. It's a 2006 TJ model with a soft top. Currently, the lip mount antenna is on the swing away door on the rear passenger side. The tire mount and third brake light aren't stable for mounting. The tire carrier has no room, and the brake light is plastic. The bumper may be a better option, but then the antenna sits lower. If I go that route, I may need to get a longer antenna.
@AE6ZW: My radio is wired directly to the battery. The great thing about the Jeep is the easy access points to the engine compartment through the firewall. It allowed for a direct power connection. I did not have to hook into the electrical relay and experience the RFI that I've heard plagues setups that are wired into the vehicle's electrical system.
@KJ6MDX: I ran into a HAM here that runs an interesting mobile set up with HF and VHF (6m and 2m). He saw me walking back to my Jeep looking disgusted and just advised me to take a trip to HRO. "It's worth the gas", was his comment.
@N3GWT: I disassembled the set up last weekend and cleaned up the connections. Still have problems with Rx & Tx. If I'm not in perfect line-of-sight, it's like I'm not even there. I don't know. It may be that the old FT-7900 needs to be serviced. I've put that radio through its paces over the past 5 or 6 years. At one point while in college, I came close to selling it. It's always been in the Jeep except for a brief period of time when auto break ins became a problem in the apartment my wife and I lived in prior to getting our house.
Right now, I'm just going to have to deal with it. Money is tight, and I can still monitor for some of my commute. Once things improve a little bit, I'll see if I can get the whole set up serviced or otherwise evaluated. I may go bother the local HAMs in the area, too, but I'm not really one to impose. I just have to roll with it, that's all. :^)
KB3MBM
04-19-2011, 06:33 PM
I was able to get a SWR/Watt meter and check things.
The radio (Yaesu FT-7800R) is putting out power as it shows in the specs. 2m: 5/10/20/50W low to high; 70cm: 5/10/20/40W low to high.
However, SWR was above 3.0:1.
I removed the entire set up out of the Jeep.
Can anyone give any helpful advice?
K8MHZ
04-19-2011, 06:50 PM
Currently, the lip mount antenna is on the swing away door on the rear passenger side.That may be the problem. You have to remember that the vehicle (or just the door in this case, meaning no horizontal plane) is half of the antenna.
I'll bet getting a different antenna that provides a better connection to the entire body steel would work much better.
KB3MBM
04-19-2011, 07:48 PM
That may be the problem. You have to remember that the vehicle (or just the door in this case, meaning no horizontal plane) is half of the antenna.
I'll bet getting a different antenna that provides a better connection to the entire body steel would work much better.
It's a definite drawback to having a soft top Jeep: There is no roof for me to mount an antenna to. I may go down to HRO next weekend --this weekend is busy -- and see if I can get a new antenna and mount for the Jeep. I also want to see about getting a magnetic antenna for using my HT in my wife's car (when I'm driving it) and our "travel vehicle" (a 2000 Ford Expedition).
WA4BRL
04-19-2011, 09:02 PM
This isn't specific to your Jeep, but it should provide a good starting point.
VHF/UHF Mobile Troubleshooting Guide:
1. Evaluate location of antenna mount.
a. Does it place the majority of the antenna in the clear above the vehicle?
b. Avoid having any part of the antenna pass by the vehicle body or other grounded components closely or parallel them significantly
c. If a lip-mount, are the set screws making good electrical contact to clean metal on the vehicle?
d. If lid/door/hood is fiberglass, have you installed a conductive ground plane on or under the fiberglass?
2. Inspect antenna cable for physical integrity. Look for kinks, mashed areas, split jacket.
3. With antenna removed from mount:
a. Visually inspect coax connector (pl-259, BNC, etc.) for integrity and quality of installation.
b. Visually inspect antenna and mount contacts. clean and burnish as necessary.
c. Check for a short circuit between the center and shield braid
d. Check for continuity of center conductor from connector to mount
e. Check for continuity of shield braid of connector to mount
4 Antenna
a. Complete all above checks. Clean & repair as necessary and reassemble system.
b. Check and adjust for lowest SWR in center of repeater band
Should be below 2:1 at enter frequency, and hopeully at each end.
