While doing a presentation about choosing the right coaxial cable, someone suggested that RG-8X (also called “Mini 8”) might be the best general-purpose cable for amateur radio. There is a lot to like about RG-8X. It is about 1/4-inch in diameter, and is flexible and affordable. This comment made me realize that I default to a larger cable (LMR-400 or RG-8) for everyday use and consider RG-8X as the cable for lightweight, portable applications (such as SOTA and POTA). But perhaps I am underestimating the capabilities of RG-8X.

So let’s take a look at the specs on RG-8X, using the DXEngineering RG-8X datasheet. Other manufacturers of RG-8X will have similar specs.

Power Rating

Most general-purpose amateur radio operation occurs at power levels of up to 100 watts for frequencies of 3 MHz to 54 MHz and up to 50 watts from 144 MHz to 450 MHz. I am thinking in terms of a station that has a 100-watt radio for HF and 6m and a typical 50-watt FM dual-band radio for 2m and 70 cm.

These power levels are easily handled by RG-8X. In fact, the cable is spec’d for over 1 kW for all of the HF bands. At 50 MHz, the power rating drops to 900 watts and further reduces to 400 watts at 150 MHz. DX Engineering does not specify the power at 440 MHz, so I looked at other websites and found that the power rating drops off to about 100 watts. So power handling is not going to be an issue.

Signal Loss

Signal loss may be a more significant limitation. How much loss are we going to be comfortable with? That is difficult to answer because each of us may make different tradeoffs to accomplish our radio operating objectives. As an upper bound, I hate to see the cable loss go as high as 3 dB, which corresponds to losing half the power in the cable! But living with 1 dB might be acceptable, which is 20% power loss. So let’s use that.

(Someone reading this is thinking: 3 dB is only half an S-unit, it won’t matter that much. To which I say: it won’t matter unless you are operating near the noise floor and 3 dB is enough loss to have your signal disappear.)

The table above shows the loss in dB per 100 feet. At 100 feet, the loss creeps up to 1.5 dB at 30 MHz. Let’s stretch our 1 dB rule of thumb to 1.5 dB, which means the loss is reasonable for all the HF bands using a 100-foot cable. At 50 MHz, the loss increases to 2.3 dB/100 feet, so to stay within 1 dB or so, we would need to limit our cable length to 50 feet. At 150 MHz, the loss rises to 3.8 dB/100 feet so we should keep our cable length less than about 25 feet. We don’t have a spec for the loss at 450 MHz but checking other websites reveals a typical loss of 6.6 dB/100 feet at 400 MHz. A 25-foot cable at 450 MHz will have a little over 1.6 dB loss.

So now the problem becomes clear: signal loss at high frequencies will be the limiting factor. (This is why I tend to grab a larger cable because I’m often operating above 50 MHz.)

Conclusions

So what can we conclude in very broad terms? Is RG-8X a good choice for a “general purpose” coaxial cable? I am going to say “Yes, But”. The key issue is signal loss and that is driven by the frequency being used and the length of the cable. So Yes, RG-8X is a good general-purpose coaxial cable but watch out for signal loss and cable length at high frequencies.

Here’s my Rules of Thumb for this cable:

For HF, RG-8X is great for all bands with cable lengths of 100 feet (maybe longer).
For 6m, RG-8X is good with a cable length of up to 50 feet.
For 2m and 70 cm, RG-8X is good with a cable length of up to 25 feet.

In all cases, checking the manufacturer’s specs and doing your own calculations is recommended. For a slightly deeper look at coaxial cables, see Hey, Which Coaxial Cable Should I Use? 

73 Bob K0NR

The post Is RG-8X the General Purpose Coaxial Cable? appeared first on The KØNR Radio Site.

I don’t usually get pulled into historical investigations, but I recently found something interesting about my call sign, KØNR. I received this vanity call in April 2002. Before me, Craig Larson W3MS held this call sign starting in 1975. These are the only two entries in the FCC database (Universal Licensing System).

The story starts with me poking around the Digital Library of Amateur Radio & Communications (DLARC), an online archive of radio communications media. I search on “K0NR” and got a number of hits, including an entry from a 1962 Callbook. Back in the olden days, ham radio callsigns and contact info were published in a thick book, kind of like a phone book.

The callsign was listed with “USNR” in the name or organization field. I wasn’t sure what USNR meant so I asked for help via Twitter. Quite a few people came back with “United States Naval Reserve”, which did turn out to be correct. The graphic below is from the 1962 call book and it has multiple callsigns labeled USNR and one labeled USN.

