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RVRN Tech Guy Archives
(9/1) David asks about tuning trapeded antennas
This question comes to us from David in Michigan. Hi, may I use a remote tuner at base of my trapped quarter wave vertical antenna?
Hello David, interesting question but a very sound no. Most commercial quarter wave antennas are designed to be built and tuned to have a low SWR. If one has a high SWR the tuner will likely protect the transceiver from this but the antenna will have very poor performance characteristics and could even create issues heat issues for the various traps. So, get out the manual and check the assembly and tuning instructions.

Best Regards

(8/30) Sam asks Does my vertical really require radials?
I would really like to put up a vertical HF antenna in my backyard. However, most of the vertical antennas I am looking at say I need a radial field for the antenna. I just don’t have the space for this. Am I really required to have this?

Sam, thank you very much for your question. the most popular vertical HF antenna today is the quarter wave vertical antenna. The radial field provides the second half of the antenna, so the vertical portion of the antenna uses the ground field to work against. So sadly, the answer to your question is yes, you will need a radio field for the antenna to work efficiently. There is an alternative, which would be to go with a halfway vertical, but those are more difficult to use primarily because of their size.

(8/29)Bill asks how to to weatherproof a PL259
This question comes from Bill in California. I have several PL 259 connections exposed to the weather. What is the proper way to weatherproof a PO 259 connection that is outdoors?
Bill, this is a very good and important question for all of us. There are essentially two steps to properly waterproof PL 259 connectors outdoors. The first is a rubberized tape from the 3M company called Temflex. This is a roll of rubberized tape that you wrap around the 259 all the way down to the coax outside sheath. This tape will adhere to itself and provide the waterproofing.

Temflex, however, has no UV protection so you must wrap this tape with a good 3M electrical tape that will provide UV protection.

You can find both of these products at DX engineering or your local hardware store.

(8/27)Paul in CO asks Can I bury coax to my antenna?
I have several coax runs in my backyard and would like to get them out of the way. Can I just bury these or do I need to use conduit to put these underground?

Paul, this is a very interesting question and one I get quite often. It’s difficult to say in your case because I do not know what the specs are for your coax. If you know who manufactured or sold the coax, you may wish to go back to them and see if this is rated for putting underground. Most coax sold today has this rating and are just fine to lay down in a trench.

The question of using a conduit to bury these is quite an involved question. It is recommended, and in fact, many professional installers do not use conduit for one simple reason, they will collect water over time. Irrespective of the conduit material condensation will allow water to build up inside the conduit and eventually the coax will sit in water day and night. If one does use conduit, a few things are recommended. First, be sure there are weep holes for any water buildup to drain. Second, try and have the conduit at a slight angle for gravity to help the water escape. It is also recommended that you use small gravel around these openings of the conduit for the water to travel away from the conduit and coax.

(8/22) Bob asks what to look for in an HF XCVR?
This question comes from Bob in Ohio. I am thinking about buying a new HF transceiver, but I’m lost in what I should look for when spending this kind of money. Do you have any suggestions to help filter out all of the options available today?
Very good question Bob and yes, there are many options today one must consider with a purchase like this. First, I would recommend you take a look at Robert Sherwood’s amazing work on profiling Amateur Radio transceivers today. He rank orders the transceivers that are on the market today and from the past. His bottom line is essentially that the electrical engineers at the major equipment manufacturers have studied their competitors products and finds the designs and performance are very very close to one another. His suggestion is to look at the aesthetics of each radio, look at the menu, structure and other features and base your decision on those areas. I tell customers to be sure to look at YouTube’s for each radio that you have interest in buying. They will provide a video overview of the performance, layout of the menus and other items for the radios. This review along with the cost of the radio should really help narrow down the purchase.

Best Regards

(8/18) John asks what type of power supply should I use?
4.) This question comes to us from John in Oregon. I am about to buy a new power supply and want to know if I should get a linear or switching type power supply.
Excellent question John, this is on the mind of many hams who are about to buy a new power supply for their shack. Had you asked me this question a decade or two ago I would have a different answer, but today the switching power supplies designed for the ham shack are very good quality and have very low noise characteristics. The engineers have gone to a great extent to eliminate any RF noise, or hash, that once was produced by these power supplies. However, be very careful using a switching power supply that was not designed for Amateur Radio use as they may still generate quite a bit of RFI. I favor the switching power supply for several reasons. First, they are typically much smaller in size and occupy less desk or floor space. Second, they have very good current capability and are lower in cost than their counterpart on the linear side. Many Ham’s, particularly old-timers, tend to favor the linear power supply, so you will still find those being sold today at your favorite Ham Radio store.
(8/15) Bob asks about braided vs solid ground straps.
This question comes from Bob in Illinois. I am preparing to put in a ground system for my station. I see in many of the Ham stores there are both braided ground strap and solid copper straps. What is the difference between these two?
Bob, this is a very good and important question. The braided ground straps you see at your Ham Radio store are suggested to be used inside for, point-to-point grounding, to your ground busbar in the shack. They are very flexible and are often sold with eyelets on each end to facilitate a quick connection to equipment and the bus bar. We do not recommend the branded strapping to be used outdoors because it tends to act like a sponge, and will collect and hold moisture, which will eventually deteriorate the strap itself. So, outdoors, we recommend the solid copper strapping for connections between the ground rod, towers, or any other outside component that needs a ground connection.
(8/11) Sam asks, do I really need an arrestor?
This question comes to us from Sam. I rarely experience lightning in my area, and when I do I lower my antenna. Do I really need an arrestor?
Sam, thank you for your question! There is a common misunderstanding about these. The arrestor protects against the near lightning strike. There are different types of the arrestor. The first type has a gas discharge tube which can be replaced. A second type has a mechanism that resets. However, the arrestor has a second property that protects our system from static discharge. When a conductor is suspended in the air with wind blowing across it a very large buildup of static occurs, large enough to take out the transceivers front end. So yes, use them at you ground Rod.