5. DC Supply
a. Is radio fed by a dedicated cable from the battery to the rig? (Do not use lighter socket or fuse block connection)
b. Are both conductors fused near the battery?
c. Measure voltage at radio (1) with radio and (2) with radio on and transmitting.
If You see more than 0.5V difference, your connections need improvement.
6. Radio
a. Check that the radio works well with a different antenna and power source (at home, for instance)
b. Check output power into a 50-Ohm dummy load
b. Set the mike gain AND deviation controls with a quality test set
Radio clubs often provide this service to members at meetings. Ask around on the air.
KB3MBM
04-20-2011, 10:57 AM
Steve,
Thanks for the checklist! It should come in handy if I'm able to get things set back up.
WA4BRL
04-20-2011, 01:52 PM
You're welcome Rich. I hope it will be helpfull to others as well.
Oops, correction... step 5c should read:
c. Measure voltage at radio (1) with radio off and (2) with radio on and transmitting.
WA9UAA
04-20-2011, 02:28 PM
Rich,
There used to be 2 meter half wave length antennas that worked fairly well with out the required ground plane. Is it possible for you to borrow an MFJ 259B? It will go a long way towards sorting out your antenna problem. The 1/2 wave length antenna would be a good bet though with your lack of ground plane.
73,
Rob WA9UAA
K0RGR
04-20-2011, 02:59 PM
It's hard to come up with a bumper-mounted antenna that will work great on 2 meters, but the mobile j-pole was a popular solution years ago. Here's a more modern version of it: http://www.hamuniverse.com/n5hiijstick.html
Someone used to sell a commercial jpole years ago that attached to the top of a long stainless whip - i.e. CB whip.
The whip acted as an antenna support for the jpole. I should tell my unemployed brother to get busy and start making them in his garage. There's nothing magical about the jpole, but a 1/2 wave antenna 10 feet off the ground will do well on 2 meters!
Hustler sells a 7 foot 2 meter antenna - the CG144 - which I've used with good success on a bumper mount. It also requires a good ground connection, though, and I bet your bumpers are plastic, so a tall half wave antenna like the J would probably work much better for you. http://www.bikexprt.com/bicycle/antennae.htm
http://www.ehow.com/how_4592772_meter-j-pole-antenna.html
KB3MBM
04-21-2011, 12:27 AM
@ WA9UAA: No, I don't have access to anything that fancy.
@ K0RGR: I'll check out those links. Thanks!
Having only ever operated mobile, I don't have any of the tools, gadgets, gizmos, and what-not that guys with a base station have available to them. Honestly, I don't think I'll ever really have a base station. I can't afford all that! Hahaha!
I'll just have to see what happens. I want to upgrade to a General Class license this summer to experience more of amateur radio then mobile. This hobby seems to have a tendency to get expensive, though. Personally, I'd like to get myself a QRP CW rig of some sort and just run a simple dipole. I've never built a kit radio in my life, but I think if I get into anything more than mobile operations I may go that route to keep costs down.
Eh... now I'm rambling...
I might have missed it in your previous posts but does your Jeep have a spare tire mount on the back?
I've seen several Jeeps with Diamond NR22L mono band antennas mounted to a bracket on the spare tire mount. This is a tall high gain antenna and requires a good strong mount but the hams I know who are using these love them.
KB3MBM
04-21-2011, 07:07 PM
@ N6YG: There's nothing metal to act as a ground plane; and it's made of cheap plastic making it unstable as a mount.
@ N6YG: There's nothing metal to act as a ground plane; and it's made of cheap plastic making it unstable as a mount.