Then Jason W5IPA came up with a page from the July 1949 issue of QST.This article shows there were many amateur call signs assigned to naval reserve stations.

Click to access QST-1949-07.pdf

Then N8URE poked around and came up with this from a 1960 telephone book:

I suspect the 5-digit telephone number is long been obsolete. There still is an address for the Naval Reserve in Dubuque but it is on Jet Center Drive, near the airport.

So there you have it: it was common for Naval Reserve centers to have amateur radio call signs assigned to them. For obvious reasons, they tended to have NR in the call sign. K0NR was assigned to the station in Dubuque, IA.

Thanks for the help from: W5IPA, N8URE, K8BCR, K4ZDH

73 Bob, Kilo Zero Naval Reserve

The post Kilo Zero Naval Reserve appeared first on The KØNR Radio Site.

The post Announcing: Extra Class License book appeared first on The KØNR Radio Site.

Being an enthusiast for bands above 50 MHz, I suppose I should weigh in on the new IC-905 from Icom. The street price for the basic unit is ~$3500, with various options and accessories at additional cost.

Let’s be clear about one thing, this radio is one impressive piece of technology. There is no other radio on the market that comes close to covering these VHF/UHF/SHF bands: 144, 430, 1200, 2400, and 5600 MHz (and optional 10 GHz). I won’t mention all of the features and specs covered here. I really appreciate that Icom is investing in equipment for VHF and higher, as evidenced by the IC-9700 and this radio.

For me, there are two main uses I would consider for the IC-905: Summits On The Air (SOTA)  and base station use:

SOTA

I focus on VHF/UHF for SOTA with 144 MHz always carrying the load in terms of making radio contacts. Lately, I have put more effort into 432 MHz and 1.2 GHz. I’ve also been trying to get out of the FM rut and work more SSB and CW on those bands. I really should get going on a portable digital station for FT8 and other modes. I have a good collection of gear to choose from, ranging from basic 5-watt FM handhelds to an IC-705 and an IC-9700. OK, the IC-9700 is a bit large to drag up most summits but I have taken it on some easy hikes and drive-up summits. Joyce/K0JJW and I also have a pair of Alinco triband handheld radios (DJ-G7T) that have 1.2 GHz FM. These radios are popular with SOTA enthusiasts due to their affordability and compact size.

What does the IC-905 offer for SOTA? Well, obviously it is a reasonable way to get on 5 or 6 bands with all modes. However, I already have the IC-705 that covers 144 and 432 MHz (and 50 MHz). Having CW/SSB on 1.2 GHz is very attractive to me but 2.4 GHz and 5.6 GHz are rarely used for SOTA. Sure, maybe the introduction of the IC-905 will change that. Maybe, but probably not. Someone commented in an online forum that you better buy two IC-905s and loan one out so you have someone to work. For my interests, I would much rather have a VHF/UHF-only variant of the IC-705 that covers the 50, 144, 440, and 1200 MHz bands. But I have come to accept the fact that radio manufacturers don’t develop radios just for me.

Base Station

The other option is to use the IC-905 to get on the higher bands from my home station. I am in the process of building a VHF+ station at our cabin in the mountains, which is in a good VHF/UHF location. Honestly, my focus is on getting a tower up with good size Yagi antennas for 50 MHz and 144 MHz. Although I have operated a lot on these bands, it has usually been from portable and rover stations, during one of the VHF contests, or as a SOTA activation. I am looking forward to having an effective permanent station on the two most popular VHF bands.  I am debating how much effort to put into the 430 MHz and 1200 MHz bands at the new station, and 2400 and 5600 MHz are not currently in my plans. Besides, the IC-9700 has me covered for 144, 430, and 1200 MHz. So right now, I don’t see the IC-905 being part of the home station, but that could certainly change with time.

Price

What about the price? $3500 is a serious piece of change but probably not unreasonable for what this radio can do. Some people have said it is worth it and some think it is way too expensive. Price is always an issue, but for me it probably doesn’t matter that much. For the most part, I am saying the radio doesn’t fit a need I have. OK, if the price were a lot lower (like $1500), it would affect my point of view. But at that price, Icom would be leaving money on the table with the folks that really want to get on 2.4, 5.6 and 10 GHz.

So my conclusion is that I probably won’t be buying an IC-905 at this time, but things can always change.

What are your thoughts?

73 Bob K0NR

The post How About An Icom IC-905? appeared first on The KØNR Radio Site.