Best Regards

(8/7) Joe asks: Can you advise in a good HF antenna?
This question comes to us from Joe in KY. Can you advise in a good HF antenna for RV operation? Usually run SSB and FT8 on the HF bands.?
Well, greetings and thank you very much for your question. You didn’t identify how your set up would be. If you are looking for a portable HF antenna, you will find many fine options with Buddipole, super antenna, or chameleon Antennas. I happen to use the first two of these for HF and find they work very well. I have also used a ground mounted Hamstick at the campsite with very good results. Other hams have used dipoles, particularly the end fed variety, with good results as well. Check out YouTube for example set ups.

Best Regards

(7/27) Gary asks about vertical antenna radiation.
Ignoring any tuner or impedance matching transformer losses, which vertical on a ladder with only RV chassis ground radiates more power at 40m: 1/4 cut vertical with a transformer or a 31 ft vertical on a tuner at the ladder? Take transformer and tuner losses at zero. Only go by the nature of the vertical.
Thank you for this question, it is an intriguing one! I would suggest you go with a mono band tuned to your specific frequency range. If you had other frequencies in mind I might go with a 31ft and tuner right at the base.


Best Regards

(7/13) Jeff asks: What kind of coax jumpers to use.
This question comes from Jeff in Florida. I am looking for a recommendation for what type of coax I can use for jumpers inside the shack. The regular coax they use like RG 213 or RG 400 max is just too large for tight turns. Is there a recommendation for smaller coax without excessive loss?
Jeff, this is a very good question and when approached correctly can be a big help making those turns in the shack.

The first suggestion and one I use is RG 8X. This coax is smaller in diameter and while it has higher loss, short runs have negligible loss for the shack.

Another favorite coax but more expensive is LMR- 240. This too is a smaller diameter coax, but has very nice loss characteristics.

You should be able to find these at your favorite Ham Radio store. Hope this answers your question, good luck.

Best Regards

(7/9) Phil asks how should I mount my solar panel?
2019 FR 19FD Epro

Came with factory 100 watt solar panel on Roof. Last year it blew off the top, left the wires! Was secured with a black adhesive on the four corners, not the best installation. No screws or other fasteners penetrating the roof. Any suggestions for attaching the new panel?

Thank you for your question and sorry to hear about the failure in the Solar panel mount. Not knowing the dimensions for the panel array, and whether it was a rigid or flexible panel makes this question a difficult one to answer. For a rigid panel array I recommend using bolts into/through the roof structure. Flexible panels can be mounted on the surface with adhesive. Drilling holes into the roof will need to be coordinated with the actual RV roof structure and structure below the roof surface. I have found many manufacturers are very helpful with questions like this.

However, if you wish to mount with a no-hole version here is a link to help generate some ideas for you. There are many more on the web. Attaching Solar Panels to RV Roof Without Drilling - portablesolarexpert.com

Here is an example of a mounting system that is very popular. Again the internet has many, many more examples for you to consider.
Install Solar Panels On Your RV Roof | Best Solar Panel Brackets To Use On Your RV Solar Series Ep 3
This is an important decision as an adhesive mount is less secure and could create liability if it comes off while driving. Take time to do some research for your specific RV type.

Thank you again for your question today!


(6/20) Brent asks how can I get a coax inside my RV?
We have a Newmar 2903 - it's their smallest model but works for us! I would like to find a good coax entry point for bringing in a stub of a feedline which I'd put PL259 on both ends for easy multi-purpose use. I brought a power feed through the firewall without issue, but would like to avoid that area with coax. I know you can't be specific, but where are a couple of good places to start looking for a way to get coax inside? I'd appreciate your thoughts.
73, Brent
Hello Brent,
Thank you for your question.

If I understand your question correctly many of us use a bulkhead connector as shown in the link below. It is likely the best, low loss way to get a good coax pass through for a side wall of the RV. The location on the wall is dependent upon the antenna mount. You will need a hole about 1/2 inch diameter for the SO-239.

I use a cap on the outside of the RV to protect against water and dirt when not in use.

Other folks have used the item in the second link as it provides a longer SO-239 connector. Using this, one could fashion a face plate on the outside wall of the RV.

Let me know what you think!

(4/21) Paul asks: What radio should I install in my truck?
This question comes to us from Paul. I have a full-size pickup truck pulling a travel trailer for my RV configuration.

I am looking to install a dual band radio and HF radio in the truck – but I could be convinced to get a newer radio that has both integrated into one

My one requirement is that it/they has to be a remote-head style.

Looking for comments and suggestions for units to go with or stay away from

Note: I have a spare IC-706 MkIIG in the shack – that I could use for HF only – so that is one option. Only point there is that the radio does not have a good way to manage repeater frequency pairs and it pre-dates DCS so (hence HF use only)

Thanks in advance for any first-hand advice

Cheers and 73,

Hello Paul, and thank you very much for your question. I had a couple suggestions for you until you said it must have a remote head, this limits you to the Icom IC – 7100 for any radio that is currently in production. This is a very good transceiver and one I use in my pick up truck. For some reason most all manufacturers have gotten away from this combination. If you can get away from the remote head requirement, your next option would be for Yaesu FT – 991A. As you note in your question, there are radios from the past that you could find on eBay or QRZ.

Best Regards