The spare tire mount is made of plastic ?? All the ones I have seen on jeeps are made of steel. Are you sure we are talking about the same thing? The spare tire mounts I've seen are the swing away mounts that hold a spare tire and look like this http://www.autopartswarehouse.com/details/QQJeepQQWranglerQQWarnQQSpare_Tire_CarrierQQ198720 06QQW3664337.html
KB3MBM
04-22-2011, 12:42 AM
No, the spare tire mount is made of metal, I misunderstood you. I was thinking of the 3rd brake light. As for the spare mount, that's a no-go. It's completely blocked by my tire. I run 31 x 10.50s on my Jeep and the tire goes nearly flush to the door.
No, the spare tire mount is made of metal, I misunderstood you. I was thinking of the 3rd brake light. As for the spare mount, that's a no-go. It's completely blocked by my tire. I run 31 x 10.50s on my Jeep and the tire goes nearly flush to the door.
Like I said I have several friends who have jeeps they have all mounted the Diamond NR22L off the spare tire mount and it works great. Using a bit of imagination you could easily fabricate a bracket that could be mounted to the spare tire mount. The Diamond NR22L is a very tall antenna and it won't matter if a portion of the bottom of the antenna is blocked by the tire.
KB3MBM
04-23-2011, 11:05 PM
@ N6YG: With the spare tire mounted, there's no room for mounting the antenna. I checked. The clearance on the mount is about nil and there's no clearance around the spare tire.
Rich,
This may sound strange, but whoever is making the Maxrad/Larsen antennas now has a base-loaded half-wave antenna that is a short base and long "stinger", and/or a 5/8 wave that looks similar. If you get the "base station kit" that is made for these antennas with NMO mounting, it can be mounted to a pipe (plastic or metal does not matter, as the "base station kit provides four short radials. If you set the pipe so that the radials are above the roof or roll-bar of your jeep, you will have a good mobile antenna that should work well for you. The following advertisement shows a picture of this device:
http://www.tessco.com/products/displayProductInfo.do?sku=38478&eventPage=1
Others may advise against using this for various reasons; I have seen it used successfully when mounted properly.
W0HU
K9PHT
05-09-2011, 04:07 PM
I have two COMET SBB7 - NMO dual band antennas mounted on my 99 TJ jeep. I ordered two of those windshield EXTERNAL SPOT LIGHT mounts for Jeeps from QUADRATEC which is a perfect platform to mount the NMO MOUNTS for the dual band antennas. Didnt have to drill any hole anywhere...
My 99 JEEP install was pretty much all standard things... Radio under the seat and control head up on the dash... I always wire directly off the battery through a fuse and junction box. Speakers under the seats. FM is always very forgiving as for as RFI hash and popping noises is concerned coming from the JEEP... the SBB7 antennas works great for me... I have always had two 2m/440 antennas on my installs and that put one within inches of the am/fm antenna but has never really bother anything. I use one SBB7 antena for my two way radio and the second one is usually for a police scanner only.
K9PHT
05-09-2011, 04:54 PM
This is what I mounted my two SBB7 NMO dual antennas too in my 99 Wrangler TJ
Rugged Ridge Windshield Light Mounting Bracket in Black
For 97-06 Jeep® Wrangler TJ & Unlimited
Quadratec Part No: 12110.23
K9PHT
05-09-2011, 05:18 PM
With the soft top I would stick to the WINDSHIELD area of the JEEP for the 2m/440 antenna. I have even got GREAT result with the through the windshield whip antennas (From RADIO SHACK when they sold them years past)... I had one installed in the two upper corners of the windshield. Had to adjust one wiper blade down a notch to keep from hitting it. Worked good. Then I got the idea of the LIGHT MOUNTS that attached to the windhield hinge and that was perfect. The HOOD is a very large metal area for your groundplane effect. My 99 Jeep has the full top but it is fiberglass... It is sitting in the driveway with a bad fuel pump now - will have to drop the fuel tank to fix it... Another project on the retirement list...
Too bad you live so far north - I would say come on down the King George VA and we can figure something out. You way up close to the north VA MTNS haha...