Sometimes you just want a close-in SOTA summit that is easy to access and allows you to get on the air. On the west side of greater Denver, a few summits meet that requirement. One of them is Green Mountain (W0C/FR-107), near the intersection of I-70 and C-470. This would make a good beginner summit or an easy-access summit for visitors to the area. Joyce/K0JJW and I activated this 1-point summit today.

Access is easy and convenient, the trailhead can be found by going west on Alameda Parkway, off C-470, then north on S Rooney Road. There is a large parking lot there and an obvious trailhead with pit toilets. From here we hiked east over C-470 into William Frederick Hayden Park. We followed signs for the Green Mountain Trail, which is basically an unimproved road, to the summit of Green Mountain (see map above). This is not the only option because the park has an extensive trail system to explore. Check out the Lakewood parks map here. Also, you can check the trail conditions here. My mapping app recorded the hike as 1.6 miles (one way) with an elevation gain of 800 feet, not very difficult but still a decent hike. On a cool Saturday afternoon, we met many hikers and mountain bikers on the trail.

This hike starts out with a lot of road noise from C-470 but things soon quiet down as we left the highway behind. On the summit, we could see many higher summits to the west and downtown Denver to the east. We only had a couple of handheld VHF/UHF radios with us and made a bunch of contacts on 2m FM. This is usually the case when you have line-of-sight to the Denver area, with plenty of activity on 146.52 MHz.

This summit is not the best SOTA summit in the state but if you are itching to do a SOTA activation without driving deep into the mountains, this one will work!

73 Bob K0NR

The post Close to Denver: Green Mountain (W0C/FR-107) appeared first on The KØNR Radio Site.

About five years ago, Eric/4Z1UG interviewed me for the QSO Today podcast. He recently retrieved and remixed the audio recording and posted it on the QSO Today webpage. There are a few places where the discussion seems dated (such as the discussion of Yaesu Fusion, which was relatively new at the time.) However, for the most part, the dialog was good and still relevant. Well, at least to me, because it was my story.

During the interview, I mention some of my Elmers, including Virgil/W0INK who influenced me early in my ham career. I also talk about the concept of 360-Degree Elmering, which means that Elmers (mentors) can be found in many different places. Other topics include: Summits On The Air, Colorado 14ers,  the Tri-Lakes Monument Radio Association (W0TLM), repeaters, DMR in Colorado. There is a plug for Ham Radio School, where I continue to help out. Somehow we got on the topic of lists in amateur radio: DXCC entities, SOTA summits, states, etc.

Anyway, you may find it interesting.

73 Bob K0NR

The post My Story on QSO Today appeared first on The KØNR Radio Site.

Here is another lazy attempt by me at generating a blog post using ChatGPT. This time I asked the machine to “tell me about Bob Witte K0NR”. I figured there are quite a few things available in the public domain about me, so it would be interesting to see what the AI came up with. Here’s the result with [my comments] inserted.

Bob Witte, also known by his callsign K0NR, is an experienced and respected ham radio operator who has been licensed since the mid-1970s. He is based in Colorado, USA and is known for his contributions to the amateur radio community. [I like the sound of this.]

Bob has a passion for promoting amateur radio and encouraging others to get involved in the hobby. He is a regular contributor to the popular ham radio blog, “The KØNR Radio Site,” where he shares his experiences and knowledge with other hams. He also co-hosts the “HamRadioNow” video podcast series, which covers a wide range of topics related to amateur radio. [Correct on my blog, but I don’t co-host any type of podcast.]

Bob is an active member of several ham radio clubs and organizations, including the American Radio Relay League (ARRL) and the Radio Society of Great Britain (RSGB). He has served in various leadership roles within these organizations and has been recognized for his contributions to the amateur radio community. [Yes on the ARRL, but I am not an RSGB member.]

Bob’s interests in ham radio include VHF/UHF weak signal work, contesting, and digital modes. He is also an avid outdoorsman and enjoys portable operations from remote locations. He has a strong interest in emergency communications and is involved in several emergency communication organizations, including the Amateur Radio Emergency Service (ARES). [Not too bad, but my involvement in ARES and other emcomm groups has faded quite a bit.]

Overall, Bob Witte K0NR is a highly respected and knowledgeable ham radio operator who has made significant contributions to the amateur radio community. [Well, I like the sound of this part.]

The post Another AI Blog Post: Who is Bob K0NR? appeared first on The KØNR Radio Site.